Isolation and identification of an antibacterial compound from grape and its application to foods

A methanol extract from grape seeds showed a potent antibacterial activity against Echerichia coli, Salmonella enteritidis, and Staphylococcus au reus. A responsible compound was isolated from the extract to be identified as gallic acid by instru mental analysis. Structure-activity correlation as says revealedthat three hydroxyl groups of the compound were effective for antibacterial activity against E. coli and S. enteritidis and all of the substituents of the benzene ring were effective against S. aureus. Minimal inhibitory concentra tion of gallic acid against E. coli and S. enteritidis was 0.5mm and that against S. aureus was 0.3 mm. Ethanol-and salt-containing foods cooperatively acted on the antibacterial activity of gallic acid. (Received September 18, 1998)