Inhibitory effects of chestnut inner skin extracts on melanogenesis

Antioxidant capacities (ABTS radical scavenging assay and ferric reducing/antioxidant power assay), mushroom tyrosinase inhibitory effect, and α-melanocyte stimulating hormone (α-MSH) induced melanogenesis inhibitory effect of 60% methanol extracts and ethylacetate fractions from chestnut inner skin in B16F10 cells were investigated to inspect whitening effect. Above research showed that 60% methanol extracts and ethylacetate fractions from chestnut inner skin resulted in a dose-dependent manner on in vitro antioxidant effects. Especially, the ethylacetate fractions inhibited enzyme activity of mushroom tyrosinases with an IC₅₀ value of 160 μg/mL. Ethylacetate fractions from chestnut inner skin also decreased cellular melanin synthesis in B16F10 melanoma cells. Expression of tyrosinase showed that ethylacetate fractions from chestnut inner skin significantly decreased cellular melanogenesis. Consequently, these results suggest that chestnut inner skin extracts can be considered for a whitening agent of human skin.     

Dual inhibitions of lemon balm (<Emphasis Type="Italic">Melissa officinalis</Emphasis>) ethanolic extract on melanogenesis in B16-F1 murine melanocytes: Inhibition of tyrosinase activity and its gene expression

The effects of wild type and UV-irradiated lemon balm (Melissa officinalis) ethanolic extracts (MOE and UMOE) on melanogenesis in vitro were examined. UMOE showed potent antioxidant activity and significantly inhibited the mushroom and melanocyte tyrosinase activity, and lowered cellular melanin content by 49% at 200 μg/mL in B16-F1 melanocytes. The key gene and protein expression of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 were reduced (−73% for TRP-1 protein at 200 μg/mL UMOE, p<0.05). MOE showed similar results to a slightly lesser degree. We found that myo-inositol, a major compound in lemon balm extracts, significantly reduced cellular melanin synthesis and its effect was greater than arbutin at 1 mM. These suggest that both MOE and UMOE have anti-melanogenic role by both direct inhibition of tyrosinase and down-regulation of gene expressions in melanogenesis. UV-irradiation slightly improved the anti-melanogenic activities. UMOE may be useful as natural anti-melanogenic biomaterials for functional foods and cosmetics.     

酸枣叶缩合单宁的分离鉴定及其对黑色素生成的抑制机制

目的:研究酸枣叶缩合单宁的结构特征及其对酪氨酸酶的效应和黑色素生成的抑制机制。方法:利用Sephadex LH-20凝胶柱色谱技术分离制备酸枣叶缩合单宁纯化物,采用硫醇降解结合高效液相色谱-电喷雾电离质谱（Thiolysis-HPLC-ESI-MS）解析酸枣叶缩合单宁的结构单元组成,运用酶动力学、紫外光谱、荧光猝灭等方法系统研究酸枣叶缩合单宁对酪氨酸酶的抑制作用机理,应用CCK-8法、多巴氧化法、NaOH裂解法和实时荧光定量PCR检测酸枣叶缩合单宁对小鼠黑色素瘤细胞（B16F10）的增殖、酪氨酸酶活性、黑色素合成及其相关基因表达水平的影响。结果:构成酸枣叶缩合单宁的主要结构单元是（表）儿茶素和（表）棓儿茶素;酸枣叶缩合单宁具有较强的酪氨酸酶单酚酶和二酚酶抑制活性,是二酚酶可逆的混合型抑制剂;酸枣叶缩合单宁可有效抑制B16F10细胞的增殖、酪氨酸酶活性、黑色素生成量以及酪氨酸酶（TYR）、酪氨酸酶相关蛋白-1（TRP-1）、小眼畸形相关转录因子（MITF）等基因的表达。结论:通过在酶水平和细胞水平的综合分析,阐明酸枣叶缩合单宁对B16F10细胞黑色素合成的分子抑制机制,为后期酸枣叶缩合单宁开发为新的美白化妆品添加剂和果蔬保鲜剂提供理论依据。     

Suppression of the melanogenesis and cellular antioxidant activity in B16 melanoma cells

The results of antioxidant activities by ORAC assay and CAA assay were evaluated for melanogenesis. Although the antioxidant activity by ORAC was not correlated with the melanogenesis, the samples which showed high antioxidant activity by CAA tended to suppress melanogenesis. Caffeic acid and Citrus depressa juice, which demonstrated inhibitory effects on mela‐nogenesis, had high antioxidant activities but no inhibitory effects on tyrosinase activity. In addition, they inhibited the melanogenesis which was increased by inhibition of catalase activity. These results may suggest that antioxidant activity by CAA can contribute to the suppression of melanogenesis in B16 melanoma.     

