(±)9-HpODE is a racemic mixture of the fatty acid hydroperoxide product (9(S)-HpODE) formed from lipoxygenase action on linoleic acid. It shows antimicrobial activity against various fungal and bacterial pathogens and thus may play a role in plant defense. In mammalian species, monocyte-induced oxidization of LDL generates significant amounts of esterified 9-HpODE, which is rapidly reduced to 9-HODE.