Inhibition of sheep platelet arachidonate metabolism by flavonoids from Spanish and Indian medicinal herbs

The influence of 22 flavonoids was studied on the arachidonic acid metabolism in sonicated sheep platelets. Flavones and flavonols possessing catechol groups inhibited 12-lipoxygenase. Sideritoflavone and quercetagetin-7-O-β-glucoside were more selective than quercetin. Cirsiliol, hypolaetin, hypolaetin-8-O-β-D-glucoside, gossypetin, gossypin, hibifolin and leucocyanidol were also 12-lipoxygenase inhibitors with some differences in potency and selectivity. Xanthomicrol was a weak cyclooxygenase inhibitor. These results suggest that lipoxygenase inhibition can play a role in the anti-inflammatory activity of hypolaetin-8-O-β-D-glucoside, sideritoflavone, gossypin and hibifolin