Bioactive sterols from the brown alga Anthophycus longifolius (Turner) Kützing, 1849 (= Sargassum longifolium)

Abstract

Anthophycus longifolius (= Sargassum longifolium), a brown seaweed commonly found in the Gulf of Mannar region, south India was investigated for bioactive compounds against human as well as marine fish/shellfish pathogens. The fractionation of ethanolic extract by bioassay guided mode yielded two compounds by column chromatography. The compounds were spectrally characterised using proton nuclear magnetic resonance spectroscopy (1H NMR) and mass spectrometry as fucosterol and hexadec-4-enoic acid. These compounds were characterised for the first time from the alcoholic extract. The antibacterial activity of the compounds against human and aquaculture pathogens by disc diffusion method showed that hexadec-4-enoic acid was more antagonistic to Vibrio parahaemolyticus, Pseudomonas fluorescens, Vibrio vulnificus, Vibrio harveyii, Aeromonas hydrophilla and Pseudomonas fluorescens when compared to fucosterol.