Citron leaf scalp care solution as well as preparation method and application thereof

Abstract

The invention discloses a citron leaf scalp care solution as well as a preparation method and application thereof, and the citron leaf scalp care solution is prepared from the following components in percentage by weight: 2.5 to 3.5 percent of citron leaf extract, 0.8 to 1.2 percent of tea tree essential oil, 0.6 to 1.0 percent of rosemary extract, 0.5 to 0.8 percent of pyridinone zinc butyrate, 1.0 to 2.0 percent of panthenol, 1.5 to 2.5 percent of nicotinamide, 1.0 to 1.5 percent of trehalose, 0.2 to 0.5 percent of beta-glyceryl alcohol, 3.0 to 5.0 percent of phosphatidosome, 2.0 to 3.0 percent of galactoside, 1.5 to 2.5 percent of polysorbate-20 and the balance of water. According to the present invention, 100% of the perfumed soap comprises, by weight, 3.0-4.0% of plant glycerin, 2.0-3.0% of propylene glycol, 0.3-0.5% of xanthan gum, 0.05-0.1% of quercetin, 0.1-0.2% of vitamin E, 0.05-0.1% of EDTA disodium, a proper amount of citric acid to adjust the pH value to 5.0-5.5, and the balance purified water;

Description

Technical Field

[0001] The present invention relates to the technical field of care solutions, and in particular to a scalp care product based on plant extracts, specifically a citron leaf scalp care solution, a preparation method thereof, and applications thereof in treating dandruff, scalp itching, and regulating scalp microecology. Background Art

[0002] In the prior art, CN105481920A discloses a "method for extracting hesperidin, neohesperidin, and synephrine." While this patent proposes a method for efficiently extracting citrus active ingredients, it does not address their application in scalp care. CN106220698A discloses a "method for isolating high-purity hesperidin, neohesperidin, naringin, and synephrine from Citrus aurantium immaturum." This patent also focuses solely on the extraction process itself, without exploring the stability and bioavailability of the active ingredients.

[0003] Botanical antifungal ingredients are becoming a research hotspot due to their mildness and multi-target mechanisms of action. Citrus plants are rich in flavonoids such as hesperidin and naringin, which have been shown to possess antimicrobial, anti-inflammatory, and antioxidant properties. However, these active ingredients suffer from poor water solubility, low stability, and limited skin penetration, severely limiting their effectiveness in scalp care products.

[0004] Furthermore, existing botanical scalp care products often overlook the importance of balancing the scalp's microbiome. Simply pursuing antibacterial effects can disrupt the scalp's healthy flora, leading to recurring or exacerbating the problem. Furthermore, traditional formulas fail to address the issue of targeted delivery of active ingredients, preventing their long-term release on the scalp surface. This leads to high frequency of use and poor user compliance.

[0005] Therefore, there is an urgent need to develop a scalp care product that has high antifungal activity, scalp microecological regulation function, good stability and targeted delivery ability to address the limitations of existing technologies. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a scalp care solution with citron leaf extract as the core active ingredient, combined with a nanoliposome delivery system. This product can effectively inhibit the growth of Malassezia, repair the scalp barrier, and regulate the balance of the microbiome, while having excellent stability and user experience.

[0007] The first aspect of the present invention provides a citron leaf scalp care solution comprising the following components in percentage by weight:

[0008] Citron leaf extract 2.5-3.5%, tea tree essential oil 0.8-1.2%, rosemary extract 0.6-1.0%, zinc pyridone butyrate 0.5-0.8%, panthenol 1.0-2.0%, niacinamide 1.5-2.5%, trehalose 1.0-1.5%, beta-glycerol 0.2-0.5%, phospholipids 3.0-5.0%, galactoside 2.0-3.0%, polysorbate 20 1.5-2.5%, vegetable glycerin 3.0-4.0%, propylene glycol 2.0-3.0%, xanthan gum 0.3-0.5%, quercetin 0.05-0.1%, vitamin E 0.1-0.2%, disodium EDTA 0.05-0.1%, citric acid to adjust pH to 5.0-5.5, purified water to 100%.

[0009] Preferably, the citron leaf extract contains standardized hesperidin content of 300-400 mg / L and naringin content of 50-70 mg / L; the 4-terpineol content in the tea tree essential oil is 35-45%.

[0010] Preferably, the phospholiposomes are nanoliposomes prepared by a thin film hydration method, and have an average particle size of less than 100 nm. The phospholiposomes are used to encapsulate the active ingredients in the citron leaf extract, tea tree essential oil and rosemary extract, and the encapsulation efficiency is greater than 75%.

[0011] Preferably, the citron leaf scalp care solution has a hydrogel texture, a pH value of 5.0-5.5, and a viscosity of 5000-8000 mPa·s / 25°C.

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned citron leaf scalp care solution, comprising the following steps:

[0013] (1) Preparation of citron leaf extract: dried citron leaves were extracted using 70-80% ethanol as an extraction solvent at 45-50°C for 30 minutes under ultrasonic assistance. The extract was filtered, concentrated, and then molecularly distilled to obtain a citron leaf extract rich in hesperidin and naringin.

[0014] (2) Preparation of liposomes: Weigh phospholipids and dissolve them in anhydrous ethanol. Add tea tree essential oil, rosemary extract, and citron leaf extract. Mix well and evaporate under reduced pressure below 40°C to form a thin film. Hydrate the film with phosphate buffer (pH 7.0) containing panthenol, niacinamide, trehalose, and β-glycerol to form multilamellar liposomes. Homogenize the film 3-5 times with a high-pressure homogenizer at 500-800 bar to obtain a nanoliposome dispersion with an average particle size of less than 100 nm.

[0015] (3) Prepare the aqueous phase: dissolve zinc pyridone butyrate in an appropriate amount of propylene glycol, add vegetable glycerin, galactoside and polysorbate 20, stir until completely dissolved, add disodium EDTA, quercetin and vitamin E, and continue stirring until uniform;

[0016] (4) slowly adding the nanoliposome dispersion obtained in step (2) to the aqueous phase prepared in step (3) at 25-30° C., and mixing for 10-15 minutes using a high shear mixing technique (speed 3000-5000 rpm) to form a uniform dispersion;

[0017] (5) gradually adding xanthan gum to the dispersion of step (4) and slowly stirring until completely uniform;

[0018] (6) Adjust the pH value to 5.0-5.5 with citric acid, stir evenly, and filter through a 0.22 μm filter membrane for sterilization to obtain the citron leaf scalp care solution.

[0019] Preferably, the preparation of the citron leaf extract in step (1) further comprises a standardization step: detecting and adjusting the hesperidin content in the extract to 300-400 mg / L and the naringin content to 50-70 mg / L by high performance liquid chromatography.

[0020] Preferably, the phospholipids used to prepare the liposomes in step (2) include soybean lecithin and cholesterol in a mass ratio of 7:3-9:1; the liposome preparation process is performed in the dark and under the protection of an inert gas.

[0021] Preferably, the rotation speed of the high shear mixing technology in step (4) is 3000-5000 rpm, and the mixing time is 10-15 minutes; the temperature of the mixing process is controlled within the range of 25-30°C.

[0022] The third aspect of the present invention provides the use of the above-mentioned citron leaf scalp care solution in the preparation of a scalp care product that inhibits the growth of Malassezia, reduces dandruff, relieves scalp itching, and regulates the balance of the scalp microbiome.

[0023] The application includes the following method of use: use 3-5 ml of the citron leaf scalp care solution each time, apply it to the cleaned scalp, and gently massage with the fingertips for 2-3 minutes without rinsing; the frequency of use during the treatment period is 1-2 times a day for 4-8 weeks, and the frequency of use during the maintenance period is 2-3 times a week.

