皮肤化学美白剂抑制酪氨酸酶活性的研究

采用化学评价法,即通过测定皮肤美白剂对酪氨酸酶的活性抑制率,对9类13种皮肤美白剂的活性进行了评价与比较,排出了抑制次序;穷乡僻壤 制了各美白剂浓度与其酪氨酸抑制率关系曲线;多数美白剂呈钟形曲线;得到了各美白剂的ICmax及IC50;探讨了酪氨酸酶抑制率与美白效果评价的关系。     

一款高效美白剂组合的研究

采用单因素试验的方法,通过测定市场常见的皮肤美白剂对酪氨酸酶活性的体外抑制率。结果表明：体外美白效果最好的为光甘草定,其次是AA2G,再次为熊果苷,它们的美白功效均优于具有美白功效的植物提取液。同时,通过正交设计实验得到一种高效的皮肤美白剂复配组合,复配组合的皮肤美白剂添加量分别为：光甘草定0.05%,AA2G1%,烟酰胺1%,芦荟粉0.3%。此复配组合对酪氨酸酶活性的抑制率高达98.97%。由此得到的一款美白乳液,pH值为6.6,通过稳定性实验,其结果符合QB/T2286—1997。     

油溶性美白剂对酪氨酸酶抑制性能的测试方法

化学分析方法测定油溶性美白剂对酪氨酸酶活性的抑制率可在有机溶剂-水体系中进行。通过测定若干单一有机溶剂和复配有机溶剂对酪氨酸酶活性的抑制率及相关的溶解参数，发现复配有机溶剂V(丙二醇)：V(乙酸乙酯)为9：1的用量为0．5mL时，对酪氨酸酶活性的抑制率为29．4％。该复配有机溶剂与水构成的测试体系可用于油溶性美白剂，如异甘草素和甘草素对酪氨酸酶活性的抑制率的测定。     

3-O-乙基维生素C抑制酪氨酸酶性能的研究

酪氨酸酶有催化氧化L-酪氨酸及L-多巴生成黑色素的作用.通过吸光光度法测定比较几种常用美白剂对酪氨酸酶活性的抑制率,以此评价3-O-乙基维生素C抑制酪氨酸酶活性的能力.实验结果表明,3-O-乙基维生素C对酪氨酸酶催化氧化L-酪氨酸活性最高抑制率为80.8%,仅次于曲酸(抑制率为95.5%),高于维生素C(抑制率为68.5%);对酪氨酸酶催化氧化L-多巴活性最高抑制率为89.1%,IC50值为0.15 mmol/L,具有很好的酪氨酸酶活性抑制性能.     

皮肤黑素成因分析与美白祛斑功效评价体系的研究

本文探讨了皮肤黑素细胞的生成与代谢、阻止黑素生物合成的关键因素,通过测定AA2G等几种典型美白剂对酪氨酸酶活性的抑制率建立了美白砝斑效果的功效评价体系。实验表明甘草等天然成份也有很好的美白祛斑效果。同时开展了高效安全的美白祛斑化妆品配方研究,产品有很好的市场前景。     

马铃薯酪氨酸酶体外筛选美白剂测定体系的建立

以儿茶酚为底物,研究了自制马铃薯酪氨酸酶的动力学性质,建立了利用马铃薯酪氨酸酶体外筛选美白剂的测定体系,测定了12种中药提取物的酪氨酸酶抑制活性。结果表明,马铃薯酪氨酸酶的适宜反应条件为:30℃、pH=6.5;以儿茶酚为底物,酶促反应产物的最大吸收波长为420 nm;马铃薯酪氨酸酶的动力学参数如下:Vmax=0.284 9 min-1;Km=5.441 2 mmol/L;在12种中药的乙醇〔φ(C2H5OH)=50%〕提取液中,生药质量浓度达到2 g/L时,红花(Carthamus tinctorius L.)、杨梅叶(Myrica rubra S.)、黄芩(Scutellaria baicalensis G.)和绿茶(Camellia sinensis L.)相对L-抗坏血酸(ρ=0.2 g/L)的酪氨酸酶抑制率分别达到128.62%、83.64%、79.65%和66.48%,它们在美白化妆品领域有潜在的应用价值。     

古方三白汤不同溶剂提取物美白作用比较研究

研究三白汤水提取物、50%乙醇提取物、纯乙醇提取物对酪氨酸酶活性的抑制作用,以筛选出最佳提取溶剂及最佳提取工艺,为进一步开发三白汤美白产品奠定基础。采用超声沉法提取三白汤不同溶剂提取物,以酪氨酸酶的抑制活性评价不同溶剂提取物的美白作用,同时对提取方法进行考察。结果表明,三白汤水提取物、50%乙醇提取物、纯乙醇提取物对酪氨酸酶活性抑制率分别为：39.02%,86.19%,80.38%。三白汤50%乙醇提取物、纯乙醇提取物对酪氨酸酶均有明显的抑制作用,其中以50%乙醇提取物作用最强,在治疗黑色素增多性疾病及美白皮肤方面有潜在的应用价值。     

