Antioxidant and antibacterial characteristics of aqueous and alcoholic extracts of Cystoseira trinodis (Forsskål) C. Agardh seaweed obtained from a coastal area of Gujarat, India

The brown seaweed contains high amount of polyphenols that have good antioxidant and antibacterial properties.The Cystoseira trinodis (Forsskl) C. Agardh seaweed was collected from the Okha and Sikka coast of Gujarat, India.This study examined the antioxidant and antimicrobial properties of aqueous, methanolic and ethanolic extracts of C. trinodis seaweed.Significant differences (p<0.05) were observed in the antioxidant activities of methanolic, ethanolic, and aqueous extracts.The TPC was found to be highest in methanolic extract, followed by ethanolic and aqueous extracts.The DPPH radical-scavenging activities of ethanolic extract was higher than any other extracts.FRAP activity differed significantly amongst the three extracts.The aqueous extract had much stronger FRAP activity than the other two.The antimicrobial activity of all the extracts were observed against food spoilage microorganisms by agar well diffusion method.All three extracts were found to be more active against Gram-positive bacteria compared to Gram-negative bacteria.Among of all the extracts, the aqueous extract was shown to possess much higher antibacterial properties against Gram-positive bacteria.