Evaluation of antimicrobial activity from extracellular pigments produced by endophytic / Avaliação da atividade antimicrobiana de pigmentos extracelulares produzidos por fungos endofíticos

Abstract

Fungi pigments have a great biotechnological potential and some properties such as antimicrobial and antioxidant activity. Fungal endophytes are closely associated with plants and are an alternative source of natural dyes, which can be used in medicine. This study aimed to investigate the antimicrobial activity of pigments produced by endophytic fungi against pathogens. They belonged to the Microorganisms Collection of the General and Applied Microbiology Laboratory at the Federal University of Tocantins. Firstly, sixty isolated samples were selected accordingly to pigment production, then they were placed in an Erlenmeyer containing 100 ml of potato broth and incubated at 30°C for 14 days. After this period, the extracellular pigments were extracted with 95% ethanol and subsequently they were filtered. Diffusion disks were used in the in vitro antagonism test, which were inoculated with 10 uL of pigment filtrates and incubated at 37 ° C for 24 hours against human pathogens, for instance, Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial activity was evaluated based on the formation of an inhibition zone. The filtrates have not showed antimicrobial potential based on the pathogens tests. Therefore, the endophytic fungi study aiming to identify antimicrobial substances is fundamentally important against bacteria and pathogenic fungi.