Potencial antibacteriano e citotóxico dos venenos variedades ‘amarela’ e ‘branca’ da serpente amazônica Crotalus durissus ruruima

Abstract

Animal venoms are one of the richest sources of biologically active substances found in nature and such prerogative has been confirmed in pharmacological and biochemical studies of proteins (enzymes), peptides, bioactive amines, and other compounds isolated from snake venoms. In this context, the purpose of the present study was to evaluate the antibacterial and antitumor potential of the individual venoms "yellow" (Cdr68 and Cdr69) and "white" varieties of the Amazonian rattlesnake Crotalus durissus ruruima. The evaluation of the antimicrobial activity of the crude venoms was performed by the disc diffusion technique against gram-positive (Staphylococcus aureus and S. epidermidis) and gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). The yellow venoms presented antibacterial activity against gram-positive bacteria Staphylococcus aureus. The cytotoxic action of the venoms was evaluated using the following cell lines SK-Mel 103 (melanoma), MCF-7 (breast adecarcinoma), HCT-116 (colorectal carcinoma) and MCR-5 (human fibroblast). Cdr68 and Cdr69 venoms were cytotoxic to all tumor lines but were more potent for the colorectal carcinoma (HCT-116) with IC50 of 1.8 μg / mL and 1.3 μg / mL for Cdr68 and Cdr69 respectively. The white variety venoms were not cytotoxic to the tested strains. The chromatographic profiles of Cdr68, Cdr69, Cdr110 and Cdr173 by molecular exclusion showed four major peaks. The isolated fractions were submitted to tests of coagulant, phospholipase A2, cytotoxic and antibacterial activity, all activities were present in Peak II of Cdr68, and in Peaks I (cytotoxic) and II of Cdr69. Peaks II of both venoms were submitted to Reverse Phase Chromatography. The FRP2 peaks of the Reverse Phase of the venoms presented phospholipase activity, cytotoxic against the strain HCT-116 in concentration of 100 μg / mL and antibacterial against S. aureus. The mass of this peak was approximately 14 kDa, compatible with PLA2. It is interesting to note that the total venom presented higher cytotoxic potential than the isolated fractions, showing a possible synergistic effect among the venom constituents.