Phenylpropanoids from the fruit of Crataegus pinnatifida exhibit cytotoxicity on hepatic carcinoma cells through apoptosis induction.

Eight new phenylpropanoids (1a/1b, 2-4, 5a/5b and 6) including two pairs of enantiomers (1a/1b and 5a/5b), along with a known analogue (7) were isolated from the fruit of Crataegus pinnatifida. Their structures were elucidated using comprehensive spectroscopic methods. Compounds 1a/1b and 5a/5b were separated successfully by chiral chromatographic column. The absolute configurations of enantiomers were determined by comparison between the experimental and calculated electronic circular dichroism (ECD) spectra. The in vitro antitumor activities of the isolates were evaluated against two human hepatocellular carcinoma HepG2 and Hep3B cells. Five compounds (1a/1b, 2-4) exhibited more potent cytotoxicity and their structure-activity relationships were also discussed. Annexin V-FITC/PI staining using flow cytometry was carried out to examine cell apoptosis, and the results showed that compounds 3-4 with the presence of two methoxy groups substituted at C-3' significantly induced apoptosis in HepG2 cells.