Natural plant acne-removing composition with high stability and application thereof

Abstract

The invention discloses a natural plant acne-removing composition with high stability. The natural plant acne-removing composition is prepared from the following components in parts by weight: 20 to 40 parts of herba verbenae extract, 30 to 60 parts of spiraea ulmus extract, 10 to 20 parts of linear aspartame extract, 1 to 3 parts of radix arnebiae seu lithospermi extract and 2 to 4 parts of tetrahydropiperine. The radix arnebiae seu lithospermi extract is wrapped by a phospholipid-cyclodextrin composite carrier, fat-soluble shikonin is converted into a water-soluble and high-stability core-shell structure, the composition can form a three-dimensional synergistic system of bacteriostasis, oil control and anti-inflammatory repair, the effect of improving light and moderate acne is remarkable, and recurrence can be effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, and in particular to a highly stable natural plant-based acne-removing composition and its application. Background Technology

[0002] Acne is a common chronic inflammatory disease of the pilosebaceous unit, and its pathogenesis involves multiple steps, including excessive sebum secretion, abnormal keratinization of the follicular opening, proliferation of Propionibacterium acnes, and the resulting inflammatory response. Currently, multi-target intervention using natural plant extracts to address these pathological mechanisms has become a research hotspot in the field of functional skincare products. Existing technologies have disclosed various plant extracts with acne-fighting effects; for example, verbena extract has antibacterial and anti-inflammatory effects, while shikonin compounds in Xinjiang comfrey extract show excellent anti-inflammatory and tissue repair activities. However, existing technologies still have significant limitations in achieving efficient delivery and sustained effects of various active ingredients in specific layers of the skin. In particular, for Xinjiang comfrey extract, although its core active ingredient shikonin has significant biological activity, its molecular structure is extremely unstable, highly sensitive to light, heat, and oxygen, and easily oxidized and inactivated. Furthermore, shikonin itself has extremely poor water solubility, making it difficult to maintain stability in aqueous matrices such as serums and gels, severely limiting its application in refreshing acne-fighting products. Therefore, it is necessary to research a highly stable natural plant-based acne-fighting composition. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a highly stable natural plant-based acne-removing composition and its application. By encapsulating comfrey extract with a phospholipid-cyclodextrin composite carrier, the fat-soluble comfrey extract is transformed into a water-soluble, highly stable core-shell structure. The composition can form a three-dimensional synergistic system of antibacterial, oil-controlling, anti-inflammatory, and repairing effects, which significantly improves mild to moderate acne and effectively prevents recurrence.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A highly stable natural plant-based acne-removing composition comprises, by weight, the following components: 20-40 parts of verbena extract, 30-60 parts of meadowsweet extract, 10-20 parts of linear asparagus extract, 1-3 parts of comfrey extract, and 2-4 parts of tetrahydropiperine.

[0006] Preferably, the aforementioned comfrey extract is a phospholipid-cyclodextrin complex carrier containing comfreyin. The complex carrier is composed of comfreyin, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin, and comfreyin is encapsulated in a core-shell structure formed by hydrogenated lecithin and hydroxypropyl-β-cyclodextrin.

[0007] Preferably, the preparation process of the aforementioned Lithospermum erythrorhizon extract includes the following specific steps:

[0008] S1. Pulverize the dried roots of Lithospermum erythrorhizon, add ammoniacal ethanol solution, extract in the dark, and filter to obtain Lithospermum erythrorhizon extract.

[0009] S2. Add hydrogenated lecithin to the shikonin extract and form a liposome precursor complex with phospholipids by solvent removal or injection.

[0010] S3. Hydroxypropyl-β-cyclodextrin solution was added to the liposome precursor complex, and the mixture was homogenized under high pressure to form a core-shell composite carrier. The carrier was then freeze-dried under vacuum to obtain powdered Lithospermum erythrorhizon extract.

[0011] Preferably, the mass ratio of the aforementioned dried root of Lithospermum erythrorhizon, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin is 100:0.5-2.5:5-12.

