황금 뿌리 추출물을 함유한 층상 구조 에멀전의 피부에 대한 임상 연구

Clinical Study on Skin of Layered Emulsion Containing Scutellaria baicalensis Root Extract

含有黄芩根提取物的层状结构乳的皮肤临床研究

Article information

Asian J Beauty Cosmetol. 2024;22(4):681-689
Publication date (electronic) : 2024 December 24
doi : https://doi.org/10.20402/ajbc.2024.0073
1Department of Optometry, Eulji University, Seongnam-si, Gyeonggi-do, Korea
2Department of Biotechnology, Major in Cosmetic Science, Eulji University, Seongnam-si, Gyeonggi-do, Korea
최윤정1, 김규리2,
1을지대학교 보건과학부 안경광학과, 경기도 성남시, 한국
2을지대학교 바이오공학부 화장품과학전공, 경기도 성남시, 한국
*Corresponding author: Gyu-Ri Kim, Department of Biotechnology, Major in Cosmetic Science, Eulji University, 553, Sanseong-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do 13135, Korea Tel.: +82 31 740 7264 Email: whiteapple80@hanmail.net
Received 2024 October 4; Revised 2024 December 6; Accepted 2024 December 18.

Abstract

목적

피부 특히 각질층은 보호와 수분 유지에 있어 중요한 역할을 한다. 본 연구는 항염증 및 항미생물 특성으로 잘 알려진 황금(Scutellaria baicalensis)의 아토피 피부의 가려움 개선 가능성을 조사하고자 한다.

방법

황금 뿌리 추출물을 함유한 층상 구조 에멀전을 제조하여 21명의 성인을 대상으로 임상시험하였다. 참가자들은 해당 에멀전을 하루 2회, 4주 동안 사용하였다. 피부 표면 수분, 경피수분손실(TEWL) 및 가려움증 심각도는 각각 Corneometer CM825, Tewameter® TM 300, 및 시각적 아날로그 척도(VAS)를 사용하여 기준선, 2주 후, 그리고 4주 후에 각각 측정하였다. 부작용 발생 여부도 모니터링하였고, 통계 분석은 SPSS Statistics 26을 사용하여 진행하였다.

결과

가려움증 심각도가 유의미하게 감소하였고(6.86에서 2.81, p<0.001), 부작용은 보고되지 않았다.

결론

본 에멀전은 피부 보습을 크게 개선하고, TEWL을 감소시키며, 가려움증을 완화하여 피부 장벽 기능을 강화하여 향후 기능성 화장품 소재로 사용 가능할 것으로 사료된다.

Trans Abstract

Purpose

The skin, particularly the stratum corneum, plays a crucial role in protection and moisture retention. Scutellaria baicalensis, well-known for its anti-inflammatory and antimicrobial properties, was studied for its potential to alleviate itch associated with atopic skin.

Methods

A lamellar structured emulsion containing Scutellaria baicalensis root extract was prepared and tested on 21 adults. Participants applied the emulsion twice daily for 4 weeks. Skin surface moisture, tran-sepidermal water loss (TEWL), and itch severity were measured at baseline, after 2 weeks, and after 4 weeks using Corneometer CM825, Tewameter® TM 300, and visual analog scale (VAS), respec-tively. Adverse reactions were monitored. Statistical analysis was performed using SPSS Statistics 26.

Results

Itch severity decreased significantly (6.86 to 2.81, p<0.001). No adverse reactions were reported.

Conclusions

The emulsion significantly improved skin hydration, reduced TEWL, and alleviated itch, indicating its potential for enhancing skin barrier function and addressing dermatological concerns.

Trans Abstract

目的

皮肤,特别是角质层,在保护和保湿方面起着至关重要的作用。黄芩以其抗炎和抗菌特性而闻名,人们对其缓解特应性皮肤瘙痒的潜力进行了研究。

方法

制备了含有黄芩根提取物的层状结构乳液,并在21名成人身上进行了测试。参与者每天使用乳液两次,持续4周。分别使用Corneometer CM825、Tewameter® TM 300和视觉模拟量表(VAS)在基线、2周后和4周后测量皮肤表面水分、经皮水分流失(TEWL)和瘙痒严重程度。监测不良反应。使用SPSS Statistics 26进行统计分析。

结果

瘙痒严重程度显着降低(6.86至2.81,p<0.001)。没有不良反应的报道。

结论

该乳液显着改善皮肤水合作用,降低 TEWL,并减轻瘙痒,表明其具有增强皮肤屏障功能和解决皮肤病学问题的潜力。

Introduction

The skin, as an organ constantly exposed to the external environment, performs the crucial role of protecting the human body from physical damage and chemical substances while preventing moisture loss. Particularly, the stratum corneum, the outermost layer of the epidermis, is essential for skin moisturization and protection. It is well-established that maintaining a moisture content of over 10% in the stratum corneum is vital for healthy skin

Moreover, lamellar structures play a significant role in skin moisturization and barrier functions. Lamellar structures are a type of emulsified membrane composed of phospholipids, which are arranged in successive layers of oil and water phases. The structural characteristics of lamellar structures provide not only moisturization but also excellent stability and usability (Proksch et al., 2008).

Scutellaria baicalensis, native to East Asia including Korea, is known for its efficacy in treating various inflammatory conditions. The major active components of Scutellaria baicalensis roots are glycosides such as baicalin and wogonoside, along with their aglycones baicalein and wogonin. Additionally, other components like chrysin and oroxylin A are present. These constituents are reported to exhibit strong antioxidant, anti-inflammatory, and antimicrobial activities within the human body (Zhao et al., 2016).

In this study, the objective is to evaluate the efficacy of a lamellar structured emulsion containing Scutellaria baicalensis root extract in improving skin surface moisture, reducing transepidermal water loss (TEWL), and alleviating itch through clinical trials (Rawlings et al., 2004).

Materials and Methods

1. Preparing Scutellaria baicalensis Extract Using Supercritical Extraction

Prepare 100 g of finely cut, dry goldenseal root and use a supercritical extractor (ARIinstrument) and supercritical extraction using supercritical carbon dioxide at 45℃ and 350 bar to obtain 0.62 g of golden extract. Meanwhile, the ethanol used as a co-solvent was removed using a reduced pressure evaporator.

2. Preparation of Lamellar Structured Emulsion Containing Scutellaria baicalensis Extract

The lamellar structure is a type of emulsified form composed of phospholipids, where oil and water layers alternately stack to form a block-like arrangement. The structural characteristics of this lamellar structure contribute to its properties. When a liquid crystal phase is formed, the viscosity of the emulsion particles increases, and the structure becomes more stable. Compared to conventional O/W or W/O structures, the lamellar structure acts as a barrier with higher moisturizing properties due to its unique characteristics.

The lamellar structure consists of multiple layers of oil and water phases, offering excellent structural characteristics that can address both effectively.

The preparation of the lamellar structured emulsion involves combining several ingredients, which are divided into two phases: Phase A and Phase B. The composition is detailed in Table 1.

Composition of lamellar structured emulsion containing Scutellaria baicalensis extract

3. A Clinical Study

A study was conducted a survey was conducted on 21 adult men and women aged 19 years or older with dry skin on the forearm area (the part from the elbow to the wrist). Patients are informed before participating in the study, and after receiving their consent, the study proceeds and is tracked through the adherence diary. Participants were instructed to apply the prepared emulsion twice daily (morning and evening). All measurements and evaluations were conducted in an environment with controlled temperature and humidity conditions (22±2℃, 50±5%), ensuring no air movement or direct sunlight exposure. For the study, the test area was cleansed during the visit, and participants were asked to wait for at least 30 minutes to allow the skin to stabilize [IRB:HE-R24-0083].

1) Evaluation of Skin Surface Moisture Improvement

Skin surface moisture content (A.U.) and average dielectric constant (ε) of the forearm area were measured before the application, after 2 weeks of use, and after 4 weeks of use to evaluate the improvement in skin surface moisture. The measurements for skin surface moisture improvement were conducted using a Corneometer CM825 Probe (Courage Khazaka GmbH, Germany) and Epsilon E100 (Biox Systems Ltd., England).

