Β-secretase inhibitor and composition for preventing or treating dementia

Abstract

The present invention pertains to a β-secretase inhibitor. The present invention also pertains to a composition for preventing or treating dementia. Specifically, the present invention pertains to a β-secretase containing at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient.

Description

β-Secretase inhibitor and composition for preventing or treating dementia

[0001] The present invention relates to a β-secretase inhibitor and a composition for preventing or treating dementia.

[0002] Amyloid beta is produced by cleaving the amyloid precursor protein (APP) with the beta-secretase enzyme. It has been shown that the accumulation of amyloid beta in the brain leads to a deterioration of brain function. The accumulation of amyloid degeneration in cerebral blood vessels, resulting in vascular abnormalities, is called cerebral amyloid angiopathy. Cerebral amyloid angiopathy, along with hypertension, is considered to be a factor in cognitive decline (vascular dementia) caused by cerebral hemorrhage.

[0003] Dementia is primarily classified as Alzheimer's disease, dementia with Lewy bodies, and vascular dementia. Alzheimer's disease is a well-known disease that causes deterioration of brain function, and amyloid beta accumulation in the brain can occur during its onset and progression. However, the accumulation of amyloid beta in the brain is not necessarily required for the onset of Alzheimer's disease. While amyloid angiopathy frequently coexists with Alzheimer's pathology, there have also been reports of cognitive decline due to amyloid angiopathy alone, without Alzheimer's pathology. Dementia with Lewy bodies develops when α-synuclein, which plays an important role in neurons, aggregates and accumulates in the brain (Lewy bodies) (Bassil, et al., Neuron. 105(2):260-275, 2020). It has also been suggested that the accumulation of amyloid beta in the brain may be a contributing factor to dementia with Lewy bodies (Shimada, et al., Mov Disord. 28(2):169-75, 2013). Furthermore, the accumulation of amyloid beta in the brain may lead to cerebral amyloid angiopathy, which is a contributing factor to vascular dementia.

[0004] Turmeric and its extracts have been known to have various physiological activities. For example, it has been reported that turmeric extracts or their components are used to improve Alzheimer's disease or Alzheimer's-type dementia (Patent Documents 1 and 2). It has also been reported that α-turmerone, β-turmerone, and ar-turmerone in turmeric extracts (hexane extract, ethyl acetate extract) inhibit β-secretase activity in a cell-free system (Patent Document 3). It has also been reported that curcumin, a component of turmeric, increases APOE expression, promotes amyloid β clearance, inhibits APP synthesis, and suppresses intracerebral inflammation, providing prevention and treatment of Alzheimer's disease (Patent Document 4).

[0005] Patent No. 6998212 Publication Patent No. 6814240 Publication Patent No. 6998212 Publication Patent No. 6814240

[0006] It is believed that inhibiting the activity of β-secretase, which is involved in the production of amyloid β, can inhibit the accumulation of amyloid β in the brain, improve brain function, or prevent the decline of brain function. Therefore, an object of the present invention is to provide new means and methods for inhibiting β-secretase activity, and further to provide means and methods for preventing or treating dementia by inhibiting the accumulation of amyloid β in the brain. It should be noted that there have been no reports to date that turmeronol A, turmeronol B, and bisacrolone, which are components contained in turmeric extract, inhibit the activity of β-secretase and reduce the accumulation of amyloid β in the brain.

[0007] In the course of intensive research into the effects of turmeric extract, the inventors discovered that turmeric extract and the components contained therein, turmeronol A, turmeronol B, and bisacron, each inhibit the activity of β-secretase. This led to the discovery that turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron can inhibit the accumulation of amyloid β in the brain, and as a result, can prevent or treat dementia caused by the accumulation of amyloid β in the brain, thereby completing the present invention.

[0008] Thus, the present invention encompasses, for example, the following: [1] A β-secretase inhibitor containing at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. [2] The β-secretase inhibitor according to [1], consisting solely of at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. [3] A composition for preventing or treating dementia, containing at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. [4] The composition according to [3], consisting solely of at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. [5] A composition for preventing or treating dementia, containing turmeric extract as an active ingredient. [6] The composition according to [5], consisting solely of turmeric extract as an active ingredient. [7] The composition according to [5], wherein the turmeric extract comprises a turmeric extract extracted with at least one extraction solvent selected from the group consisting of water and hydrophilic organic solvents. [8] The composition according to [5], wherein the turmeric extract comprises a mixture of a turmeric extract obtained by extraction with water and a turmeric extract obtained by extraction with supercritical carbon dioxide. [9] The composition according to [5], wherein the turmeric extract contains at least one of turmeronol A, turmeronol B, and bisacron.

