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Y.-J. SURH, College of Pharmacy, Seoul National Univ., Shinlim-dong, Kwanak-ku, Seoul, 151-742, South Korea Chemoprevention is an attempt to use either naturally occurring or synthetic substances or their mixtures to intervene in the progress of carcinogenesis, before the malignancy manifests. Numerous chemical substances have been found to prevent or halt carcinogenesis, and it is noticeable that a substantial body of chemopreventive agents are derived from dietary and medicinal plants. Phenolic substances present in some spices and herbs have substantial anticarcinogenic and antimutagenic activities. Curcumin, a yellow colouring agent contained in turmeric (Curcuma longa L., Zingiberaceae), has been reported to possess strong anti-tumor promotional as well as antioxidant and anti-inflammatory activities. Recent studies from this laboratory have revealed that curcumin inhibits expression of cyclooxygenase-2 (COX-2) in mouse skin treated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) through inactivation of the redox-sensitive eukaryotic transcription factor NF-κB. Inhibition of NF-κB by curcumin appears to be mediated by blocking ERK1/2 and p38 MAP kinases. Some diarylheptanoids structurally related to curcumin are widely present in the edible plants cultivated in South East Asian countries. These compounds have strong anti-inflammatory and antioxidative properties which may contribute to chemopreventive activities. [6]-Gingerol, a pungent ingredient present in ginger (Zingiber officinale Roscoe, Zingiberaceae), inhibited TPA-induced tumor necrosis facror-alpha production, ornithine decarboxylase activity, and skin tumor promotion in female ICR mice. Its anti-tumor promoting effects appears to be associated with inhibition of p38 MAP kinase and of subsequent NF-κB activation. Capsaicin, a major pungent priniciple of hot chili pepper (Capsicum annuum L., Solanaceae) with potential anti-inflammatory and anti-tumor promoting properties, also suppressed TPA-induced activation of NF--κB and AP-1, in mouse skin in vivo. It also exhibits proapoptotic, antiangiogenic and antimetastatic activities. 6-methylthiohexyl isothiocyanate (6MHITC) isolated from Wasabi (Japanese mustard) induced the expression of phase-2 detoxification enzymes such as quinone reductase. Ginseng also has substantial chemopreventive potential, and identification of active ingredients merits further investigation.
Session 10, Natural antioxidants in herbs and spices
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |