ANTIMICROBIAL ACTIVITY IMPROVEMENT AFTER FRACTIONATING ORGANIC EXTRACTS FROM LASIODIPLODIA SP. FERMENTATION / MELHORIA DA ATIVIDADE ANTIMICROBIANA APÓS FRACIONAMENTO DE EXTRATOS ORGÂNICOS DE LASIODIPLODIA SP. FERMENTAÇÃO

Abstract

Endophytes constitute a promising source of bioactive substances with therapeutic potentialities. Thereby, an endophytic fungi was isolated from Handroanthus impetiginosus leaves and classified as Lasiodiplodia sp. by DNA sequence analysis and phylogenetic inference in this study. Chlorophorm (Ld-Chlo) and ethyl acetate extracts (Ld-EAm, Ld-AE and Ld-EA + ) obtained from fungus fermentation broth have been fractionated, whose extracts and fractions have been tested for assessing their antimicrobial activity against four Gram-positive, two Gram-negative and three yeast strains. It was observed an antimicrobial profile regarding crude extracts against Gram-positive and yeast pathogens. The major inhibition was achieved by Ld-Chlo (MIC of 12.5-25 µg.mL -1 ) and Ld-EAm (MIC of 12.5-25 µg.mL -1 ), both against Candida parapsilosis . The extracts were more efficient against Listeria monocytongenes and C. parapsilosis pathogens. Fractionation increased the antimicrobial activity of fractions if compared to crude extracts, probably due to a higher concentration of bioactive compounds. Gass Chromatography (GC-MS) was performed using fractions from Ld-Chlo, through which it was possible to identify four known compounds with recognized antimicrobial activity: (Z)-docos-13-enamide (1), methyl (Z)-octadec-9-enoate (2), (Z)-octadec-9-enamide (3) and dodecanamide (4).. Thence, it is suggested that the fractionation of crude extracts improve antibacterial and antifungal activities and that the identified bioactive compounds are at the helm of the antimicrobial activity presented by some fractions.