The sensitizing capacity of the antioxidants propyl, octyl, and dodecyl gallate and some related gallic acid esters

8 alkyl gallates, including the widely used antioxidants propyl, octyl, and dodecyl (= lauryl) gallate, have been subjected to experimental sensitization in guinea pigs. Using a modern sensitization procedure, the results showed that all gallates are moderate to strong contact sensitizers: dodecyl (= lauryl) gallate was found to be the strongest. A characteristic correlation between side chain length and mean response was observed, giving a maximum of sensitization at a length of 12 carbon atoms (dodecyl gallate). A literature review revealed that the frequency of reports of allergic contact dermatitis from antioxidants of the gallate type has increased in the last 4 years. In most cases, the moderate sensitizer propyl gallate was the source of sensitization.     

Allergic contact dermatitis to propyl gallate

The antioxidant propyl gallate in a moisturizing cream caused an allergic contact dermatitis in a patient previously sensitized to gallates while working in a bakery.     

Dodecyl gallate, permitted in food, is a strong sensitizer

Additives are now an established part of our packaged food. Some, like colouring agents and flavouring compounds are hardly necessary or even redundant. Others, mainly antimicrobials and antioxidants, are very important. Antioxidants are not only added to food, but also to cosmetics, pharmaceuticals and industrial products. Dodecyl gallate belongs with propyl- and octyl-gallate to the synthetic esters of gallic acid. These lipid-soluble phenols are very effective antioxidants. We found contact allergy in 4 of 10 workers having only limited contact with dodecyl gallate in the very low concentration of 0.05%. It is important to recognize its strong sensitizing capacity. Workers working with dodecyl gallate should avoid direct skin contact.     

Protective effect of epigallocatechin gallate on the immune function of dendritic cells after ultraviolet B irradiation

Aim  To investigate the protective effect of epigallocatechin gallate (EGCG) on the immune function of dendritic cells (DCs) after ultraviolet B irradiation (UVB) and its underlying mechanisms.
Methods  The monocytes were isolated from peripheral blood and cultivated into DCs with cytokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4. DCs were harvested after cultivation for 7 days and subjected to irradiation with different dosages of UVB. Then, 200 μg/mL of EGCG was added in certain groups 24 h before irradiation. DCs simply treated with UVB or treated with both UVB and EGCG were co-cultured with lymphocytes, and Mono-nuclear cell direct cytotoxicity (MTT) assay was used to detect the ability of DCs to stimulate proliferation of lymphocytes. Surface markers CD80, CD86, human leukocyte antigen(locus)-DR (HLA-DR), and CD40 were detected using flow cytometry, and the levels of IL-10 and IL-12 secreted from DCs 24 h after cultivation were measured using ELISA.
Results  UVB irradiation was able to inhibit the ability of DCs to stimulate the proliferation of lymphocytes and surface expressions of CD80, CD86, HLA-DR, and CD40 on DCs in a dose-dependent manner. The inhibition rate of DCs was improved to some extent after treatment with 200 μg/mL of EGCG. UVB showed no significant influence on the secretion of IL-10 and IL-12 from DCs, while EGCG was able to down-regulate the secretion level of IL-12 and up-regulate that of IL-10.
Conclusions  EGCG can antagonize the inhibitory effect on DCs induced by UVB irradiation. This function has some relationship with its protecting effect of the expression of the costimulating molecules on the surface of DCs and the secretion level of IL-10 and IL-12.     

表没食子儿茶素没食子酸酯对紫外线诱导的角质形成细胞分泌血管内皮生长因子的影响

目的：研究绿茶中表没食子儿茶素没食子酸酯（EGCG）对中波紫外线（UVB）诱导角质形成细胞HaCaT株（简称HaCaT细胞）分泌血管内皮生长因子（VEGF）的影响。方法：试验共设立空白对照组、单纯加药组、单纯照光组和加药照光组4组,以15mJ/cm^2 UVB的剂量照射细胞,酶联免疫吸附试验（EUSA）方法检测不同时间细胞上清液中VEGF含量。反转录（RT）-PCR测定VEGFmRNA表达。结果：UVB照射后,HaCaT细胞分泌的VEGF在照光后12h开始明显增加,随时间延长。VEGF水平逐渐增加。EGCG对UVB诱导的VEGF升高有明显抑制作用。在12、18、24h3个时间点．EGCG明显抑制VEGF水平的升高。结论：EGCG可以抑制紫外线诱导的HaCaT细胞分泌VEGF。     

Clinical Evaluation of a New-Formula Shampoo for Scalp Seborrheic Dermatitis Containing Extract of Rosa centifolia Petals and Epigallocatechin Gallate: A Randomized,Double-Blind,Controlled Study

Background

Scalp seborrheic dermatitis is a chronic type of inflammatory dermatosis that is associated with sebum secretion and proliferation of Malassezia species. Ketoconazole or zinc-pyrithione shampoos are common treatments for scalp seborrheic dermatitis. However, shampoos comprising different compounds are required to provide patients with a wider range of treatment options.

