Streptomyces bottropensis SY8-derived eumelanin exhibits skin wound healing activity and prevents H2O2 or UV-induced skin aging

Abstract

Streptomyces-derived melanins exhibit diverse bioactive properties. This study aims to (1) produce melanin production from Streptomyces bottropensis SY8 (GenBank accesion number: PQ565816), (2) characterize the melanin, and (3) investigate its bioactive properties (toxicity and irritancy as well as invitro wound healing and anti-skin aging activities). Under optimized culture conditions, melanin production of 3.26 g/L was achieved in shaking flask cultures of the bacterium. The purified melanin was characterized as eumelanin. Compared to the control (Vitamin C), the purified melanin was found to have moderate antioxidant activity in radical scavenging assays. It did not cause toxicity on fibroblast cell line and irritancy in HET-CAM test (hen's egg test on chorioallantoic membrane test). The melanin reduced reactive oxygen species (ROS) accumulation and cell senescence induced by H₂O₂ or UV in fibroblast cells, indicating its anti-skin aging potential. When compared the control (melanin free), the melanin doses of 500 µg/mL and 1000 µg/mL caused increments of 17.59 % and 24.53 % in wound closure ratios at the end of the 24th hour, respectively. This is the first report on melanin production from S. bottropensis. Besides, in vitro wound healing and anti-skin aging activities of Streptomyces-derived melanins were investigated for the first time. Furthermore, HET-CAM test was used for the first time to analyze irritancy property of melanins. The results of this study indicate that S. bottropensis SY8-derived eumelanin can be exploited as an ingredient of anti-aging creams or wound dressings.

Keywords: Anti-aging; Melanin; Streptomyces; Wound healing.