三种美白剂对酪氨酸酶活性的抑制

酪氨酸酶为黑色素生成的关键酶 ,抑制其活力即可抑制黑色素的生成。用L -酪氨酸酶作底物 ,体外测定了三种常用美白剂 (对苯二酚、熊果苷、曲酸 )对酪氨酸酶活性的影响。发现这些美白剂均能不同程度地抑制酪氨酸酶活性 ,并初步探讨了其增白作用的机制。     

基于美白功效优化白芍花的提取工艺

以亳白芍（安徽亳州产白芍）非药用部位白芍花为原料，酪氨酸酶活性抑制率和DPPH自由基清除率的综合评分为指标，采用单因素试验和正交试验优选出白芍花美白活性成分的最佳提取工艺。结果显示，白芍花的最佳提取工艺为：体积分数为70%的乙醇，料液比1∶20(g/mL)，提取时间2 h，提取温度80℃。在此条件下得到的白芍花提取物，其酪氨酸酶活性抑制率为（60.54%±1.54%）,DPPH自由基清除率为（87.00%±1.60%），美白度为（73.77%±1.38%）。说明该白芍花提取物具有较好的美白功效，可为其日化产品的进一步开发提供理论依据。     

美白祛斑剂的复配研究及在化妆品中的应用

筛选出三种新型用于复配的美白祛斑剂,分别是传明酸、壬二酸衍生物、红景天提取物,探讨初选的三个美白剂质量含量分别为1％、2％、3％、4％、5％时的酪氨酸酶抑制率,确定了最佳的复配含量,通过稳定性评价和微生物检测实验,鉴定了复配产品是否符合国家化妆品生产管理规范。     

2,4,6,4＇-四羟基脱氧安息香的合成及其抑制酪氨酸酶活性的研究

合成2,4,6,4'-四羟基脱氧安息香(THDB),对其抑制酪氨酸酶活性进行评价。在无水氯化锌和氯化氢存在下,以间苯三酚和对羟基苯乙腈为原料,进行THDB的合成,并对所得化合物在0.05%、0.10%、0.20%、0.25%、0.30%、0.35%、0.40%七个浓度下与根皮素、熊果苷和曲酸进行抑制酪氨酸酶对比实验。收率由原来报导的46.5%提高到60.0%,在0.4%浓度时THDB对酪氨酸酶的抑制率达98.2%。本工艺是合成THDB的较佳工艺,THDB对酪氨酸酶的抑制作用比熊果苷和曲酸好,与根皮素相当。     

Evaluation of Depigmenting Activity by 8-Hydroxydaidzein in Mouse B16 Melanoma Cells and Human Volunteers

In our previous study, 8-hydroxydaidzein (8-OHDe) was demonstrated to be a potent and unique suicide substrate of mushroom tyrosinase. In this study, the compound was evaluated for in vitro cellular tyrosinase and melanogenesis inhibitory activities in mouse B16 melanoma cells and for in vivo skin-whitening activity in human volunteers. Tyrosinase activity and melanogenesis in the cell culture incubated with 10 μM of 8-OHDe were decreased to 20.1% and 51.8% of control, respectively, while no obvious cytotoxicity was observed in this concentration. In contrast, a standard tyrosinase inhibitor, kojic acid, showed 69.9% and 71.3% of control in cellular tyrosinase and melanogenesis activity, respectively, at a concentration as high as 100 μM. Hence, 8-OHDe exhibited more than an inhibitory effects on melanin production in B16 cells 10-fold stronger than kojic acid. In addition, when a cream containing 4% 8-OHDe was applied to human skin in an in vivo study, significant increases in the dL*-values were observed after three weeks. Moreover, the increase in the dL*-values after 8-week treatment with 4% 8-OHDe (from −0.57 to 1.94) is stronger than those of 2% 8-OHDe treatment (from 0.26 to 0.94) and 2% ascorbic acid-2-glucoside treatment (from 0.07 to 1.54). From the results of the study, it was concluded that 8-OHDe, the potent suicide substrate of mushroom tyrosinase, has depigmenting activities in both mouse melanoma cells and in human volunteers. Thus, the compound has significant potential for use in cosmetics as a skin-whitening ingredient.     

Biocatalysis of tyrosinase in chloroform medium,using selected phenolic substrates

The biocatalysis of mushroom tyrosinase was optimized in chloroform medium using as substrates selected phenolic compounds, including chlorogenic acid (CA), p‐aminophenol (pAP) and hydroquinone (HQ). The specific activity of tyrosinase was found to be much higher in the chloroform medium than that obtained in the aqueous one. The optimal pH and temperature as well as other kinetic parameters for tyrosinase biocatalysis was also determined. The presence of catechol in the chloroform medium resulted in an increase in tyrosinase activity when CA was used as substrate; however, no activatory effect was found with pAP or HQ. The presence of ethylenediamine tetraacetic acid in the chloroform medium showed different effects on tyrosinase activity depending on the nature of the substrate. FT‐IR analyses confirmed the bioconversion of selected phenolic substrates into o‐quinones by tyrosinase activity in the chloroform medium. © 2000 Society of Chemical Industry     