[10] The composition according to [3] or [5], wherein the dementia is dementia with Lewy bodies or vascular dementia.

[11] The composition according to [3] or [5], wherein the dementia is not Alzheimer's dementia.

[0009]

[12] Use of at least one of turmeronol A, turmeronol B, and bisacron for the production of a β-secretase inhibitor.

[13] Use of at least one of turmeronol A, turmeronol B, and bisacron for the production of a composition for the prevention or treatment of dementia.

[14] Use of turmeric extract for the production of a composition for the prevention or treatment of dementia.

[0010]

[15] A method for suppressing β-secretase activity in a subject, comprising administering at least one of turmeronol A, turmeronol B, and bisacron to a subject in need of such suppression, and suppressing β-secretase activity in the subject.

[16] A method for preventing or treating dementia in a subject, comprising administering at least one of turmeronol A, turmeronol B, and bisacron to a subject in need of such suppression, and preventing or treating dementia in the subject.

[17] A method for preventing or treating dementia in a subject, comprising administering a turmeric extract to a subject in need of such suppression, and preventing or treating dementia in the subject.

[0011]

[18] At least one compound selected from turmeronol A, turmeronol B, and bisacron for use in inhibiting β-secretase activity.

[19] At least one compound selected from turmeronol A, turmeronol B, and bisacron for use in the prevention or treatment of dementia.

[20] A turmeric extract for use in the prevention or treatment of dementia.

[0012] According to one or more embodiments of the present invention, there is provided a β-secretase inhibitor. According to another one or more embodiments of the present invention, there is provided a composition for preventing or treating dementia.

[0013] 1 is a graph showing that turmeric extract inhibits β-secretase activity in mouse BV-2 microglial cells, and that turmeronol A, turmeronol B, or bisaclone inhibits β-secretase activity in mouse BV-2 microglial cells.

[0014] This specification includes the disclosure of Japanese Patent Application No. 2023-116111, filed on July 14, 2023, from which this application claims priority.

[0015] The present invention is based on the finding that administration or ingestion of turmeric extract, or its components turmeronol A, turmeronol B, and / or bisacron, inhibits the activity of β-secretase, an enzyme that produces amyloid β protein, a causative agent of dementia, thereby inhibiting the accumulation of amyloid β in the brain. While cerebral amyloid angiopathy alone did not cause cognitive decline in human studies, it has been reported that there was a difference in cognitive decline between those with severe and mild Aβ accumulation in the brain parenchyma (Malek-Ahmadi, et al., J Alzheimers Dis. 67(1):411-422, 2019). Therefore, inhibiting Aβ accumulation in the brain parenchyma may be able to prevent or treat dementia, particularly vascular dementia.

[0016] Therefore, in one aspect, the present invention provides a β-secretase inhibitor containing, as an active ingredient, turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron. In yet another aspect, the present invention provides a composition for preventing or treating dementia, containing, as an active ingredient, turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron.

[0017] <Composition Containing Turmeric Extract> The composition of the present invention contains turmeric extract. In the present invention, turmeric extract refers to an extract (turmeric extract) of a plant material derived from a plant of the genus Curcuma in the Zingiberaceae family, using an extraction solvent. Turmeric extract is not limited to solvent extracts obtained by extraction with an extraction solvent, but also includes solvent extracts that have been further fractionated and purified by column chromatography or the like. The turmeric extract used in the present invention can be in the form of an extract liquid after the extraction procedure (including fractionation and purification if fractionation and purification is performed), a concentrate obtained by partially removing the solvent from the extract liquid, or a dried product obtained by removing the solvent from the extract liquid. The solvent can be removed from the extract by volatilizing the solvent by heating and / or reducing pressure, etc. The heating and pressure reduction methods are not particularly limited, and for example, conventionally known methods can be used.

[0018] Examples of the plant material include the rhizomes of plants of the genus Curcuma in the Zingiberaceae family, such as Curcuma longa (turmeric), Curcuma aromatica, Curcuma zedoaria, Curcuma phaeocaulis, Curcuma kwangsiensis, Curcuma wenyujin, and / or Curcuma xanthorrhiza. The rhizomes of Curcuma longa are particularly preferred. The rhizomes may be collected from the ground, and an appropriate portion of the rhizome may be used intact, cut to an appropriate size or shape, or pulverized. These plant materials may be appropriately dried.