[0012] Preferably, in step S1, the mass of the ammoniacal ethanol solution is 6-10 times that of the Lithospermum erythrorhizon, the extraction time is 1.5-3 hours, and the temperature is ≤40℃.

[0013] Preferably, in step S3, the pressure of the high-pressure homogenization process is 600-800 bar, and the process is repeated 3-5 times.

[0014] Preferably, the aforementioned meadowsweet extract and linear asparagus extract are prepared by a combined extraction process, specifically: the meadowsweet and linear asparagus raw materials are mixed at a mass ratio of 3:1 and extracted using ultrasonic-assisted extraction technology.

[0015] The application of acne-reducing compositions in skincare products, with the acne-reducing composition accounting for 1%-3% of the weight of the skincare product.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) This invention encapsulates the limonite extract with a phospholipid-cyclodextrin composite carrier, transforming the fat-soluble limonite into a water-soluble, highly stable core-shell structure, effectively solving the problems of limonite's easy oxidation, poor water solubility, and difficulty in being stably added to an aqueous matrix; this composite carrier technology significantly improves the stability, transdermal absorption efficiency, and bioavailability of limonite, ensuring the full realization of its anti-inflammatory and repairing effects;

[0018] (2) The composition of the present invention can form a three-dimensional synergistic system of antibacterial-oil control-anti-inflammatory repair. Verbena officinalis extract plays a core antibacterial role; Spiraea japonica extract and linear asparagus extract work together to effectively regulate sebaceous gland secretion; and comfrey extract, after stabilization treatment, specifically reduces inflammatory response and repairs damaged skin. The three work together to significantly improve mild and moderate acne and effectively prevent recurrence. Moreover, the core ingredients are all derived from natural plant extracts and are free of chemically synthesized antibacterial agents, hormones and other irritating ingredients, making them gentle and not damaging to the skin barrier. Detailed Implementation

[0019] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0020] A highly stable natural plant-based acne-removing composition comprises, by weight, the following components: 20-40 parts of verbena extract, 30-60 parts of meadowsweet extract, 10-20 parts of linear asparagus extract, 1-3 parts of comfrey extract, and 2-4 parts of tetrahydropiperine.

[0021] Mix verbena extract, meadowsweet extract, linear asparagus extract, Xinjiang lithospermum extract and tetrahydropiperine according to the specified ratio, and dry in a vacuum drying oven at 40°C for 2 hours to remove moisture and avoid clumping. Mix for 20 minutes to ensure uniform dispersion to obtain a natural plant acne-removing composition. Store the composition in a brown sealed container away from light for later use.

[0022] The extraction process of comfrey extract includes the following specific steps:

[0023] S1. Crush the dried roots of Lithospermum erythrorhizon into powder, add an ammoniacal ethanol solution (the mass of the ammoniacal ethanol solution is 6-10 times that of the Lithospermum erythrorhizon), extract in the dark for 1.5-3 hours at a temperature ≤40℃, and filter to obtain the shikonin extract. The alkaline environment can catalyze the hydrolysis of ester bonds in the Lithospermum erythrorhizon derivatives, efficiently converting them into free active shikonin.

[0024] S2. Add hydrogenated lecithin to the shikonin extract. The mass ratio of dried shikonin root, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin is 100:0.5-2.5:5-12. Shikonin and phospholipids form a liposome precursor complex by solvent removal or injection. Using solvent removal, shikonin molecules are embedded between the hydrophobic tails of phospholipids to form a preliminary liposome precursor.

[0025] S3. Add hydroxypropyl-β-cyclodextrin solution to the liposome precursor complex, perform high-pressure homogenization at a pressure of 600-800 bar, and cycle 3-5 times to form a core-shell composite carrier. During this process, the hydrophobic core of the shikonin molecule is captured by the cavity of hydroxypropyl-β-cyclodextrin to form a guest complex, while the outside is secondary-encapsulated by a hydrogenated lecithin bilayer, forming a stable "core-shell" structure.

