Abstract:
Objective To determine the classification status of endophytic fungus Eef-10. To isolate and identify secondary metabolites of Eef-10 and evaluate their antibacterial and antitumor activities in order to obtain natural active compounds.
Method The endophytic fungus was identified by combining morphology and molecular biology methods. The secondary metabolites were mainly separated and purified by vacuum silica gel column chromatography, sephadex LH-20 column chromatography and semi-preparative HPLC. The compounds were identified mainly based on 1H NMR and 13C NMR spectral data as well as related references. The antibacterial activities against five different test bacteria were determined by the MTT method and the antitumor activities against two cancer cells were determined by the CCK8 method.
Result Three compounds were isolated from the endophytic fungus Eef-10, namely atraric acid (Compound Ⅰ), ethyl 2, 4-dihydroxy-3, 6-dimethylbenzoate (Compound Ⅱ) and 4-methyl-5, 6-dihydro-2 H-pyran-2-one (Compound Ⅲ). Compound Ⅱ displayed strong inhibitory activities against five test gram-negative bacteria, and the IC50 values were 35.87−55.50 μg/mL. The IC50 values of compound Ⅰ were 67.25−130.55 μg/mL, while compound Ⅲ had IC50 values of more than 200 μg/mL for all five bacteria. The IC50 value of compound Ⅱ for Hep-G2 was 1.50 μg/mL, which was stronger than the positive control camptothecin of 3.6 μg/mL.
Conclusion Compounds Ⅰ−Ⅲ were isolated from the endophytic fungus Chaetomium sp. Eef-10 and compound Ⅱ showed great antibacterial and antitumor activities on R. solanacearum and Hep-G2 tumor cells.