Atividade antimicrobiana e antitríptica das proteínas de sementes do quiabo (Abelmoschus esculentus L. MOENCH)

Abstract

Studies with protease inhibitors have been the subject of continuous interest of researchers, mainly due to potential biological activities, such as: antioxidant, insecticidal, antifungal and antimicrobial activity. The presence of trypsin inhibitors in some plants may limit their use in human food; mainly due to its effects of reduction in protein digestibility. In animals fed soybean and bean seeds that have protease inhibitors, the growth and hypertrophic response of the pancreas and small intestine has been scientifically demonstrated. Based on this, this work aimed to investigate and characterize new trypsin inhibitors present in okra (Abelmoschus esculentus L. Moench) seeds. Thus, after extraction with water, the crude protein extract (EB) obtained was precipitated with ammonium sulfate in a single fractionation in the range of 0-80%. The resulting fraction was subjected to inhibitory activity assay and ion exchange chromatography to purify the inhibitors. The soluble protein contents in the research steps were quantified by the Bradford method and visualized by electrophoresis (PAGE-SDS). The quantification of the soluble protein content showed a considerable protein content, being these levels similar to those found in bean seeds. Regarding the antitríptic activity, high values of inhibition of the enzyme trypsin were found in the EB and SF (supernatant of fraction 0-80), with 75.8% and 97.1%, respectively. In the ion exchange chromatography of the supernatant of the fraction, four peaks were obtained by elution in a gradient of NaCl concentration (0-0.4 mol / L). The electrophoresis analysis (PAGE-SDS) of the crude extract. fractions and chromatographic peaks showed that EB, SF and PF (0-80% fraction precipitate) presented protein bands in the range between 38 and 12 kDa and of 76 kDa. EB, SF and PF were positive in antimicrobial growth inhibition test of Candida sp. the chromatographic peaks on the other hand show a negative result for such tests. Thus, it was concluded that okra seeds have a high content of proteins as well as trypsin inhibitors, which were partially purified, justifying the continuity of the research in order to purify these inhibitors, as well as to verify their probable biological activities.