Anti-inflammatory activity of dichloromethane extract of Heterotheca inuloides in vivo and in vitro.

The dichloromethane extract from the dried flowers of Heterotheca inuloides Cass. was investigated on several pharmacological models of inflammation in vivo and in vitro. It showed anti-inflammatory activity on the croton oil-induced oedema test in mouse ear, at 1 mg/ear. The compound isolated from this extract, 7-hydroxy-3,4-dihydrocadalin, showed anti-inflammatory effect on the same experimental model (ED50 of 0.9 mumol/ear), as well as on COX-1 and COX-2 catalysed prostaglandin biosynthesis assays, with IC50 values of 22 microM and 526 microM, respectively. No effect was observed on carrageenan-induced oedema and on fMLP/PAF-induced exocytosis of human neutrophils. The COX-1 inhibitory effect showed by 7-hydroxy-3,4-dihydrocadalin might be related to the anti-inflammatory activity on the topical oedema induced by croton oil.