We investigated a synthetic coumestan named LQB93 and similar compounds abilities to antagonize activities of Bothrops jararacussu and Bothrops jararaca crude venoms in different protocols. The antimyotoxic activity was evaluated in vitro by the rate of release of creatine kinase (CK) from isolated mouse extensor digitorum longus muscle (EDL) induced by B. jararacussu (25 g/ml). For in vivo studies, B. jararacussu venom (1.0 mg/kg) was preincubated with LQB93 (0.1-30 mg/kg), during 30 min, for later injection in mouse tight and evaluation of the antimyotoxic and anti-edematogenic effects. LQB93 antagonized in vitro, the increase of CK release from the EDL muscle (IC(50)=0.0291 M). It also showed in vivo, antimyotoxic and anti-edematogenic effects that were dose-dependent with ID50 of 0.17 mg/kg and 0.14 mg/kg, respectively. The hemorrhage induced by B. jararaca (1.0 mg/kg) venom in the mouse skin, was abolished by LQB93 (10.0 mg/kg) preincubated with venom. Like wedelolactone, LQB93 protected rat isolated heart on a Langendorff preparation, from the cardiotoxicity of B. jararacussu venom. LQB93 inhibit the effects of Bothrops venoms like wedelolactone, a natural compound isolated from the plant Eclipta prostrata.

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Synthesis and Pharmacological Evaluation of Prenylated and Benzylated Pterocarpans Against Snake Venom. -Analogues of the natural pterocarpan edunol (IXf) are designed and synthesized. The antimyotoxic, antiproteolytic and PLA2 inhibitor activity of the natural product are improved by replacement of the prenyl group at position 4 by a benzyl group [cf. (IXa)]. -(DA SILVA, A. J. M.; COELHO, A. L.; SIMAS, A. B. C.; MORAES, R. A. M.; PINHEIRO, D. A.; FERNANDES, F. F. A.; ARRUDA, E. Z.; COSTA*, P. R. R.; MELO, P. A.; Bioorg. Med.