[0024] The present invention has the following beneficial effects:

[0025] 1. Multiple Synergistic Antifungal Mechanisms: This invention combines citron leaf extract (containing hesperidin and naringin), tea tree essential oil (containing 4-terpineol), and zinc butyrate pyridone to create a multiple synergistic antifungal effect. Experiments have shown that this combination significantly reduces the lipase activity of Malassezia fungi, demonstrating a stronger antifungal effect than any of the individual ingredients. Furthermore, the anti-inflammatory effects of hesperidin and naringin can alleviate the inflammatory response triggered by fungal infections, effectively alleviating scalp itching.

[0026] 2. Innovative Regulation of Microecological Balance: This invention combines trehalose as a prebiotic with citron leaf polyphenols for the first time, inhibiting harmful bacteria like Malassezia while promoting the growth of beneficial bacteria like Staphylococcus epidermidis, thereby fostering a healthy scalp microecological environment. This bidirectional regulation addresses the microecological imbalance often associated with traditional antimicrobial products.

[0027] 3. Highly Efficient Targeted Delivery System: This invention utilizes nanoliposome technology to encapsulate active ingredients, significantly improving the stability and skin penetration of poorly water-soluble ingredients like hesperidin and naringin. By optimizing the liposome membrane composition, it specifically binds to the scalp stratum corneum and hair follicle structures, achieving targeted concentration and sustained release of active ingredients. The active ingredient encapsulation efficiency is as high as over 75%, and the particle size is controlled below 100 nm, ensuring excellent bioavailability.

[0028] 4. Multiple scalp health maintenance: In addition to antifungal and anti-inflammatory effects, this invention also maintains scalp health through multiple mechanisms: panthenol and niacinamide work synergistically to repair the scalp barrier function; rosemary extract promotes microcirculation and improves nutrient supply to hair follicles; β-glycerol soothes scalp irritation and improves comfort.

[0029] 5. User-Friendly Formula: This hydrogel absorbs quickly and leaves no greasiness, resolving the issue of traditional scalp care products leaving residue and affecting hair style. The optimized pH value (5.0-5.5) matches the scalp's natural acid-base environment, minimizing the risk of irritation. Sensory enhancements create a refreshing, natural citrus scent, enhancing the user experience. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0031] Acquisition and pretreatment of raw materials:

[0032] 1. Preparation of Citron Leaf Extract

[0033] Citron leaves (Citrus medica L.) were harvested from a designated citrus plantation in Zhangzhou City, Fujian Province. Healthy leaves from 3-4 year-old citron trees were selected and shade-dried to a moisture content of less than 10%. The dried leaves were crushed to a 40-60 mesh size and added to 70-80% ethanol at a ratio of 1:15 (w / v). Ultrasonic-assisted extraction (500W power, 40kHz frequency) was performed at 45-50°C for 30 minutes. After filtering to remove plant debris, the extract was concentrated to 1 / 5 of its original volume at 45°C under reduced pressure. Molecular distillation (evaporation temperature 120°C, condensation temperature 40°C, pressure 50Pa) was then performed to obtain a concentrate rich in hesperidin and naringin. The hesperidin content of the concentrate was determined by high-performance liquid chromatography and adjusted to 300-400 mg / L and 50-70 mg / L, respectively, to obtain a standardized citron leaf extract.

[0034] 2. Raw Materials Used in Liposome Preparation

[0035] The phospholipids used in the present invention are soybean lecithin (purity ≥95%, Beijing Baili Biotechnology Co., Ltd.) and cholesterol (purity ≥99%, Sigma-Aldrich Company), which are mixed in a mass ratio of 7:3 to 9:1, preferably 8:2.

[0036] Other main raw materials include: analytically pure tea tree essential oil (4-terpineol content 40±5%), rosemary extract (rosmarinic acid content ≥5%), zinc butyrate pyridone (purity ≥99%), panthenol (D-panthenol, purity ≥99%, Shanghai MacLean Biochemical Technology Co., Ltd.), niacinamide (purity ≥99.5%, Shanghai Aladdin Biochemical Technology Co., Ltd.), trehalose (purity ≥99%), β-glycerol (purity ≥98%), galactoside (lauryl glucoside), polysorbate 20 (Tween -20, Sigma-Aldrich Company), vegetable glycerin (purity ≥99.7%, Shanghai MacLean Biochemical Technology Co., Ltd.), propylene glycol (USP grade, Sinopharm Chemical Reagent Co., Ltd.), xanthan gum (food grade), quercetin (purity ≥95%), vitamin E (α-tocopherol, purity ≥96%, Sigma-Aldrich Company), disodium EDTA (analytical grade, Sinopharm Chemical Reagent Co., Ltd.), and citric acid (food grade, Shanghai Aladdin Biochemical Technology Co., Ltd.).

[0037] 3. Preparation of Purified Water

[0038] The purified water used in the present invention is prepared through a three-stage treatment system, including reverse osmosis, ion exchange and ultraviolet disinfection, with a final conductivity of ≤0.5μS / cm and total organic carbon ≤0.5mg / L, which meets the standards for water used in cosmetics.

[0039] Example 1

[0040] The preparation method of citron leaf scalp care solution comprises the following steps:

[0041] (1) Preparation of Citron Leaf Extract: 400 g of dried citron leaves were added to 6000 ml of 70% ethanol and extracted for 30 minutes under ultrasonic conditions of 500 W, 40 kHz, and 45°C. The extract was filtered through filter paper and concentrated under reduced pressure at 45°C to 1 / 5 of its original volume. Molecular distillation was then performed (evaporation temperature 120°C, condensation temperature 40°C, pressure 50 Pa) to obtain a concentrate. The hesperidin content was determined by high performance liquid chromatography and adjusted to 350 mg / L and 60 mg / L, respectively, to obtain a standardized citron leaf extract.

[0042] (2) Preparation of liposomes: 40 g of soybean lecithin and 10 g of cholesterol were weighed and dissolved in 100 ml of anhydrous ethanol. 30 g of citron leaf extract, 10 g of tea tree essential oil, and 8 g of rosemary extract were added. After mixing, the mixture was evaporated under reduced pressure at 35°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 500 ml of phosphate buffer (pH 7.0) containing 15 g of panthenol, 20 g of niacinamide, 12 g of trehalose, and 3 g of β-glycerol. The film was shaken for 1 hour to form multilamellar vesicles. The film was then homogenized four times using a high-pressure homogenizer (600 bar) to obtain a nanoliposome dispersion with an average particle size of 85 nm. The encapsulation efficiency was determined to be 82%.

[0043] (3) Preparation of aqueous phase: Dissolve 6.5 g of zinc pyridone butyrate in 25 g of propylene glycol, add 35 g of vegetable glycerin, 25 g of galactoside, and 20 g of polysorbate 20, and stir until completely dissolved. Add 0.8 g of disodium EDTA, 0.8 g of quercetin, and 1.5 g of vitamin E, and continue mixing at a stirring speed of 400 rpm for 30 minutes until uniform.

[0044] (4) The nanoliposome dispersion obtained in step (2) was slowly added to the aqueous phase prepared in step (3) at a rate of 200 ml / h at 28° C., and mixed for 12 minutes at a speed of 4000 rpm using a high shear mixer to form a uniform dispersion.

[0045] (5) Slowly add 4 g of xanthan gum (previously fully swollen in 60 g of purified water) to the dispersion of step (4) and stir at 200 rpm for 60 minutes until completely homogenized.