[0026] S4. Powdered comfrey extract was obtained by vacuum freeze-drying. Because no liquid heating process was involved, the molecular configuration of comfrey was perfectly preserved. The resulting inclusion complex contained ≥3% comfrey, and its dispersibility in water was hundreds of times greater than that of the original component.

[0027] The extraction process of verbena extract includes the following steps:

[0028] (1) Raw material pretreatment: Take dried verbena whole herb, remove impurities, wash, crush, pass through 40-60 mesh sieve to obtain verbena powder, and set aside.

[0029] (2) Extraction: Put the prepared verbena powder into the extraction tank, add 65%-75% ethanol aqueous solution as the extraction solvent, the material-liquid ratio (g:mL) is 1:10-1:14, control the extraction temperature at 45-55℃, reflux extraction twice, the first extraction is 1.5-2h, the second extraction is 1-1.5h, collect the two extracts, and combine them to obtain the total extract.

[0030] (3) Purification: Filter the total extract through a 0.45 μm filter membrane to remove suspended impurities and obtain a clear extract; dilute the clear extract with 10%-30% ethanol aqueous solution and load it onto an AB-8 macroporous adsorption resin or D101 macroporous adsorption resin column, control the flow rate to 2-3 column volumes / hour, first elute with 15% ethanol aqueous solution for 4 column volumes to remove impurities, then elute with 25%-30% ethanol aqueous solution for 4-5 column volumes, and collect the eluent to obtain a purified solution.

[0031] (4) Concentration and drying: Place the refined liquid in a vacuum concentration device, control the vacuum degree to 0.06-0.08MPa and the temperature to 40-50℃, and concentrate under reduced pressure until there is no alcohol smell to obtain verbena extract; place the extract in a vacuum drying oven and vacuum dry at 45-50℃ to constant weight, pulverize and pass through an 80-mesh sieve to obtain verbena extract (verrucaside content ≥0.8%, ursolic acid content ≥0.5%).

[0032] The combined extraction process of meadowsweet extract and linear asparagus extract includes the following steps:

[0033] (1) Raw material pretreatment: Take the dried aerial parts of Spiraea japonica and the dried stems and leaves of Asparagus cochinchinensis, remove impurities and pulverize them into 40-mesh fine powder respectively. Mix them at a mass ratio of 3:1 (corresponding to the weight range of the two in the composition) to obtain mixed herbal powder.

[0034] (2) Extraction steps: Add 10 times (w / v) of 60% ethanol solution to the mixed herbal powder, and use ultrasonic-assisted extraction with ultrasonic power of 300W, temperature of 50℃, extraction time of 40min, extract twice, combine the extracts, and filter through a 100-mesh filter cloth to remove residue.

[0035] (3) Purification and concentration: Centrifuge the filtrate for 15 min using a high-speed centrifuge (8000 r / min) and take the supernatant; concentrate under reduced pressure (vacuum degree -0.08 MPa, temperature 50℃) to a relative density of 1.15-1.20 (50℃), add 3 times the amount of deionized water and stir to disperse, let stand for 12 h, and filter to remove the precipitate.

[0036] (4) Drying the finished product: Spray dry the clarified filtrate (inlet air temperature 180℃, outlet air temperature 80℃, feed rate 5mL / min) to obtain a powdered mixed extract (flavonoid content ≥10%, polyphenol content ≥12%), and store it in a sealed container for later use.

[0037] Example 1

[0038] A natural plant-based acne-removing composition comprises the following components by weight: 30 parts verbena extract, 45 parts meadowsweet extract, 15 parts linear asparagus extract, 2 parts comfrey extract, and 3 parts tetrahydropiperine.

[0039] The preparation process of the comfrey extract includes the following specific steps:

[0040] S1. Crush the dried roots of Lithospermum erythrorhizon into powder, add an ammoniacal ethanol solution (the mass of which is 8 times that of the Lithospermum erythrorhizon), extract in the dark for 2 hours at 30°C, and filter to obtain the Lithospermum erythrorhizon extract.

