Journal of Ethnopharmacology 95 (2004) 385–392 Insulin-like effects of Bauhinia forficata aqueous extract upon Tityus serrulatus scorpion envenoming Fl´ avio Vasconcelos a , Suely V. Sampaio b , Maria A.R. Gar ´ ofalo c , Luiz Fernando L. Guimar˜ aes a , Jos´ e R. Giglio c , Eliane C. Arantes a,∗ a Departamento de F´ ısica e Qu´ ımica-Faculdade de Ciˆ encias Farmacˆ euticas de Ribeir ˜ ao Preto, USP, Av. do Caf´ e, s/n, 14040-903 Ribeir ˜ ao Preto, SP, Brazil b Departamento de An ´ alises Cl´ ınicas, Toxicol´ ogicas e Bromatol´ ogicas-Faculdade de Ciˆ encias Farmacˆ euticas de Ribeir ˜ ao Preto, Ribeir˜ ao Preto, USP c Departamento de Bioqu´ ımica e Imunologia, Faculdade de Medicina de Ribeir˜ ao Preto, Ribeir˜ ao Preto, USP Received 1 July 2004; received in revised form 12 August 2004; accepted 12 August 2004 Available online 28 September 2004 Abstract Scorpion envenoming causes an intense autonomic discharge, leading to a massive release of neurotransmitters, giving rise to several patho- physiological effects. In this work we report the effects of a Bauhinia forficata aqueous extract (BfAE) upon hyperglycemia, glycogenolysis, increase of plasma catecholamines, lethality and changes in serum insulin and plasma electrolytes induced by Tityus serrulatus scorpion venom (TSV). We compare them with the effects of the regular insulin therapy. The following treatments were performed: TSV (500 g/kg, i.p.); BfAE (1 g/kg, p.o.), 24, 12 and 1 h before and immediately after TSV or saline and insulin in a single dose (1.5 IU/kg, s.c.) after TSV. BfAE reduces the fast hyperglycemia induced by TSV, but it is deprived of hypoglycemic activity. The extract also did not reduce either the intense glycogenolysis or the release of catecholamines and did not stimulate the release of endogenous insulin, although causing changes in the electrolyte plasma levels similarly to insulin. Although BfAE and insulin antagonize some effects of TSV, they should be avoided in the treatment of Tityus serrulatus envenoming, since they enhance the lethality of the venom. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Bauhinia forficata; Tityus serrulatus; Scorpion venom; Insulin; Catecholamines; Plasma electrolytes 1. Introduction Scorpion stings are important for their potential ability to induce severe and, eventually, fatal clinical situations, espe- cially among children, whose severity has aroused interest among concerned scientists to investigate the scorpion en- venoming syndrome (for review see Ismail, 1995). The yellow scorpion Tityus serrulatus Lutz and Mello (family Buthidae) is considered the most dangerous scorpion in South America. In Brazil, about 10,000 human cases of Abbreviations: BfAE, Bauhinia forficata; HPLC, High performance liquid chromatography; LD 50 , Median lethal dose; TSV, Tityus serrulatus soluble venom ∗ Corresponding author. Tel.: +55 16 602 4275; fax: +55 16 633 2960. E-mail address: ecabraga@facfrp.usp.br (E.C. Arantes). scorpion stings are treated at hospital centers and notified an- nually (Cardoso et al., 1995). Most deaths occur in children stung by Tityus serrulatus (Cupo et al., 1994; Freire-Maia et al., 1994; Cardoso et al., 1995; Brazilian Ministry of Health, 1998). The high toxicity of scorpion venoms is due to the pres- ence of basic proteins with neurotoxic activity, which in- teract with ionic channels of excitable cells inducing an intense autonomic discharge, leading to a massive release of neurotransmitters, causing several pathophysiological ef- fects, such as hyperglycemia, suppression of insulin se- cretion, rise in counter-regulatory hormones (Correa et al., 1997; Radha Krishna Murthy and Haghnazari, 1999; Radha Krishna Murthy, 2000) and changes in electrolyte levels (Ismail et al., 1978; Ismail and Abd-Elsalam, 1988). 0378-8741/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2004.08.006