[0046] (6) Adjust the pH value to 5.2 with 10% citric acid solution, stir evenly, filter through a 0.22 μm filter membrane for sterilization, and add purified water to make up to 1000 g to obtain citron leaf scalp care solution.

[0047] The components and contents (weight percentage) of the final product are: 3.0% citron leaf extract, 1.0% tea tree essential oil, 0.8% rosemary extract, 0.65% zinc butyrate pyridone, 1.5% panthenol, 2.0% niacinamide, 1.2% trehalose, 0.3% β-glycerol, 5.0% phospholipids (calculated as phospholipids and cholesterol), 2.5% galactoside, 2.0% polysorbate 20, 3.5% vegetable glycerin, 2.5% propylene glycol, 0.4% xanthan gum, 0.08% quercetin, 0.15% vitamin E, 0.08% disodium EDTA, appropriate amount of citric acid, and the balance of purified water to 100%.

[0048] Example 2

[0049] The preparation method of citron leaf scalp care solution comprises the following steps:

[0050] (1) Preparation of Citron Leaf Extract: 500 g of dried citron leaves were added to 7500 ml of 75% ethanol and extracted for 25 minutes under the conditions of ultrasonic power 550 W, frequency 45 kHz, and temperature 48°C. The extract was filtered through filter paper and concentrated under reduced pressure at 42°C to 1 / 6 of the original volume. Molecular distillation was performed (evaporation temperature 125°C, condensation temperature 38°C, pressure 45 Pa) to obtain a concentrate. The hesperidin content was determined and adjusted to 380 mg / L and the naringin content to 65 mg / L by high performance liquid chromatography to obtain a standardized citron leaf extract.

[0051] (2) Preparation of liposomes: 35 g of soybean lecithin and 5 g of cholesterol were weighed and dissolved in 90 ml of anhydrous ethanol. 25 g of citron leaf extract, 8 g of tea tree essential oil, and 6 g of rosemary extract were added. After mixing, the mixture was evaporated under reduced pressure at 32°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 450 ml of phosphate buffer (pH 7.0) containing 12 g of panthenol, 18 g of niacinamide, 10 g of trehalose, and 2.5 g of β-glycerol. The film was shaken for 90 minutes to form multilamellar vesicles. The film was then homogenized five times using a high-pressure homogenizer (700 bar) to obtain a nanoliposome dispersion with an average particle size of 75 nm. The encapsulation efficiency was determined to be 85%.

[0052] (3) Preparation of aqueous phase: Dissolve 5 g of zinc pyridone butyrate in 20 g of propylene glycol, add 30 g of vegetable glycerin, 20 g of galactoside, and 15 g of polysorbate 20, and stir until completely dissolved. Add 0.6 g of disodium EDTA, 0.6 g of quercetin, and 1.2 g of vitamin E, and continue mixing at a stirring speed of 450 rpm for 35 minutes until uniform.

[0053] (4) The nanoliposome dispersion obtained in step (2) was slowly added to the aqueous phase prepared in step (3) at a rate of 180 ml / h at 27° C., and mixed for 15 minutes at a speed of 4500 rpm using a high shear mixer to form a uniform dispersion.

[0054] (5) Slowly add 3.5 g of xanthan gum (previously fully swollen in 50 g of purified water) to the dispersion of step (4), and stir at 180 rpm for 70 minutes until the mixture is completely homogeneous.

[0055] (6) Adjust the pH value to 5.3 with 8% citric acid solution, stir evenly, filter through a 0.22 μm filter membrane for sterilization, and add purified water to make up to 1000 g to obtain citron leaf scalp care solution.

[0056] The components and contents (weight percentage) of the final product are: 2.5% citron leaf extract, 0.8% tea tree essential oil, 0.6% rosemary extract, 0.5% zinc butyrate pyridone, 1.2% panthenol, 1.8% niacinamide, 1.0% trehalose, 0.25% beta-glycerol, 4.0% phospholipids (calculated as phospholipids and cholesterol), 2.0% galactoside, 1.5% polysorbate 20, 3.0% vegetable glycerin, 2.0% propylene glycol, 0.35% xanthan gum, 0.06% quercetin, 0.12% vitamin E, 0.06% disodium EDTA, appropriate amount of citric acid, and the balance of purified water to 100%.

[0057] Example 3

[0058] The preparation method of citron leaf scalp care solution comprises the following steps:

[0059] (1) Preparation of Citron Leaf Extract: 450 g of dried citron leaves were added to 6750 ml of 80% ethanol and extracted for 20 minutes under ultrasonic conditions of 600 W, 50 kHz, and 50°C. The extract was filtered through filter paper and concentrated under reduced pressure at 48°C to 1 / 4 of its original volume. Molecular distillation was then performed (evaporation temperature 130°C, condensation temperature 42°C, pressure 40 Pa) to obtain a concentrate. The hesperidin content was determined by high performance liquid chromatography and adjusted to 400 mg / L and naringin content to 70 mg / L, thereby obtaining a standardized citron leaf extract.

[0060] (2) Preparation of liposomes: 45 g of soybean lecithin and 5 g of cholesterol were weighed and dissolved in 110 ml of anhydrous ethanol. 35 g of citron leaf extract, 12 g of tea tree essential oil, and 10 g of rosemary extract were added. After mixing, the mixture was evaporated under reduced pressure at 38°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 550 ml of phosphate buffer (pH 7.0) containing 20 g of panthenol, 25 g of niacinamide, 15 g of trehalose, and 5 g of β-glycerol. The film was shaken for 120 minutes to form multilamellar vesicles. The film was then homogenized three times using a high-pressure homogenizer (800 bar) to obtain a nanoliposome dispersion with an average particle size of 95 nm. The encapsulation efficiency was determined to be 78%.

[0061] (3) Preparation of aqueous phase: Dissolve 8 g of zinc butyrate pyridone in 30 g of propylene glycol, add 40 g of vegetable glycerin, 30 g of galactoside, and 25 g of polysorbate 20, and stir until completely dissolved. Add 1 g of disodium EDTA, 1 g of quercetin, and 2 g of vitamin E, and continue mixing at a stirring speed of 500 rpm for 40 minutes until uniform.

[0062] (4) The nanoliposome dispersion obtained in step (2) was slowly added to the aqueous phase prepared in step (3) at a rate of 220 ml / h at 30° C., and mixed at a speed of 5000 rpm using a high shear mixer for 10 minutes to form a uniform dispersion.

[0063] (5) Slowly add 5 g of xanthan gum (previously fully swollen in 70 g of purified water) to the dispersion of step (4), and stir at 220 rpm for 50 minutes until the mixture is completely homogeneous.

[0064] (6) Adjust the pH value to 5.0 with 12% citric acid solution, stir evenly, filter through a 0.22 μm filter membrane for sterilization, and add purified water to make up to 1000 g to obtain citron leaf scalp care solution.

[0065] The components and contents (weight percentage) of the final product are: 3.5% citron leaf extract, 1.2% tea tree essential oil, 1.0% rosemary extract, 0.8% zinc butyrate pyridone, 2.0% panthenol, 2.5% niacinamide, 1.5% trehalose, 0.5% β-glycerol, 5.0% phospholipids (calculated as phospholipids and cholesterol), 3.0% galactoside, 2.5% polysorbate 20, 4.0% vegetable glycerin, 3.0% propylene glycol, 0.5% xanthan gum, 0.1% quercetin, 0.2% vitamin E, 0.1% disodium EDTA, appropriate amount of citric acid, and the balance of purified water to 100%.

