Spectroscopic studies, Antioxidant and Anticancer attributes of diffusible eumelanin produced by marine Streptomyces rochei

The diffusible melanin pigment from marine Streptomyces rochei isolated from Vishakhapatnam coast was characterized using UV Spectrophotometer, GC-MS, NMR, EPR Spectroscopy, CHNS elemental analysis, Ramon Spectroscopy and found to be a pure form of eumelanin. Anticancer activity of the melanin pigment from Streptomyces rochei was studied by MTT assay using MFB4 cell lines with an IC₅₀ value of 26 μg/mL, in comparison the standard 5fluorouracil exhibited an IC₅₀ value of 16.5 μg/mL and the DNA damage was also assessed by alkaline single-cell gel electrophoresis (COMET assay). The antioxidant activity was assessed by DPPH assay and the percentage of inhibition at 100 μg/mL concentration of melanin was found to be 71.53 which was higher than that for 5fluorouracil at 63.32 and ascorbic acid at 51.43. The potential for commercial exploitation of this melanin for its biotechnological role is enormous and the Streptomyces rochei strain can be a credible source of melanin and can serve as cost effective substitute for the currently marketed products.