The effects of xanthoangelol E on arachidonic acid metabolism in the gastric antral mucosa and platelet of the rabbit.

The effects of a new chalcone derivative, xanthoangelol E, isolated from Angelica keiskei Koidzumi, on arachidonic acid metabolism in the gastric antral mucosa and platelet of the rabbit were examined. When gastric antral mucosal slices were incubated with xanthoangelol E (0.05-1.0 mM), there was no significant effect on the production of prostaglandin (PG) E2, PGF2 alpha and their metabolites. On the other hand, this compound inhibited effectively the production of thromboxane B2 and 12-hydroxy-5,8,10-heptadecatrienoic acid from exogenous arachidonic acid in platelets, and the concentration required for 50% inhibition (IC50) was approximately 5 microM. The formation of 12-hydroxy-5,8,10,14-eicosatetraenoic acid was also reduced by this drug (IC50, 50 microM). These results suggest that xanthoangelol E has the potential to modulate arachidonic acid metabolism in platelets and that this action may participate in some pharmacological effect of the plant.