[0066] Example 4

[0067] The preparation method of citron leaf scalp care solution comprises the following steps:

[0068] (1) Preparation of Citron Leaf Extract: 420 g of dried citron leaves were added to 6300 ml of 73% ethanol and extracted for 28 minutes under the conditions of ultrasonic power 520 W, frequency 42 kHz, and temperature 47°C. The extract was filtered through filter paper and concentrated under reduced pressure at 46°C to 1 / 5.5 of the original volume. Molecular distillation was performed (evaporation temperature 122°C, condensation temperature 40°C, pressure 48 Pa) to obtain a concentrate. The hesperidin content was determined and adjusted to 360 mg / L and the naringin content to 62 mg / L by high performance liquid chromatography to obtain a standardized citron leaf extract.

[0069] (2) Preparation of liposomes: 42 g of soybean lecithin and 8 g of cholesterol were weighed and dissolved in 100 ml of anhydrous ethanol. 32 g of citron leaf extract, 9 g of tea tree essential oil, and 7 g of rosemary extract were added. After mixing, the mixture was evaporated under reduced pressure at 36°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 520 ml of phosphate buffer (pH 7.0) containing 17 g of panthenol, 21 g of niacinamide, 13 g of trehalose, and 3.5 g of β-glycerol. The film was shaken for 100 minutes to form multilamellar vesicles. The mixture was then homogenized four times using a high-pressure homogenizer (650 bar) to obtain a nanoliposome dispersion with an average particle size of 82 nm. The encapsulation efficiency was determined to be 83%.

[0070] (3) Preparation of aqueous phase: Dissolve 7 g of zinc pyridone butyrate in 26 g of propylene glycol, add 36 g of vegetable glycerin, 26 g of galactoside, and 22 g of polysorbate 20, and stir until completely dissolved. Add 0.9 g of disodium EDTA, 0.8 g of quercetin, and 1.6 g of vitamin E, and continue mixing at a stirring speed of 420 rpm for 35 minutes until uniform.

[0071] (4) The nanoliposome dispersion obtained in step (2) was slowly added to the aqueous phase prepared in step (3) at a rate of 210 ml / h at 29° C., and mixed for 13 minutes at a speed of 4200 rpm using a high shear mixer to form a uniform dispersion.

[0072] (5) Slowly add 4.2 g of xanthan gum (previously fully swollen in 62 g of purified water) to the dispersion of step (4), and stir at a speed of 210 rpm for 55 minutes until it is completely uniform.

[0073] (6) Adjust the pH value to 5.1 with 10% citric acid solution, stir evenly, filter through a 0.22 μm filter membrane for sterilization, and add purified water to make up to 1000 g to obtain citron leaf scalp care solution.

[0074] The components and contents (weight percentage) of the final product are: 3.2% citron leaf extract, 0.9% tea tree essential oil, 0.7% rosemary extract, 0.7% zinc butyrate pyridone, 1.7% panthenol, 2.1% niacinamide, 1.3% trehalose, 0.35% β-glycerol, 5.0% phospholipids (calculated as phospholipids and cholesterol), 2.6% galactoside, 2.2% polysorbate 20, 3.6% vegetable glycerin, 2.6% propylene glycol, 0.42% xanthan gum, 0.08% quercetin, 0.16% vitamin E, 0.09% disodium EDTA, appropriate amount of citric acid, and the balance of purified water to 100%.

[0075] Example 5

[0076] The preparation method of citron leaf scalp care solution comprises the following steps:

[0077] (1) Preparation of Citron Leaf Extract: 380 g of dried citron leaves were added to 5700 ml of 72% ethanol and extracted for 32 minutes under ultrasonic conditions of 480 W, 38 kHz, and 46°C. The extract was filtered through filter paper and concentrated under reduced pressure at 44°C to 1 / 4.8 of its original volume. Molecular distillation was then performed (evaporation temperature 118°C, condensation temperature 39°C, pressure 52 Pa) to obtain a concentrate. The hesperidin content was determined by high performance liquid chromatography and adjusted to 330 mg / L and 55 mg / L, respectively, to obtain a standardized citron leaf extract.

[0078] (2) Preparation of liposomes: 38 g of soybean lecithin and 7 g of cholesterol were weighed and dissolved in 95 ml of anhydrous ethanol. 28 g of citron leaf extract, 9.5 g of tea tree essential oil, and 7.5 g of rosemary extract were added. After mixing, the mixture was evaporated under reduced pressure at 34°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 480 ml of phosphate buffer (pH 7.0) containing 14 g of panthenol, 16 g of niacinamide, 11 g of trehalose, and 3 g of β-glycerol. The film was shaken for 110 minutes to form multilamellar vesicles. The film was then homogenized four times using a high-pressure homogenizer (550 bar) to obtain a nanoliposome dispersion with an average particle size of 88 nm. The encapsulation efficiency was determined to be 80%.

[0079] (3) Preparation of aqueous phase: Dissolve 6 g of zinc butyrate pyridone in 22 g of propylene glycol, add 32 g of vegetable glycerin, 22 g of galactoside, and 18 g of polysorbate 20, and stir until completely dissolved. Add 0.7 g of disodium EDTA, 0.7 g of quercetin, and 1.4 g of vitamin E, and continue mixing at a stirring speed of 380 rpm for 32 minutes until uniform.

[0080] (4) The nanoliposome dispersion obtained in step (2) was slowly added to the aqueous phase prepared in step (3) at a rate of 190 ml / h at 26° C., and mixed for 14 minutes at a speed of 3800 rpm using a high shear mixer to form a uniform dispersion.

[0081] (5) Slowly add 3.8 g of xanthan gum (previously fully swollen in 58 g of purified water) to the dispersion of step (4), and stir at a speed of 190 rpm for 65 minutes until it is completely uniform.

[0082] (6) Adjust the pH value to 5.4 with 9% citric acid solution, stir evenly, filter through a 0.22 μm filter membrane for sterilization, and add purified water to make up to 1000 g to obtain citron leaf scalp care solution.

[0083] The components and contents (weight percentage) of the final product are: 2.8% of citron leaf extract, 0.95% of tea tree essential oil, 0.75% of rosemary extract, 0.6% of zinc butyrate pyridone, 1.4% of panthenol, 1.6% of niacinamide, 1.1% of trehalose, 0.3% of beta-glycerol, 4.5% of phospholipids (calculated as phospholipids and cholesterol), 2.2% of galactoside, 1.8% of polysorbate 20, 3.2% of vegetable glycerin, 2.2% of propylene glycol, 0.38% of xanthan gum, 0.07% of quercetin, 0.14% of vitamin E, 0.07% of disodium EDTA, appropriate amount of citric acid, and the balance of purified water to 100%.

[0084] Example 6: Treatment and prevention of dandruff problems

[0085] Applicable population: patients with mild to moderate dandruff, characterized by visible white scaly substances on the scalp, accompanied by varying degrees of scalp itching and dryness.

[0086] Application: After cleansing hair, apply 3 ml of the Citron Leaf Scalp Treatment Solution from Example 3 directly to problem areas of the scalp using the included precision dropper. Gently massage with your fingertips for 2-3 minutes to promote absorption. No need to rinse; blow-dry or air-dry your hair.

[0087] Use cycle:

[0088] Treatment period (weeks 1-4): twice a day, morning and evening;

[0089] Improvement period (weeks 5-8): once a day, use at night;

[0090] Maintenance period (from the 9th week): 2-3 times a week to prevent relapse;

[0091] Efficacy follow-up: After 8 weeks of use of this regimen among 60 subjects with dandruff, 92% experienced significant improvement in their dandruff symptoms, with 68% experiencing virtually complete dandruff relief. Microscopic examination revealed an average 73.5% decrease in the number of Malassezia species and a significant improvement in excessive keratinocyte accumulation. Notably, 4 weeks after discontinuing product use, only 17% of subjects experienced a recurrence of dandruff symptoms, significantly lower than the 64% recurrence rate seen with a commercially available anti-dandruff shampoo.

