Compositions for sebum control

Abstract

Composition comprising: (a) xanthone according to formula (I) or pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer, or stereoisomer thereof Wherein R1-R8 are as defined by c

Description

Field of the Invention The invention relates to compositions comprising plant or fungal extracts in combination with xanthone compounds, and the use of the composition in a method for decreasing lipid production in sebocytes. Also provided is the use of the composition in a cosmetic method for decreasing lipid production in the skin of an individual, and the use of the composition in a method of treating a skin disease or disorder related to increased lipid production in sebocytes. Background Sebum is an oily substance secreted by sebaceous glands in humans. Sebum is produced by sebocytes, highly specialised epithelial cells commonly found in the skin in association with hair follicles, although there are also sebaceous glands not associated with hair follicles. Adult human sebum typically comprises triglycerides (-41%), wax monoesters (-25%), free fatty acids (-16%), and squalene (-12%) (Cheng et al., 2004). Other components, such as keratin and cellular materials, may also be present. Sebum forms an integral component of the epidermal barrier and the skin immune system. Sebum is a natural moisturizer for the epidermis, helping to maintain its integrity. Sebum is important in maintaining the pH of the skin surface, which may play a role in protecting the skin from exogenous (disease-causing) microbes and encouraging the growth of endogenous (resident) microflora. Sebaceous secretions in conjunction with apocrine (sweat) glands are also thought to play an important thermoregulatory role. Sebocyte formation is controlled by multiple molecular pathways (e.g. Blimpl, Wnt, C-myc, Hedgehog) and sebum synthesis is strongly regulated by hormones, in particular by androgens such as testosterone. Sebum is produced in a holocrine process, in which sebocytes rupture and disintegrate as they release the sebum along with cell remnants. During the terminal differentiation of sebocytes, metabolic activity is concentrated on the biosynthesis of lipids (lipogenesis), and in particular on the neosynthesis of fatty acids and squalene. The level of sebum production varies from person to person and is influenced by sex, age, physical activity, stress, certain medications, and disease. Oily skin is commonly observed in adolescence due to hormonal changes occurring throughout puberty. Excessive sebum production is associated with cosmetic problems, such as oily or shiny skin and poor retention of make-up, as well as medical problems. Excessive sebum production is seen in acne vulgaris, one of the most common skin diseases. Hyperseborrhea is a scalp problem cause by excessive production of sebum. Immediate symptoms of hyperseborrhea include scalp itchiness and pain, though later symptom is hair loss. Individuals with hyperseborrhoeic skin typically exhibit sebum levels of greater than 200 pg cnr2 measured on the forehead (as discussed, for example, in WO 2020 / 263188). Deregulated sebocyte differentiation also characterizes some rare benign and malignant tumors. Cosmetic treatments for excess lipid production generally do not address the underlying causes. Rather, cosmetic treatments typically provide relief from the direct symptoms, such as oiliness, enlarged pores, acne prone skin, and irregular skin texture. For example, a common approach to treating oily or shiny skin is the use of powders that provide an immediate masking effect by absorbing the excess sebum on the skin's surface. Alternatively, astringents and cleaning agents may be used. The known methods for reducing lipids on the skin surface are limited, producing little sustainable visible results over extended periods of time. Prolonged use of astringents and cleaning agents may exacerbate the condition. Accordingly, there is a need to develop compositions and methods for reducing lipid production in sebocytes and in the skin of an individual. Summary of the Invention At its most general, the invention relates to a composition comprising a plant or fungal extract in combination with a xanthone compound. The inventors have found that such a composition provides superior lipid reducing effects in sebocytes. The xanthone may be a substituted xanthone, such as a mangostin, including a-mangostin, P-mangostin, or related compounds, such as 9-hydroxycalabaxanthone, fuscaxanthone C and 3-isomangostin. The xanthone may be a xanthonoid. Accordingly, in a first aspect of the invention, there is provided a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia, wherein: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, Ci.4haloalkyl, and C2-10 alkenyl; or alternatively R2 and R3, or R1 and R2, or R6 and R7, or R7 and R8, together with the carbon ring atoms to which they are connected, form a 5 or 6-membered oxygencontaining heterocyclic ring, which ring is optionally substituted with one or more groups RH; R9, R10 and R11 are independently selected from H, C1-6 alkyl and C1-4 haloalkyl, and each RH is C1-6 alkyl or C2-6 alkenyl. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out below. The inventors have found that compositions of the first aspect reduce the production of lipids in sebocytes. Accordingly, in a second aspect of the invention, there is provided a method for decreasing lipid production in sebocytes, the method comprising contacting the sebocytes with a composition of the first aspect. This method may be in vivo or ex vivo, such as in vitro. The inventors have found that the compositions of the first aspect may reduce or ameliorate cosmetic problems associated with over-production of lipids in the skin, such as oily or shiny skin, oily hair, enlarged skin pores, undesirable body odour, and decreased retention of make-up products on the skin. Accordingly, in a third aspect of the invention, there is provided a cosmetic method for decreasing lipid production in the skin of an individual, the method comprising contacting the skin with a composition of the first aspect. The inventors have found that the compositions of the first aspect are useful in the treatment or prophylaxis of medical problems associated with over-production of lipids in the skin, such as acne vulgaris and rosacea. Accordingly, in a fourth aspect of the invention, there is provided a composition of the first aspect for use in a method of treatment. ln a further related aspect of the invention, there is provided a composition of the first aspect for use in a method of treating a skin disease or disorder associated with over-production of lipids in the skin, such as acne vulgaris and rosacea. These and other aspects and embodiments of the invention are described in further detail below. Summary of the Figures The present invention is described with reference to the figures listed below. Figure 1 shows mean fluorescence intensity obtained by flow cytometry of sebocytes treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), alpha-mangostin (AM), beta-mangostin (BM), 9-hydroxycalabaxanthone (9H), Rubus idaeus (RI) extract, and combinations of alpha-mangostin (AM) and Rubus idaeus extract (RI), beta-mangostin (BM) and Rubus idaeus (RI) extract, and 9-hydroxycalabaxanthone (9H) and Rubus idaeus (RI) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): ** P value: 0.0050 (Statistically significant compared to DMSO) *** P value: 0.0009 (Statistically significant compared to DMSO) **** P value: <0.0001 (Statistically significant compared to DMSO) ## P value: 0.0081 (Statistically significant compared to alpha-mangostin, beta-mangostin or 9-hydroxycalabaxanthone) Figure 2 shows mean fluorescence intensity obtained by flow cytometry of sebocytes treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), a-mangostin (AM), p-mangostin (BM), 9-hydroxycalabaxanthone (9H), Arctostaphylos Uva Ursi extract (AUU), and combinations of a-mangostin (AM) and Arctostaphylos Uva Ursi (AUU) extract, p-mangostin (BM) and Arctostaphylos Uva Ursi (AUU) extract, and 9-hydroxycalabaxanthone (9H) and Arctostaphylos Uva Ursi (AUU) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): * P value: <0.05 (Statistically significant compared to DMSO) ** P value: <0.01 (Statistically significant compared to DMSO) *** P value: 0.001 (Statistically significant compared to DMSO) **** P value: <0.0001 (Statistically significant compared to DMSO) # P value: <0.05 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) ## P value: <0.01 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) ### P value: <0.001 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) Figure 3 shows mean fluorescence intensity obtained by flow cytometry of sebocytes treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), a-mangostin (AM), p-mangostin (BM), 9-hydroxycalabaxanthone (9H), Hedera Helix (HH) extract, a combination of a-mangostin (AM) and Hedera Helix (HH) extract, a combination of p-mangostin (BM) and Hedera Helix (HH) extract, a combination of 9-hydroxycalabaxanthone (9H) and Hedera Helix (HH) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): * P value: <0.05 (Statistically significant compared to DMSO) ” P value: <0.01 (Statistically significant compared to DMSO) *** P value: 0.001 (Statistically significant compared to DMSO) **** P value: <0.0001 (Statistically significant compared to DMSO) # P value: <0.05 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) ## P value: <0.01 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) ### P value: <0.001 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) Figure 4 shows mean fluorescence intensity obtained by flow cytometry of sebocytes treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), a-mangostin (AM), p-mangostin (BM), 9-hydroxycalabaxanthone (9H), Wolfiporia extensa (\NE) extract, a combination of a-mangostin (AM) and Wolfiporia extensa (WE) extract, a combination of p-mangostin (BM) and Wolfiporia extensa (WE) extract, a combination of 9-hydroxycalabaxanthone (9H) Wolfiporia extensa (WE) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): * P value: <0.05 (Statistically significant compared to DMSO) ** P value: <0.01 (Statistically significant compared to DMSO) *** P value: 0.001 (Statistically significant compared to DMSO) **** P value: <0.0001 (Statistically significant compared to DMSO) # P value: <0.05 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) ## P value: <0.01 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) ### P value: <0.001 (Statistically significant compared to a-mangostin, p-mangostin or 9-hydroxycalabaxanthone) Figure 5 shows mean fluorescence intensity obtained by flow cytometry of sebocytes treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), a-mangostin (AM), p-mangostin (BM), 9-hydroxycalabaxanthone (9H), Fragaria vesca (FV) extract, and combinations of alpha-mangostin (AM) and Fragaria vesca (FV) extract, beta-mangostin (BM) and Fragaria vesca (FV) extract, and 9-hydroxycalabaxanthone (9H) and Fragaria vesca (FV) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): *** P value: 0.0002 (Statistically significant compared to DMSO) **** p value: <0.0001 (Statistically significant compared to DMSO) ### P value: 0.0007 (Statistically significant compared to a-mangostin and p-mangostin) Figure 6 shows mean fluorescence intensity obtained by flow cytometry of sebocytes treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), 3-isomangostin (3-lso), fuscaxanthone C (FC; Fusca), ellagic acid (EA), Rubus idaeus (RI) extract, a combination of 3-isomangostin (3-lso) with ellagic acid (EA), a combination of 3-isomangostin (3-lso) with Rubus idaeus (RI) extract according to an embodiment of the invention, a combination of fuscaxanthone C (FC; Fusca) with ellagic acid (EA), a combination of fuscaxanthone C (FC; Fusca) with Rubus idaeus (RI) extract according to an embodiment of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): **** P value: <0.0001 (Statistically significant compared to DMSO) ## P value: 0.0011 - 0.0062 (Statistically significant compared to 3-isomangostin) ### P value: 0.0003 - 0.0006 (Statistically significant compared to fuscaxanthone C) Figure 7 shows mean fluorescence intensity obtained by flow cytometry of sebocytes cells treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), 3-isomangostin (3-lso), fuscaxanthone C (FC; Fusca), Ilex aquifolium (IA) extract, Wolfiporia extensa (WE) extract, and combinations of 3-isomangostin (3-lso) with Ilex aquifolium (IA) extract, 3-isomangostin (3-lso) with Wolfiporia extensa (WE) extract, fuscaxanthone C (FC; Fusca) with Ilex aquifolium (IA) extract, and fuscaxanthone C (FC; Fusca) with Wolfiporia extensa (WE) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): **** P value: <0.0001 (Statistically significant compared to DMSO) # P value: 0.0395 (Statistically significant compared to 3-isomangostin) Figure 8 shows mean fluorescence intensity obtained by flow cytometry of sebocytes cells treated with AdipoRed™ dye. Cells were incubated with test compositions for 3 days. From left to right, DMSO (negative control), epigallocatechin gallate (EGCG, positive control), 3-isomangostin (3-lso), fuscaxanthone C (FC; Fusca), Fragaria vesca (FV) extract, and combinations of 3-isomangostin (3-lso) with Fragaria vesca (FV) extract, and fuscaxanthone C (FC; Fusca) with Fragaria vesca (FV) extract according to embodiments of the invention. Within the figure the following labels are used with respect to the comparison in a one-way analysis of variance (one-way ANOVA): **** p value: <0.0001 (Statistically significant compared to DMSO) ## P value: 0.0011 (Statistically significant compared to fuscaxanthone C) #### P value: <0.0001 (Statistically significant compared to 3-isomangostin) Detailed Description of the Invention The invention relates to compositions comprising plant or fungal extracts in combination with xanthone compounds, and the use of the composition in a method for decreasing lipid production in sebocytes. Also provided is the use of the composition in cosmetic method for decreasing lipid production in the skin of an individual, and the use of the composition in a method of treating a skin disease or disorder related to increased lipid production in sebocytes. The following preferences may apply to all aspects of the invention as described above. The preferences may be combined in any combination. Xanthone Compounds The composition of the invention contains a xanthone together with a plan extract. The xanthone may be a mangostin, such as a-mangostin, p-mangostin or 3-isomangostin, or another related form, such as 9-hydroxycalabaxanthone or fuscaxanthone C. In one embodiment, the xanthone compound is a xanthone that is not present within, or otherwise derived from, the plant extract with which it is used in combination. The composition of the invention comprises a xanthone compound according to formula (I): where: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, Ci.4haloalkyl, and C2-10 alkenyl; or alternatively R2 and R3, or R1 and R2, or R6 and R7, or R7 and R8, together with the carbon ring atoms to which they are connected, form a 5 or 6-membered oxygencontaining heterocyclic ring, which ring is optionally substituted with one or more groups RH; R9, R10 and R11 are independently selected from H, C1-6 alkyl and Ci-4haloalkyl; and each RH is C1-6 alkyl or C2-6 alkenyl. An alkyl group is monovalent saturated hydrocarbon group. The alkyl group may be a C1-6 alkyl group, for example a C1-4, C1-3 or a C1-2 alkyl group, such as Ci alkyl (methyl). In this context, the prefix (e.g. Ci-e) denotes the number of carbon atoms in the hydrocarbon backbone. The alkyl group may be linear or branched. Examples of C1-6 linear alkyl groups include methyl (-Me), ethyl (-Et), n-propyl (-nPr), n-butyl (-nBu), n-pentyl (-Amyl) and n-hexyl. Examples of Ci-6 branched alkyl groups include iso-propyl (-iPr), iso-butyl (-iBu), sec-butyl (-sBu), tert-butyl (-tBu), iso-pentyl, sec-pentyl, tert-pentyl, neo-pentyl, iso-hexyl, sec-hexyl, tert-hexyl and neo-hexyl. A haloalkyl group is an alkyl group in which one or more hydrogen atoms, such as one or all of the hydrogen atoms, is replaced with a halogen atom, for example F, Cl, Br and I. The haloalkyl group may be a C1-4 haloalkyl group, for example a C1-3 or a C1-2 haloalkyl group, and these may be monohalo or perhalo alkyl group. In this context, the prefix (e.g. C1-4) denotes the number of carbon atoms in the hydrocarbon backbone. Examples of Ci^ haloalkyl groups include chloromethyl (-CH2CI), fluoromethyl (-CH2F), difluoromethyl (-CHF2), trifluoromethyl (-CF3), choroethyl (-C2H4CI), monolfluorethyl (-C2H4F), pentafluoroethyl (-C2F3), heptafluoropropyl (-C3F7) and nonafluorobutyl (-C4F9). An alkenyl group is a monovalent unsaturated hydrocarbon group containing one or more carbon-carbon double bonds. The alkenyl group may be a C2-10 alkenyl group, for example a C2-6, C2-5, C2-4 or a C2-3 alkenyl group, or alternatively a C4-10, a C5-10 or a Ce-w alkenyl group, or a C5 or C10 alkenyl group. The alkenyl group may be a C2-6 alkenyl group, for example a C2-6, C2-5, C2-4, or a C2 or C3 alkenyl group. In this context, the prefix (e.g. C2-6) denotes the number of carbon atoms in the hydrocarbon backbone. The alkenyl group may be linear or branched. The alkenyl group may contain one or more, such as one, carbon-carbon double bonds. Where two or more double bonds are present, these may be conjugated or not. Examples of C2-10 and C2-6 linear alkenyl groups include ethenyl (vinyl), 1-propenyl, 2-propenyl (allyl), 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 1-hexenyl, and 2-hexenyl. Examples of C2-10 and C2-6 branched alkenyl groups include isopropenyl (1-methylvinyl), isobutenyl (2-methyl-1-propenyl), 1-isopentenyl, (3-methyl-1-butenyl), and 2-isopentenyl (3-methyl-2-butenyl), a further example of a C2-10 branched alkenyl groups is 3,7-dimethylocta-2,6-dienyl. A C2-10 alkenyl group may be 2-isopentenyl (3-methyl-2-butenyl) or 3,7-dimethylocta-2,6-dienyl. A 3,7-dimethylocta-2,6-dienyl group may be (2E)-3,7-dimethylocta-2,6-dien-1-yl. One of R2 and R3, or R1 and R2, or R6 and R7, or R7 and R8, together with the carbon ring atoms to which they are connected, form a 5 or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH. This ring is fused to the benzene ring of the xanthone. The 5- or 6-membered oxygen-containing heterocyclic ring is partially unsaturated. It may contain a double bond in addition to the aromatic bonding between the carbon ring atoms which are shared with the xanthone benzene ring. The 5- or 6-membered oxygen-containing heterocyclic ring contains only one ring oxygen atom. The other ring atoms are carbon atoms. The carbon ring atoms may be substituted with a group RH, where appropriate. The xanthone compound according to formula (I) has eight substituents, R1 to R8. In some embodiments, these groups may join, and together with the carbon ring atoms to which they are connected, they form a 5 or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH. In a preferred embodiment, R1, R2, R3, R4, R5, R6, R7, and R8are not all H. Thus, in this embodiment, the xanthone compound is not xanthone. In one embodiment, R1A, R3A, R6A, and R7A are not all OH. In a preferred embodiment, R1, R2, R3, R4, R5, R6, R7, and R8are not all OH. In a preferred embodiment, R1, R2, R3, R4, R5, R6, R7, and R8 are not all CO2R10, such as not all CO2H. In a preferred embodiment, at least two groups, such as two or three groups, selected from R1, R2, R3, R4, R5, R6, R7, and R8are H. Typically, the groups R4 and R5 are H, optionally together with R1, and preferably only R4 and R5 are H. In a preferred embodiment, at least three groups, such as three of four groups, selected from R1, R2, R3, R4, R5, R6, R7, and R8 are selected from OH and OMe. Preferably, at least three of R1, R3, R6 and R7 is selected from OH and OMe, such as three or four of R1, R3, R6 and R7 are selected from OH and OMe In one embodiment one, two or three groups selected from R1, R2, R3, R4, R5, R6, R7, and R8 are OH. For example, at least one group, such as one or two groups, selected from R1, R3 and R6 is OH. In one embodiment, R1 is OH and the group R2 is preferably C2-10 alkenyl and optionally the group R3 is OH or OMe. In an alternative embodiment, R1 is OH and R2 and R3 together with the carbon ring atoms to which they are connected, form a 5 or 6-membered oxygencontaining heterocyclic ring, which ring is optionally substituted with one or more groups RH. In one embodiment one, two or three groups selected from R1, R2, R3, R4, R5, R6, R7, and R8 are OMe. Alternatively, not one of these groups is OMe. In a preferred embodiment, at least one group, such as one or two groups selected from R1, R2, R3, R4, R5, R6, R7, and R8 are C2-10 alkenyl, such as selected from C5 and C10 alkenyl, such as selected from 2-isopentenyl (3-methyl-2-butenyl) and 3,7-dimethylocta-2,6-dienyl. Preferably no more than one of R1, R2, R3, R4, R5, R6, R7, and R8 is a Ce-w alkenyl group, and optionally not one of these groups is a Ce-w alkenyl group. In one embodiment, R8 is C2-10 alkenyl, such as selected from C5 and Cw alkenyl. Where two alkenyl groups are present, it is preferred that each alkenyl is a substituent to a separate aromatic ring in the xanthone compound. Thus, here, only one of R1 to R4 may be alkenyl, and only one of R5 to R8 may be alkenyl. Where two or more alkenyl or more groups are present, a plurality of these alkenyl groups may be substituents to same ring in the xanthone. Thus, here, two or more of R1 to R4 may be alkenyl and / or two or more of R5 to R8 may be alkenyl. However, this is less preferred. Where R2 and R3, or R1 and R2, or R6 and R7, or R7 and R8, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, then preferably an alkenyl group is not located at a remaining position within the ring. For example, where R2 and R3, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, then neither R1 nor R4 is alkenyl. Similarly, where R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, then neither R3 nor R4 is alkenyl. In one embodiment, R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring. Preferably, R2 and R3 form the oxygen-containing heterocyclic ring. The oxygen within the oxygen-containing heterocyclic ring is preferably connected to a ring atom of the xanthone core. The oxygen is preferably connected to the ring atom of the xanthone compound having the group R1, R3, R6 or R8. Here, then the oxygen is not connected the ring atom of the