RESUMO
A melanin producer bacteria Halomonas venusta was isolated from a marine sponge Callyspongia sp. and optimized for melanin production. The optimized fermented media supplemented with 1% tyrosine yielded 4.92 mg/ml of melanin. The melanin incorporated cream was formulated and fortified with concentrates of seaweed Gelidium spinosum. Melanin and seaweed concentrate were found to be rich in antioxidant activity and were effectively inhibited the growth of S. aureus (MTCC 96) and S. pyogenes (MTCC 442). Various combinations of the cream were optimized and selected a formula containing 0.25% of melanin and 0.75% of seaweed concentrate which showed improved texture quality of cream. The formulated cream showed a pH of 5.52, spreadability 23 mm, and smooth and homogeneous texture. On application over skin provides a cooling effect and immediate disappearance without formation of white or oily film. Texture analysis of newly formulated cream showed similar results with that of control cream in terms of firmness, cohesiveness, index of viscosity and consistency. The formulated cream showed significant reduction of reactive oxygen species generated on exposure to direct sunlight. The cream showed protective effect on photohemolysis thus protecting the skin from lysis of red blood cells. The sun protection factor of the formulated cream F3 was found to be 18.373 ± 1.45. The combined antimicrobial and antioxidant effect of melanin and seaweed concentrate increased the shelf life of cream over the control. This study was the first report on photoprotective cream formulation using melanin and seaweed concentrate, which improved antioxidant and wound healing properties. The antimicrobial effect of the formulated natural cream could reduce the emergence of drug resistant bacteria and side effects of synthetic creams.