Ação antibacteriana antifúngica e antiparasitária de veneno de serpentes do gênero Bothrops e suas frações fosfolipase A2 e L-Aminoácido oxidase

• Ano de defesa: 2009
• Autor(a) principal: Torres, Alba Fabiola Costa
• Orientador(a): Martins , Alice Maria Costa
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Fosfolipases A2; Venenos de Serpentes
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/4195

Snakes venoms contain biologically active substances primarily consisting of proteins (90-95%). Some of these present enzymatic activities, such as phospholipases A2 and the L-amino acid oxidases. In this study we verify the action of Bothrops leucurus (BleuTV) and Bothrops marajoensis (BmarTV) venoms, and fractions PLA2 (BleuPLA2 and BmarPLA2) and LAAO (BleuLAAO and BmarLAAO) on strains of bacteria, yeast, Leishmania sp and T. cruzi. The susceptibility of bacterial and yeast strains was analyzed through disc-diffusion assay, for determination of antimicrobial potential; and the microdilution method, for determination of MIC and MLC, with modifications. The antiparasitic activity was evaluated through of the culture treatment of parasites with different concentrations of venoms or their fractions. The forms promastigotes of Leishmania sp. had been cultived, during 72h, in NNN/Schneider media, 28ºC; and the forms epimastigotes of T. cruzi had been cultived in LIT media, during 5d, 28ºC. The macrophages were cultured in RPMI 1640 media, during 24h, 37ºC and 5% of CO2, with different concentrations of venoms or fractions. After, they were analyzed by MTT method. The results was statistically analyzed with t test or ANOVA followed the Bonferroni’s test, when appropriated, with p<0.05. The BmarLAAO was able to inhibit the growth of gram negative P. aeruginosa, of yeast C. albicans and of gram positive S. aureus; and the BleuTV inhibited the growth of S. aureus, being the inhibitions dose-dependent. The order of susceptibility of microorganisms tested against BmarLAAO was S. aureus > C. albicans > P. aeruginosa. On the other hand the BmarTV, BmarPLA2, BleuPLA2 and BleuLAAO had not provided any degree of inhibition on strains in study. The inhibitory effect was more significant on S. aureus presenting CIM= 50µg/mL and CLM=200µg/mL for BmarLAAO, and CIM=CLM=25µg/mL for the BleuTV. In concentrations greater than 1.56µg/mL BmarLAAO was able to inhibit the growth of promastigotes forms of L. chagasi and L.amazonensis, after 72h of culture. The IC50 values were 2.55µg/mL for L. amazonenis, and 2.86 µg/mL for L. chagasi. BmarTV and BleuTV also provided significant inhibition of the parasitic growth, with an IC50 value of 86.56 µg/mL for L. amazonensis and 79.02 µg/mL for L. chagasi, when treated with BmarTV; and 5.49µg/mL for L. amazonensis and 1.94µg/mL for L. chagasi, when treated with BleuTV. The venoms and BmarLAAO showed inhibitory effect on epimastigotes forms of T. cruzi. The IC50 value for BleuTV, BmarTV and BmarLAAO where, respectively 1.14µg/mL, 24.19µg/mL and 0.89µg/mL.This effects presented behavior dose-dependent. The fractions BmarPLA2, BleuPLA2 and BleuLAAO had not been capable to promote any inhibition on the growth of these parasites. The BmarLAAO, BmarTV and BleuTV presented low toxicity in studied concentrations. In conclusion, the whole venoms as well as the L-amino acid oxidase from Bothrops marajoensis showed to be capable to interfere in the growth of several microorganisms as S.aureus, Candida albicans, Pseudomonas aeruginosa, Leishmania sp. and T. cruzi.