In vitro study on antitumor activity of aurantiamide acetate extracted from Polygonum capitatum

Aurantiamide acetate is a dipeptide derivative with antibacterial, antiviral, anti-inflammatory and analgesic activities. However, its antitumor activity has not been documented. This study aimed to prepare aurantiamide acetate from Polygonum capitatum and investigate its antitumor activity in vitro. The petroleum ether extract fraction of 80% ethanol extract from P. capitatum was separated by silica gel column chromatography. Aurantiamide acetate was obtained and identified by physicochemical properties, MS and NMR spectral data. The inhibitory effect of different doses of this compound on the proliferation of human umbilical vein endothelial cells (HUVECs), human gastric cancer BGC-823 cells, lung cancer A549 cells and colorectal cancer Caco-2 cells was detected by CCK-8 method. Morphological changes of BGC-823 cells were observed under the inverted microscope. The effect of aurantiamide acetate on BGC-823 apoptosis and cycle was detected by flow cytometry. The expression of Bax and caspase-3 in BGC-823 cells was detected by Western blotting. Aurantiamide acetate inhibited BGC-823, A549 and Caco-2 cell proliferation at the concentrations from 25 μmol/L to 100 μmol/L, but had no inhibitory effect on HUVECs at the concentrations from 12.5 μmol/L to 100 μmol/L. The inhibitory effect of Aurantiamide acetate was most pronounced on BGC-823 cell proliferation at IC50 of 56.73 μmol/L, most probably by increasing the protein expression of caspase-3 and Bax in BGC-823 cells, and arresting cell cycle in G2/M phase. This is the first time that we isolated aurantiamide acetate from P. capitatum with a purity of 98.21%, and found that Aurantiamide acetate could in inhibit the proliferation of various cancer cell types in vitro. This finding may provide a new resource for developing anti-tumor drugs in future.