[0041] S2. Add hydrogenated lecithin to the shikonin extract. The mass ratio of dried shikonin root, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin is 100:2:7. The shikonin and phospholipids are combined to form a liposome precursor complex by solvent removal or injection.

[0042] S3. Add hydroxypropyl-β-cyclodextrin solution to the liposome precursor complex, perform high-pressure homogenization at a pressure of 600 bar, and cycle 3 times to form a core-shell composite carrier.

[0043] S4. The powdered Lithospermum extract was obtained by vacuum freeze-drying.

[0044] Example 2

[0045] A natural plant-based acne-removing composition comprises, by weight, the following components: 30 parts verbena extract, 60 parts meadowsweet extract, 20 parts linear asparagus extract, 3 parts comfrey extract, and 2 parts tetrahydropiperine. The preparation process of the comfrey extract is the same as in Example 1.

[0046] Example 3

[0047] A natural plant-based acne-removing composition comprises, by weight, the following components: 30 parts verbena extract, 35 parts meadowsweet extract, 12 parts linear asparagus extract, 1 part comfrey extract, and 4 parts tetrahydropiperine. The preparation process of the comfrey extract is the same as in Example 1.

[0048] Example 4

[0049] The difference between this embodiment and Embodiment 1 is that the mass ratio of dried Lithospermum erythrorhizon root, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin is adjusted to 100:0.5:7.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that verbena extract was not added.

[0052] Comparative Example 2

[0053] The difference between this comparative example and Example 1 is that no meadowsweet extract was added.

[0054] Comparative Example 3

[0055] The difference between this comparative example and Example 1 is that linear asparagus extract was not added.

[0056] Comparative Example 4

[0057] The difference between this comparative example and Example 1 is that no comfrey extract was added.

[0058] Comparative Example 5

[0059] The difference between this comparative example and Example 1 is that the comfrey extract was extracted using conventional ethanol reflux extraction and was not encapsulated by the composite carrier as in Example 1.

[0060] Comparative Example 6

[0061] The difference between this comparative example and Example 1 is that tetrahydropiperine was not added.

[0062] Comparative Example 7

[0063] The difference between this comparative example and Example 1 is that only hydroxypropyl-β-cyclodextrin is used for inclusion, and hydrogenated lecithin is not added.

[0064] Comparative Example 8

[0065] The difference between this comparative example and Example 1 is that only hydrogenated lecithin is used for encapsulation, and hydroxypropyl-β-cyclodextrin is not added.

[0066] Performance testing

[0067] The acne-removing compositions from Examples 1-4 and Comparative Examples 1-8 were respectively prepared into acne-removing essence skincare products, and the specific methods were as follows:

[0068] Prepare an 8kg batch. Place 120g of the acne-removing composition (1.5% addition ratio) into a reaction vessel, add 8 times the volume (960g) of 50% butylene glycol aqueous solution (480g butylene glycol + 480g deionized water), and stir at room temperature until completely dissolved. Dissolve 30g of carbomer 2020, 10g of xanthan gum, 80g of PEG40 hydrogenated castor oil, 20g of preservative (phenoxyethanol), and 80g of glycerin in the remaining deionized water. Heat to 75-80℃ and stir until homogeneous. Cool to 50-55℃, adjust the pH to 5.0 with triethanolamine, and directly add the pre-dissolved acne-removing composition solution, stirring until homogeneous. Continue stirring the aqueous phase until cooled to below 45℃, stirring until homogeneous to obtain the acne-removing essence.

