Stability and antioxidative activities of melanin from Plectania sp. YM421
暗盘孢属YM421黑色素稳定性及其抗氧化活性

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.