[0019] The extraction solvent can be at least one selected from the group consisting of water and hydrophilic organic solvents. The at least one extraction solvent selected from the group consisting of water and hydrophilic organic solvents can be water, a hydrophilic organic solvent, or a mixed solvent of water and a hydrophilic organic solvent. The hydrophilic organic solvent can also be a mixed solvent of multiple hydrophilic organic solvents. "Water" also includes hot water. Hot water, for example, can be hot water at 95°C or higher. The hydrophilic organic solvent can include at least one alcohol (or a mixed solvent of multiple alcohols). The alcohol is not particularly limited, but ethanol is preferred. When a mixed solvent of alcohol and water is used as the extraction solvent, the mixing ratio is not particularly limited, but is preferably in the range of 10:90 to 90:10 by weight, and more preferably 20:80 to 50:50 by weight. Supercritical carbon dioxide can also be used as the extraction solvent.

[0020] The method for extracting turmeric extract from plant materials is not particularly limited, and any extraction method commonly used in the art can be employed.

[0021] In the present invention, the turmeric extract may contain one type of turmeric extract, or may contain two or more types of turmeric extracts obtained using different extraction solvents and / or extraction methods. In one embodiment, the turmeric extract comprises a mixture of a turmeric extract obtained using at least one extracting solvent selected from the group consisting of water and a hydrophilic organic solvent, and a turmeric extract obtained using supercritical carbon dioxide, for example, a mixture of a turmeric extract obtained by extraction with water and a turmeric extract obtained by extraction with supercritical carbon dioxide. The ratio of each extract in the mixture is not particularly limited, and may be, for example, a weight ratio of 1:0.01 to 1:1.

[0022] In a preferred embodiment, the turmeric extract comprises at least one of an extract with water, such as hot water, and an extract with supercritical carbon dioxide.

[0023] In one embodiment, the turmeric extract used in the present invention contains at least one of turmeronol A, turmeronol B, and bisacronol.

[0024] <Agent or composition containing at least one of turmeronol A, turmeronol B, and bisacron> The agent or composition according to the present invention contains at least one of turmeronol A, turmeronol B, and bisacron.

[0025] Turmeronol A and turmeronol B are compounds each having the following planar structure.

[0026]

[0027]

[0028] In the present invention, turmeronol A and turmeronol B each have the above-mentioned planar structure, and may be any optical isomer or a mixture of multiple optical isomers.

[0029] It is known that the configuration of the 6-carbon atom in the partial structure of 2-methyl-2-hepten-4-one in natural products isolated from turmeric extracts, such as turmeronol A and turmeronol B, is S. However, in the present invention, turmeronol A and turmeronol B may have the above-mentioned planar structure, and the configuration may be S, R, or a mixture of S and R.

[0030] In the present invention, bisacron is a compound having the following planar structure: Bisacron has an asymmetric carbon at the position indicated by the * mark in the planar structural formula and may contain multiple optical isomers, but in the present invention, bisacron may be any optical isomer or a mixture of two or more optical isomers.

[0031]

[0032] At least one of turmeronol A, turmeronol B, and bisacron (hereinafter sometimes referred to as "active compound") used in the present invention may be derived from a plant or may be artificially synthesized. For example, optically active (+)-turmeronol A can be synthesized by the method described in Biosci Biotechnol Biochem. 1993; 57(7):1137-40.

[0033] The active compound used in the present invention is more preferably derived from a plant material, more preferably derived from a plant of the genus Curcuma of the Zingiberaceae family. Specific examples of plants of the genus Curcuma of the Zingiberaceae family and their parts are as described above. The active compound can be obtained from parts such as the rhizomes of plants of the genus Curcuma of the Zingiberaceae family.

[0034] The active compounds can be extracted from plant materials containing them by the extraction method described above. The active compounds may be in the form of a plant extract, particularly a turmeric extract with at least one extraction solvent selected from the group consisting of water and hydrophilic organic solvents.

[0035] Furthermore, fractions containing highly purified active compounds from plant extracts containing active compounds may be used in the present invention or incorporated into the compositions of the present invention. For example, the plant extract containing the active compounds may be subjected to liquid-liquid partitioning between ethyl acetate and water, and the active compounds may be highly purified in the ethyl acetate fraction. Alternatively, the plant extract containing the active compounds or fractions thereof may be subjected to a purification process by chromatography to obtain highly purified active compounds. Chromatography methods that can be used include reverse-phase column chromatography and normal-phase thin-layer chromatography.