[0069] (1) In vitro inhibition test of Propionibacterium acnes

[0070] The acne-removing essences prepared from the acne-removing compositions in Examples 1-4 and Comparative Examples 1-8 were aged at 42°C for 90 days, and their antibacterial effects were tested using the Oxford cup method. The specific steps were as follows: Propionibacterium acnes was inoculated onto Clostridium enrichment agar slant, anaerobically cultured at 37°C for 48 hours, eluted with 5 mL of Clostridium enrichment medium, and adjusted to a bacterial concentration of 10 by turbidimetric method. 5 -10 6 CFU / mL; Pour 18-20 mL of Clostridium enrichment agar medium into the petri dish, 5-6 mm thick. After solidification, aseptically aspirate 100 μL of bacterial suspension and spread it evenly. Place Oxford cups (6 mm inner diameter, 8 mm outer diameter, 10 mm height) on the medium, and add 200 μL of the sample to be tested to each cup. Each group has 3 replicates, with a spacing of ≥30 mm between Oxford cups. Anaerobic incubate at 37℃±1℃ for 72 h. Observe the inhibition zone visually and measure the diameter with calipers, and take the average value. Sterile water was set as a blank control. Specific results are shown in Table 1.

[0071] Table 1. Results of in vitro inhibition test of Propionibacterium acnes by the acne-removing composition.

[0072]

[0073] As shown in Table 1, the inhibition zone diameters of the compositions in Examples 1-4 against Propionibacterium acnes were all greater than 17 mm, which was significantly better than the comparative examples. The inhibition zone diameter of Comparative Example 1 was the smallest, indicating that Verbena extract played a core antibacterial role, and that there was a synergistic antibacterial mechanism between Verbena and Lithospermum erythrorhizon inclusion complex. Verbena glycoside interfered with bacterial energy metabolism, while shikonin specifically attacked cell membrane lipid components.

[0074] (2) Sebum secretion inhibition experiment

[0075] The acne-reducing essences prepared from the acne-reducing compositions in Examples 1-4 and Comparative Examples 1-8 were aged at 42°C for 90 days, and their oil-controlling efficacy was tested. The test method was as follows: Male SD rats were fasted overnight and then sacrificed. The livers were homogenized, centrifuged at 12000 r / min for 30 min at 4°C, and the supernatant was taken as the 5α-reductase extract. The extract was then refrigerated at -80°C. 0.2 mL of enzyme solution, 0.01 mL of testosterone (final concentration 10 μmol / L), and 0.1 mL of... were added according to the specified ratio. NADPH (final concentration 0.5 mmol / L), 0.1 mL of the sample to be tested, and phosphate buffer to 1 mL; react at 37℃ and 200 rpm for 3 h on a shaker, stop by adding 2 volumes of anhydrous ethanol, centrifuge at 12000 rpm for 8 min, and filter the supernatant through a 0.22 μm filter membrane; HPLC detection: mobile phase methanol:water = 35:65 (V / V), flow rate 1.0 mL / min, detection wavelength 254 nm, column temperature 30℃, calculate testosterone consumption; inhibition rate calculation: inhibition rate (%) = [(testosterone consumption in blank tube - testosterone consumption in sample tube) / testosterone consumption in blank tube] × 100%. Specific results are shown in Table 2.

[0076] Table 2. Effect of acne-reducing compositions on inhibiting sebum secretion.

[0077]

[0078] As shown in Table 2, the compositions of Examples 1-4 all exhibited an inhibition rate of over 33% against 5α-reductase, significantly higher than the comparative compositions lacking either Spiraea elm extract or linear asparagus extract. This indicates that the two components synergistically regulate sebum secretion. The polyphenols in linear asparagus not only act as antioxidants to protect the enzyme source environment but also exhibit a heterologous effect with the flavonoids in Spiraea elm, jointly occupying the active site of 5α-reductase, resulting in excellent oil control.

[0079] (3) Inflammatory factor inhibition experiment

[0080] The acne-removing essences prepared from the acne-removing compositions in Examples 1-4 and Comparative Examples 1-8 were aged at 42°C for 90 days to verify their inhibitory ability on inflammatory factors (TNF-α, IL-6) and evaluate their anti-inflammatory efficacy. The test method was as follows: RAW264.7 cells were aged at 2×10⁻⁶ cells / day. 5Cells were seeded per well in 12-well plates and cultured at 37°C with 5% CO2 for 24 h. The cells were divided into a blank group (culture medium only), a model group (culture medium + LPS), and a sample group (culture medium + LPS + test sample, final sample concentration 1%), with three replicates per group. After induction with 1 μg / mL lipopolysaccharide for 24 h, the cell supernatant was collected. Following the ELISA kit instructions, the absorbance at 450 nm was measured using a microplate reader, and the concentrations of inflammatory factors were calculated. The inhibition rate was calculated as follows: Inhibition rate (%) = [(Model group concentration - Sample group concentration) / (Model group concentration - Blank group concentration)] × 100%. Specific results are shown in Table 3.

[0081] Table 3. Results of the inflammatory factor inhibition experiment of the acne treatment composition.

[0082]

[0083] As shown in Table 3, the inhibition rates of the compositions in the examples against TNF-α and IL-6 both exceeded 25%, significantly higher than the comparative composition lacking comfrey extract. This indicates that the comfrey extract prepared by the process of this invention is the core anti-inflammatory component, synergistically alleviating skin inflammation with other components. The comfrey core-shell inclusion complex exhibits higher monomer dispersibility in the aqueous phase, fundamentally blocking the outbreak of pro-inflammatory factors.

[0084] (4) Skin cell repair test

[0085] The acne-removing serums prepared from the acne-removing compositions in Examples 1-4 and Comparative Examples 1-8 were aged at 42°C for 90 days to verify their promoting effect on the migration of keratinocytes (HaCaT) and to evaluate skin repair ability. The test method was as follows: HaCaT immortalized keratinocytes were aged at 4 × 10⁻⁶ m² / h ... 5 Cells were seeded per well in 6-well plates and cultured at 37°C with 5% CO2 until 90% confluence. A sterile 200 μL pipette tip was used to vertically scratch the cells, and detached cells were washed away with PBS. Serum-free medium containing the test sample (final concentration 0.5%) was added, while serum-free medium was added to the control group. Scratch images were taken at 0h, 6h, and 24h, and the scratch area was measured using ImageJ. Cell migration rate was calculated. Migration rate (%) = [(0h scratch area - post-culture scratch area) / 0h scratch area] × 100%. Specific results are shown in Table 4.

[0086] Table 4. Skin cell repair test results of the acne treatment composition

[0087]

[0088] As shown in Table 4, the 24-hour migration rate of HaCaT cells exceeded 79%, which was significantly higher than that of each control group. This indicates that the components of the composition synergistically promote skin cell migration and accelerate the repair of damaged skin. The comfrey extract and other components work together to enhance the repair effect. Tetrahydropiperine directly pumps the inclusion complex to the damaged basal cells, stimulating the proliferation and migration potential of keratinocytes.

[0089] (5) Human efficacy test

[0090] The acne-removing essences prepared from the acne-removing compositions in Examples 1-4 and Comparative Examples 1-8 were aged at 42°C for 90 days to verify their actual effects on acne removal, oil control, anti-inflammatory repair on humans. Sixty volunteers aged 20-35 years, meeting the diagnostic criteria for mild (Grade I) and moderate (Grade II) acne in the "Chinese Acne Treatment Guidelines (2019 Edition)," were recruited. They were randomly divided into 6 groups of 10 people each, using the products from Examples 1-3, Comparative Examples 5-6, and a blank control group (basic skincare products without the compositions of this invention), respectively. The testing method was as follows: After cleansing the face morning and evening, the acne-removing essence containing 1.5% of the composition was evenly applied to the face for 28 consecutive days, during which other functional skin care products were discontinued; the skin oil content was measured using a Sebumeter SM 815 analyzer; the number of inflammatory papules and pimples was counted over 28 days using the VISIA facial image analysis system; the proportion of facial inflammatory red area was analyzed using the VISIA system over 28 days; the improvement rate was calculated as follows: Improvement rate (%) = [(value before use - value after use) / value before use] × 100%. Specific results are shown in Table 5.

[0091] Table 5. Actual effects of the acne-removing composition on acne treatment, oil control, anti-inflammatory and repairing properties.

