Antioxidant and anti-tumor promoting activities of the methanol extract ofheat-processed ginseng

Heat treatment of Panax ginseng C.A. Meyer at a temperature higher than tha t applied to the conventional preparation of red ginseng yielded a mixture of saponins with potent antioxidative properties. Thus, the methanol extrac t of heat-processed neo-ginseng (designated as 'NGMe') attenuated lipid per oxidation in rat brain homogenates induced by ferric ion or ferric ion plus ascorbic acid. Furthermore, the extract protected against strand scission in empty set X174 supercoiled DNA induced by UV photolysis of H2O2, and was also capable of scavenging superoxide generated by xanthine-xanthine oxida se or by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocytic leukemia (HL-60) cells. Topical application of NGMe onto sha ven backs of female ICR mice 10 min prior to TPA, significantly ameliorated skin papillomagenesis initiated by 7,12-dimethylbenz[a]anthracene. Moreove r, TPA-induced enhancement of epidermal ornithine decarboxylase (ODC) activ ity and ODC mRNA expression was abolished by a topical dose (0.68 mg) of NG Me. Likewise, TPA-induced production of tumor necrosis factor- in mouse ski n was inhibited by NGMe pretreatment. (C) 2000 Elsevier Science Ireland Ltd . All rights reserved.