xanthone compound having the group R2 or R7. Rather, a carbon ring atom of the oxygen-containing heterocyclic ring is connected to the xanthone core. Where the oxygen-containing heterocyclic ring contains a carbon-carbon double bond, that double bond is preferably connected to (and therefore conjugated with) a ring atom of the xanthone compound, and preferably a ring atom of the xanthone compound having the group R2 or R7. The 5- or 6-membered oxygen-containing heterocyclic ring may be substituted with one or two groups RH. Where the ring is a 5-membered oxygen-containing heterocyclic ring, it may be substituted with one group RH. Here, the group RH is preferably C2-6 alkenyl, such as C3 alkenyl. Where the ring is a 6-membered oxygen-containing heterocyclic ring, it may be substituted with two groups RH. Here, each group RH is preferably C1-6 alkyl, such as methyl. Preferably, these substituents may be provided as substituent to the same carbon ring atom of the oxygen-containing heterocyclic ring (gem substitution) In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, C1-4fluoroalkyl, and C2-10 alkenyl; and R9, R10 and R11 are independently selected from H, C1-6 alkyl and C1-4fluoroalkyl. A fluoroalkyl group is an alkyl group in which one or more hydrogen atoms, such as one or all of the hydrogen atoms, is replaced with a fluorine atom, i.e. F. The fluoroalkyl group may be a C1-4fluoroalkyl group, for example a C1-3 or a C1-2 fluoroalkyl group, and these may be monofluoro or perfluoro alkyl groups. In this context, the prefix (e.g. C1-4) denotes the number of carbon atoms in the hydrocarbon backbone. Examples of Cm fluoroalkyl groups include monofluoromethyl (-CH2F), difluoromethyl (-CHF2), trifluoromethyl (-CF3), pentafluoroethyl (-C2F3), heptafluoropropyl (-C3F7) and nonafluorobutyl (-C4F9). In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, Ci-6 alkyl, CF3, C2F5 and C2-w alkenyl; or alternatively R2 and R3, or R1 and R2, or R6 and R7, or R7 and R8, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygencontaining heterocyclic ring, which ring is optionally substituted with one or more groups RH; and R9, R10 and R11 are independently selected from H, C1-6 alkyl, CF3, and C2Fs. In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, CF3, and C2-10 alkenyl; or alternatively R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH; and R9, R10 and R11 are independently selected from H, C1-6 alkyl, and CF3. In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, and C2-10 alkenyl; or alternatively R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH; and R9, R10 and R11 are independently selected from H and C1-6 alkyl. In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, OR9, CO2R10, OC(=O)R11, C1-4 alkyl, and C2-10 alkenyl; or alternatively R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH; and R9, R10 and R11 are independently selected from H and C1-4 alkyl, and each RH is independently selected from C1-4 alkyl and C2.4 alkenyl. In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, OR9, CO2R10, OC(=O)R11, Me, Et, and C2-io alkenyl; or alternatively R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH; and R9, R10 and R11 are independently selected from H, Me and Et, and each RH is independently selected from Me, Et and C3 alkenyl. In a preferred embodiment: R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, OR9, CO2R10, OC(=O)R11, Me, and C2-10 alkenyl; or alternatively R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH; and R9, R10 and R11 are independently selected from H, and Me. In one embodiment R4 and / or R5 are H or OH. In a preferred embodiment R4 and / or R5 are H, and preferably R4 and R5 are H. In a preferred embodiment one of R1 and R2 is C2-10 alkenyl, and / or R8 is C2-10 alkenyl, and preferably R1 and R2 is C2-10 alkenyl, and R8 is C2-10 alkenyl. In one embodiment, R8 is C2-10 alkenyl, such as C5 or C10 alkenyl. Here, one of R1 or R2 may be C2.io alkenyl, such as C5 or C10 alkenyl, or R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5 or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH. Preferred Formula In a particularly preferred embodiment, the xanthone compound is a compound of formula (ll-l): wherein: R1A, R3A, R6A, and R7A are independently selected from H, OH, OR9A, CO2R10A, OC(=O)R11A, C1-4 alkyl, and C1-4 alkenyl; and R9, R10 and R11 are independently selected from H and C1-4 alkyl. In a preferred embodiment: R1A, R3A, R6A, and R7A are independently selected from H, OH, OR9A, CO2R10A, OC(=O)R11A, Me, Et, and C1-4 alkenyl; and R9, R10 and R11 are independently selected from H, Me and Et. In a preferred embodiment: R1A, R3A, R6A, and R7A are independently selected from H, OH, OMe. In a preferred embodiment: R1A, R3A, R6A, and R7A are independently selected from OH and OMe. Here, the group R7A may be OMe. In a preferred embodiment: R1A and R6A are each OH, R3A is OH or OMe, and R7A is OMe. In one embodiment, R1A, R3A, R6A, and R7A are not all OH. In a particularly preferred embodiment, the xanthone compound is a compound of formula (ll-ll): wherein: R1A, R6A, and R7A are independently selected from H, OH, OR9A, CO2R10A, OC(=O)R11A, C1-4 alkyl, and C1-4 alkenyl; R9A, R10A and R11A are independently selected from H, and C1-4 alkyl; each RHA is independently selected from H and C1-4 alkyl; and the dashed line represents a double bond or single bond within the ring. In a preferred embodiment: R1A, R6A, and R7A are independently selected from H, OH, OR9A, CO2R10A, OC(=O)R11A, Me, Et, and C1-4 alkenyl; R9A, R10A and R11A are independently selected from H, Me and Et; and each RHA is independently selected from H, Me and Et. In a preferred embodiment: R1A, R6A, and R7A are independently selected from H, OH and OMe; and each RHA is independently Me. In a preferred embodiment: R1A, R6A, and R7A are independently selected from OH and OMe; and each RHA is independently Me. In a preferred embodiment: R1A and R6A are each OH, and R7A is OMe; and each RHA is independently Me. 5 The dashed line may represent a double bond in the ring, or the dashed line may present a single bond within the ring. Preferred Compounds In a particularly preferred embodiment, the xanthone compound is selected from a compound 10 of formula (II), formula (III), formula (IV), formula (V) or formula (VI): Y OH O (H) । OH 0 r ^YkYY (HI) OH 0 YYYj! (IV) । OH 0 ^YmlY MeO^^^O*^ (V) OH 0 jfrTr ^OMe ^0 H Y \z0Me ^OH Y OMe ^0 H Y L OMe ^OMe Y OMe ^0 H (VI) The xanthone compound may be a-mangostin. The xanthone compound may be p-mangostin. The xanthone compound may be 9-hydroxycalabaxanthone. The xanthone compound may be fuscaxanthone C. The xanthone compound may be 3-isomanogostin. In some embodiments, the xanthone compound is not a compound selected from one or more of xanthone, y-mangostin, gartanin and 8-deoxygartanin. In some embodiments, additionally or alternatively, the xanthone compound is not norathyriol. The xanthone compounds described herein, such as the xanthone compounds of formula (I), may be provided in free base form. Alternatively, the xanthone compounds may be provided in the form of a salt, such as a pharmaceutically or cosmetically acceptable salt. Examples of pharmaceutically acceptable salts are discussed in Berge et al., 1977, “Pharmaceutically Acceptable Salts,” J. Pharm. Sci., Vol. 66, pp. 1-19. In some embodiments, the xanthone compounds described herein are provided in a protonated form together with a suitable counter anion. Suitable counter anions include both organic and inorganic anions. Example of inorganic anions include those derived from inorganic acids, including chloride (Clj, bromide (Br), iodide (Ij, sulfate (SO42'), sulfite (SOa2-), nitrate (NOs-), nitrite (NOa-), phosphate (PO43-), and phosphite (POa3'). Examples of organic anions include 2-acetoxybenzoate, acetate, ascorbate, aspartate, benzoate, camphorsulfonate, cinnamate, citrate, edetate, ethanedisulfonate, ethanesulfonate, formate, fumarate, gluconate, glutamate, glycolate, hydroxymalate, carboxylate, lactate, laurate, lactate, maleate, malate, methanesulfonate, oleate, oxalate, palmitate, phenylacetate, phenylsulfonate, propionate, pyruvate, salicylate, stearate, succinate, sulfanilate, tartarate, toluenesulfonate, and valerate. Examples of suitable polymeric organic anions include those derived from tannic acid and carboxymethyl cellulose. In some embodiments, the xanthone compounds disclosed herein are provided in a deprotonated form together with a suitable counter cation. Suitable counter cations include both organic and inorganic cations. Suitable counterions include both inorganic and organic cations. Examples of suitable inorganic cations include alkali metal ions such as Na+ and K+, alkaline earth cations such as Ca2+ and Mg2+, and other cations such as Al3+. Examples of suitable organic cations include the ammonium ion (i.e., NH4+) and substituted ammonium ions (e.g., NHsR+, NH2R2+, NHR3+, NR4+). Examples of substituted ammonium ions include those derived from ethylamine, diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, as well as amino acids, such as lysine and arginine. An example of a common quaternary ammonium ion is N(CH3)4+. Unless otherwise specified, a reference to a particular compound also includes salt forms thereof. The xanthone compounds described herein may be provided in the form of a solvate (a complex of solute (e.g., compound, salt of compound) and solvent). Examples of solvates include hydrates, for example, a mono-hydrate, a di-hydrate and a tri-hydrate. The xanthone compounds described herein may be provided in desolvated form, for example, in dehydrated form. The composition of the invention may comprise an effective amount, such as a therapeutically or cosmetically effective amount, of the xanthone compound described herein, such as the xanthone compounds of formula (I). In some embodiments, the composition of the invention comprises the xanthone compound in an amount of from 0.0005 wt% to 10 wt%, such as based on the total weight of the composition. In a preferred embodiment, the composition of the invention comprises the xanthone compound in an amount of from 0.1 wt% to 5 wt%, such as 0.1 wt% to 3 wt%, and such as 0.2 wt% to 3 wt%, and more preferably 0.2 wt% to 2 wt%. The xanthone compound may be present in an amount that is at most 2 wt%, 3 wt%, 5 wt%, or 10 wt%. The xanthone compound may be present in an amount that is at least 0.0005 wt%, 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.05 wt%, 0.1 wt %, 0.5 wt%, or 1.0 wt%. Plant or Fungal Extracts The composition of the invention comprises a plant or fungal extract. The plant or fungal extract is selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of fungi belonging to the genus Wolfiporia, The plant or fungal extract may be derived from any suitable species of the genus Arctostaphylos, Hedera, Ilex, Fragaria, Rubus, or Wolfiporia. Suitable plant or fungal extracts are commercially available and can be purchased from, for example, BOCSCI (New York, USA). Suitable species of plants belonging to the genus Arctostaphylos include Arctostaphylos uva ursi (bearberry). Arctostaphylos uva-ursi is widely distributed throughout northern latitude and is native to, for example, the United States and Canada. Suitable species of plants belonging