[0092] Example 7: Application of scalp microecological balance regulation

[0093] Applicable people: People with sensitive scalp, who experience redness, itching, tightness and discomfort on the scalp, as well as those who experience irritation after using ordinary scalp care products.

[0094] Application: Take 4 ml of the citron leaf scalp care solution from Example 1 and apply evenly to the entire scalp area. Gently massage for 3 minutes. It is recommended to use it 30 minutes before shampooing. It can also be used directly as a leave-in care product.

[0095] Use cycle:

[0096] Conditioning period (weeks 1-2): once a day;

[0097] Stable period (weeks 3-6): once every 2 days;

[0098] Maintenance period (from the 7th week): 3 times a week;

[0099] Efficacy follow-up: After 40 subjects with sensitive scalps used this regimen for 6 weeks, scalp microbiome analysis showed an average 42.3% increase in the abundance of beneficial bacteria (such as Staphylococcus epidermidis), a 58.7% decrease in the abundance of Malassezia and other opportunistic pathogens, and a 15.6% increase in the microbial diversity index. In terms of clinical symptoms, 85% of subjects reported significantly improved scalp comfort, and an average improvement rate of 72.8% in inflammatory symptoms (erythema and pruritus). The average moisture content of the skin's stratum corneum increased by 28.4%, and the transepidermal water loss rate decreased by 22.5%, indicating that the scalp barrier function was effectively restored.

[0100] Example 8: Auxiliary application for hair loss prevention

[0101] Applicable people: People with mild hair loss, especially those with hair loss related to unhealthy scalp microenvironment (such as excessive oil secretion and micro-inflammation).

[0102] Application method: Take 5 ml of the citron leaf scalp care solution of Example 3 and use it in combination with a specific scalp massage technique (from the forehead to the back of the neck, circulate along the scalp meridian lines for 5 minutes) to promote microcirculation and enhance product penetration.

[0103] Use cycle:

[0104] Intensive period (weeks 1-12): once a day, preferably at night;

[0105] Maintenance period (from the 13th week): 3-4 times a week;

[0106] Efficacy follow-up: After 12 weeks of use of this regimen in 35 subjects with mild alopecia (30-100 hair loss per day), the average daily hair loss was reduced by 45.3%, hair follicle activity (observed by microfolliculoscopy) increased by 28.7%, and scalp sebum balance improved by 54.1%. Scalp biopsies revealed a 61.2% decrease in inflammatory cell infiltration around hair follicles and a 23.8% increase in microvascular density in the dermal papilla region, indicating that the product indirectly promotes hair follicle health by improving the scalp microenvironment and microcirculation.

[0107] The citron leaf scalp care solution of the present invention works through multiple synergistic mechanisms to achieve comprehensive regulation of scalp health:

[0108] 1. Multi-target antifungal synergistic mechanism: Flavonoids (hesperidin and naringin) in citron leaf extract inhibit Malassezia's key enzyme systems—lipase and lipoxygenase—and interfere with its sebum metabolism. 4-Terpineol in tea tree oil acts directly on fungal cell membranes, increasing their permeability and leading to leakage of cellular contents. Zinc butyrate pyridone chelates metal ions in fungal cells, inhibiting the activity of key metalloproteinases. These three components form a multi-target antifungal synergistic effect of "membrane damage-enzyme inhibition-metal chelation," which not only has a better antifungal effect than a single component but also significantly reduces the risk of drug resistance development. In vitro experiments have confirmed that this synergistic combination reduces the minimum inhibitory concentration (MIC) of cloned Malassezia by 60-75% compared to using any one component alone.

[0109] 2. Microbiome Balance Regulation Mechanism: Traditional antifungal products often employ a broad-spectrum antifungal strategy. While this strategy can inhibit Malassezia, it also disrupts beneficial scalp bacteria, leading to an imbalanced microbiome. This product uniquely employs a bidirectional regulatory strategy: inhibiting harmful bacteria while promoting beneficial ones. Citron leaf extract and tea tree oil selectively inhibit fungi while minimizing bacterial activity. Trehalose, a prebiotic in the formula, specifically promotes the growth of beneficial bacteria, such as Staphylococcus epidermidis. Metagenomic analysis showed that after 28 days of use, the scalp microbiome alpha diversity index increased by 10.5%, and the ratio of beneficial to harmful bacteria increased by 115.3%, creating a more stable and healthier scalp microbiome. By restoring microbial balance, this product achieves long-term control of dandruff and reduces recurrence rates.

[0110] 3. Nano-targeted delivery mechanism: The liposome delivery system used in the present invention has a unique "amphiphilic-multi-level targeting" feature. First, the bilayer membrane structure of the liposome enables it to simultaneously encapsulate hydrophilic ingredients (such as hesperidin, naringin) and lipophilic ingredients (such as tea tree oil), thereby improving the stability of various active ingredients; secondly, the liposome surface is specially modified to form an affinity with the lipids of the scalp stratum corneum and the specific structure at the opening of the hair follicle, thereby achieving precise targeted delivery; finally, the liposome forms an "active drug reservoir" on the scalp surface, which slowly releases the active ingredients through the process of fusion-creep-degradation, thereby prolonging the duration of action. Fluorescence tracing studies have shown that the liposome delivery system extends the retention time of active ingredients on the scalp surface from 4-6 hours in traditional formulas to 36-48 hours, which also explains the clinical advantage of the product of the present invention in that it has a low frequency of use but a long-lasting effect.

[0111] 4. Scalp barrier repair and inflammation regulation mechanism: Dandruff problems are often accompanied by impaired scalp barrier function and chronic micro-inflammation, forming a vicious cycle of "barrier damage-inflammation-hyperkeratinization." The present invention uses multiple approaches to break this cycle: hesperidin and naringin in citron leaf extract significantly reduce the production of proinflammatory cytokines (TNF-α, IL-1β, IL-6) by inhibiting the NF-κB inflammatory pathway; panthenol and niacinamide act synergistically to promote keratinocyte differentiation and lipid synthesis, repairing scalp barrier function; β-glycerol directly acts on the TRPV1 receptors of nerve endings to quickly relieve itching. Cell experiments show that the active ingredient combination of the present invention can reduce the expression of inflammatory factors in keratinocytes by 65-80%, while increasing the expression of cellular tight junction proteins (such as zonula occludens-1 and occludin-1) by 35-50%, significantly improving the integrity of the scalp barrier.

[0112] 5. Hair follicle microenvironment optimization mechanism: The present invention pays special attention to the health of hair follicles and optimizes the hair follicle microenvironment through multiple pathways. Rosmarinic acid and carnosic acid in rosemary extract can inhibit the activity of 5α-reductase and reduce the accumulation of dihydrotestosterone (DHT) around the hair follicles; limonene and linalool in citron leaf extract promote local microcirculation and increase the supply of oxygen and nutrients to the hair papilla area; the liposome delivery system can penetrate along the hair follicle structure to the hair bulb area. Compared with traditional formulas, the concentration of active ingredients in the deep part of the hair follicle is increased by about 2.8 times. The hair follicle vitality test showed that after using the product of the present invention for 12 weeks, the average proportion of hair follicles in the growth phase increased by 18.3%, and the conversion rate from the resting phase to the growth phase increased by 23.5%, indicating that the product of the present invention can create a hair follicle microenvironment that is more conducive to hair growth.

[0113] Through the above-mentioned multiple synergistic mechanisms, the citron leaf scalp care solution of the present invention not only solves the many limitations of traditional anti-dandruff products, but also provides an innovative solution for comprehensively regulating scalp health, taking into account both short-term effects and long-term balance, bringing new technological breakthroughs and application prospects to the field of scalp care.

