暗盘孢属YM421黑色素稳定性及其抗氧化活性

对暗盘菌Plectania sp.YM421菌株所产黑色素的稳定性及其抗氧化活性进行了研究。结果表明:该黑色素易溶于氢氧化钠溶液和二甲亚砜,微溶于蒸馏水,不溶于盐酸、无水乙醇、乙酸乙酯、氯仿、二甲苯、丙酮和乙醚;该黑色素在pH≥6时稳定,pH≤5时产生沉淀;对室光、日光、紫外光、亚硫酸钠、Na+和K+稳定;添加苯甲酸钠、柠檬酸钠、蔗糖、葡萄糖、乳糖、麦芽糖对黑色素有增色或护色作用;而双氧水、柠檬酸、VitC、Mg2+、Cu2+、Zn2+、Ca2+、Fe3+、Al3+降低其稳定性;该黑色素与VitC还原能力的EC50值(吸光度为0.5时的浓度)分别为169.6μg/mL和31.88μg/mL,对羟基清除作用的IC50值(清除率为50%时的浓度)分别为360.4μg/mL和183μg/mL。作为一种新型的天然色素,YM421黑色素有望应用于食品、化妆品以及医药等行业。

Stability and antioxidative activities of melanin from Plectania sp. YM421

The stability and antioxidative activities of melanin from Plectania sp. YM421 were studied. The results showed that the melanin was soluble in NaOH solution and dimethylsulfoxide, slightly soluble in distilled water, and insoluble in HCl, anhydrous ethanol, ethyl acetate, chloroform, dimethyibenzene, acetone and ether. The melanin was stable in the solution at pH≥6, but deposited at pH<5. The melanin was stable to room light, sunlight, ultraviolet light, Na_2SO_3, Na~+ and K~+. Sodium benzoate, sodium citrate, sucrose, glucose, lactose and maltose had the function of color increase or color preservation to the melanin; while H_2O_2,citric acid, Vit C, Mg~(2+), Cu~(2+), Zn~(2+), Ca~(2+), Fe~(3+)and Al~(3+)decreased melanin stability. For the melanin and Vit C, the EC_(50) value (the effective concentration at which the absorbance was 0.5) of the reducing power were 169.6μg/mL and 31.88μg/mL, and the IC_(50)value (the effective concentration at which the scavenging rate was 50%) of hydroxyl radical scavenging activity were 360.4μg/mL and 183μg/mL, respectively. As a kind of new-style natural pigment, YM421 melanin is expected to be utilized in food, cosmeticand and medicine industry.