Estudo da ação antiofídica e da toxicidade aguda do extrato aquoso de Schizolobium parahyba

Abstract

CHAPTER II - Many medicinal plants have been recommended for the treatment of snakebites. The aqueous extracts prepared from leaves of Schizolobium parahyba (plant found in Mata Atlantica in Southeastern Brazil) were assayed for their ability to inhibit some enzymatic and biological activities induced by Bothrops pauloensis and Crotalus durissus terriffcus venoms as well as by their isolated toxins neuwiedase (metalloproteinase), BnSP-7 (basic Lys49 PLA2) and CB (PLA2 from crotoxin complex). Phospholipase A2, coagulant, fibrinogenolytic, hemorrhagic, and myotoxic activities induced by B. pauloensis and C. d. terrificus venoms, as well as by their isolated toxins were significantly inhibited when different amounts of S. parahyba were previously incubated with these venoms and toxins before assays. However, when S. parahyba was administered at the same route after the venoms or toxins injections, the tissue local damage, such as hemorrhage and myotoxicity was only partially inhibited. We also evaluated the inhibitory effect of S. parahyba upon the spreading of venom proteins from the injected area into systemic circulation. The neutralization of systemic alterations induced by i.m. injection of B. pauloensis venom was evaluated by measuring platelet and plasma fibrinogen levels which were significantly maintained when S. parahyba extract inoculation occurred at the same route after B. pauloensis venom injection. In conclusion, our observations confirmed that the aqueous extract of S. parahyba possesses potent snake venom neutralizing properties. It may be used as an alternative treatment to serum therapy and as a rich source of potential inhibitors of toxins involved in several physiopathological human and animal diseases. CHAPTER III - Schizolobium parahyba (Sp) is a plant used against ophidism. Recent studies have been showing that the extract of Sp has potent effect against lesions induced by toxins presents in snake venoms. This work evaluated the acute toxicity of the aqueous extract of Sp after 24 hours of the administration i.p. in Swiss males mice (18-22 g). The acute toxicity was evaluated by analysis of biochemical, hematological and histopatological alterations. Alterations were observed in the transaminases levels, bilirrubin, albumin and time of prothrombin, probably due to the hepatic alterations that were confirmed by light microscopia. The Histopathological analysis of the liver revealed the presence of inflammatory infiltrate. It was not found any other histopathologic alteration us other appraised organs due to the use of Sp. Our results confirm the low toxicity of the extract of Schizolobium parahyba. This study, therefore it serves as initial model for future researches that determine the acute toxicity of the extract of Sp and for discovery of doses that don't cause damages to the organism.