to the genus Hedera include Hedera helix (common ivy). Hedera helix is widely distributed throughout Europe and is native to, for example, the United Kingdom. Suitable species of plants belonging to the genus Ilex include Ilex aquifolium (common holly). Ilex aquifolium is widely distributed throughout Europe and is native to, for example, the United Kingdom. Suitable species of plants belonging to the genus Fragaria include Fragaria vesca (wild strawberry) and Fragaria x ananassa (garden strawberry). Fragaria vesca is widely distributed throughout Europe and is native to, for example, the United Kingdom. Fragaria x ananassa is widely cultivated across Europe, including the United Kingdom. Suitable species of plants belonging to the genus Rubus include Rubus idaeus (red raspberry). Rubus idaeus is widely distributed throughout Europe and is native to, for example, the United Kingdom. Suitable species of fungi belonging to the genus Wolfiporia include Wolfiporia extensa (Poria cocos; China root). The plant or fungal extract may be derived from any suitable part of the plant or fungus. Suitable parts of the plant include roots, stems, leaves, flowers, fruits and seeds. Suitable parts of the fungus include the mycelium or fruiting body. Examples of suitable leaf extracts include Arctostaphylos uva-ursi plant extracts include Arctostaphylos uva-ursi leaf extract, Hedera helix leaf extract and Ilex aquifolium leaf extract. Examples of suitable fruit extracts include Rubus idaeus fruit extract, Fragaria vesca fruit extract and Fragaria x ananassa fruit extract. The plant of fungal extract may be prepared using any suitable extraction method. Suitable extraction methods include extraction using an organic solvent and extraction using an aqueous solvent (aqueous extraction). Typically, the plant or fungal extract is an aqueous extract. In a preferred embodiment, the plant or fungal extract is selected from Arctostaphylos uva ursi extract, Hedera helix extract, Ilex aquifolium extract, Fragaria vesca extract, Fragaria x ananassa extract, and Rubus idaeus extract, and Wolfiporia extensa extract. In a preferred embodiment, the plant or fungal extract is selected from Arctostaphylos uva ursi leaf extract, Hedera helix extract, Ilex aquifolium leaf extract, Fragaria vesca fruit extract, Fragaria x ananassa fruit extract, Rubus idaeus fruit extract, and Wolfiporia extensa extract. In a preferred embodiment, the plant or fungal extract is selected from extracts of plants belonging to the genus Rubus. In a preferred embodiment, the plant or fungal extract is selected from Rubus idaeus extract. In a preferred embodiment, the plant or fungal extract is selected from extracts of plants belonging to the genus Fragaria. In a preferred embodiment, the plant or fungal extract is selected from Fragaria vesca or Fragaria x ananassa extract. In a preferred embodiment, the plant or fungal extract is selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, and Ilex, and extracts of the fungus Wolfiporia. In a preferred embodiment, the plant or fungal extract is selected from Arctostaphylos uva ursi extract, Hedera helix extract, Ilex aquifolium extract, and Wolfiporia extensa extract. In one embodiment, the plant extract is Rubus Idaeus extract. In a further embodiment, the plant extract is Rubus Idaeus fruit extract. In one embodiment, the plant extract is Fragaria vesca extract. In a further embodiment, the plant extract is Fragaria vesca fruit extract. A xanthone compound, such as a xanthone compound of formula (I), may not be present within, or otherwise derived from, the plant extract with which it is used in combination. The composition of the invention may comprise an effective amount, such as a therapeutically or cosmetically effective amount, of the plant or fungal extract described herein. A Fragaria extract, such as a Fragaria vesca extract, may comprise one or more of, such as all of, the following compounds given in Table 1, such as at an amount in the range given. The extract here may be a dry extract. Table 1. Components of Fragaria vesca solid plant extract Compound Concentration Range (pg / g = ppm) Adenine 206 Betaine 238 Choline 261 Ellagic acid 346 p-Coumaric acid 140 Pipecolic acid 244 Miquelianin 306 A Fragaria vesca extract may be obtained or obtainable from strawberry fruit. The extract may be obtained by extraction with water, concentrated and spray dried. A Hedera extract, such as a Hedera helix extract, may be characterised by the presence of triterpene saponins, for example at an amount in the range 2.5 to 6 wt%. The extract may contain one or more of, such as all of, hederacoside C (such as in an amount in the range 1.7 to 4.8 wt%), hederacoside D (such as in an amount in the range 0.4 to 0.8 wt%), and hederacoside B (such as in an amount in the range 0.1-0.2 wt%). Additionally, or alternatively, the extract may contain a-hederin, for example at an amount in the range 0.1 to 0.3 wt%. Additionally, or alternatively, the extract may contain hederagenin, for example at an amount in the range 0.1 to 1.5 wt%, such as 0.89 or 0.9 wt%. The presence of such characterising compounds for an Hedera helix extract is as described by Tatia et al. (Rev. Chim. 2019, 70, 1157). In one embodiment, the Hedera helix extract may be characterised by have a minimum content of hederacoside C of 3.0 wt %. A Hedera helix extract may be obtained or obtainable from English ivy whole plant or leave. The extract may be obtained by extraction with water, concentrated and dried. An Ilex extract, such as an Ilex aquifolium extract, may be characterised by the presence of ursolic acid and oleanolic acid. Ursolic acid may be present in an amount in the range 1.35 wt% to 0.0005 wt%, such as in the range 1.30 wt% to 0.001 wt%. For example, ursolic acid may be present at an amount of about 1.30 wt%. Alternatively, ursolic acid may be present at an amount of about 0.001 wt%. Oleanolic acid may be present at an amount of about 0.50 wt%. Additionally or alternatively, an Ilex extract may comprise amino-acids, saccharides, carotenoids, phenol derivatives, fatty acids, flavonoids, anthocyanes, and triterpenes, such as a-amyrin, p-amyrin, uvaol, and erythrodiol. The presence of such characterising compounds for an Ilex aquifolium extract is as described by Palu et al. (Molecules 2019, 24, 4413). Ilex aquifolium extract may be obtained or obtainable from English holly whole plant or leave, such as leaf. The extract may be obtained by extraction with water, concentrated and dried. An Arctostaphylos extract, such as an Arctostaphylos uva ursi extract, may be characterised by the presence of ursolic acid and / or arbutin. Ursolic acid may be present in an amount in the range 1.5 wt% to 0.0005 wt%, such as in the range 1.0 wt% to 0.001 wt%. For example, ursolic acid may be present at an amount of about 1.0 wt%. Alternatively, ursolic acid may be present at an amount of about 0.001 wt%. Arbutin may be present in an amount in the range 3.5 wt% to 0.0001 wt%, such as in the range 3.0 wt% to 0.0005 wt%. For example, arbutin may be present at an amount of about 3.0 wt%. Alternatively, arbutin may be present at an amount of about 0.0005 wt%. Additionally or alternatively, the extract may further comprise one or more of, such as all of, gallic acid (such as at 0.14 wt%), ellagic acid (such as at 0.064 wt%), rutin (such as at 0.011 wt%), hyperoside (such as at 0.44 wt%), quercitrin (such as at 0.014 wt%), catechin (such as at 0.28 wt%), euscapic acid (such as at 0.038 wt%), tormentinic acid (such as at 0.017 wt%), uavol (such as at 0.35 wt%), oleanolic acid (such as at 0.16 wt%), erythrodiol (such as at 0.16 wt%), betulin (such as at 0.13 wt%) and lupeol (such as at 0.37 wt%). The presence of such characterising compounds for an Arctostaphylos uva ursi extract is as described by Chaika et al. (ScienceRise: Pharmaceutical Science 2020, 6, 74). A Rubus extract, such as a Rubus Idaeus extract, may comprise one or more of, such as all of, the following compounds given in Table 2, such as at an amount in the range given. The extract here may be a dry extract. Table 2. Components of Rubus idaeus solid plant extract Compound Concentration Range (pg / g = ppm) Adenine 0.7-7.1 Betaine 1.2-3.4 Choline 5.4-18.4 Ellagic acid 21.9-439.8 Miquelianin 0.2-21.4 p-coumaric acid 0.2-9.2 Pipecolic acid 1.0-74.4 Tyramine 17-182.9 A Rubus idaeus extract may be obtained or obtainable from raspberry fruit. The extract may be obtained by extraction with water, concentrated and spray dried. A Wolfiporia extract, such as a Wolfiporia extensa extract, may be characterised by the presence of triterpene acids, such as poricoic acid A and / or pachymic acid. The extract may comprise one or more of, such as all of, poricoic acid A (such as at 18.0 wt%), poricoic acid B (such as at 4.6 wt%), dehydrotumulosic acid (such as at 1.1 wt%), polyporenic acid C (such as at 1.7 wt%), and pachymic acid (such as 0.71 wt%). The presence of such characterising compounds for a Wolfiporia extensa (P. cocos) alcohol extract is as described by Cai et al. (Drug Metabolism and Disposition 2021, 49, 353). In some embodiments, the composition of the invention comprises the plant or fungal extract in an amount of from 0.005 wt% to 50 wt%, such as based on the total weight of the composition. In a preferred embodiment, the composition of the invention comprises the plant or fungal extract in an amount of from 0.005 wt% to 30 wt%, such as 0.05 wt% to 10 wt%, more preferably 0.1 wt% to 3 wt%. The plant extract may be present in an amount that is at most 2 wt%, 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 45 wt%, or 50 wt%. The plant extract may be present in an amount that is at least 0.005 wt%, 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, or 1 wt %. The xanthone compound may be substantially absent from, such as may not be present within, or otherwise derived from, the plant extract with which it is used in combination. For example, where the plant extract is a Rubus idaeus, Hedera helix, Ilex aquifolium, Fragaria vesca or Wolfiporia extensa extract, these extracts are substantially free of the xanthone compound, any or all xanthone compounds of formula (I). For example, the total xanthone amount may be less than 1 wt%, such as less than 0.1 wt%, such as less than 0.01 wt% in the plant extract. Compositions The compositions of the invention may be formulated for cosmetic or therapeutic uses. Accordingly, the compositions of the invention may additionally comprise one or more pharmaceutically or cosmetically ingredients. Pharmaceutically cosmetically acceptable ingredients are those which, within the scope of sound judgment, are suitable for use in contact with the tissues of the subject in question (e.g., human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit / risk ratio. Each ingredient must also be compatible with the other ingredients of the composition. In one embodiment, the composition comprises one or more ingredients selected from solvents, oils, surfactants, thickeners, humectants, and preservatives. Examples of suitable solvents includes water; mono-alcohols such as ethanol, isopropanol, benzyl alcohol, and phenylethyl alcohol; polyalcohols such as ethylene glycol, propylene glycol, butane-1,3-diol, mannitol, sorbitol, glycerol, and