1997 Volume 43 Issue 2 Pages 249-259
Recently, a new potent antioxidant was isolated from Tempeh (a traditional fermented soybean food in Indonesia) and was identified as 3-hydroxyanthranilic acid (HAA). This study deals with the antioxidant mechanism of HAA under biological systems and the cytokill-ing function of HAA to human malignant cells. HAA eliminated free radicals and inhibited the formation of fatty acid hydroperoxide in vitro, suggesting that HAA would serve as an antioxidant in the initial reaction in lipid oxidation systems. Actually, HAA inhibited the formation of the dominant product of membrane lipids, 12-hydroxyeicosatetraenoic acid (12-HETE) at a high concentration, while HAA accelerated 12-HETE formation at a low concentration in mammalian tissue. HAA oxidized glutathione and inhibited superoxide dismutase in vitro. Furthermore, HAA inhibited cell growth and induced apoptosis to HuH-7, a human hepatoma-derived cell line. As long as HAA is taken as a component of Tempeh, and not in large doses as a chemical, it may possibly act as a prooxidant rather than an antioxidant in vivo.