2) Evaluation of TEWL Improvement

The TEWL of the forearm area (g/m2h) was measured before the application, after 2 weeks of use, and after 4 weeks of use to evaluate the improvement in TEWL. The TEWL measurements were conducted using a Tewameter® TM 300 (Courage Khazaka electronic GmbH).

3) Evaluation of Itch Improvement

The itch scores of the forearm area were measured before the application, after 2 weeks of use, and after 4 weeks of use to evaluate the improvement in itching. The itch improvement was evaluated using the visual analog scale (VAS) assessment method (10-point scale) as shown in Table 2.

Classification of itch severity

4) Evaluation of Adverse Skin Reactions

During the study period, the examiner monitored the occurrence of adverse skin reactions and the use of concomitant medications that could potentially affect the study outcomes. In the event of any adverse reaction, the examiner promptly notified the principal investigator. Upon verification, the principal investigator took appropriate measures and determined whether the participant could continue with the study.

5) Data Analysis and Interpretation

Statistical analysis was conducted using SPSS Statistics 26 to verify the statistical significance of changes before and after the use of the test product. Significance was confirmed at a 95% confidence interval with a p-value of <0.05. Continuous variables derived from device evaluations were expressed as means and standard deviations, while categorical variables from survey evaluations were expressed as frequencies and percentages. Normality of the data was assessed using the Shapiro-Wilk test. If normality was confirmed, parametric methods such as Repeated Measures ANOVA were used, followed by Bonferroni correction for post hoc analysis. In cases where normality was not satisfied, non-parametric methods such as the Friedman test were used, followed by Bonferroni correction and post hoc analysis with the Wilcoxon signed-rank test.

Results

1. Effect of Improving Skin Moisture

The skin surface moisture content (A.U.) of the forearm area significantly increased after 2 weeks and 4 weeks of using the test product compared to the baseline (Table 3). The initial average moisture content was 24.11±3.10 A.U., which increased to 31.71±2.78 A.U. after 2 weeks and 37.27±2.53 A.U. after 4 weeks. The statistical significance was confirmed with p-values of <0.001 for both time points. This indicates a substantial improvement in skin moisture, with improvement rates of 32.48% and 54.58% at 2 and 4 weeks, respectively, compared to the baseline.

Corneometer® CM 825 measurement results of skin moisture (N=21)

The average dielectric constant (ε) of the forearm area showed a significant increase after 2 weeks and 4 weeks of using the test product compared to the baseline measurements (Table 4). Initially, the average dielectric constant was recorded at 5.61± 2.18. After 2 weeks of application, it increased to 16.38±2.56, and after 4 weeks, it further rose to 21.46±2.63. The statistical significance of these changes was confirmed with p-values of <0.001 for both time points, indicating that the product effectively improved the dielectric properties of the skin, which correlates with enhanced moisture content.

Epsilon E100 measurement results of average dielectric constant (N=21)

2. Effect of Reducing TEWL

The TEWL in the forearm area significantly decreased after 2 and 4 weeks of using the test product compared to baseline levels (Table 5). The baseline TEWL was 11.02±1.77 g/m2h, which decreased to 9.49±1.43 g/m2h after 2 weeks and further to 8.19 ±1.13 g/m2h after 4 weeks. Both reductions were statistically significant with p-values of <0.001. These results demonstrate that the product effectively reduced water loss from the skin, showing improvement rates of 13.88% and 25.68% at 2 and 4 weeks, respectively, compared to baseline.

Tewameter® TM 300 measurement results of TEWL (N=21)

3. Effect of Alleviating Itch

This section highlights significant reductions in itch scores on a 10-point scale after 2 and 4 weeks of using the test product compared to baseline (Table 6). The baseline itch score was 6.86 ±0.91, which decreased to 4.90±0.83 after 2 weeks and 2.81± 1.12 after 4 weeks. These reductions were statistically significant with p-values of <0.001 for both time points. The improvement rates were 28.47% and 59.03% at 2 and 4 weeks, respectively, indicating a notable reduction in itch severity.