Objective

This study was designed to evaluate a new-formula shampoo that contains natural ingredients-including extract of Rosa centifolia petals and epigallocatechin gallate (EGCG)-that exert antioxidative, anti-inflammatory, and sebum secretion inhibitory effects, and antifungal agents for the treatment of scalp seborrheic dermatitis.

Methods

Seventy-five patients were randomized into three treatment groups; new-formula shampoo, 2% ketoconazole shampoo, and 1% zinc- pyrithione shampoo. The clinical severity scores and sebum levels were assessed by the same dermatologists at baseline (week 0), and at 2 and 4 weeks after using the shampoo. User satisfaction and irritation were also assessed with the aid of a questionnaire.

Results

The efficacy of the new-formula shampoo was comparable to that of both the 1% zinc-pyrithione shampoo and the 2% ketoconazole shampoo. Furthermore, it was found to provide a more rapid response than the 1% zinc-pyrithione shampoo for mild erythema lesions and was associated with greater user satisfaction compared with the 2% ketoconazole shampoo. However, the new-formula shampoo did not exhibit the previously reported sebum inhibitory effect.

Conclusion

Extract of R. centifolia petals or EGCG could be useful ingredients in the treatment of scalp seborrheic dermatitis.     

Efficacy of anti-sebum moisturizing cream containing 2% l-carnitine and 5% epigallocatechin gallate in seborrhea: A randomized clinical trial

Background

Seborrhea leads to facial greasiness and unpleasant feeling. People with seborrhea also have trouble with selecting moisturizers. l -Carnitine and epigallocatechin gallate (EGCG) are reported anti-sebum properties. However, neither efficacy comparison nor the combination effect of the two topical anti-sebum agents was studied. Moisturizing cream with these agents is supposed to provide skin with an optimal water–oil balance.

Aims

To compare the efficacy of moisturizer containing 2% l -carnitine or 5% EGCG alone on sebum controlling, and the synergistic effect of these two agents.

Methods

Three study creams were formulated by adding three kinds of anti-sebum agents which were 2% l -carnitine, 5% EGCG, and 2% l -carnitine plus 5% EGCG in moisturizing cream base of dimethicone and glycerin. A randomized clinical trial was conducted. Ninety subjects, divided into three groups, applied the cream for 4 weeks. Sebum level, skin capacitance, and transepidermal water loss (TEWL) were evaluated at Weeks 0, 1, 2, and 4. Life qualities and subjective outcomes were assessed before and after treatment.

Results

The mean sebum reduction from baseline was statistically significant in all treatment groups (p < 0.01). The median time to oil control was longer in l -carnitine group. The combine group had significantly greater anti-sebum efficacy than l -carnitine group (p = 0.009). All three groups had significant improvement of other objective parameters and subjective outcomes.

Conclusions

The anti-sebum moisturizing cream exhibited beneficial effect on the sebum reduction with improve skin hydration in people with seborrhea and made users satisfied. The EGCG group and the combine group show the greater anti-sebum effect than the l -carnitine group.     

紫外线对皮肤角质形成细胞和成纤维细胞产生MMP-1和MMP-3的影响

目的:研究中波紫外线辐射对体外培养的表皮角质形成细胞和真皮成纤维细胞产生基质金属蛋白酶-1(MMP-1)和MMP-3的直接和间接影响,研究绿茶中的主要活性成分表没食子儿茶酚没食子酸酯(EGCG)对此影响的保护作用。方法:体外培养角质形成细胞株HaCaT和真皮成纤维细胞,中波紫外线辐射、不同浓度IL-6刺激及EGCG处理后,ELISA方法测定上清液中Pro-MMP-1和MMP-3蛋白含量,半定量RT-PCR方法测细胞中mRNA含量。结果:UVB30mJ/cm2辐射后角质形成细胞分泌的pro-MMP-1和MMP-3并未增加(P>0.05),真皮成纤维细胞合成和分泌MMP-1和MMP-3mRNA含量和蛋白水平均显著增加(P<0.05),IL-6(8、16、24pg/mL)可显著增加成纤维细胞产生MMP-1和MMP-3(P<0.05)。EGCG(0.15、0.3mM)能够显著抑制紫外线诱导成纤维细胞产生MMP含量的增加(P<0.05),但IL-6刺激成纤维细胞所产生的MMP-1和MMP-3的增加不受EGCG的影响(P>0.05)。结论:中波紫外线辐射并不能直接导致角质形成细胞分泌MMP-1和MMP-3增加,但紫外线辐射后角质形成细胞分泌的IL-6可促进成纤维细胞产生MMP。EGCG对IL-6刺激成纤维细胞产生MMP增加没有影响,但它可以显著抑制紫外线辐射直接导致的成纤维细胞产生MMP-1和MMP-3的增加,对防治皮肤光老化可能有一定作用。     

