Flavonoids ornithine decarboxylase inhibition

Ornithine decarboxylase catalyzes the transformation of ornithine to the polycationic bases, putresine, spermine, and spermidine. These compounds exert regulatory effects on cell growth. It has been shown that quercetin (10 to 30 pmol/mouse) markedly suppressed the stimulatory effect of the transporters associated with antigen processing (TPA) on ornithine decarboxylase (ODC) activity and on skin tumor formation in mice initiated with dimethylbenzanthracene. Such inhibition may be related to the activation of the catalytic site, which is under nonconventional regulation by small molecules. Also, the synthetic flavonoid flavone acetic acid was shown to inhibit the activity of ODC in stimulated human peripheral blood lymphocytes and human colonic lamina propria lymphocytes. 

Rosemary (Rosmarinus officinalis) contains flavonoids, phenols, volatile oil and terpenoids. Topical application of rosemary extract, carnosol or ursolic acid to mouse skin inhibited the covalent binding of benzo[a]pyrene to epidermal DNA (Huang et al. 1994), tumour initiation by 7,12-dimethylbenz [ajanthracene (Singletary and Nelshoppen 1991), 12-0-tetradecano)dphorbol-13-acetate-induc-ed tumour promotion, ornithine decarboxylase (EC 4.1.1.17) activity and inflammation. Carnosol showed potent antioxidative activity in a,a-diphe-nyl-P-picrylhydrazyl free radicals scavenge and DNA protection from Fenton reaction (Lo et al. 2002). 

Nakadate T, Yamamoto S, Aizu E, Kato R 1984 Effects of flavonoids and antioxidants on 12-0-tetradecanoyl-phorbol-13-acetate-caused epidermal ornithine decarboxylase induction and tumor promotion in relation to lipoxygenase inhibition by these compounds. Gann 75 214-222... 

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