Evaluation results of itch on a 10-point scale (N=21)

4. Safety Evaluation

The evaluation of adverse skin reactions in test subjects revealed that after both 2 weeks and 4 weeks of product usage, no adverse skin reactions such as erythema (redness), edema (swelling), scaling, itching, pain, burning sensation, stiffness, or tingling were observed.

Discussion

Strengthening the skin barrier to solve a problem, During the research on substances that help to improve skin barrier and skin itching, it was confirmed that Scutellaria baicalensis supercritically extracted under certain conditions has useful activity for improving skin itching by containing circular liquid crystal lamellar structure, and this substance was developed. Therefore, the present invention has been developed to provide the above-mentioned benefits without side effects in humans (Lee & Park, 2015; Kim et al., 2022).

The present study aims to provide a cosmetic composition comprising Scutellaria baicalensis as an active ingredient that has excellent effects on strengthening the skin barrier and improving skin itching.

Lamellar structures, composed of phospholipids arranged in alternating layers of oil and water, are significant for their role in skin hydration and barrier function. These structures not only enhance the skin’s moisture content but also contribute to the stability and usability of skincare formulations. The effectiveness of lamellar emulsions in improving skin hydration has been demonstrated in various studies, indicating their potential for widespread application in dermatology (Egawa & Hirao, 2007).

Scutellaria baicalensis, a plant native to East Asia, is renowned for its anti-inflammatory, antioxidant, and antimicrobial properties. Its major active components include glycosides like baicalin and wogonoside, and their aglycones, baicalein and wogonin. These constituents have been extensively studied for their biological activities, which include significant benefits for skin health, such as reducing inflammation and protecting against oxidative (Chanchal et al., 2023).

The study investigated the efficacy of a lamellar structured emulsion containing Scutellaria baicalensis root extract in improving skin surface moisture, reducing TEWL, and alleviating itch. The study involved 21 adult participants who applied the emulsion twice daily for four weeks. Measurements of skin surface moisture, TEWL, and itch severity were taken at baseline, after two weeks, and after four weeks using standardized instruments and methods, ensuring reliable and reproducible results (Yan et al., 2024; Safta et al., 2024; Zhu et al., 2006).

The results demonstrated significant improvements in skin hydration, as evidenced by the increase in skin moisture content from 24.11 to 37.27 A.U. and the dielectric constant from 5.61 to 21.46 after four weeks of use (p<0.001). These findings are consistent with previous research that underscores the effectiveness of lamellar structures in enhancing skin moisturization. Additionally, the study showed a significant reduction in TEWL from 11.02 to 8.19 g/m2h, indicating an improved barrier function (p<0.001). This is particularly important as TEWL is a critical indicator of the integrity of the skin barrier. The reduction in itch severity from 6.86 to 2.81 (p<0.001) further supports the emulsion’s potential in managing conditions associated with dry and itchy skin, aligning with the known anti-inflammatory properties of Scutellaria baicalensis. This aligns with the known properties of baicalin, a major component of Scutellaria baicalensis, which inhibits pro-inflammatory cytokines such as IL-6 and TNF-α (Li et al., 2004; Yoon et al. 2013).

Furthermore, the study (Wang et al., 2022; Park et al., 2024) demonstrates the effectiveness of Scutellaria baicalensis extract in alleviating conditions associated with dry and itchy skin, supporting the findings of this study. Further research is recommended to explore long-term effects and broader applications in skincare formulations (Kasolang et al., 2020; Kim et al., 2022).

No adverse reactions were reported during the study, suggesting that the emulsion is well-tolerated and safe for regular use. This is an important consideration for any skincare product, particularly those intended for sensitive or compromised skin (Ruge et al., 2021).

Conclusions

The lamellar structured emulsion containing Scutellaria baicalensis root extract demonstrated significant improvements in skin hydration, reduced TEWL, and alleviated itch without causing any adverse skin reactions. These findings suggest that the emulsion can effectively enhance skin barrier function and address common dermatological concerns such as dryness and itchiness. The emulsion's ability to improve skin moisture and reduce TEWL highlights its potential as a valuable addition to skincare formulations aimed at enhancing skin health.

Notes

Author's contribution

GRK designed all experimental studies and YJC assisted in experimental design. GRK and YJC supervised the project and contributed to all aspects of analysis and experimental design. YJC supervised the safety of the research experiments as a physician.