Effects of topical application of EGCG on testosterone-induced hair loss in a mouse model

Abstract: We investigated the effect of topical epigallocatechin‐3‐gallate (EGCG) on testosterone (T)‐induced hair loss in mice. Marked hair loss was observed at the T‐injected site, and topical EGCG significantly reduced the hair loss (P < 0.05). TUNEL staining showed apoptosis of follicular epithelial cells in the T‐injected groups where topical EGCG was found to significantly diminish T‐induced apoptosis (P < 0.05). Topical EGCG down‐regulated the T‐induced expression of androgen receptor but did not down‐regulate 17β‐hydroxysteroid dehydrogenase (HSD) and three β‐HSD expression. Analysis using liquid chromatography tandem mass spectrometry (LC‐MS/MS) on serum and tissue samples revealed no significant difference in T and dihydrotestosterone concentrations between the T‐injected and T + EGCG groups. Thus, we found that T injection in a mouse model induces hair loss by apoptosis of the hair follicles rather than through the androgen metabolic pathway and also saw that T‐induced apoptosis of hair follicles was reduced by topical EGCG.     

表没食子儿茶素没食子酸酯和补骨脂对莫诺苯宗诱导白癜风样小鼠的影响

目的 探讨表没食子儿茶素没食子酸酯（EGCG）和补骨脂对莫诺苯宗诱导的白癜风样小鼠的影响。 方法 C57BL/6小鼠40只,脱去背部2 cm × 2 cm区域毛,随机分为4组,每组10只。阴性对照组涂抹凡士林乳膏;模型组涂抹40%莫诺苯宗乳膏;EGCG组先后涂抹5% EGCG、40%莫诺苯宗乳膏;补骨脂组先后涂抹7%补骨脂、40%莫诺苯宗乳膏。观察小鼠皮肤和毛发脱色情况,组织病理检查观察淋巴细胞浸润,免疫荧光检测CD8+ T细胞表达量。 结果 阴性对照组小鼠皮肤和毛发无脱色现象。模型组小鼠在用药部位及非用药部位均有脱色现象,EGCG组和补骨脂组小鼠用药部位全部出现脱色,用药部位出现脱色斑的平均时间分别为16.7、29.3和19.9 d,脱色面积指数分别为4.00 ± 0.00、2.11 ± 0.54、2.84 ± 0.79,EGCG组、补骨脂组和模型组之间脱色面积指数差异有统计学意义（F = 14.17,P < 0.05）,EGCG组和补骨脂组分别与模型组比较,脱色面积指数差异均有统计学意义（均P < 0.05）;同时,EGCG组和补骨脂组非用药部位的脱色面积指数差异同样有统计学意义（P < 0.05）。EGCG组和补骨脂组CD8+ T细胞表达量均低于模型组,EGCG组和补骨脂组差异亦有统计学意义（P < 0.05）。 结论 EGCG和补骨脂对莫诺苯宗诱导的小鼠皮肤和毛发脱色均有干预作用,EGCG的干预作用比补骨脂的干预作用强,该动物模型与人类白癜风具有极高相似性。     