[0036] The plant extract or fraction thereof containing the active compound may be processed by a conventional method such as drying, powdering, granulation, or solution.

[0037] <β-Secretase Inhibitor of the Present Invention> In one aspect, the present invention relates to a β-secretase inhibitor containing at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. In another aspect, the present invention relates to a β-secretase inhibitor containing turmeric extract as an active ingredient. By administering the agent of the present invention according to this aspect to a subject such as a human, the activity or function of β-secretase can be suppressed or inhibited in the subject. Here, each of the active ingredients is administered in an amount effective for suppressing or inhibiting β-secretase activity. Preferred administration routes include oral, intranasal, intracerebral, and intrathecal administration, with oral or intranasal administration being more preferred, and oral administration being particularly preferred. The agent of the present invention suppresses the activity of β-secretase in the brain, thereby suppressing the production of amyloid precursor protein (APP), and as a result, the accumulation of amyloid β in the brain.

[0038] β-secretase activity can be measured by methods known in the art, and kits that can be used for activity measurement are commercially available. Inhibition of β-secretase activity refers to activity that is significantly inhibited compared to the activity in the absence of the inhibitor of the present invention, for example, activity that is inhibited to 95% or less, preferably 90% or less, and more preferably 80% or less compared to the activity in the absence of the inhibitor of the present invention.

[0039] <Composition of the Present Invention> In one aspect, the present invention relates to a composition for preventing or treating dementia, comprising at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. In another aspect, the present invention relates to a composition for preventing or treating dementia, comprising turmeric extract as an active ingredient. By administering the composition of the present invention according to these aspects to a subject, such as a human, dementia can be prevented or treated in the subject. Here, each of the active ingredients is administered in an amount effective for preventing or treating dementia. Preferred administration routes include oral, intranasal, intracerebral, and intrathecal administration, with oral or intranasal administration being more preferred, and oral administration being particularly preferred. The composition of the present invention can prevent or treat dementia by inhibiting the activity of β-secretase in the brain, thereby suppressing the production of amyloid precursor protein (APP), and consequently suppressing the accumulation of amyloid β in the brain.

[0040] Dementia is known as a disorder in which cognitive functions such as memory and thinking decline due to various causes, interfering with daily and social life. In the present invention, this refers to dementia that can be prevented or treated by suppressing the accumulation of amyloid beta in the brain. Such dementia includes Alzheimer's disease, dementia with Lewy bodies, vascular dementia, etc. In one embodiment, the target dementia is dementia with Lewy bodies or vascular dementia. In another embodiment, the target dementia is not Alzheimer's disease.

[0041] Prevention or treatment of dementia includes preventing or delaying the onset of dementia, treating or delaying the progression of dementia, and improving at least one symptom of dementia (e.g., memory impairment, aphasia, disorientation, impaired comprehension / judgment, etc.). Diagnosis of dementia and its severity is known in the art and can be performed by neuropsychological tests, brain imaging tests (CT, MRI, etc.), etc.

[0042] The agent or composition of the present invention may be in the form of a pharmaceutical, food or drink, feed, food additive, feed additive, or the like, and is more preferably a pharmaceutical or food or drink. Food and drink also include those in the form of functional food, food for specified health use, nutritional supplement, or the like. The agent or composition of the present invention is in the form of a composition that is ingested or administered orally, intranasally, intracerebrally, or intrathecally, preferably in the form of a composition that is ingested or administered orally or intranasally, and more preferably in the form of a composition that is ingested or administered orally.

[0043] In the agent or composition of the present invention according to an embodiment, which contains at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient, the content of at least one of turmeronol A, turmeronol B, and bisacron per daily intake or dosage of the agent or composition of the present invention, preferably per daily intake or dosage for one human, particularly an adult, is preferably 17 μg or more, preferably 28 μg or more, more preferably 43 μg or more, even more preferably 57 μg or more, and most preferably 77 μg or more of turmeronol A, and / or 5 μg or more, preferably 8 μg or more, more preferably 12 μg or more, even more preferably 16 μg or more, and most preferably 22 μg or more of turmeronol B, and / or 80 μg or more, preferably 133 μg or more, more preferably 200 μg or more, even more preferably 267 μg or more, and most preferably 360 μg or more of bisacron, in order to effectively obtain the effect of inhibiting β-secretase activity and the effect of preventing or treating dementia. Here, the "daily intake or administration amount" typically refers to 0.1 g to 500 g of the agent or composition of the present invention when ingested or administered orally, nasally, intracerebrally, or intrathecally, preferably orally or nasally, more preferably orally. The agent or composition of the present invention may be ingested or administered continuously, or may be ingested or administered as needed.