Author details

Yoon-Jung Choy (Professor), Department of Optometry, Eulji University, 553, Sanseong-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do 13135, Korea; Gyu-Ri Kim (Professor), Department of Biotechnology, Major in Cosmetic Science, Eulji University, 553, Sanseong-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do 13135, Korea.

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Article information Continued

Table 1.

Composition of lamellar structured emulsion containing Scutellaria baicalensis extract

Phase Ingredient Composition (wt%)
A Water Up to 100
Butylene glycol 10
B Dipropylene glycol 10
Cholesterol 0.5
Polyglyceryl-10 caprate 0.5
Ceramide ENP 1.6
Ceramide NP 0.4
Cetearyl alcohol 4
Lecithin 2
Scutellaria baicalensis root extract 1

Table 2.

Classification of itch severity

Score Degree of itchiness
0 No itchiness
1-3 Mild pruritus
3-7 Moderate pruritus
7-9 Severe pruritus
10 Very severe pruritus

Table 3.

Corneometer® CM 825 measurement results of skin moisture (N=21)

Location, Evaluation parameter Forearm, Skin moisture (A.U.)
Time point
Before using the test product 24.11±3.10
After 2 weeks of use 31.71±2.78
After 4 weeks of use 37.27±2.53
Significant probability* Compared to before use (2 weeks) <0.001
Compared to before use (4 weeks) <0.001
Improvement rate Compared to before use (2 weeks) 32.48%
Compared to 100% before use (2 weeks) 132.48%
Compared to before use (4 weeks) 54.58%
Compared to 100% before use (4 weeks) 154.58%
*

p-value: significant probability, repeated measures ANOVA, post-hoc Bonferroni correction (p <0.05, comparison to initial value); Mean±Standard deviation.

Table 4.

Epsilon E100 measurement results of average dielectric constant (N=21)

Location, Evaluation parameter Forearm, Average dielectric constant (ε)
Time point
Before using the test product 5.61±2.18
After 2 weeks of use 16.38±2.56
After 4 weeks of use 21.46±2.63
Significant probability* Compared to before use (2 weeks) <0.001
Compared to before use (4 weeks) <0.001
Improvement rate Compared to before use (2 weeks) 191.98%
Compared to 100% before use (2 weeks) 291.98%
Compared to before use (4 weeks) 282.53%
Compared to 100% before use (4 weeks) 382.53%
*

p-value: significant probability, repeated measures ANOVA, post-hoc Bonferroni correction (p <0.05, comparison to initial value); Mean±Standard deviation.

Table 5.

Tewameter® TM 300 measurement results of TEWL (N=21)

Location, Evaluation parameter Forearm, TEWL (g/m2h)
Time point
Before using the test product 11.02±1.77
After 2 weeks of use 9.49±1.43
After 4 weeks of use 8.19±1.13
Significant probability* Compared to before use (2 weeks) <0.001
Compared to before use (4 weeks) <0.001
Improvement rate Compared to before use (2 weeks) 13.88%
Compared to 100% before use (2 weeks) 113.88%
Compared to before use (4 weeks) 25.68%
Compared to 100% before use (4 weeks) 125.68%
*

p-value: significant probability, repeated measures ANOVA, post-hoc Bonferroni correction (p <0.05, comparison to initial value); Mean±Standard deviation.

Table 6.

Evaluation results of itch on a 10-point scale (N=21)

Location, Evaluation parameter Forearm, Itch score (score)
Time point
Before using the test product 6.86±0.91
After 2 weeks of use 4.90±0.83
After 4 weeks of use 2.81±1.12
Significant probability* Compared to before use (2 weeks) <0.001
Compared to before use (4 weeks) <0.001
Improvement rate Compared to before use (2 weeks) 28.47%
Compared to 100% before use (2 weeks) 128.47%
Compared to before use (4 weeks) 59.03%
Compared to 100% before use (4 weeks) 159.03%
*

p-value: significant probability, repeated measures ANOVA, post-hoc Bonferroni correction (p <0.05, comparison to initial value); Mean±Standard deviation.