谷胱甘肽和壳聚糖美白活性的研究

通过测定壳聚糖、壳低聚糖、谷胱甘肽对酪氨酸酶活性的抑制率，对它们的美白功效进行了测定，并与熊果苷进行了比较。结果表明，壳聚糖、壳低聚糖、谷胱甘肽对酪氨酸酶活性有明显的抑制作用，其中谷胱甘肽的抑制作用最为明显，在较低的浓度下就具有很高的抑制效果；把壳聚糖和谷胱甘肽与熊果苷复配，可使抑制率达到90％以上。     

香草酸对酪氨酸酶催化活性的抑制作用

采用酶动力学方法研究了香草酸对酪氨酸酶单酚酶和二酚酶活力的抑制效应。结果表明,香草酸对酪氨酸酶单酚酶和二酚酶活性均有抑制作用,导致单酚酶活力和二酚酶活力下降50%的香草酸浓度(IC50)约分别为1.3 mmol/L和2.6 mmol/L。香草酸能明显延长单酚酶的迟滞时间,2 mmol/L香草酸能使迟滞时间由1.1 m in延长至4.7 m in。香草酸对二酚酶的抑制作用表现为混合型抑制,对游离酶的抑制常数(KI)和对酶-底物络合物的抑制常数(KIS)分别为1.76 mmol/L和8.57 mmol/L。     

火焰子生物碱对酪氨酸酶的抑制作用

以磷酸缓冲溶液为反应体系、以左旋多巴为底物,采用分光光度法研究了火焰子生物碱对马铃薯酪氨酸酶活性的影响.结果表明,火焰子生物碱对马铃薯酪氨酸酶有抑制作用,抑制作用随着浓度的增大而增强,当火焰子生物碱浓度为1.25 mg·mL-1时,抑制率达最大,为29.27%,导致酶活力下降一半所需的抑制剂浓度(IC50)为0.93 ...     

4-[(2-四氢吡喃)氧]苯酚的合成

4-[(2-四氢吡喃)氧]苯酚(脱氧熊果苷)是一种有效的酪氨酸酶抑制剂,可作为化妆品添加剂来实现美白功能。今以对苯二酚为原料,经过对苯二酚单苄醚化、另一酚羟基四氢吡喃醚化、加氢脱苄基等步骤合成4-[(2-四氢吡喃)氧]苯酚。该路线中二氢吡喃保护羟基采用了吡啶对甲苯磺酸盐(PPTS)作催化剂,获得了满意的结果。各步反应比较适宜的工艺条件(反应温度,反应时间,摩尔收率)分别为,对苯二酚单苄醚化:75℃,3h,36%;另一酚羟基四氢吡喃醚化:30℃,5h,80%;加氢:30℃,24h,79%。产物熔点与文献报道相符,并通过1H-NMR确认了脱氧熊果苷的结构。     

Determination of the Thermodegradation of deoxyArbutin in Aqueous Solution by High Performance Liquid Chromatography

Tyrosinase is the key and rate-limiting enzyme responsible for the conversion of tyrosine into melanin. Competitive inhibition of tyrosinase enzymatic activity results in decreased or absent melanin synthesis by melanocytes in human skin. DeoxyArbutin (4-[(tetrahydro-2H-pyran-2-yl)oxy]phenol), a novel skin whitening agent, was synthesized through the removal of hydroxyl groups from the glucose side-chain of arbutin. DeoxyArbutin not only shows greater inhibition of tyrosinase activity but is also safer than hydroquinone and arbutin. Hence, deoxyArbutin is a potential skin whitening agent for cosmetics and depigmenting drugs; however, stability of this compound under some conditions remains a problem. The lack of stability poses developmental and practical difficulties for the use of deoxyArbutin in cosmetics and medicines. Improving the thermostability of deoxyArbutin is an important issue for its development. In this research, we established an analytical procedure to verify the amount of deoxyArbutin in solutions using a high performance liquid chromatographic (HPLC) method. The results indicate that this novel skin whitening agent is a thermolabile compound in aqueous solutions. Additionally, the rate constant for thermodegradation (k) and the half-life (t(1/2)) of deoxyArbutin were determined and can be used to understand the thermodegradation kinetics of deoxyArbutin. This information can aid in the application of deoxyArbutin for many future uses.     

十一碳烯酰基苯丙氨酸的合成及其抑制酪氨酸酶二酚酶活性的研究

以十一烯酸和苯丙氨酸为原料,使用氯化亚砜将十一烯酸酰氯化,采用肖顿-鲍曼法(Schotten-Baumann)缩合反应合成了十一碳烯酰基苯丙氨酸钠,再经酸化分离后得到了十一碳烯酰基苯丙氨酸。利用IR,MS和~1H NMR对合成产物的结构进行了表征,同时考察了十一碳烯酰基苯丙氨酸对酪氨酸酶二酚酶活性抑制的机制。结果表明,十一碳烯酰基苯丙氨酸对酪氨酸酶二酚酶活性的抑制作用为竞争性可逆抑制,其半抑制浓度为3.711 g/L,抑制常数(K_i)为3.651 g/L。