Inhibition of the lethal and myotoxic activities of Crotalus durissus terrificus venom by Tabernaemontana catharinensis: Identification of one of theactive components

In Brazilian folk medicine, victims of bites by poisonous animals are usual ly treated with plant extracts derived from the diverse national flora. The chemical and pharmacological properties of most extracts were yet not inve stigated. In the rural community of Assis-SP, the root bark of Tobernaemont ana catharinensis ("leiteiro", "cow milk") is applied to the site of the sn ake bite and believed to neutralize the effect of the venom. We report here the ability of the lyophilized aqueous extract (AE) and of a pure compound obtained from the ethanolic extract of T. catharinensis to inhibit the let hal and myotoxic activities of C. d. terrificus (South American rattlesnake ) venom. Doses of 10 mg AE/100 g, injected (i.m., rat) 20 s after injecting (i.m.) the venom and that of 2.5 mg AE/100 g, incubated for 1 h at 25 degr ees C with the venom before injection (i.m.) were able to neutralize the le thal activity of 2LD(50). These data indicate that T. catharinensis could b e used as a source of a model molecule able to neutralize the lethality and myotoxicity induced by C. d. terrificus venom. Its ethanolic extract was t hen fractionated on a silica gel 60 chromatography column affording fractio ns A to F. Fraction A consisted basically of non-polar compounds, terpenes and sterols. Fraction D showed a pronounced antiophidian activity which was later correlated with the presence of the quaternary alkaloid 12-methoxy-4 -methylvoachalotine in this fraction. This alkaloid was isolated and inhibi ted 100% lethality when injected 20 s after 2 LD50 at 1.7 mg/100 g.