Anti-inflammatory and analgesic effects of 6α,7β-dihydroxy-vouacapan-17β-oic acid isolated from Pterodon emarginatus Vog. fruits.

6α,7β-dihydroxy-vouacapan-17β-oic (tricyclic furanoid diterpene; DHVO) acid was isolated from the hexane extract of Pterodon emarginatus fruits and evaluated for anti-inflammatory and analgesic effects using an assay that induces paw oedema with carrageenan, dextran and prostaglandin E(2) (PGE(2)) in rats and the writhing and formalin tests in mice. Oral administration of 50 mg/kg DHVO significantly inhibited carrageenan-induced oedema formation by 24% (p < 0.05). This treatment did not inhibit dextran-induced oedema but was effective when the inflammatory effect was triggered by PGE(2), inhibiting oedema formation by 39% (p < 0.05). In the writhing test, doses of 50, 200 and 400 mg/kg resulted in a dose-dependent effect with a correlation coefficient (r) of 0.983 (F = 29.04, ANOVA). Doses of 50 and 100 mg/kg inhibited both the neurogenic and inflammatory phases (p < 0.05) in the formalin test but were not effective for increasing the lag time in the hot plate test. Together, these results suggest that DHVO has both anti-inflammatory and peripheral analgesic effects.