[0044] The content of the turmeric extract in the composition of the present invention according to the embodiment containing the turmeric extract as an active ingredient is such that the total amount of turmeronol A and turmeronol B is 100 μg or more per daily intake or administration of the composition of the present invention, preferably per daily intake or administration for one human, particularly one adult, and / or the amount of turmeronol A is 17 μg or more, preferably 28 μg or more, more preferably 43 μg or more, even more preferably 57 μg or more, and most preferably 80 μg or more. In order to effectively achieve the β-secretase inhibitory effect and the preventive or therapeutic effect for dementia, it is preferable to contain turmeronol B in an amount of 5 μg or more, preferably 8 μg or more, more preferably 12 μg or more, even more preferably 16 μg or more, and most preferably 20 μg or more, and / or bisacronol in an amount of 80 μg or more, preferably 133 μg or more, more preferably 200 μg or more, even more preferably 267 μg or more, and most preferably 360 μg or more. Here, the "daily intake or administration amount" typically refers to 0.1 g to 500 g of the composition of the present invention when administered orally, intranasally, intracerebrally, or intrathecally, preferably orally or intranasally, more preferably orally. The composition of the present invention may be ingested or administered continuously or as needed.

[0045] In an embodiment, the agent or composition of the present invention containing at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient may be at least one of the compounds turmeronol A, turmeronol B, and bisacron itself, or may contain the compound and at least one other ingredient. When the agent or composition of the present invention contains the compound and at least one other ingredient, it may be an agent or composition in which the compound and at least one other ingredient are mixed, or an agent or composition in which the compound and at least one other ingredient are formulated by an appropriate means, or an agent or composition in which the compound and at least one other ingredient are further formulated and mixed with other ingredients. In one embodiment, the agent or composition of the present invention is an agent or composition consisting solely of at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient. The phrase "consisting of at least one of turmeronol A, turmeronol B, and bisacron as the active ingredient" means that the active ingredient exhibiting the desired activity (beta-secretase inhibitory effect, or dementia prophylactic or therapeutic effect) is at least one of turmeronol A, turmeronol B, and bisacron, and does not contain any other active ingredients. However, components other than the active ingredients, such as carriers and excipients, may also be contained in the agent or composition of the present invention.

[0046] The composition of the present invention, according to an embodiment, containing the turmeric extract as an active ingredient may be the turmeric extract itself, or may be a composition containing the turmeric extract and at least one other ingredient. When the composition of the present invention contains the turmeric extract and at least one other ingredient, it may be a composition obtained by mixing the turmeric extract and at least one other ingredient, a composition obtained by formulating the turmeric extract and at least one other ingredient by an appropriate means, or a composition obtained by mixing a formulation of the turmeric extract and at least one other ingredient with other ingredients. In one embodiment, the composition of the present invention is a composition consisting solely of turmeric extract as the active ingredient. The phrase "consisting solely of turmeric extract as the active ingredient" means that the turmeric extract is the only active ingredient exhibiting the desired activity (beta-secretase inhibition or dementia prevention or treatment), and no other active ingredients are present. However, components other than the active ingredient, such as carriers or excipients, may also be contained in the composition of the present invention.

[0047] The form of the agent or composition of the present invention is not particularly limited, and may be, for example, any form such as liquid, fluid, gel, semi-solid, or solid.

[0048] The at least one other component that may be contained in the agent or composition of the present invention is not particularly limited, but preferably includes a component that is acceptable in the final form of a pharmaceutical product, food or drink, nutritional supplement, supplement, feed, food additive, feed additive, etc., and that can be orally ingested.

[0049] Such other ingredients include, for example, sweeteners, acidulants, vitamins, minerals, thickeners, emulsifiers, antioxidants, water, etc. Furthermore, colorants, flavorings, preservatives, antiseptics, fungicides, and other physiologically active substances may also be added as necessary.

[0050] Examples of sweeteners include monosaccharides and disaccharides such as glucose, fructose, sucrose, lactose, maltose, palatinose, trehalose, and xylose, isomerized sugars (glucose-fructose corn syrup, fructose-glucose corn syrup, mixed sugar isomerized sugars, etc.), sugar alcohols (erythritol, xylitol, lactitol, palatinit, sorbitol, reduced starch syrup, etc.), honey, and high-intensity sweeteners (sucralose, acesulfame potassium, thaumatin, stevia, aspartame, etc.).

