Isolamento e seleção de fungos endofíticos produtores de compostos bioativos associados à Eugenia pyriformis (Myrtaceae).

Abstract

The endophytic fungi have aroused the scientific community interest especially by its diversity and its potential in the production of secondary metabolites. Eugenia pyriformis (Cambess), known as uvaia, is a fruit species of Myrtaceae’s family, demonstrating the potential for the production of bioactive compounds. This dissertation aimed to isolate the endophytic fungal community associated with E. pyriformis and assess the potential to produce bioactive metabolites with antimicrobial activity, antiproliferative and antiparasitic. 200 fungi were isolated in the autumn period, from mature leaves. Half of the isolates were subjected to fermentation and extraction with ethyl acetate. The extracts were tested in an antimicrobial screening assay. For the agar diffusion's test the microorganisms were tested: Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. In total, 54 of 100 endophytic fungi tested showed antimicrobial activity against at least one microorganism. The S. aureus was inhibited by 34 extracts, the C. albicans had their growth inhibited by 12 extracts, and 8 extracts showed activity for E.coli. Based on the antimicrobial test results, the following fungal extracts were selected F6F3, F12F2 and F15F1 to the MIC assays and MBC against of Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922, Proteus mirabilis ATCC 25933, Micrococcus luteus ATCC 9341, Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 22228, Enterobacter cloacae LMI-UNIFAL, Serratia marcescens LMI-UNIFAL, besides the anti-proliferative and antiparasitic assays. The extracts showed good results in the MIC test and the values varied between 250 and 1000 µg/mL. The extracts showed bactericidal capacity at 1000 µg/mL. The results of the antiproliferative assay showed that the three extracts were inactive front the tumor cell lineage, in addition the F6F3 and F15F1 extracts also were not able to inhibit the growth of promastigotes, and the F12F2 extract was weakly active in leishmanicidal test, contrary to expectations. However, the results demonstrate the great antimicrobial potential of endophytic fungi isolated from E. pyriformis, and highlight the importance to further study of the endophytic fungi, since from them some compounds and new substances may be isolated and identified from it, probably derived from the complex endophytic/host interaction, with pharmacological interest activities.