ANTIPARASITIC ACTIVITY OF THE GLANDULAR SECRETIONS FROM THE MONTE DESERT TOADS

RODRIGUEZ, Y; BARRERA, P; SOSA, M.; SANABRIA E.; BUSTOS, D.

San Juan

Congreso; Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2023

SBC

The glandular secretions of Bufonidae are notable for being a rich source of bioactive compounds, of significant importance in the life cycle ofamphibians, with biological activity against various microorganisms and potential use in the pharmaceutical industry. The objective of thisstudy was to evaluate the potential of venom extracted from Rhinella arenarum and Rhinella spinulosa as antiparasitic agents againstTrypanosoma cruzi. The secretions of R. arenarum and R. spinulosa were collected in situ (Parque Sarmiento and Quebrada de la Flecha,respectively) by manually compressing the parotid gland and stored in tubes at -15°C and -20°C for future use. Subsequently, the secretionswere vacuum-dried and pulverized with a mortar. For the antiparasitic activity assays, epimastigotes of T. cruzi (strain Dm28c or Tulahuen)were cultured in vitro in Diamond medium (0.1 M NaCl, 0.05 M K2HPO4, 0.0625% tryptose, 0.625% tryptone, 0.625% yeast extract, pH7.2) at 28°C. The medium was supplemented with 10% heat-inactivated fetal bovine serum (Gibco) and 12.5 μg/mL of Hemina. For theproliferation experiment, 2 x 106 parasites were cultured, treated with amphibian venom (50, 100, 200, and 1000 μg/mL) for 48 hours.Control groups were treated with DMSO (10 μg/mL) and without venom. Aliquots of the cultures were taken every 24 hours and fixed with2% paraformaldehyde in PBS. They were counted using a hemocytometer (Neubauer chamber) to assess proliferation, measured inparasites/mL (x 106), and the percentage of inhibition. The proliferation of epimastigotes treated with Rhinella arenarum venom (200 and1000 μg/mL) at 48 hours was significantly lower than the controls (untreated and DMSO). The percentage of inhibition of parasiteproliferation reached 100% in experiments with venom from both toad species at 1000 μg/mL within the first 24 hours, whereas only withthe extract obtained from R. arenarum (200 μg/mL), a 70% inhibition was observed at 24 and 48 hours. The results indicate that toad venoms,mainly from R. arenarum, hold potential as antiparasitic agents against T. cruzi.