[0051] The acidulant may be citric acid, malic acid, gluconic acid, tartaric acid, lactic acid, phosphoric acid, or salts thereof, and one or more of these may be used.

[0052] Vitamins include vitamin A, vitamin B1, vitamin B2, vitamin B6, vitamin E, niacin, inositol, etc.

[0053] Examples of minerals include calcium, magnesium, zinc, and iron.

[0054] Examples of thickeners include carrageenan, gellan gum, xanthan gum, gum arabic, tamarind gum, guar gum, locust bean gum, karaya gum, agar, gelatin, pectin, soybean polysaccharides, and carboxymethylcellulose (CMC).

[0055] Examples of emulsifiers include glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, lecithin, plant sterols, and saponin.

[0056] Examples of antioxidants include vitamin C, tocopherol (vitamin E), enzyme-treated rutin, etc. The other components can be appropriately blended in amounts within the ranges that would normally be used by those skilled in the art in compositions such as foods and beverages, pharmaceuticals, etc.

[0057] The agent or composition prepared by appropriate means from the agent or composition of the present invention and at least one other ingredient may be in the form of a solid composition such as powder, granules, capsules, or tablets (including coated tablets such as sugar-coated tablets or multi-layer tablets, orally disintegrating tablets, chewable tablets, etc.), or in the form of a liquid composition such as a solution.

[0058] Furthermore, the agent or composition of the present invention is relatively safe and can be easily taken continuously over a long period of time. Therefore, the agent or composition of the present invention can be preferably used in foods and beverages, nutritional supplements, dietary supplements, and feed. In addition to having the above-mentioned functions or activities, the agent or composition of the present invention contains turmeric extract, which has been conventionally taken, and / or at least one of turmeronol A, turmeronol B, and bisacron, which are components contained therein, and is therefore relatively safe. Furthermore, it can be added to various foods and beverages and taken continuously, and is expected to exert the desired function or effect.

[0059] The agent or composition of the present invention is preferably an agent or composition that is taken continuously, specifically, an agent or composition that is taken once or twice a day or more continuously, preferably for 4 weeks or more, more preferably 8 weeks or more, and most preferably 12 weeks or more.

[0060] <Method for inhibiting β-secretase activity> A further aspect of the present invention relates to a method for inhibiting β-secretase activity, comprising administering the turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron to a subject in need of inhibition of β-secretase activity, and inhibiting β-secretase activity in the subject.

[0061] The turmeric extract or at least one of turmeronol A, turmeronol B and bisacron used in the method according to this embodiment may be in the form of the agent of the present invention as described above.

[0062] The subject in the method according to this embodiment is typically a human, but may also be a mammal other than a human.

[0063] In the method according to this embodiment, the route of administration is preferably oral administration, nasal administration, intracerebral administration or intrathecal administration, more preferably oral or nasal administration, and particularly preferably oral administration.

[0064] In the method of this embodiment, the amount of the turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron administered to a subject is not particularly limited, as long as it is an amount effective for inhibiting β-secretase activity. For example, if the subject is an adult, it is preferable to administer the turmeric extract, or at least one of turmeronol A, turmeronol B, and bisacron per adult per day so that the total amount of turmeronol A and turmeronol B is 100 μg or more, and / or turmeronol A is 17 μg or more, preferably 28 μg or more, more preferably 43 μg or more, even more preferably 57 μg or more, and most preferably 80 μg or more, and / or turmeronol B is 5 μg or more, preferably 8 μg or more, more preferably 12 μg or more, even more preferably 16 μg or more, and most preferably 20 μg or more, and / or bisacron is 80 μg or more, preferably 133 μg or more, more preferably 200 μg or more, even more preferably 267 μg or more, and most preferably 360 μg or more.

[0065] The dosage of the agent of the present invention varies depending on the age and weight of the subject, the route of administration / intake, the frequency of administration / intake, and the purpose of administration (e.g., inhibition of β-secretase activity), and can be varied widely at the discretion of those skilled in the art to achieve the desired effect. The proportion of turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron in the agent is not particularly limited and can be appropriately adjusted depending on the ease of production, the desired daily dosage, etc. Because turmeric extract and the compounds contained therein are relatively safe, the dosage can be further increased. The daily dosage may be taken in a single dose or in several divided doses. The frequency of administration / intake is also not particularly limited and can be appropriately selected depending on various conditions such as the route of administration / intake, the age and weight of the subject, and the desired effect.

