Avaliação do potencial antimicrobiano de infusões de folhas de cajueiro (Anacardium occidentale Lin) frente a bactéria Streptococcus mutans

Abstract

The cultivation of Anacardium occidentale Lin, more known as cashew tree, is one of the most important agriculture and stock-breeding activities in the northeast of Brazil. It is used in traditional medicine with therapeutic purposes, including antigerm activitiy. The objective of this work is to check the antigerm potential by infusing the leaves of the cashew tree in different hours of collection before the bacterium Streptococcus mutans. Its objective also includes the analysis of the toxical and cytotoxical potential of these infusions in used concentrations. The Minimum Inhibitory Concentration (MIC) was determined in the time- tables 7,9,11,13,15,17 and 19H using the cepa of S.mutans UA159. It was also determined the Minimum Bactericidal Concentration (MBC), when tests of toxicity of infusions were done in Artemia salina Leach and cytotoxicity in the presence of LDH enzyme in human neutrophil. The results of the antigerm samples showed that the infusions of the leaves of the cashew tree may stimulate, inhibit or not present effects on the bacterium growth, according to the time of collection and concentration. The values of the MIC (Minimum Inhibitory Con- centration) were 250 µg.mL-1 (7h), 125 µg. mL-1 (9-15h) e 62,5 µg. mL-1 (17 e 19h). Some stimulus occured in the bacterium growth in the following concentrations: 15,62 µg. mL-1 (9- 19h), 31,25 µg mL-1 .(15h) e 62,50 µg. mL-1 (15h). The collected infusion at 7 A.M. did not present any stimulus concentration. In the tests of Minimum Bactericidal Concentration (MBC), the infusions were considered bacteriostatic. The tests of toxicity in Artemia salina resulted in values for the average lethal concentration (CL50) of 266,15; 285,48 and 345,15 in the collection times of 11, 17 and 19h, respectively. Therefore, for the hours of colletion the infusions were considered nontoxical in their values of Minimum Inhibitory Concentration (125 e 62,5µg.mL-1 ). The tests of cytotoxicity showed that the infusions were not toxical in the concentrations of 1, 10, 100 e 200µg. mL-1.