Abstract

Plant oxylipins, the metabolic products of polyunsaturated fatty acids have been variously implicated in control of microbial pathogens. To get a better insight into the biological activities of oxylipins, in vitro growth inhibition assays were used to investigate the direct antimicrobial activities of 9 and 13-lipoxygenase (LOX) products against a set of plant pathogenic bacteria and fungi. LOX hydroperoxides derived from seeds of Capsicum annum showed differential antimicrobial activity. It was found that the LOX hydroperoxides, that is, 9-hydroperoxy octadecadienoic acid (9-HPODE) and 9-hydroperoxy octadecatrienoic acid (9-HPOTrE) showed antimicrobial activity against various fungal and bacterial pathogens. LOX hydroperoxides, that is, 9-hydroperoxy octadecatrienoic acid (9-HPOTrE) showed maximum antimicrobial activity than 9-hydroperoxy octadecadienoic acid (9-HPODE). The antimicrobial activity of oxylipins suggests their role in plant defense mechanism.

Key words: Antimicrobial activity, chilli, hydroperoxides, minimum inhibitory concentration (MIC).