In vivo studies on the anti-inflammatory activity of pachymic and dehydrotumulosic acids

Pachymic and dehydrotumulosic acids were studied in different models of acu te and chronic inflammation. They proved to be active in most of the method s applied. None of them were active against arachidonic acid-induced ear ed ema. Dehydrotumulosic acid significantly diminished the mouse ear edema ind uced by ethyl phenylpropiolate, while pachymic acid was ineffective. When t he putative corticoid-like mechanism of both compounds was explored, pachym ic acid activity was partially abolished by the glucocorticoid receptor ant agonist progesterone, but dehydrotumulosic acid activity was not affected. In vivo experiments demonstrated the inhibition by both principles of the p hospholipase A(2) (PLA(2))-induced extravasation. The previous report on th e effects of both compounds in vitro against PLA(2), together with the pres ent in vivo results, support the idea that the inhibition of this enzyme pr obably constitutes their main mechanism of action.