[0092]

[0093] As shown in Table 5, the skin oil, number of acne lesions and inflammatory red areas were significantly improved. The overall efficacy was significantly better than that of the comparative and blank control groups, indicating that the composition achieved a synergistic effect of "antibacterial-oil control-anti-inflammatory repair" in the human body, and its acne removal and skin improvement effects were clear.

[0094] (6) Physicochemical properties of Lithospermum erythrorhizon extract

[0095] The particle size and distribution of the *Lithospermum erythrorhizon* extracts in Examples 1, 4, and Comparative Examples 7-8 were characterized to verify whether the composite carrier formed a uniform nanoscale system. The test method was as follows: each sample was diluted with deionized water to a suitable concentration (approximately 0.1 mg / mL), and the average particle size (Z-average) and polydispersity index (PDI) were determined using DLS. The morphology of the samples was observed using TEM. Each group of samples was measured three times, and the average value was taken. The specific results are shown in Table 6.

[0096] Table 6 Physicochemical properties of Lithospermum erythrorhizon extract

[0097]

[0098] As shown in Table 6, both Examples 1 and 4 formed nanoscale composite carriers with clear core-shell structures in TEM images. In contrast, the single HP-β-CD inclusion complex had a particle size of only about 15 nm and no core-shell structure; the single liposome had a particle size of about 95 nm and no core-shell structure. This indicates that the phospholipid-cyclodextrin composite carrier successfully constructed a nanoscale core-shell structure, laying the foundation for subsequent transdermal absorption.

[0099] (7) Encapsulation efficiency and drug loading of shikonin

[0100] The encapsulation efficiency and drug loading of shikonin in Examples 1, 4 and Comparative Examples 7-8 were determined to verify the inclusion efficiency of the composite carrier. The test method was as follows: 10 mg of each sample was weighed and dissolved in 10 mL of deionized water. 1 mL of the solution was placed in an ultrafiltration centrifuge tube and centrifuged at 12000 rpm for 30 min. The filtrate was collected, and the free shikonin content was determined by HPLC. Another 1 mL of the solution was taken, methanol was added to destroy the carrier, and the total shikonin content was determined. The encapsulation efficiency and drug loading were calculated. The specific results are shown in Table 7.

[0101] Table 7 Encapsulation efficiency and drug loading of Lithospermum erythrorhizon extract

[0102]

[0103] As shown in Table 7, the encapsulation efficiency and drug loading of Examples 1 and 4-6 were significantly higher than those of the single HP-β-CD inclusion complex and the single liposome. This indicates that the phospholipid-cyclodextrin complex carrier achieved efficient encapsulation of shikonin through a dual inclusion mechanism.

[0104] (8) Stability test of Lithospermum erythrorhizon extract

[0105] The stability of the *Lithospermum erythrorhizon* extract in Examples 1, 4, and Comparative Examples 7-8 under accelerated and light-induced conditions was verified to demonstrate the protective effect of the composite carrier on shikonin. The accelerated stability test method was as follows: each sample powder was placed in a constant temperature and humidity chamber at 40℃ and 75% relative humidity for 30 days. The shikonin content was determined by HPLC, the retention rate was calculated, and the color change of the powder was observed. The light-induced stability test method was as follows: each sample was placed in a light incubator at 25℃ and 4500±500 Lux for 15 days. The shikonin content was determined by HPLC, and the retention rate was calculated. Specific results are shown in Table 8.

[0106] Table 8. Stability test of Lithospermum erythrorhizon extract

[0107]

[0108] As shown in Table 8, the accelerated stability and light stability of Example 1 are significantly better than those of the conventional extraction group and the single HP-β-CD inclusion complex group. This indicates that the phospholipid-cyclodextrin complex carrier further isolates shikonin from the external environment through the protection of the outer phospholipid membrane, thus significantly improving its chemical stability.