[0066] <Method for preventing or treating dementia> A further aspect of the present invention relates to a method for preventing or treating dementia, comprising administering the turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron to a subject in need of such prevention or treatment, and preventing or treating dementia in the subject.

[0067] The turmeric extract or at least one of turmeronol A, turmeronol B and bisacron used in the method according to this embodiment may be in the form of the composition of the present invention as described above.

[0068] The subject in the method according to this embodiment is typically a human, but may also be a mammal other than a human.

[0069] In the method according to this embodiment, the route of administration is preferably oral administration, nasal administration, intracerebral administration or intrathecal administration, more preferably oral or nasal administration, and particularly preferably oral administration.

[0070] In the method of this embodiment, the amount of the turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron administered to a subject is not particularly limited, as long as it is an effective amount for preventing or treating dementia. For example, if the subject is an adult, it is preferable to administer the turmeric extract, or at least one of turmeronol A, turmeronol B, and bisacron per adult per day so that the total amount of turmeronol A and turmeronol B is 100 μg or more, and / or turmeronol A is 17 μg or more, preferably 28 μg or more, more preferably 43 μg or more, even more preferably 57 μg or more, and most preferably 80 μg or more, and / or turmeronol B is 5 μg or more, preferably 8 μg or more, more preferably 12 μg or more, even more preferably 16 μg or more, and most preferably 20 μg or more, and / or bisacron is 80 μg or more, preferably 133 μg or more, more preferably 200 μg or more, even more preferably 267 μg or more, and most preferably 360 μg or more.

[0071] The dosage of the composition of the present invention varies depending on the age and weight of the subject, the route of administration / intake, the frequency of administration / intake, and the purpose of administration (e.g., prevention or treatment of dementia), and can be varied widely at the discretion of those skilled in the art to achieve the desired effect. The proportion of turmeric extract or at least one of turmeronol A, turmeronol B, and bisacron in the composition is not particularly limited and can be adjusted appropriately based on ease of production, the desired daily dosage, etc. Because turmeric extract and the compounds contained therein are relatively safe, the dosage can be further increased. The daily dosage may be taken in a single dose or in several divided doses. The frequency of administration / intake is also not particularly limited and can be selected appropriately depending on various conditions such as the route of administration / intake, the age and weight of the subject, and the desired effect.

[0072] [Reference Examples] (1) Methods for Preparing Turmeric Extracts Turmeric extracts were prepared by water extraction and supercritical gas extraction. In the water extraction method, turmeric rhizome parts were extracted with water (including hot water), and the resulting extract was then dried under reduced pressure to remove moisture. In the supercritical gas extraction method, turmeric rhizome parts were contacted with supercritical carbon dioxide, and the extracted components were mixed with vegetable oil. In the following examples, turmeric extracts prepared by each extraction method were mixed at a weight ratio of 8:1.

[0073] (2) Amounts of Turmeronol A, Turmeronol B, and Bisacron in Turmeric Extract The amounts of turmeronol A, turmeronol B, and bisacron in the turmeric extract were measured using HPLC as follows. The amounts of turmeronol A, turmeronol B, and bisacron per gram of turmeric extract were confirmed to be 724 μg, 578 μg, and 2182 μg, respectively.

[0074] Turmeronol A analysis: Turmeric extract was weighed, water and ethyl acetate were added, and the mixture was centrifuged. The ethyl acetate was removed from the resulting supernatant by vacuum distillation, and then the mixture was dissolved in acetonitrile. The resulting liquid was used as the measurement sample and subjected to HPLC. HPLC was performed under the following conditions: Column: L-column ODS 5 μm (4.6 mm φ × 250 mm) Mobile phase: 48% acetonitrile (20 min) ⇒ 100% acetonitrile (5 min) ⇒ 48% acetonitrile (10 min) Flow rate: 1.0 mL / min Column temperature: 40°C Detection wavelength: 238 nm