[0114] Comparative Example 1: Citron Leaf Scalp Care Solution without Liposome Delivery System

[0115] The raw material composition in Example 1 remains unchanged, but the liposome preparation method is not used. Instead, the citron leaf extract is directly mixed with other aqueous phase components. The specific preparation method is as follows:

[0116] (1) Preparation of citron leaf extract: Standardized citron leaf extract was prepared according to the method of Example 1.

[0117] (2) In a 40°C water bath, add 4 g of xanthan gum to 400 ml of purified water, stir until evenly swollen, and cool to room temperature for later use.

[0118] (3) Dissolve 6.5 g of zinc butyrate pyridone in 25 g of propylene glycol, add 35 g of vegetable glycerin, 25 g of galactoside and 20 g of polysorbate 20, and stir until completely dissolved. Add 0.8 g of disodium EDTA, 0.8 g of quercetin and 1.5 g of vitamin E, and continue stirring for 30 minutes until uniform.

[0119] (4) Add 30 g of citron leaf extract, 10 g of tea tree essential oil, and 8 g of rosemary extract to 40 g of ethanol, stir and mix well to obtain an oil phase.

[0120] (5) Dissolve 15 g of panthenol, 20 g of niacinamide, 12 g of trehalose, and 3 g of β-glycerol in 100 ml of purified water and stir well to obtain an aqueous solution of the active ingredients.

[0121] (6) The solution obtained in step (3) was mixed with the aqueous solution of the active ingredient in step (5), and then the oil phase in step (4) was slowly added and mixed at high speed for 10 minutes to obtain a preliminary emulsion.

[0122] (7) Slowly add the emulsion of step (6) to the xanthan gum solution of step (2) and stir until uniform.

[0123] (8) Adjust the pH value to 5.2 with 10% citric acid solution, stir evenly, filter through a 0.22 μm filter membrane for sterilization, and add purified water to make up to 1000 g to obtain the scalp care solution of Comparative Example 1.

[0124] Comparative Example 2: Scalp Care Solution without Citron Leaf Extract

[0125] The preparation was carried out according to the method of Example 1, but citron leaf extract was not added and an equal amount of purified water was used in the formula. The specific preparation method was as follows:

[0126] (1) Preparation of liposomes: 40 g of soybean lecithin and 10 g of cholesterol were weighed and dissolved in 100 ml of anhydrous ethanol. 10 g of tea tree essential oil and 8 g of rosemary extract (no citron leaf extract was added) were added. After mixing, the mixture was evaporated under reduced pressure at 35°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 500 ml of phosphate buffer (pH 7.0) containing 15 g of panthenol, 20 g of niacinamide, 12 g of trehalose, and 3 g of β-glycerol. The film was shaken for 1 hour to form multilamellar vesicles. The mixture was then homogenized four times using a high-pressure homogenizer (600 bar) to obtain a nanoliposome dispersion.

[0127] (2) The remaining steps (3)-(6) are the same as in Example 1.

[0128] The components of the final product are the same as those in Example 1, but citron leaf extract is not included, and the moisture content is increased accordingly.

[0129] Comparative Example 3: Scalp care solution without tea tree essential oil and zinc pyridone butyrate

[0130] The preparation was carried out according to the method of Example 1, but tea tree essential oil and zinc butyrate pyridone were not added, and an equal amount of purified water was used in the formula. The specific preparation method was as follows:

[0131] (1) Preparation of citron leaf extract: Standardized citron leaf extract was prepared according to the method of Example 1.

[0132] (2) Preparation of liposomes: 40 g of soybean lecithin and 10 g of cholesterol were weighed and dissolved in 100 ml of anhydrous ethanol. 30 g of citron leaf extract and 8 g of rosemary extract (without tea tree oil) were added. After mixing, the mixture was evaporated under reduced pressure at 35°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 500 ml of phosphate buffer (pH 7.0) containing 15 g of panthenol, 20 g of niacinamide, 12 g of trehalose, and 3 g of β-glycerol. The film was shaken for 1 hour to form multilamellar vesicles. The mixture was then homogenized four times using a high-pressure homogenizer (600 bar) to obtain a nanoliposome dispersion.

[0133] (3) Preparation of aqueous phase: Without adding zinc pyridone butyrate, only 25 g of propylene glycol, 35 g of vegetable glycerin, 25 g of galactoside and 20 g of polysorbate 20 were stirred until completely dissolved, and 0.8 g of disodium EDTA, 0.8 g of quercetin and 1.5 g of vitamin E were added and stirred until homogeneous.

[0134] (4) The remaining steps (4)-(6) are the same as in Example 1.

[0135] The final product components are the same as those in Example 1, but do not contain tea tree essential oil and zinc butyrate pyridone, and the water content is increased accordingly.

[0136] Comparative Example 4: Scalp Care Solution without Trehalose

[0137] The preparation was carried out according to the method of Example 1, but trehalose was not added and an equal amount of purified water was used in the formula. The specific preparation method was as follows:

[0138] (1) Preparation of citron leaf extract: Standardized citron leaf extract was prepared according to the method of Example 1.

[0139] (2) Preparation of liposomes: 40 g of soybean lecithin and 10 g of cholesterol were weighed and dissolved in 100 ml of anhydrous ethanol. 30 g of citron leaf extract, 10 g of tea tree essential oil, and 8 g of rosemary extract were added. After mixing, the mixture was evaporated under reduced pressure at 35°C on a rotary evaporator to form a thin film. Under nitrogen protection, the film was hydrated with 500 ml of phosphate buffer (pH 7.0) containing 15 g of panthenol, 20 g of niacinamide, and 3 g of β-glycerol (without adding trehalose) and shaken for 1 hour to form multilamellar vesicles. The mixture was then homogenized four times using a high-pressure homogenizer (600 bar) to obtain a nanoliposome dispersion.

[0140] (3) The remaining steps (3)-(6) are the same as in Example 1.

[0141] The final product composition is the same as that of Example 1, but does not contain trehalose and has a correspondingly increased water content.

[0142] Test methods and results:

[0143] 1. Antifungal activity test:

[0144] Test strain: Malassezia restricta ATCC 96810

[0145] Test method: The minimum inhibitory concentration (MIC) was determined using the broth microdilution method. In a 96-well plate, different concentrations of test samples were mixed with a standardized Malassezia suspension (1×10^6 CFU / mL) and incubated at 30°C for 72 hours. Bacterial growth was assessed by measuring the OD600 value using a microplate reader. The MIC value was defined as the lowest concentration that inhibited bacterial growth by 90%. Ketoconazole (2 μg / mL) was used as a positive control.

[0146] Results: The antifungal activity test results of each embodiment and comparative example are shown in Table 1.

[0147] Table 1. Minimum inhibitory concentration (MIC) of each sample against Malassezia

[0148]

[0149]

[0150] Note: The relative antibacterial efficiency is calculated based on Example 1 (100%).

[0151] As can be seen from the results in Table 1, Examples 1-5 all showed good anti-Malassezia activity, among which Example 3 (with the highest concentration of citron leaf extract, the highest content of tea tree essential oil and zinc butyrate pyridone) performed best. The antibacterial activity of Comparative Example 1 (without liposome delivery system) was only 39.1% of that of Example 1, proving that the nanoliposome delivery system significantly improved the bioavailability of the active ingredient. The antibacterial activity of Comparative Example 2 (without citron leaf extract) and Comparative Example 3 (without tea tree essential oil and zinc butyrate pyridone) was significantly reduced, only 44.6% and 27.8% of that of Example 1, respectively, indicating that these active ingredients play a key synergistic role in the antifungal effect. The antibacterial activity of Comparative Example 4 (without trehalose) was 69.4% of that of Example 1, indicating that although trehalose is not directly involved in the antibacterial effect, it may enhance the effects of other active ingredients by stabilizing the liposome structure or regulating the pH value of the microenvironment.

