Topical anti-inflammatory effect of tirucallol, a triterpene isolated from Euphorbia lactea latex

Latex from Euphorbia lactea (Euphorbiaceae), a native Dominican medicinal plant, is claimed to be useful in the treatment of inflammation. Topical application of tirucallol, a tetracyclic triterpene isolated from Euphorbia lacteal latex, suppressed ear edema in the mouse model in a dose-dependent manner, as well as affecting the influx of polymorphonuclear cells in response to topical application of 12-O-tetradecanoylphorbol-acetate (TPA) in the mouse ear. In addition, the effect of tirucallol, on some macrophage functions was analyzed in vitro. Non-toxic concentrations of tirucallol potently inhibited nitrite production in lipopolysaccharide-stimulated macrophages. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression although tirucallol slightly affected to prostaglandin E(2) (PGE(2)) generation. The results of the study revealed that tirucallol (0.3%), present in Euphorbia lactea latex, exerts a topical anti-inflammatory effect in vivo, via a mechanism of action related to the neutrophil migration. On the other hand, it can be deduced that the mechanism of the anti-inflammatory activity of this triterpene is related to the control of the production of NO and its effect on the expression of iNOS.