[0075] Analysis of Turmeronol B Turmeric extract was weighed, water and ethyl acetate were added, and the mixture was centrifuged. The ethyl acetate was removed from the resulting supernatant by vacuum distillation, and the resulting solution was dissolved in acetonitrile. The resulting solution was used as the measurement sample and subjected to HPLC. HPLC was performed under the following conditions: Column: COSMOSIL 5PYE Packed Column (4.6 mm φ x 150 mm) Mobile phase: 57% methanol (30 min) ⇒ 100% methanol (5 min) ⇒ 57% methanol (15 min) Flow rate: 1.0 mL / min Column temperature: 40°C Detection wavelength: 238 nm

[0076] Analysis of Bisacron The turmeric extract was weighed, water and ethyl acetate were added, and the mixture was centrifuged to obtain a supernatant. The ethyl acetate was then removed under reduced pressure from the resulting supernatant, and the mixture was dissolved in acetonitrile. The resulting liquid was used as a measurement sample and subjected to HPLC. HPLC was performed under the following conditions: Column: Wakopak Navi C18-5 (4.6 mm φ x 250 mm) Mobile phase: 30% acetonitrile (20 minutes) ⇒ 20% acetonitrile (5 minutes) ⇒ 80% acetonitrile (10 minutes) Flow rate: 0.7 mL / min Column temperature: 50°C Detection wavelength: 240 nm

[0077] (3) Obtaining Turmeronol A, Turmeronol B, and Bisacron Turmeronol A, Turmeronol B, and Bisacron were purchased as commercially available products from Nagara Science Co., Ltd., and dissolved in dimethyl sulfoxide before use in the test.

[0078] Example 1 Evaluation of the effect of inhibiting β-secretase activity in microglial cells 1 Mouse microglial cells BV-2 were suspended in DMEM medium (containing 10% FBS) and plated in a 100 mm cell culture dish at a cell count of 4.0 × 10 6 The cells were seeded at 100 μg / mL and cultured at 37°C in the presence of 5% CO2. After 48 hours, turmeric extract prepared in the Reference Example was added to the dishes at concentrations of 100 μg / mL, 200 μg / mL, and 400 μg / mL, and cultured for 24 hours. After the culture was completed, the β-secretase activity of the cells was measured according to the protocol included with the Beta-Scretase Activity Assay Kit (Fluorometric) (Abcam: ab65357).

[0079] The results are shown in Figure 1. Figure 1 shows that 200 and 400 μg / mL of turmeric extract inhibited the β-secretase activity of mouse microglial cells BV-2.

[0080] Example 2 Evaluation of the effect of inhibiting β-secretase activity in microglial cells 2 Mouse microglial cells BV-2 were cultured in the same manner as in Example 1. After 48 hours, turmeronol A, turmeronol B, and bisacron were added to the dish at concentrations of 6.25 μM, 12.5 μM, and 25 μM, respectively, and the cells were cultured for 24 hours. After the culture was completed, the β-secretase activity of the cells was measured according to the protocol attached to the Beta-Scretase Activity Assay Kit (Fluorometric) (Abcam: ab65357).

[0081] The results are shown in Figure 2. Figure 2 shows that β-secretase activity in mouse microglial cells BV-2 was inhibited by 6.25 to 25 μM turmeronol A and turmeronol B, and 12.5 and 25 μM bisaclone.

[0082] All patents, patent applications and publications cited herein are hereby incorporated by reference in their entirety.

Claims

1. A beta-secretase inhibitor containing at least one of turmeronol A, turmeronol B, and bisacron as an active ingredient.

2. The β-secretase inhibitor according to claim 1, which consists of at least one of turmeronol A, turmeronol B and bisacron as active ingredients.

3. A composition for preventing or treating dementia, comprising at least one of turmeronol A, turmeronol B and bisacron as an active ingredient.

4. The composition according to claim 3, which consists solely of at least one of turmeronol A, turmeronol B and bisacron as active ingredients.

5. A composition for preventing or treating dementia, comprising turmeric extract as an active ingredient.

6. The composition according to claim 5, which consists solely of turmeric extract as an active ingredient.

7. The composition of claim 5, wherein the turmeric extract comprises an extract of turmeric with at least one extraction solvent selected from the group consisting of water and hydrophilic organic solvents.

8. The composition according to claim 5, wherein the turmeric extract comprises a mixture of a turmeric extract obtained by extraction with water and a turmeric extract obtained by extraction with supercritical carbon dioxide.

9. The composition of claim 5, wherein the turmeric extract contains at least one of turmeronol A, turmeronol B and bisacron.

10. The composition of claim 3 or 5, wherein the dementia is Lewy body dementia or vascular dementia.

11. The composition of claim 3 or 5, wherein the dementia is not Alzheimer's disease.

Images