Identificação e potencial antimicrobiano de fungos endofíticos isolados da espécie Eleutherine bulbosa (Mill.) Urb. (Iridaceae).

Abstract

The plants of the Brazilian flora have a great potential in the production of new antimicrobial substances, such as Eleutherine bulbosa (Mill.) Urb. (Iridaceae), for example. This species is easily found in the Brazilian Amazon region, where it is popularly known as “Marupazinho”, and used in folk medicine for therapeutic purposes, in addition to having antimicrobial, antiparasitic, anti-inflammatory and analgesic properties. Associated with these plants are endophytic microorganisms, such as some fungi that inhabit the internal tissues of these plants without causing apparent damage, in addition to being responsible for the production of secondary metabolites with bioactive potential. Thus, the present work aims to isolate and identify endophytic fungi associated with E. bulbosa with the potential to produce substances with antimicrobial activity. E. bulbosa samples were collected at three points located in the municipality of Santarém, Pará, which were submerged in disinfectant solutions and had parts of leaves, bulbs and roots fragmented (5 mm in size) and inoculated in Potato Agar culture medium Dextrose (BDA), plus the antibiotic Chloramphenicol (0.05 g/L) for fungal isolation. The strains obtained were characterized macroscopically and microscopically and subjected to molecular identification. Sixty-five endophytic fungi distributed into 17 morphotypes were isolated, of which 10 strains were selected and cultivated in Dextrose Potato Broth (CDB) liquid medium to obtain the crude metabolite broth. The antimicrobial activity was tested using the pour-plate technique in diffusion in wells of 5 mm in diameter against standard strains Amerycan Type Culture Collection – ATCC (Candida albicans ATCC 60193, Echerichia coli ATCC 25922, Enterococcus faecium ATCC6560, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 33591). Of the total of fungi isolated, eight taxa were elucidated, being the genus Muyocopron Speg. was the most frequent (21.54%). Of the 10 strains submitted to the antimicrobial activity test, five showed inhibition halos in at least one of the tested strains (Fusarium (Link), Muyocopron (Speg.), Paecilomyces (Bainier), Penicillium (Link), Phaeoacremonium (W. Gams)). Through this study, it was possible to know part of the diversity of cultivable endophytic fungi associated with E. bulbosa, in addition to suggesting that this plant species may have its own endophytic community, larger than that observed and with antimicrobial potential still unknown.