A Simple Screening Method for Antioxidants and Isolation of Several Antioxidants Produced by Marine Bacteria from Fish and Shellfish

We developed a simple screening method for antioxidant-producing strains using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and screened bacteria from 16 kinds of marine animals that lived in different environments in the sea to find 112 bacterial isolates-producing antioxidants. Guided by decoloration of DPPH sprayed on silica gel TLC, uric acid, indole, 3,4-dimethoxyphenol, and 3-hydroxyindolin-2-one were isolated from the bacterial fermentation broth. Some strains isolated from viscera of fish and shellfish produced uric acid and indole much more under aerobic conditions than less aerobic conditions, strongly suggesting that the bacterial production of the antioxidative compounds is a kind of adaptation to the aerobic conditions.