Screening and characterization of fungal taxol-producing endophytic fungi for evaluation of antimicrobial and anticancer activities

Bioactive compounds produced by fungal endophytes have potential benefits, such as low cost, rapid growth, facile genetic manipulation, and industrial scaleup with fewer negative effects. Millingtonia hortensis is a valuable medicinal plant found throughout South Asia. To the best of our knowledge, no reports are available for the screening of endophytic fungal taxol in this medicinal plant. Hence, seven previously reported endophytic fungi from Millingtonia hortensis L. were used in the present study. Of these, five were found to produce taxol. The agar well diffusion method was used to assess the antibacterial and antifungal activities of partially pure fungal taxol against human and fungal pathogens. Fungal taxol effectively inhibited all tested pathogens. Based on the significant antibacterial activity, the sorting of bacterial cells against the compounds (MID6 and MID9) was analyzed by flow cytometry. MID9 showed a moderate level of cell death compared to the control. The MTT assay was used to examine the cytotoxic effects of fungal taxol against the human liver cancer cell line HepG2. A significant decrease (0.05-0.5 mu M) was observed in the cell viability and IC50 dosage was fixed as 0.25 mu M after 24 h of treatment. Morphological changes were also observed. From these results, we conclude that this is the first description of the taxol-yielding potential of Cochliobolus hawaiiensis. In addition, fungal taxols exhibit potential antibacterial, antifungal, and anticancer effects. In the future, Cochliobolus hawaiiensis could be a new source of taxol, a revolutionary therapeutic drug.