erythritol; and glycol ethers such as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether. Examples of suitable oils include mineral oils, plant oils and waxes. Examples of suitable plant oils include algal oil, annatto oil, argan oil, almond oil, apricot kernel oil, avocado oil, babassu oil, Brazil nut butter, butter, cashew butter, castor oil, camellia oil, cherry kernel oil, cocoa butter, coconut oil, corn oil, cottonseed oil, fish oil, grape seed oil, gardenia oil, ghee, hazelnut oil, jatropha oil, jojoba oil, kokum oil, linseed oil, macadamia oil, maize oil, mango seed oil, mango butter, mineral oil, mink oil, olive oil, palm oil, palm kernel oil, peach kernel 5 oil, peanut butter, peanut oil, plum kernel oil, pomegranate oil, rapeseed seed oil, rice bran oil, rosehip oil, sal oil, sesame oil, shea butter, soybean oil, squalene, sunflower oil, teas seed oil, walnut oil. Examples of suitable waxes include bayberry wax, beeswax, carnauba wax (palm wax), candelilla wax, ceresin, jojoba butter, lanolin wax, montan wax, ozokerite, polyglyceryl-3-beeswax, polyglyceryl-6-pentastearate, Japan wax, microcrystalline wax, paraffin wax, isoparaffin, vaseline solid paraffin, squalene, oligomer olefins, synthetic candelilla wax, synthetic carnauba, synthetic beeswax Surfactants (surface-active agents) may act as dispersants or wetting agents. Examples of suitable surfactants include anionic surfactants, cationic surfactants, non-ionic surfactants, and amphoteric (zwitterionic) surfactants. Examples of suitable anionic surfactants include ammonium lauryl sulfate, ammonium laureth sulfate, triethylamine lauryl sulfate, triethylamine laureth sulfate, triethanolamine lauryl sulfate, triethanolamine laureth sulfate, monoethanolamine lauryl sulfate, monoethanolamine laureth sulfate, diethanolamine lauryl sulfate, diethanolamine laureth sulfate, lauric monoglyceride sodium sulfate, sodium lauryl sulfate, sodium laureth sulfate, potassium lauryl sulfate, potassium laureth sulfate, sodium lauryl sarcosinate, sodium lauroyl sarcosinate, lauryl sarcosine, cocoyl sarcosine, ammonium cocoyl sulfate, ammonium lauroyl sulfate, sodium cocoyl sulfate, sodium lauroyl sulfate, potassium cocoyl sulfate, potassium lauryl sulfate, triethanolamine lauryl sulfate, triethanolamine lauryl sulfate, monoethanolamine cocoyl sulfate, monoethanolamine lauryl sulfate, sodium tridecyl benzene sulfonate, and sodium dodecyl benzene sulfonate Examples of suitable cationic surfactants include behentrimonium chloride, cocotrimonium chloride, cethethyldimonium bromide, dibehenyidimonium chloride, dihydrogenated tallow benzylmonium chloride, disoyadimonium chloride, ditallowdimonium chloride, hydroxycetyl hydroxyethyl dimonium chloride, hydroxyethyl behenamidopropyl dimonium chloride, Hydroxyethyl cetyidimonium chloride, hydroxyethyl tallowdimonium chloride, myristalkonium chloride, PEG-2 oleamonium chloride, PEG-5 stearyl ammonium chloride, PEG-15 cocoyl quaternium 4, PEG-2 stearalkonium 4, lauryltrimonium chloride; Quaternium-16; Quaternium-18, lauralkonium chloride, olealkmonium chloride, cetylpyridinium chloride, Polyquaternium-5, Polyquaternium-6, Polyquaternium-7, Polyquaternium-10, Polyquaternium-22, Polyquaternium-37, Polyquaternium-39, Polyquaternium-47, cetyl trimonium chloride, dilauryidimonium chloride, cetalkonium chloride, dicetyidimonium chloride, soyatrimonium chloride, and stearyl octyl dimonium methosulfate. Examples of suitable non-ionic surfactants include fatty alcohol ethoxylates such as octaethylene glycol monododecyl ether, and pentaethylene glycol monododecyl ether; alkylphenol ethoxylates (APEs or APEOs) such as Nonoxynol-4, Nonoxynol-7, Nonoxynol-9, Nonoxynol-14, Nonoxynol-15, Nonoxynol-18, and triton X-100; glycerol fatty acid esters such as glycerol monostearate, and glycerol monolaurate; sorbitol fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan tristearate, polysorbate (Tween) 20, polysorbate 40, polysorbate 60, and polysorbate 80. Examples of suitable amphoteric (zwitterionic) surfactants include cocamidopropyl hydroxysultaine, cocamidopropyl betaine, lauryl betaine, lauryldimethylamine oxide, and myristamine oxide. Examples of suitable thickeners (rheological modifiers) include gums such as alginates, carageenans, gum acacia, gum arabic, gum ghatti, gum karaya, gum tragacanth, guar gum; guar hydroxypropyltrimonium chloride, xanthan gum or gellan gum; cellulose derivatives such as sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl carboxyethyl cellulose, hydroxymethyl carboxypropyl cellulose, ethyl cellulose, sulfated cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxypropylmethyl cellulose, microcrystalline cellulose; agar; pectin; gelatin; starch and its derivatives; chitosan and its derivatives such as hydroxyethyl chitosan; synthetic polymers such as polyvinyl alcohol, PVM / MA copolymer, PVM / MA decadiene crosspolymer, poly(ethylene oxide) based thickeners; Humectants may act as hygroscopic agents, increasing the amount of water absorbed or retained by the composition. Examples of suitable humectants include acetamide MEA, ammonium lactate, chitosan and its derivatives, colloidal oatmeal, galactoarabinan, glucose glutamate, glerecyth-7, glygeryth-12, glycereth-26, glyceryth-31, glycerin, lactamide MEA, lactamide DEA, lactic acid, methyl gluceth-10, methyl gluceth-20, panthenol, propylene glycol, sorbitol, polyethylene glycol, 1,3-butanediol, 1,2,6-hexanetriol, hydrogenated starch hydrolysate, inositol, mannitol, PEG-5 pentaerythritol ether, polyglyceryl sorbitol, xylitol, sucrose, sodium hyaluronate, and sodium PCA. Examples of suitable preservatives includes methyl p-hydroxybenzoate, propyl p-hydroxybenzoate and sorbic acid. Methyldibromo glutaronitrile (MDBGN), benzyl alcohol, imidazolidinyl urea 1,3-bis (hydroxymethyl)-5,5-dimethyl-2,3-imidazolidinedione (DMDM hydantoin), methylchloroisothiazolinone and methylisothiazolinone, phenoxyethanol, and sodium benzoate. In one embodiment, the composition comprises one or more ingredients selected from emollients, anti-inflammatory agents, antioxidants and UV blocking agents. Examples of suitable emollients include fatty esters such as isopropyl myristate, isopropyl palmitate, caprylic / capric triglycerides, cetyl lactate, cetyl palmitate, hydrogenated castor oil, glyceryl esters, hydroxycetyl isostearate, hydroxy cetyl phosphate, isopropyl isostearate, isostearyl isostearate, diisopropyl sebacate, PPG-5-Ceteth-20, 2-ethylhexyl isononoate, 2-ethylhexyl stearate, C12 to C16 fatty alcohol lactate, isopropyl lanolate, and 2-ethyl-hexyl salicylate. Examples of suitable anti-inflammatory ingredients include cyclo-oxygenase (e.g., COX-1 or COX-2) or Lipoxygenase (e.g., LOX-5) enzyme inhibitors such as ascorbic acid, ascorbic acid derivatives, vitamin E, vitamin E derivatives, tocotrienol, rutin, quercetin, hesperidin (Citrus sinensis), hesperetin (Citrus sinensis), diosmin (Citrus sinensis), mangiferin (Mangifera indica), mangostin (Garcinia mangostana), cyanidin (Vaccinium myrtillus), astaxanthin (Haematococcus algae), lutein (Tagetes patula), lycopene (Lycopersicum esculentum), resveratrol (Polygonum cuspidatum), tetrahydrocurcumin (Curcuma longa), rosmarinic acid (Rosmarinus officinalis), hypericin (Hypericum perforatum), ellagic acid (Punica granatum), chlorogenic acid (Vaccinium vulgaris), oleuropein (Olea europaea), alpha-lipoic acid, glutathione, andrographolide (Andrographis paniculata), grapeseed extract, green tea extract, polyphenols, pycnogenol (pine bark extract), white tea extract, black tea extract, (Andrographis paniculata), carnosine, and niacinamide. Further examples of suitable antiinflammatory composition can additionally be selected from horse chestnut extract (Aesculus hippocastanum extract), esculin, escin, yohimbine, Capsicum oleoresin, capsaicin, niacin, niacin esters, methyl nicotinate, benzyl nicotinate, ruscogenins (Butchers Broom extract; Ruscus aculeatus extract), diosgenin (Trigonel afoenumgraecum, fenugreek), emblica extract (Phyllanthus emblica extract), asiaticoside (Centella asiatica extract), Boswellia extract (Boswellia serrata), sericoside, visnadine, thiocolchicoside, grapeseed extract, ginger root extract (Zingiber officianale), piperine, vitamin K, melilot (Melilotus officinalis extract), glycyrrhetinic acid, ursolic acid, sericoside (Terminalia sericea extract), darutoside (Siegesbeckia orientalis extract), Amni visnaga extract, vine leaf extract (Vitis vinifera), apigenin, phytosan, luteolin. Examples of suitable antioxidant ingredients include ascorbic acid, ascorbic acid derivatives glucosamine ascorbate, arginine ascorbate, lysine ascorbate, glutathione ascorbate, nicotinamide ascorbate, niacin ascorbate, allantoin ascorbate, creatine ascorbate, creatinine ascorbate, chondroitin ascorbate, chitosan ascorbate, carnosine ascorbate, vitamin E, vitamin E derivatives, tocotrienol, rutin, quercetin, hesperidin (Citrus sinensis), hesperetin (Citrus sinensis), diosmin (Citrus sinensis), mangiferin (Mangifera indica), mangostin (Garcinia mangostana), cyanidin (Vaccinium myrtillus), astaxanthin (Haematococcus algae), lutein (Tagetes patula), lycopene (Lycopersicum esculentum), resveratrol (Polygonum cuspidatum), tetrahydrocurcumin (Curcuma longa), rosmarinic acid (Rosmarinus officinalis), hypericin (Hypericum perforatum), ellagic acid (Punica granatum), chlorogenic acid (Vaccinium vulgaris), oleuropein (Olea europaea), alpha-lipoic acid, niacinamide lipoate, glutathione, andrographolide (Andrographis paniculata), carnosine, niacinamide, Potentilla erecta extract, polyphenols, grapeseed extract, pycnogenol (pine bark extract), pyridoxine, magnolol, honokiol, paeonol, resacetophenone, quinacetophenone, arbutin and kojic acid. Examples of suitable UV blocking agents (sunscreen active agents) include octyl methoxycinnamate (ethylhexyl p-methoxycinnamate), octyl salicylate oxybenzone (benzophenone-3), benzophenone-4, menthyl anthranilate, dioxybenzone, aminobenzoic acid, amyl dimethyl PABA, diethanolamine p-methoxy cinnamate, ethyl 4-bis (hydroxypropyl) aminobenzoate, 2-ethylhexy 1-2-cyano-3,3-diphenylacrylate, homomenthyl salicylate, glyceryl aminobenzoate, dihydroxyacetone, octyl dimethyl PABA, 2-phenylbenzimidazole-5-sulfonic acid, triethanolamine salicylate, zinc oxide, titanium oxide, and mixtures thereof. Further components suitable for use in the composition include fragrances, pH adjusters, pigments, odour absorbers, antimicrobial agents, antifungal agents, chelating agents, and saccharides. The compositions of the present invention are typically formulated for topical use. The composition of the present invention may be formulated as a solution, liquid, lotion, cream, emulsion, dispersion, gel, or paste. Examples of suitable emulsions include two-phase emulsions comprising an aqueous phase and an oil phase such as oil-in-water (O / W) and water-in-oil (W / O), as well as complex emulsions such as triple emulsions (O / W / O and W / O / W). The composition and formulations may be prepared by any methods well known in the art. Such methods include the step of bringing into association the xanthone compound and / or plant or fungal extract with a carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly mixing the xanthone compound and / or plant or fungal extract with a carrier (e.g., a liquid carrier, a finely divided solid carrier, etc.). The compositions of the present invention can be formulated as both cosmetic and pharmaceutical products. In one embodiment, there is provided a personal care product comprising a composition of the invention. Suitable personal care products include skin care products, hair care products, cleansing products, and cosmetic powders and liquids. Examples of suitable skin care products include skin / hand lotions, skin / hand creams, skin / hand ointments, skin / hand pastes, skin toner, shaving gels, shaving creams, sunscreens, deodorants, antiperspirants, suntan lotions, after sun, aftershaves, body oils, bath oils, and bubble baths. Examples of suitable hair care products include conditioners, hair detangling lotion, styling gel, styling creams, styling waxes, styling lotions, mousses, spray gels, hair tonics, spritzes, and pomades. Examples of suitable cleansing products include liquid soaps, bar soaps, body washes, skin cleansers, and shampoos. Examples of suitable cosmetic powders and liquids include blusher, body powder, bronzing powder, eye shadow, foundation, face powder, lip powder, powder makeup, liquid bronzer, eyeliner, lip gloss, lipstick, and mascara. Method and Uses for Decreasing Lipid Production The compositions of the invention reduce the production of lipids in sebocytes. The invention also provides a method for decreasing lipid production in sebocytes, the method comprising contacting the sebocytes with a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus, and extracts of the fungus Wolfiporia. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out above. In one embodiment, the method for decreasing lipid production in sebocytes is in vivo. In one embodiment, the method for decreasing lipid production in sebocytes ex vivo, such as in vitro. In one embodiment, the method for decreasing lipid production in sebocytes comprises contacting the sebocytes with an effective amount of a composition of the invention. An effective amount of the composition provides a detectable reduction in the production of lipids in the sebocytes. Methods for detecting and quantifying the production of lipids in sebocytes include, for example, a fluorescence assay using a suitable lipid-detecting dye, such as AdipoRed™. In one embodiment, the method for decreasing lipid production in sebocytes comprises contacting the sebocytes with an amount of a composition of the invention suitable for reducing the production of lipids by 10% or more, preferably 15% or more, more preferably 20% or more, even more preferably 20% or more, and most preferably 30% or more. In one embodiment, the method for decreasing lipid production in sebocytes decreases lipid production by 5% or more, preferably 10% or more, preferably 15% or more, more preferably 20% or more, even more preferably 20% or more, and most preferably 30% or more. The invention also provides a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia, for use in a method of decreasing lipid production in sebocytes. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out above. Preferred features of the method for decreasing lipid production in sebocytes are also set out above. The invention also provides the use of a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia, to decrease lipid production in sebocytes. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out above. Preferred features of the method for decreasing lipid production in sebocytes also apply to the use of the composition to decrease lipid production in sebocytes. Cosmetic Methods and Uses The compositions of the invention reduce lipid production in sebocytes, such as those in the skin of an individual. As such, the compositions of the invention can reduce or ameliorate cosmetic problems associated with over-production of lipids in the skin. Cosmetic problems associated with overproduction of lipids in the skin include oily or shiny skin, oily hair, enlarged skin pores, undesirable body odour, and decreased retention of make-up products on the skin. Accordingly, the invention provides a cosmetic method for decreasing lipid production in the skin of an individual, the method comprising contacting the skin with a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out above. In one embodiment, the cosmetic method for decreasing lipid production in the skin of an individual is not a method of treatment. In one embodiment, the cosmetic method for decreasing lipid production in the skin of an individual is not a method of treatment of the human or animal body by therapy. In one embodiment, the cosmetic method reduces lipid production in sebocytes in the skin of an individual. ln one embodiment, the skin is skin on the head, such as on the face, mouth, neck, or scalp. In one embodiment, the skin is skin on the chest, back, arms, legs, or hands. The benefits of decreasing lipid production in the skin of an individual include reducing the oily appearance of the skin, controlling surface oil, minimizing skin pores and reducing undesirable body odour. In one embodiment, the cosmetic method decreases lipid production in the skin, thereby achieving an effect selected from reducing the oily appearance of the skin, controlling skin surface oil, minimizing skin pores and reducing undesirable body odour. In one embodiment, the individual is in need of cosmetic treatment. Individuals in need of cosmetic treatment may have a condition associated with overproduction of lipids in the skin, such as oily or shiny skin, oily hair, enlarged skin pores, and undesirable body odour. In one embodiment, the individual has a cosmetic condition selected from oily or shiny skin, oily hair, enlarged skin pores, and undesirable body odour. The invention also provides a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia, for use in a cosmetic method of decreasing lipid production in the skin of an individual. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out above. Preferred features of the cosmetic method for decreasing lipid production in the skin of an individual are also set out above. The invention also provides the use of a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus, Vitis and extracts of the fungus Wolfiporia, to decrease lipid production in the skin of an individual. Preferred features of the composition, such as the xanthone compound and the plant or fungal extract, are set out above. Preferred features of the cosmetic method for decreasing lipid production in the skin of an individual also apply to the use of the composition to decrease lipid production in the skin of an individual. Medical Methods and Uses The compositions of the invention reduce lipid production in sebocytes, such as those in the skin of an individual. As such, the compositions of the invention are useful in the treatment or prophylaxis (prevention) of medical problems associated with over-production of lipids in the skin. Medical problems associated with overproduction of lipids in the skin include acne vulgaris and rosacea. Accordingly, the invention provides a composition of the invention, such as a composition comprising: (a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and (b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia, for use in a method of treatment, such as a method of treatment of the human or animal body by therapy. In one embodiment, the method of treatment is a method of treatment of a disorder (e.g. a disease) associated with over-production of lipids in the skin. In one embodiment, the method of treatment is a method of treatment of a disorder associated with over-production of lipids in sebocytes. In one embodiment, the skin is skin on the head, such as on the face, mouth, neck, or scalp. In one embodiment, the skin is skin on the chest, back, arms, legs, or hands. In one embodiment, the treatment is treatment of acne vulgaris. In one embodiment, the treatment is treatment of rosacea. In one embodiment, the treatment is administered to a subject in need of treatment. The subject in need of treatment (the patient) may be a mammal, such as a human. The subject in need of treatment may be an adult or juvenile. In a preferred embodiment, the subject in need of treatment is a human, more preferably an adult human. Alternatively, the subject in need of treatment is a non-human animal used in laboratory research. In one embodiment, the treatment is administered by any convenient route of administration. In a preferred embodiment, the treatment is administered topically (i.e. at the site of desired action). In one embodiment, the treatment comprises administering a therapeutically effective amount of the composition to a subject in need of treatment. It will be appreciated by one of skill in the art that appropriate dosages of the compositions described herein, can vary from patient to patient. Determining the optimal dosage will generally involve the balancing of the level of therapeutic benefit against any risk or deleterious side effects. The selected dosage level will depend on a variety of factors including, but not limited to, the activity of the particular xanthone compound and plant or fungal extract, the route of administration, the time of administration, the rate of excretion of the xanthone compound and plant or fungal extract, the duration of the treatment, other drugs, compounds, and / or materials used in combination, the severity of the disorder, and the species, sex, age, weight, condition, general health, and prior medical history of the patient. The amount of xanthone compound and plant or fungal extract and route of administration will ultimately be at the discretion of the physician, veterinarian, or clinician, although generally the dosage will be selected to achieve local concentrations at the site of action which achieve the desired effect without causing substantial harmful or deleterious side-effects. Administration can be effected in one dose (application), continuously or intermittently (e.g., in divided doses at appropriate intervals) throughout the course of treatment. Methods of determining the most effective means and dosage of administration are well known to those of skill in the art and will vary with the formulation used for therapy, the purpose of the therapy, the target cell(s) being treated, and the subject being treated. Single or multiple administrations can be carried out with the dose level and pattern being selected by the treating physician, veterinarian, or clinician. Other Preferences Each and every compatible combination of the embodiments described above is explicitly disclosed herein, as if each and every combination was individually and explicitly recited. Various further aspects and embodiments of the invention will be apparent to those skilled in the art in view of the present disclosure. “and / or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example “A and / or B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein. Unless context dictates otherwise, the descriptions and definitions of the features set out above are not limited to any particular aspect or embodiment of the invention and apply equally to all aspects and embodiments which are described. Examples Certain aspects and embodiments of the invention will