表没食子儿茶素没食子酸酯抑制白细胞介素17诱导的角质形成细胞增殖和凋亡

目的 探讨表没食子儿茶素没食子酸酯(EGCG)对白细胞介素17(IL-17)诱导的角质形成细胞损伤的保护作用及其机制.方法 实验分空白对照组、IL-17组、IL-17+ EGCG组、IL-17+ SP600125组和IL-17+EGCG+茴香霉素组.CCK-8试剂盒检测细胞增殖;流式细胞仪检测细胞凋亡;ELISA试剂盒检测IL-6、IL-23和IL-8的表达;Western印迹检测JNK和P-JNK的表达.结果 IL-17促进HaCaT细胞增殖,且增殖率与IL-17浓度有关,90 μg/L IL-17组的细胞增殖率最高(P＜0.05).60 μmol/L EGCG显著抑制90 μg/L IL-17诱导的细胞增殖(P＜0.05),促进细胞凋亡(P＜0.05),降低IL-6、IL-23和IL-8的表达(P＜0.05).与IL-17组相比,IL-17+ EGCG组、IL-17+ SP600125组的P-JNK表达显著下调(P＜ 0.05),细胞增殖率降低(P＜0.05),IL-6、IL-23和IL-8的表达减少(P＜0.05);与IL-17+ EGCG组相比,IL-17+ EGCG+茴香霉素组的P-JNK表达显著上调(P＜0.05),细胞增殖率和IL-6、IL-23、IL-8的表达均明显上升(P＜0.05).结论 EGCG对IL-17诱导的HaCaT细胞增殖凋亡、炎症反应等损伤具有保护作用,其保护作用可能与抑制JNK信号通路有关.     

全乙酰化表没食子儿茶素没食子酸酯对氧化应激导致黑素细胞损伤的保护作用研究

目的 研究全乙酰化表没食子儿茶素没食子酸酯（AcEGCG）对H2O2诱导的人表皮黑素细胞损伤的保护作用,探讨其可能的作用机制。 方法 体外培养人表皮黑素细胞,采用H2O2诱导细胞损伤模型。实验分对照组、H2O2组、不同浓度表没食子儿茶素没食子酸酯（EGCG）组和AcEGCG组。MTS法测定细胞存活率,LDH测试盒检测乳酸脱氢酶（LDH）的漏出量,流式细胞仪检测细胞内活性氧（ROS）的表达水平;Western印迹法检测半胱氨酸天冬氨酸蛋白酶9（caspase-9）和半胱氨酸天冬氨酸蛋白酶3（caspase-3）的表达情况。多个样本均数比较采用单因素方差分析,各样本间多重比较采用SNK-q检验。 结果 与对照组相比,H2O2处理组黑素细胞存活率明显降低（22.99% ± 0.53%,P < 0.01）,细胞内LDH漏出量增加（36.58% ± 0.73%,P < 0.01）,细胞内ROS水平明显升高（19.08 ± 0.57,P < 0.01）,caspase-9和caspase-3表达升高（分别为2.65 ± 0.079和2.36 ± 0.057,均P < 0.01）。与H2O2组相比,细胞存活率在10、20、40 μmol/L AcEGCG组（79.50% ± 3.62%、86.52% ± 5.13%、97.81% ± 5.21%）及EGCG组（43.19% ± 1.68%、63.34% ± 3.60%、70.82% ± 2.1%）明显增加（均P < 0.01）,caspase-9分别降低为1.44 ± 0.067、1.26 ± 0.059、1.10 ± 0.072及2.31 ± 0.085、2.13 ± 0.091、1.35 ± 0.064,caspase-3分别降低为1.70 ± 0.053、1.57 ± 0.057、1.24 ± 0.068及2.09 ± 0.076、1.98 ± 0.093、1.79 ± 0.056,差异均有统计学意义（P < 0.05）;LDH含量均明显下降（P < 0.01）;40 μmol/L AcEGCG或EGCG处理后,ROS含量明显下降（均P < 0.01）。 结论 AcEGCG对H2O2诱导的黑素细胞氧化应激损伤有显著的保护作用,且显著优于EGCG,可能通过清除自由基、抗氧化、降低caspase-9及caspase-3表达等途径发挥作用。     

EGCG对中波紫外线诱导HaCaT细胞p53基因和蛋白表达的实验研究

目的:研究表没食子儿茶素没食子酸酯(EGCG)对中波紫外线(UVB)照射诱导永生化角质形成细胞株-HaCaT细胞的p53 mRNA和p53蛋白表达的影响。方法:以一定剂量UVB照射HaCaT细胞,并以200μg/mL EGCG处理照射后的HaCaT细胞,分别用RT-PCR法和Western blot方法检测各处理条件下p53 mRNA和/或p53蛋白的表达水平。结果:30 mJ/cm2的UVB照射后HaCaT细胞的p53 mR-NA和p53蛋白表达逐渐增加,4 h达到峰值,4 h后随照射剂量增加而增加,24 h后有所恢复;加入EGCG可下调UVB诱导的表达作用。结论:UVB照射对HaCaT细胞p53 mRNA和p53蛋白的诱导表达有时效性与量效性,EGCG可下调UVB照射的这种诱导作用。