Investigação da atividade antimicrobiana e antioxidante da espécie Cratylia hypargyrea Martius ex. Bentham (leguminosae)

Abstract

The research for biologically active substances, originated mainly from plants, has led to discovery of molecules clinically beneficial. Chemical studies on the Leguminosae family reported the production of biological markers such as phenolic compounds, that have significant activity against gram-positive and gram-negative micro-organisms, fungi, viruses, analgesic effect, among others. In semi-arid of Bahia are found several genus of this family, among them, the Cratylia, extensively researched due to its fodder ability, especially in periods of extreme dryness. This study aimed to preliminary investigation of classes of compounds, the antimicrobial and antioxidant activity of leaves and stems of the specie Cratylia hypargyrea, collected at Itaberaba - Bahia. The plant material was identified, cleaned, dried and crushed, with subsequent maceration in methanol to obtain methanolic extract. The fractionation of this extract was performed by using the method of liquid-liquid partition to obtain the fractions: hexane, dichloromethane, ethyl acetate and butanol. The antioxidant activity was analyzed by thin-layer chromatography and spectrophotometry using scavenging of DPPH radical method. Antimicrobial activity was evaluated against four strains of gram-positive bacterias, four gram-negative bacterias and four yeasts by determining the Minimum Inhibitory Concentration (MIC), the Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (CFM). In the fractions obtained from extracts of leaves and stems were detected the presence of terpenes, triterpenes, steroids and phenolic compounds. In the analysis of antioxidant capacity was observed that all samples were able to inhibit the free radical DPPH, with reference to the fraction in dichloromethane. All samples in analysis also showed antimicrobial activity, and the fraction of hexane in both organs showed the highest bacteriostatic power against especially Bacillus cereus, Salmonella choleraesuis and Candida parapsilosis, as the greatest bactericidal and fungicidal activity was observed in fraction hexane of stems against S. choleraesuis and C. parapsilosis. The results of this study indicate that this specie has antioxidant and antimicrobial potential, so further investigations aimed at isolation and identification of these substances are necessary.