Antimicrobial Activity of Submerged Cultures of Endophytic Fungi Isolated from Three Chilean Nothofagus Species

Endophyte fungi (EF) are considered a new and valuable reservoir of bioactive molecules of biotechnological interest for pharmacy, agricultural and forestry industries. In this study, thirty EFs, isolated from three Chilean <i>Nothofagus</i> species (<i>N. alpina</i>, <i>N. dombeyi</i>, <i>N. oblicua</i>) were identified and cultured in submerged liquid fermentations aimed at searching for natural active substances. The extracts obtained were evaluated against pathogenic bacteria and fungi. Sixteen extracts (53.3%) presented antibacterial and fourteen (46.6%) presented antifungal activities in different intensities. Extracts from isolates <i>Coryneum</i> sp.-72 and <i>P. cinnamomea</i>-78 exhibited the highest antimicrobial activity. Using bioautography, the compounds responsible for the antimicrobial activity exhibited by <i>Coryneum</i> sp.-72 and <i>P. cinnamomea</i>-78 were detected and characterized. <i>Coryneum</i> sp.-72 showed bactericidal properties at 200 μg/mL and bacteriostatic effects at 50 μg/mL against <i>B. cereus</i>, <i>B. subtilis</i>, <i>L. monocytogenes</i> and <i>S. aureus</i>. MIC values indicated that <i>P. cinnamomea</i>-78 exhibited a strong fungistatic and fungicidal effect against <i>B. cinerea</i> and <i>C. gloesporioides</i> at 10-50 μg/mL. Isolates were grouped in the following order: Botryosphaeriales, Diaporthales, Eurotiales, Helotiales, Hypocreales, Pleosporales, Magnaporthales, Sordariales and Polyporales. EF isolated, identified and evaluated constitute the first report for Chilean <i>Nothofagus</i> genus.