Inhibition of 5-lipoxygenase activity by the natural anti-inflammatory compound aethiopinone.

Abstract

We have investigated the mechanisms of action of aethiopinone, an anti-inflammatory compound from Salvia aethiopis L. roots. Human neutrophils from healthy volunteers and murine peritoneal macrophages. Swiss mice were randomly divided into groups of six animals. Test compounds were applied topically in the mouse ear oedema test. In the air pouch, mice received aethiopinone (0.001-0.5 pmol/pouch or 12.5-50 mg/kg p.o.). LTB4 production was assayed in human neutrophils and COX-2 and iNOS activities in murine macrophages. Air pouches were induced subcutaneously in mice and injected with zymosan on the day six. Mouse ear oedema was induced by arachidonic acid. Dunnett's t-test was employed for statistical analysis. We have observed potent inhibitory effects on human neutrophil LTB4 production without effects on COX or NOS activities. Aethiopinone is an in vitro inhibitor of 5-LO from human neutrophils (IC50 = 0.11 microM). In addition, aethiopinone reduced leukocyte accumulation and showed in vivo inhibitory activity on this enzyme. Our results indicate that inhibition of 5-LO could participate in the anti-inflammatory properties of this natural product.