[0109] (9) In vitro transdermal absorption and skin retention test of Lithospermum erythrorhizon extract

[0110] The transdermal absorption assay was performed as follows: pig ear skin was fixed on a Franz diffusion cell with the stratum corneum facing upwards. PBS buffer (pH 7.4, containing 0.1% sodium azide) was added to the receiving cell, and 0.5 mL of the test sample (containing an equal amount of shikonin, concentration 0.05%) was added to the supply cell. The water bath temperature was 32℃, and the magnetic stirring speed was 300 rpm. After 24 h, 0.5 mL of the receiving solution was collected, and an equal amount of fresh PBS was added. The shikonin content in the receiving solution was determined by HPLC, and the cumulative transdermal absorption was calculated. The skin retention assay was performed as follows: After the transdermal experiment, the skin was removed, and any remaining sample on the surface was wiped off with a cotton swab. The skin was then minced, and methanol was added for ultrasonic extraction for 30 min. The mixture was centrifuged at 12000 rpm for 10 min, and the supernatant was collected. The shikonin content in the skin tissue was determined by HPLC. Specific results are shown in Table 9.

[0111] Table 9. Results of in vitro transdermal absorption and skin retention tests of Lithospermum erythrorhizon extract.

[0112]

[0113] Table 9 shows that the skin retention of Example 1 was significantly higher than that of Comparative Examples 5, 8, and 9. Although the single HP-β-CD inclusion complex had the highest transdermal rate, its skin retention was only 46% of that of Example 1, indicating that it was easy to transdermally penetrate but difficult to retain in the skin layer. Example 1, on the other hand, achieved a balance between moderate transdermal penetration and efficient retention, forming a drug reservoir in the skin layer, which is conducive to long-term anti-inflammatory and repairing effects.

[0114] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A highly stable natural plant-based acne-removing composition, characterized in that, The product comprises the following components by weight: 20-40 parts verbena extract, 30-60 parts meadowsweet extract, 10-20 parts linear asparagus extract, 1-3 parts comfrey extract, and 2-4 parts tetrahydropiperine.

2. The acne-removing composition according to claim 1, characterized in that, The comfrey extract is a phospholipid-cyclodextrin complex carrier containing shikonin. The complex carrier is composed of shikonin, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin, and shikonin is encapsulated in a core-shell structure formed by hydrogenated lecithin and hydroxypropyl-β-cyclodextrin.

3. The acne-removing composition according to claim 2, characterized in that, The preparation process of the comfrey extract includes the following specific steps: S1. Pulverize the dried roots of Lithospermum erythrorhizon, add ammoniacal ethanol solution, extract in the dark, and filter to obtain Lithospermum erythrorhizon extract. S2. Add hydrogenated lecithin to the shikonin extract and form a liposome precursor complex with phospholipids by solvent removal or injection. S3. Hydroxypropyl-β-cyclodextrin solution was added to the liposome precursor complex, and the mixture was homogenized under high pressure to form a core-shell composite carrier. The carrier was then freeze-dried under vacuum to obtain powdered Lithospermum erythrorhizon extract.

4. The acne-removing composition according to claim 3, characterized in that, The mass ratio of the dried root of Lithospermum erythrorhizon, hydrogenated lecithin and hydroxypropyl-β-cyclodextrin is 100:0.5-2.5:5-12.

5. The acne-removing composition according to claim 3, characterized in that, In step S1, the mass of the ammoniacal ethanol solution is 6-10 times that of the Lithospermum erythrorhizon, the extraction time is 1.5-3 hours, and the temperature is ≤40℃.

6. The acne-removing composition according to claim 3, characterized in that, In step S3, the pressure of the high-pressure homogenization process is 600-800 bar, and the process is repeated 3-5 times.

7. The acne-removing composition according to claim 1, characterized in that, The extracts of Spiraea elm and linear asparagine were prepared by a combined extraction process, specifically: Spiraea elm and linear asparagine raw materials were mixed at a mass ratio of 3:1 and extracted using ultrasonic-assisted extraction technology.

8. The use of the acne-removing composition according to any one of claims 1-7 in a skin care product, characterized in that, The acne-fighting composition constitutes 1%-3% of the total mass of the skincare product.

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