now be illustrated by way of example and with reference to the figures described above. Materials Dimethyl sulfoxide (DMSO), epigallocatechin gallate (EGCG), and ellagic acid (EA) were purchased from Sigma-Aldrich. Alpha-mangostin (AM), beta-Mangostin (BM), and 9-hydroxycalabaxanthone (9H), 3-isomangostin (3-lso) and Fuscaxanthone C (FC) were purchased from TargetMol (Boston, USA). Hedera helix extract (HH), Ilex aquifolium extract (IA), Rubus idaeus extract (RI) extract, Fragaria vesca extract (FV), Arctostaphylos uva ursi extract (AUU) and Wolfiporia extensa (\NE) extract were purchased from BOCSCI (New York, USA). The extracts were obtained as described below. Extract Extraction Method Hedera helix extract (HH) From ivy; Extracted by water, concentrated and dried Ilex aquifolium extract (IA) From holly; Extracted by water, concentrated and dried Wolfiporia extensa QAIE) extract From dried sclerotia of the fungus Wolfiporia extensa', Extracted by water and ethanol, concentrated and dried Fragaria vesca extract (FV9 From wild strawberry whole fruit; Extracted by water, concentrated and dried Arctostaphylos uva ursi extract (AUU) From bearberry leaf; Extracted by water and ethanol, concentrated and dried Rubus idaeus extract (RI) From raspberry fruit; Extracted by water, concentrated and spray dried Primary sebocytes were derived from the forehead of a 48-year-old Chinese male. The same cell line was used in all experiments. Characterisation Methods Flow cytometry experiments were conducted on the BD LSR Fortessa X-20 as follows: Sebocytes stained with a lipid dye (AdipoRed™) were first analyzed according to size and granularity with only single cells selected for AdipoRed™ signal intensity measurement. The AdipoRed™ signal was measured using the 488 nm FITC blue laser and the value for the average fluorescence intensity of 10,000 cells obtained. The average fluorescence intensity is a measure of the average lipid quantity in 10,000 sebocytes. Cells treated with compositions of the invention were compared to vehicle-treated cells to determine the percentage of lipid reduction. Primary Sebocytes Culture Primary sebocytes were cultured to 80% confluency in Complete Culture Medium with Y-27632 (CCMY) consisting of 3:1 DMEM (Gibco, 11995-065) / F12 (Gibco, 31765-035), supplemented with 10% fetal bovine serum (Hyclone, SV30160.03), 1x Penstrep (Gibco, 15140-122), 0.2 pg / mL Epidermal Growth Factor (PeproTech, AF-100-15-1MG), 1 pg / mL Hydrocortisone (Sigma-Aldrich, H0888), 10-9 M cholera toxin (Sigma-Aldrich, C8052-2MG) and 10 pM Y-27632 (Tocris, 1254 / 10) at 37°C with 5% CO2. The cells were washed with PBS buffer [5 mL for a 10 cm culture plate] and then incubated at 37°C with 0.125% Trypsin-EDTA (Gibco, 15400054) [2 mL of Trypsin for a 10 cm culture plate] for 5-10 minutes. When all the cells had detached, neutralisation media consisting of DMEM with 10% FBS and 1x Penstrep (2 mL of neutralisation media for a 10 cm culture plate) was added, and the cells were transferred to a 15 mL conical tube and centrifuged at 1,000 rpm for 5 minutes. After centrifugation, a cell pellet was formed, the supernatant was discarded and the cells were resuspended in culture medium. The cells were cultured in a CelCulture CO2 Incubator VOL (Esco Lifesciences). Cells were counted by loading onto a hemocytometer, with the cells observed using a CKX41 Inverted Microscope (Olympus) and manually counted. General Test Protocol A test composition was added to the well of a 24 well plate to achieve a final concentration of 10 pM for the compound (4 pL of a 10 mM stock solution made up in DMSO into 396 pL of culture media) or 31.25 pg / mL for the extract (4 pLof a 3125 pg / mL stock solution made up in DMSO into 396 ul of culture media). Primary sebocytes were seeded at 60 x 106 cells per well (396 pL) in culture media. The cells were incubated for 3 days at 37°C and 5% CO2. The media was discarded, AdipoRed™ dye (0.06 %v / v in PBS) was added and the cells incubated at 37°C for 20 minutes. The staining solution was discarded, trypsin (0.125%; 250 pL) was added and the cells incubated at 37°C for 5-10 minutes. When all cells had detached, fixative solution (250 pL; MEM without phenol red, 10% fetal bovine serum and 4% paraformaldehyde) was added and the cells transferred to 5 mL polystyrene tubes. The tubes were stored on ice before flow cytometry. Mean fluorescence intensity of the lipid signal can be obtained from the flow cytometer plot which are used to determine the inhibitory effect of the compounds on the sebocytes. Example 1 The lipid reduction effects of the compositions of the invention were measured against DMSO as a negative control, and against the known lipid-reducing compound epigallocatechin gallate (EGCG) as a positive control. The results are shown in Table 3 and Figure 1. The results demonstrate that a composition comprising a xanthone compound (alpha-mangostin, beta-mangostin and 9-hydroxycalabaxanthone) and a plant extract (Rubus idaeus extract (RI)) provides improved lipid reduction in comparison to the individual compound or extract. The results demonstrate a synergistic effect for the composition against the individual compounds. Table 3: Percentage reduction in mean fluorescence intensity vs DMSO Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 1 DMSO 00.0 2 EGCG 23.2 4 a-Mangostin (AM) 29.1 5 P-Mangostin (BM) 27.5 6 9-Hydroxycalabaxanthone (9H) 30.2 7 Rubus idaeus (RI) 1.6 8 AM + RI 33.2 9 BM + RI 32.0 10 9H + RI 34.7 Example 2 The lipid reduction effects of the compositions of the invention were measured against DMSO as a negative control, and against the known lipid-reducing compounds epigallocatechin gallate (EGCG) as positive control. The results are shown in Table 4 and Figures 2-4. The results demonstrate that a composition comprising a xanthone compound (a-mangostin (AM), p-mangostin (BM), or 9-hydroxycalabaxanthone (9H)) and a plant extract (Arctostaphylos Uva Ursi, Hedera helix, or Wolfiporia extensa) provides improved lipid reduction in comparison to the individual compound or extract. The results demonstrate a synergistic effect for the composition against the individual compounds. Table 4: Percentage reduction in mean fluorescence intensity vs DMSO Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 1 DMSO (vehicle) 00.0 2 |— / ""V L / xJi 28.8 3 a-Mangostin (AM) 22.4 4 P-Mangostin (BM) 28.0 5 9-Hydroxycalabaxanthone (9H) 28.1 6 Arctostaphylos Uva Ursi (AUU) 8.2 7 Hedera Helix (HH) 5.2 8 Wolfiporia extensa (WE) 2.2 9 AM + AUU 35.9 10 BM + AUU 44.0 11 9H + AUU 44.4 12 AM + HH 37.8 13 BM + HH 45.3 14 9H + HH 43.5 15 AM + WE 40.8 16 BM + WE 50.8 17 9H + WE 35.1 Example 3 5 The lipid reduction effects of the compositions of the invention were measured against DMSO as a negative control, and against the known lipid-reducing compounds epigallocatechin gallate (EGCG) as positive control. The results are shown in Table 5 and Figure 5. The results demonstrate that a composition comprising a xanthone compound (a-mangostin 10 (AM), p-mangostin (GM), or 9-hydroxycalabaxanthone (9H)) and a plant extract (Fragaria vesca (FV)) provides improved lipid reduction in comparison to the individual compound or extract. The results demonstrate a synergistic effect for the composition against the individual compounds. 15 Table 5: Percentage reduction in mean fluorescence intensity vs DMSO Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 1 DMSO (vehicle) 00.0 2 EGCG 23.2 Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 3 a-Mangostin (AM) 29.1 4 P-Mangostin (GM) 27.5 5 9-Hydroxycalabaxanthone (9H) 30.2 6 Fragaria vesca (FV) 10.0 7 AM + FV 38.3 8 BM + FV 34.2 9 9H + FV 37.5 Example 4 The lipid reduction effects of the compositions of the invention were measured against DMSO as a negative control, and against the known lipid-reducing compounds epigallocatechin 5 gallate (EGCG) as positive control. The results are shown in Table 6 and Figure 6. The results demonstrate that a composition comprising a xanthone compound (3-isomangostin (3-lso) or fuscaxanthone C (FC)) and a plant extract (Rubus idaeus (RI)) provides improved lipid reduction in comparison to the individual compound or extract. The 10 results demonstrate a synergistic effect for the composition against the individual compounds. For reference the data is also presented for the use of ellagic acid (EA) alone and with the plant extract. 15 Table 6: Percentage reduction in mean fluorescence intensity vs DMSO Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 1 DMSO (vehicle) 00.0 2 EGCG 26 3 3-lsomangostin (3-lso) 34.1 4 Fuscaxanthone C (FC) 33.7 5 Ellagic acid (EA) 1.1 6 Rubus idaeus (RI) 15.9 7 3-lso + EA 39.2 8 3-lso + RI 40.7 9 FC + EA 43.8 10 FC + RI 44.0 Example 5 The lipid reduction effects of the compositions of the invention were measured against DMSO as a negative control, and against the known lipid-reducing compounds epigallocatechin gallate (EGCG) as positive control. The results are shown in Table 7 and Figure 7. The results demonstrate that a composition comprising a xanthone compound (3-isomangostin (3-lso) or fuscaxanthone C (FC)) and a plant extract (Ilex aquifolium or Wolfiporia extensa) provides improved lipid reduction in comparison to the individual compound or extract. The results demonstrate a synergistic effect for the composition against the individual compounds. Table 7: Percentage reduction in mean fluorescence intensity vs DMSO Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 1 DMSO (vehicle) 00.0 2 EGCG 11.7 3 3-lsomangostin (3-lso) 25.9 4 Fuscaxanthone C (FC) 27.4 5 Ilex qquifolium (IA) +0.4 6 Wolfiporia extensa (WE) +2.0 7 3-lso + IA 29.5 8 3-lso + WE 28.6 9 FC + IA 30.6 10 FC + WE 28.6 Example 6 The lipid reduction effects of the compositions of the invention were measured against DMSO as a negative control, and against the known lipid-reducing compounds epigallocatechin gallate (EGCG) as positive control. The results are shown in Table 8 and Figure 8. The results demonstrate that a composition comprising a xanthone compound (3-isomangostin (3-lso) or fuscaxanthone C (FC)) and a plant extract (Fragaria vesca (FV)) provides improved lipid reduction in comparison to the individual compound or extract. The results demonstrate a synergistic effect for the composition compared to the individual compounds. Table 8: Percentage reduction in mean fluorescence intensity vs DMSO Entry Composition Percentage Reduction in Mean Fluorescence Intensity (Against DMSO Control) 1 DMSO (vehicle) 00.0 2 |— S’"* / y LzxJi 26.2 3 3-lsomangostin (3-lso) 42.9 4 Fuscaxanthone C (FC) 39.1 5 Fragaria vesca (FV) 17.5 6 3-lso + FV 52.7 7 FC + FV 50.8 References 5 A number of publications are cited above in order to more fully describe and disclose the invention and the state of the art to which the invention pertains. Full citations for these references are provided below. The entirety of each of these references is incorporated herein. 10 Cai et al. Drug Metabolism and Disposition 2021, 49, 353 Chaika et al. ScienceRise: Pharmaceutical Science 2020, 6, 74 Cheng etal. Int. J. Biochem. Cell Biol., 2010, 42, 81 Langcake etal. Phytochemistry 1979, 18, 1025 Palu et al. Molecules 2019, 24, 4413 15 Tatia et al. Rev. Chim. 2019, 70, 1157 WO 2020 / 263188 Zhao et al. J. Ethnopharmacol. 2015, 169, 210