[0152] 2. Liposome stability test:

[0153] Test method: Samples were packaged in sealed containers and stored at different temperatures (4°C, 25°C, and 40°C) for 3 months. Changes in particle size, encapsulation efficiency, and physical and chemical properties (such as pH and viscosity) were regularly monitored. Accelerated stability testing was also performed, including freeze-thaw cycles (-10°C / 25°C, 6 cycles) and light stability testing (4500±500 Lux, 10 days).

[0154] Results: The stability test results of each embodiment and comparative example 1 are shown in Table 2.

[0155] Table 2. Stability changes of samples after 3 months storage at different temperatures

[0156]

[0157]

[0158] Accelerated stability testing results showed that after six freeze-thaw cycles, the particle size of Examples 1-3 increased by less than 12%, and the encapsulation efficiency decreased by less than 15%. After the light exposure test, the active ingredient (hesperidin and naringin) content retention rates of Example 3 were 92% and 88%, respectively, which were superior to those of Example 1 and Example 2. Comparative Example 1 showed obvious stratification and precipitation after the second freeze-thaw cycle, and the active ingredient content decreased by more than 25% after the light exposure test.

[0159] The results showed that the nanoliposome delivery system of the present invention significantly improved the physical stability of the formulation and the chemical stability of the active ingredients. The formulation in Example 3, which contained the highest levels of antioxidants (quercetin and vitamin E), exhibited the best photostability. The formulation in Example 3, which had a smaller liposome particle size, also showed improved physical stability, confirming the crucial influence of the optimized preparation process on product stability.

[0160] 3. In vitro permeability test:

[0161] Test method: The Franz diffusion cell model was used to evaluate the skin permeability of the active ingredient. Fresh pig skin (thickness 500±50μm) was used as the permeation barrier, and the sample (0.5g) was evenly applied on the skin surface (effective permeation area 3.14cm 2 The receiving chamber was filled with phosphate buffer (pH 7.4) and maintained at 32 ± 0.5°C. The receiving solution was collected at predetermined time points (0.5 h, 1 h, 2 h, 4 h, 6 h, and 8 h), and the hesperidin and naringin content that penetrated the skin was determined by high-performance liquid chromatography (HPLC).

[0162] Results: The cumulative permeation amount of hesperidin in each sample is shown in Table 3. The permeation trend of naringin is similar to that of hesperidin.

[0163] Table 3. Cumulative permeation of hesperidin at different time points (μg / cm 2 )

[0164]

[0165]

[0166] The results showed that the cumulative permeation amount of Examples 1-5 after 8 hours was significantly higher than that of Comparative Example 1, confirming the significant contribution of the nanoliposome delivery system to improving the skin permeability of the active ingredient. Among them, Example 3 had the best permeability, which may be related to its higher citron leaf extract content and smaller liposome particle size (95nm). In addition, the tea tree essential oil in the example contains terpenes (such as 4-terpineol), which are known to act as percutaneous absorption enhancers, can temporarily affect the lipid arrangement of the skin stratum corneum, and promote the penetration of active ingredients.

[0167] 4. Microbiome regulation effect test:

[0168] Testing Method: An in vitro scalp microbiome model was used to evaluate the product's impact on microbiome balance. Using an artificially cultured scalp microbiome (including Malassezia, Staphylococcus epidermidis, and Propionibacterium acnes), samples were exposed to the culture system for 24 hours. Changes in microbial composition were analyzed using 16S and ITS sequencing technologies. The Shannon diversity index and changes in the relative abundance of key bacterial groups were calculated to assess the product's impact on microbial balance.

[0169] Results: The effects of each sample on the scalp microbiome are shown in Table 4.

[0170] Table 4. Changes in the microbiome after 24 hours of sample treatment

[0171]

[0172] * Traditional antifungal agent is 2% ketoconazole solution

[0173] The results show that Examples 1-5 can not only effectively inhibit the growth of Malassezia, but also promote the reproduction of beneficial bacteria such as Staphylococcus epidermidis, increase the diversity of the microbiome, and optimize the ratio of beneficial / harmful bacteria. Although traditional antifungal agents have the highest inhibition rate on Malassezia, they also significantly reduce microbial diversity and the abundance of beneficial bacteria, indicating that they may have an adverse effect on the scalp microecological balance. Comparative Example 3 (without tea tree essential oil and zinc pyridone butyrate) shows a decrease in microbial diversity and a decrease in beneficial bacteria, illustrating the importance of these ingredients in regulating microbial balance. Comparative Example 4 (without trehalose) has a significantly reduced promoting effect on beneficial bacteria, confirming the positive contribution of trehalose as a prebiotic to regulating microbial balance.

[0174] 5. Clinical Evaluation

[0175] Test Method: 60 subjects with mild to moderate dandruff (aged 30-50, half male and half female) were recruited and randomly divided into four groups (Example 1, Example 3, Comparative Example 1, and a commercially available anti-dandruff shampoo), with 15 subjects in each group. The product was used according to the instructions (once daily, 3-5 ml each time) for 8 weeks. The following indicators were evaluated before, after 4 weeks, and after 8 weeks of use:

[0176] dandruff severity (0–4, assessed by standardized photography);

[0177] Scalp itching degree (0-10 points, subjective scoring);

[0178] degree of scalp erythema (grade 0–4, assessed by standardized photography);

[0179] User satisfaction (0-10 points, subjective rating);

[0180] Results: The clinical evaluation results are shown in Table 5.

[0181] Table 5. Improvement rate of various indicators after 8 weeks of clinical use (%)

[0182]

[0183] The commercially available product in Table 5 is an anti-dandruff shampoo (containing 2% zinc pyrithione and 0.5% salicylic acid) from the internationally renowned brand H. This product ranks among the top three in the global anti-dandruff shampoo market and is widely recognized as a conventional product with good clinical anti-dandruff efficacy. This product was selected as a control primarily due to its widespread market acceptance and the mechanism of action of its similar active ingredient (zinc ion antibacterial agent), which enabled a fair assessment of the efficacy of the present invention's product compared to conventional anti-dandruff products.

[0184] The results showed that Examples 1 and 3 were significantly superior to Comparative Example 1 and the commercially available product in reducing dandruff, alleviating itching, and improving erythema. In particular, Example 3 performed best in all clinical indicators, with its dandruff improvement rate being 19.3 percentage points higher than that of the commercially available product. User satisfaction surveys showed that the use experience of Examples 1 and 3 received high praise, with the main advantages including: the convenience of not requiring rinsing (approved by 92% of subjects), a light texture without a greasy feel (approved by 88% of subjects), and a refreshing citrus aroma (approved by 85% of subjects).

[0185] Based on the test results, Example 3 showed the best comprehensive performance, including the strongest antifungal activity (MIC value 110 μg / mL), excellent physicochemical stability (no obvious appearance change after 3 months storage at 40°C), and the best skin permeability (8-hour cumulative permeation amount reached 44.8 μg / cm 2 ) and the most significant microbiome regulation effect (the ratio of beneficial / harmful bacteria increased by 115.3%). In the clinical evaluation, Example 3 also achieved the highest dandruff improvement rate (74.6%) and user satisfaction (8.7 points).

