Abstract: In this study, a strain of endophytic fungus JXP21 with good antioxidant activity was isolated from the barks of Dalbergia odorifera T. Chen, and was identified as Alternaria alternata through ITS-rDNA sequence alignment and phylogenetic analysis, whose ITS-rDNA sequence was 100% similar with GenBank accession number KP979753.1. The compound genistein was detected as one of its metabolites by high performance liquid chromatography tandem mass spectrometry. The protective effect of the metabolites of JXP21 at different concentrations (0, 10, 20, 40 and 80 μg/mL) on oxidative damage induced by 200 μmol/L H2O2 in HepG2 cells was investigated by measuring malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. The results showed that the fungal metabolites decreased the increase in MDA content from 4.65 to 3.68 nmol/mg protein, increased SOD activity from 6.88 to 8.64 U/mg pro and GSH-Px activity from 8.45 to 9.68 U/mg pro. In conclusion, the results of this study indicated that the endophytic fungal metabolites can protect against oxidative damage induced by H2O2.

Key words: Dalbergia odorifera T. Chen, endophytic fungi, superoxide dismutase, glutathione peroxidase, malondialdehyde