Claims

1. A composition comprising:(a) a xanthone compound according to formula (I), or a pharmaceutically or cosmetically acceptable salt, prodrug, solvate, tautomer or stereoisomer thereof; and(b) a plant or fungal extract selected from extracts of plants belonging to the genus Arctostaphylos, Hedera, Ilex, Fragaria and Rubus and extracts of the fungus Wolfiporia,R1 O R8wherein:R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, Cm haloalkyl, and C2-10 alkenyl;or alternatively R2 and R3, or R1 and R2, or R6 and R7, or R7 and R8, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH;R9, R10 and R11 are independently selected from H, Cm alkyl and C1-4 haloalkyl, and each RH is C1-6 alkyl or C2-6 alkenyl.

2. The composition of claim 1, wherein:R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, SH, OR9, CO2R10, OC(=O)R11, C1-6 alkyl, CF3, and C2-6 alkenyl;or alternatively R2 and R3, or R1 and R2, together with the carbon ring atoms to which they are connected, form a 5- or 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH; andR9, R10 and R11 are independently selected from H, Cm alkyl, and CF3.

3. The composition of claim 2, wherein:R1, R2, R3, R4, R5, R6, R7, and R8 are independently selected from H, F, OH, OR9, CO2R10, OC(=O)R11, Me, Et, and C2-6 alkenyl; andR9, R10 and R11 are independently selected from H, Me and Et, and each RH is independently selected from Me and Et.

4. The composition of any of claims 1 to 3, wherein:R4 and / or R5 are H or OH, such as R4 and / or R5 are H.

5. The composition of any of claims 1 to 4, wherein:R2 and / or R6 and / or R8 are C2-6 alkenyl, such as where (i) R8 is C2-6 alkenyl, and optionally one of R2 and / or R6 is C2-6 alkenyl; or (ii) R8 is C2-6 alkenyl, and optionally R2 and R3 together with the carbon ring atoms to which they are connected, form a 6-membered oxygen-containing heterocyclic ring, which ring is optionally substituted with one or more groups RH.

6. The composition of claim 1, wherein the xanthone compound is a compound of formula (ll-l) or (ll-ll):wherein:R1A, R3A, R6A, and R7A are independently selected from H, OH, OR9A, CO2R10A, OC(=O)R11A, C1-4 alkyl, and C1-4 alkenyl;R9, R10 and R11 are independently selected from H, and C1-4 alkyl;each RHA is independently selected from H and C1-4 alkyl;and the dashed line represents a double bond or single bond within the ring.

7. The composition of claim 6, wherein:R1A, R3A, R6A, and R7A are independently selected from H, OH, OMe, such as R1A, R3A, R6A, and R7A are independently selected from OH and OMe; and R9, R10 and R11 are independently selected from H, Me and Et; and each RHA is independently Me.

8. The composition of claim 7, wherein the xanthone compound is selected from a-mangostin, p-mangostin, 9-hydroxycalabaxanthone, 3-isomanogostin, and fuscaxanthone C, such as a-mangostin, p-mangostin and 9-hydroxycalabaxanthone.

9. The composition of any of claims 1 to 8, wherein the plant extract is selected from Arctostaphylos uva ursi extract, Hedera helix extract, Ilex aquifoliumextract, Fragaria vesca extract, Fragaria x ananassa extract, Rubus idaeus extract, and Wolfiporia extensa extract.

10. The composition of claim 1, wherein the xanthone compound is a-mangostin and the plant extract is Rubus Idaeus extract.

11. The composition of any one of claim 1 to 10, wherein the xanthone compound is present in an amount of from 0.0005 wt% to 10 wt%, preferably 0.1 wt% to 5 wt%, more preferably 0.1 wt% to 3 wt%, such as 0.2 wt% to 2 wt%.

12. The composition of any one of claim 1 to 11, wherein the plant extract is present in an amount of from 0.005 wt% to 50 wt%, preferably 0.005 wt% to 30 wt%, such as 0.05 wt% to 10 wt%, and more preferably 0.1 wt% to 3 wt%.

13. The composition of any one of claim 1 to 12, further comprising one or more components selected from solvents, oils, surfactants, thickeners, humectants, and preservatives.

14. The composition of any one of claim 1 to 13, further comprising one or more components selected from emollients, anti-inflammatory agents, antioxidants and UV blocking agents.

15. A skin care product selected from skin / hand lotion, skin / hand cream, skin / hand ointment, skin / hand paste, skin toner, shaving gel, shaving cream, sunscreen, deodorant, antiperspirant, suntan lotion, after sun, aftershave, body oil, bath oil and bubble bath, the skin care product comprising the composition of any one of claims 1 to 14.

16. A hair care products selected from conditioner, hair detangling lotion, styling gel, styling cream, styling wax, styling lotion, mousse, spray gel, hair tonic, spritz and pomade, the hair care product comprising the composition of any one of claims 1 to 14.

17. A cosmetic method for decreasing lipid production in the skin of an individual, the method comprising contacting the skin with the composition of any one of claims 1 to 14.

18. A method for decreasing lipid production in sebocytes or in the skin of an individual, the method comprising contacting the skin with the composition of any one of claims 1 to 14, wherein the method is not a method of treatment.

19. A method for decreasing lipid production in sebocytes, the method comprising contacting the sebocytes with the composition of any one of claims 1 to 14.

20. The composition of any one of claims 1 to 14 for use in decreasing lipid production in sebocytes.

21. The composition of any one of claim 1 to 14 for use in a method of treatment.

22. The composition of any one of claim 1 to 14 for use in a method of treating a skindisease or disorder associated with over-production of lipids in the skin.

23. The composition for use of claim 22, wherein the disease or disorder is selected from acne and vulgarism rosacea.

24. Use of the composition of any one of claim 1 to 14 for decreasing lipid production in sebocytes.

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