In vitro and in vivo evaluation of ellagic acid on melanogenesis inhibition

The efficacy of ellagic acid (EA), one of the naturally occurring polyphenols, in inhibiting melanogenesis was examined in vitro and in vivo. When mushroom-derived tyrosinase, a metaloprotein containing copper, was incubated with EA, enzymatic activity tended to decrease with decreasing copper concentration. Enzyme activity partially recovered when copper was added to the inactivated enzyme. Tyrosinase activity in the B16 melanoma cells was observed to recover in a dose-dependent manner when copper ions were added to the medium containing EA. Based on these results, EA is thought to react specifically with the copper located at the active centre of the tyrosinase molecule. Furthermore, when EA was applied for 6 weeks to brownish guinea-pigs, which have melanocytes in their skin, at the same time as irradiating for 2 weeks with ultra-violet light, skin pigmentation was clearly suppressed and the skin to which EA had been applied showed features similar to that of non-irradiated skin. These areas were irradiated again when the application of EA had been completed, and skin pigmentation occurred at the former site of EA application. In similar studies with hydroquinone, re-pigmentation did not occur on the sites at which hydroquinone (1%) had been applied. Based on the results reported here, EA is thought to suppress melanogenesis by reacting with activated melanocytes and without injuring cells.     

Antioxidant Activity of Phosvitin in Phosphatidylcholine Liposomes and Meat Model Systems

ABSTRACT: Phosvitin, an iron-chelating protein, was tested for its ability to inhibit lipid oxidation in phosphatidylcholine (PC) liposomes and meats. Inhibition of thiobarbituric acid reactive substances (TBARS) formation increased with increasing phosvitin concentrations with maximal inhibition occurring at 40 and 15 mM in PC liposomes and pork muscle homogenates, respectively. Phosvitin lost only 2 to 15% of its antioxidant activity after being heated for 10 min at 60 to 100 °C. The ability of phosvitin to inhibit TBARS formation was maximal at pH 7.0. Phosvitin was a more effective antioxidant in cooked ground pork with 20 mM inhibiting 11 to 39% of oxidation compared with 0 to 20% inhibition in uncooked, salted ground pork containing 60 mM phosvitin.     

Bioactivities of hen's egg yolk phosvitin and its functional phosphopeptides in food industry and health

Phosvitin, one of the most noteworthy bioactive components of hen egg yolk, is an amphiphilic protein that stands out with its unique composition and functionality in the food industry and health. Phosvitin consists of 4% of egg yolk dry matter and 11% of egg yolk proteins. It is considered as the most phosphorylated protein with 10% phosphorus. Besides, some potential novel phosphopeptides containing clusters of phosphoserines can be derived from hen's egg yolk phosvitin. Phosvitin, which has many functional features thanks to its unique structure, is known primarily for its metal bonds binding (iron, calcium, etc.) feature. On the other hand, its phosphopeptides may increase the bioavailability of metals compared to phosvitin. Although this feature of phosvitin may partially decrease the bioavailability of especially iron in the egg, it allows the phosvitin to have many bioactivities in the food industry and health. Lipid oxidation, which is a serious problem in the food industry, can be inhibited by adding phosvitin and its derived phosphopeptides to the food production chain via inhibiting bivalent iron. Because phosvitin is an amphiphilic protein capable of chelating, it also shows potential antibacterial effects against the Gram-negative bacteria. Moreover, the literature has recently been attempting to define the promising relationship between phosvitin and its phosphopeptides and plenty of health-promoting activities such as immune-enhancing, melanogenesis inhibitor, anti-ageing, and anticancer. In this review, current information on the hen's egg yolk phosvitin and its phosphopeptides and their bioactivities in the food industry and health are discussed and some future directions are given.     