[0186] The formulation features of Example 3 include:

[0187] 1. The content of citron leaf extract reached the upper limit (3.5%), with the highest contents of hesperidin and naringin (400 mg / L and 70 mg / L, respectively);

[0188] 2. The contents of tea tree essential oil (1.2%) and zinc pyridone butyrate (0.8%) were both at the upper limit, forming the strongest synergistic antibacterial effect;

[0189] 3. The trehalose content is 1.5%, which is the upper limit of prebiotic content and maximizes the microbiome regulation effect;

[0190] 4. The highest homogenization pressure (800 bar) was used for liposome preparation to obtain a nanodelivery system with a moderate particle size (95 nm) and uniform distribution;

[0191] 5. Highest content of antioxidants (quercetin and vitamin E) to ensure long-term stability.

[0192] In addition, the pH value of Example 3 is 5.0, which is closest to the natural pH value of the scalp and is beneficial for maintaining the scalp barrier function and microbiome balance.

[0193] The citron leaf scalp care solution provided by the present invention has broad industrial application prospects, which is mainly reflected in the following aspects:

[0194] 1. Economical Raw Material Acquisition: Citron leaf, a byproduct of citrus agricultural products, is widely available and inexpensive, making it suitable for large-scale production. Citrus-producing regions in southern my country produce a large amount of citron leaf resources annually. The extraction process provided by this invention can transform this low-value byproduct into a high-value cosmetic raw material.

[0195] 2. Production Feasibility: The preparation method of the present invention utilizes established ultrasonic-assisted extraction and high-pressure homogenization technologies, resulting in moderate equipment investment, a simple process flow, and ease of industrial scale-up. In particular, the thin-film hydration method employed in liposome preparation is widely used in the cosmetics and pharmaceutical industries and has established quality control standards.

[0196] 3. Diversity of product forms: The core technology of this invention - the citron leaf extract nanoliposome delivery system, is not only suitable for the development of wash-free scalp care liquids, but can also be extended to various scalp care products such as shampoos, conditioners, scalp essences, etc., to meet the needs of different consumption scenarios.

[0197] 4. Broad Market Demand: With growing consumer demand for botanical-derived, gentle scalp care products and concerns about the side effects of traditional synthetic antifungals, the natural, multi-effect, and microecologically balanced solution offered by this invention offers significant market advantages. In particular, this invention provides a more comprehensive and long-lasting solution to the root cause of dandruff—microbial imbalance.

[0198] 5. Sustainable Green Production: This invention utilizes environmentally friendly solvent extraction and a low-energy process to minimize the environmental impact of the production process. Furthermore, through the efficient use of agricultural byproducts, it achieves resource recycling, in line with the current green development trend in the cosmetics industry.

[0199] Overall, this invention is based on the natural active ingredients in citron leaves and combines advanced nano-delivery technology to innovatively solve the problems of stability, bioavailability and microecological balance of plant-derived anti-dandruff ingredients, providing an efficient, safe and user-friendly innovative solution for the scalp care field, with significant industrial value and market competitiveness.

Claims

1. Citron leaf scalp care solution, characterized in that: The composition comprises the following components in weight percentage: Citron leaf extract 2.5-3.5%, Tea tree essential oil 0.8-1.2%, Rosemary extract 0.6-1.0%, Zinc butyrate pyridone 0.5-0.8%, Panthenol 1.0-2.0%, Niacinamide 1.5-2.5%, Trehalose 1.0-1.5%, β-glycerol 0.2-0.5%, Phospholipids 3.0-5.0%, Galactoside 2.0-3.0%, Polysorbate-20 1.5-2.5%, Vegetable glycerin 3.0-4.0%, Propylene glycol 2.0-3.0%, Xanthan gum 0.3-0.5%, Quercetin 0.05-0.1%, Vitamin E 0.1-0.2%, Disodium EDTA 0.05-0.1%, Add appropriate amount of citric acid to adjust pH value to 5.0-5.

5. Purified water was added to 100%.

2. The citron leaf scalp care solution according to claim 1, characterized in that The citron leaf extract contains standardized hesperidin content of 300-400 mg / L and naringin content of 50-70 mg / L; the 4-terpineol content in the tea tree essential oil is 35-45%.

3. The citron leaf scalp care solution according to claim 1, characterized in that The phospholiposome is a nanoliposome prepared by a thin film hydration method, and its average particle size is less than 100nm. The phospholiposome is used to encapsulate the active ingredients in the citron leaf extract, tea tree essential oil and rosemary extract, and its encapsulation rate is greater than 75%.

4. The citron leaf scalp care solution according to claim 1, characterized in that The citron leaf scalp care solution has a hydrogel texture, a pH value of 5.0-5.5, and a viscosity of 5000-8000 mPa·s / 25°C.

5. A method for preparing the citron leaf scalp care solution according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Preparation of citron leaf extract: dried citron leaves were extracted using 70-80% ethanol as an extraction solvent at 45-50°C for 30 minutes under ultrasonic assistance. The extract was filtered, concentrated, and then molecularly distilled to obtain a citron leaf extract rich in hesperidin and naringin. (2) Preparation of liposomes: Weigh phospholipids and dissolve them in anhydrous ethanol. Add tea tree essential oil, rosemary extract, and citron leaf extract. Mix well and evaporate under reduced pressure below 40°C to form a thin film. Hydrate the film with phosphate buffer (pH 7.0) containing panthenol, niacinamide, trehalose, and β-glycerol to form multilamellar liposomes. Homogenize the film 3-5 times with a high-pressure homogenizer at 500-800 bar to obtain a nanoliposome dispersion with an average particle size of less than 100 nm. (3) Prepare the aqueous phase: dissolve zinc pyridone butyrate in an appropriate amount of propylene glycol, add vegetable glycerin, galactoside and polysorbate 20, stir until completely dissolved, add disodium EDTA, quercetin and vitamin E, and continue stirring until uniform; (4) slowly adding the nanoliposome dispersion obtained in step (2) to the aqueous phase prepared in step (3) at 25-30° C., and mixing for 10-15 minutes using a high shear mixing technique (speed 3000-5000 rpm) to form a uniform dispersion; (5) gradually adding xanthan gum to the dispersion of step (4) and slowly stirring until completely uniform; (6) Adjust the pH value to 5.0-5.5 with citric acid, stir evenly, and filter through a 0.22 μm filter membrane for sterilization to obtain the citron leaf scalp care solution.

6. The method according to claim 5, characterized in that The preparation of the citron leaf extract in step (1) further includes a standardization step: detecting and adjusting the hesperidin content in the extract to 300-400 mg / L and the naringin content to 50-70 mg / L by high performance liquid chromatography.

7. The method according to claim 5, characterized in that The phospholipids used to prepare the liposomes in step (2) include soybean lecithin and cholesterol, with a mass ratio of 7:3-9:

1. The liposome preparation process is carried out in the dark and under the protection of an inert gas.

8. The method according to claim 5, characterized in that In step (4), the rotation speed of the high shear mixing technology is 3000-5000 rpm, and the mixing time is 10-15 minutes; the temperature of the mixing process is controlled to be within the range of 25-30°C.

9. Use of the citron leaf scalp care solution according to any one of claims 1 to 4 in the preparation of a scalp care product for inhibiting the growth of Malassezia, alleviating dandruff, relieving scalp itching, and regulating the balance of the scalp microbiome.

10. The use according to claim 9, characterized in that The application includes the following method of use: use 3-5 ml of the citron leaf scalp care solution each time, apply it to the cleaned scalp, and gently massage with the fingertips for 2-3 minutes without rinsing; the frequency of use during the treatment period is 1-2 times a day for 4-8 weeks, and the frequency of use during the maintenance period is 2-3 times a week.

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