TOXINS FROM BRAZILIAN SAVANNAH SNAKES: INHIBITION, STRUCTURAL AND FUNCTIONAL CHARACTERIZATION.

HOMSI-BRANDEBURGO, M.I. (1); HAMAGUCHI, A.(1); RODRIGUES, V.M.(1).

(1) Laboratório de Toxinas Animais e Inibidores. Instituto de Genética e Bioquímica  Universidade Federal de Uberlândia. Uberlândia – M.G. – Brasil.

The majority of ophidic accidents registered in the Clinical Hospital from Uberlândia, M.G, Brazil are caused mainly by B. moojeni, B. neuwieidi and B. alternatus snake venoms. Bothrops snake venoms induces release of pharmacologically active substances with pronounced local effects such as hemorrhage, edema and tissue necrosis. In addition, relevant haemostatic and hematological alterations are frequent. These venoms are complex mixtures of proteins, including phospholipase A2 (EC 3.1.1.4), myotoxins, hemorrhagic metalloproteinases, cytotoxins and others proteases that act by different mechanisms. Many of these toxins have been isolated, functional and structurally characterized by our group. The native people from our community utilize parts of plants (leaves, roots, bark, etc) to prepare infusion or tea to treat snake bite envenomation. Medicinal plant extracts, a rich source of nature inhibitors and pharmacologically active compounds, have been shown to antagonize the activity of some venoms and toxins. Our studies in this field have demonstrated that aqueous or methanolic extracts of Casearia sylvestris, C. mariquitensis, C. gossypiosperma and C. grandiflora; Schizolobium parahyba and Stryphnodendron adstringes include bioactive products such as flavonoids, catequins and poliphenols able to inhibit some these venoms and isolated toxins. The isolation and structural elucidation of these compounds will allow the understanding of the interaction with these toxins and, consequently, their inhibition mechanism. Furthermore, these inhibitors can be used as molecular models for development of new therapeutical agents in treatment of ophidian accidents.

FINANCIAL SUPPORT: FAPEMIG, CAPES, CNPq, UFU.

CORRESPONDENCE TO: MARIA INÊS HOMSI BRANDEBURGO, Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia, Uberlândia, M.G. fone: (34) 3218.2203 R: 22; fax: (34) 3218.2203 R: 24. e-mail: homsi@ufu.br