Conditions Affecting Emulsifying Properties of Egg Yolk Phosvitin

The effects of protein concentration (0.1–2.0%), oil volume fraction (0.17–0.67), mixing speed (10,000–22,000 rpm) and mixing time (0.5–8 min) on the emulsifying properties of phosvitin and bovine serum albumin (BSA) were compared. Emulsifying activity and emulsion stability increased with protein concentration, oil volume fraction and mixing. Effects of these variables were assessed quantitatively using an empirical equation. Mixing speed had the greatest influence and protein concentration had the least influence on emulsifying activity for both phosvitin and BSA. For emulsion stability, mixing speed had the greatest influence for phosvitin; oil volume fraction had the greatest influence for BSA. Phosvitin was a better emulsifier than BSA at pH7.     

鸡蛋中卵黄高磷蛋白的提取

建立了一种简单且适合于批量提取鸡蛋中的卵黄高磷蛋白的方法．先分离出其它水溶性蛋白质,再将沉淀物脱去脂肪,然后用１０％的ＮａＣｌ溶液（ｐＨ７．０）从所得的颗粒中提取卵黄高磷蛋白．每１００ｇ蛋黄提取１ｇ卵黄高磷蛋白粗制品,含氮１１．２２％,含磷７．７％,氮磷含量比值３．６４．卵黄高磷蛋白在ＳｅｐｈａｃｒｙｌＳ－２００图谱上有两个主峰,分别是α－ＰＶ和β－ＰＶ,相对分子质量为１６００００和１９００００．在聚丙烯酰胺凝胶电泳上出现相对应的两条谱带．经ＳＤＳ－聚丙烯酰胺凝胶电泳后,则出现相对分子质量从１０４～９×１０４左右的多条谱带,预示卵黄高磷蛋白是由多亚基组成的     

Effects of protein hydrolysate from chicken feather meal on tyrosinase activity and melanin formation in B16F10 murine melanoma cells

Tyrosinase is a copper-containing enzyme that controls mammalian melanogenesis. Tyrosinase inhibitors are important for their potential application in cosmetic products. Chicken feather meal is a rich source of amino acids, which have been linked with tyrosinase inhibition activity. This study investigated the tyrosinase inhibitory properties of protein hydrolysates prepared from chicken feather meal. Protein hydrolysates prepared by pepsin-pancreatin with MW <3 kDa exhibited strong tyrosinase inhibition activity for both monophenolase (IC₅₀ 5.780 ± 0.188 µg/mL) and diphenolase activities (IC₅₀ 0.040 ± 0.024 µg/mL) in a cell-free mushroom tyrosinase system. These samples were uncompetitive inhibitors with Ki values of 18.149 and 27.189 µg/mL in monophenolase and diphenolase activities, respectively. A cell culture model showed that this hydrolysate had the strongest inhibition on the viability of B16F10 cells (IC₅₀ 1.124 ± 0.288 µg/mL) and 0.210 µg/mL of the sample exhibited inhibition of tyrosinase activity by 50.493% and melanin synthesis by 14.680% compared to the control.     

卵黄高磷蛋白乳化性的研究进展

卵黄高磷蛋白是蛋黄中重要的活性功能成分之一,具有和酪蛋白相类似的组成与结构,表现出优异的乳化活性和乳化稳定性。文中分别从蛋白自身组成及结构、乳化作用环境、蛋白改性以及蛋白与其他添加剂协同作用等方面对卵黄高磷蛋白乳化特性的影响进行了阐述。     

Antioxidant and antityrosinase activity of aqueous extracts of green asparagus

The effect of aqueous extracts of green asparagus (AGA) on antioxidation and tyrosinase inhibition in acellular and cellular systems was investigated. The results showed that AGA inhibited tyrosinase with an IC₅₀ value of 1.21 mg/ml in a mixed-type inhibition. In the range of 0.05–1 mg/ml, the inhibitory effect on tyrosinase activity in B16 cells increased with increasing concentration of AGA. Meanwhile, the levels of glutathione in B16 cells were elevated by AGA in comparison to the control. In addition, AGA, in the range of 0.1–0.5 mg/ml, also exhibited radical scavenging, chelating activities and protected liposome against oxidative damage. The high performance liquid chromatography analysis indicated that polyphenolic components such as rutin, quercetin, kaempferol, and isorhamnetin were present in the AGA. This study suggested that AGA could play an important role in the regulation of tyrosinase activity and seem to be a natural inhibitor of browning reaction.