Antimicrobial and cytotoxic activities of endophytic fungi isolated from Piper crocatum Ruiz & Pav

Objective: To investigate antimicrobial and cytotoxic activities of endophytic fungi isolated from Piper crocatum Ruiz & Pav (P. crocatum). Methods: Ethyl acetate extracts were obtained by liquid-liquid partition of fermentation broth of endophytes followed by evaporation. The antimicrobial activities were determined by diffusion techniques followed by thin layer chromatography-bioautography. Cytotoxicity studies were conducted using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Data generated were used to plot a dose-response curve, of which the concentration of extract required to kill 50% of cell population (IC50) was determined. Results: Two endophytes were isolated from leaves and stem of P. crocatum, designated as DS1 and BS1. Ethyl acetate extracts of BS1 was found to inhibit the growth of Bacillus subtilis, Escherichia coli and Staphylococcus aureus at minimum dose of 31.25, 125 and 250 µg, respectively. thin layer chromatography-bioautography of this extract resulted in at least two inhibition zones. BS1 extract also inhibited the growth of WiDr and T47D cell lines with IC50 of 120.38 µg/mL and 37.43 µg/mL, respectively. Conclusions: BS1 extract produced by endophytic fungi of P. crocatum is potential to be developed as source of novel bioactive compounds