Prunella vulgaris L. belongs to the Prunella genus and has been proven effective in the treatment of gastric cancer, however, the therapeutic activity of the endophytic fungi is not yet well understood. The results of the present study suggest that the ethyl acetate extract (S03-EA) of the endophytic fungus XKC-S03, isolated from Prunella vulgaris L. spica, is a potent anticancer agent with the potential to treat gastric cancer. In the present study, the effects of S03-EA on gastric cancer in vitro and in vivo were determined using the 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan assay and the human gastric cancer SGC 7901 cell xenograft model. The tumor tissue was fixed with 10% formaldehyde solution and the levels of the apoptotic proteins, B-cell lymphoma protein-2 (Bcl-2), Bcl-2-associated X protein (Bax) and pro-angiogenic vascular endothelial growth factor (VEGF), were measured by immunohistochemistry. The results indicated that treating SGC 7901 cells with petroleum ether (S03-PE), ethyl acetate (S03-EA) or dichloromethane (S03-DM) extracts from the XKC-S03 fermentation broth inhibited cell proliferation. S03-EA demonstrated the best activity, with a half maximal inhibitory concentration of 25.89 μg/ml and dose-dependent suppression of the SGC 7901 tumor cells in vivo, without any evident adverse effects. In addition, the 100-mg/kg/day S03-EA-treated tumor tissue revealed a downregulation of Bcl-2 and VEGF expression and an upregulation of Bax expression. In conclusion, the S03-EA extract of XKC-S03, isolated from Prunella vulgaris L. spica, exhibits a growth-suppressive activity on gastric cancer in vitro and in vivo.
Keywords: Prunella vulgaris L.; endophytic fungi; ethyl acetate extract; gastric cancer.