Cytotoxic and antioxidant dihydrobenzofuran neolignans from the seeds of Crataegus pinnatifida.

Eight new dihydrobenzofuran neolignans, pinnatifidanin C I-VIII (1-8), together with two known analogs (9-10) were isolated from the seeds of Crataegus pinnatifida. Their structures were elucidated by spectroscopic analyses, especially 1D, 2D NMR and CD spectra. The cytotoxic activities of all isolates against human cancer cell lines were assayed, and most interestingly, compound 10 revealed preferred cytotoxicity on the HT-1080 cell line and displayed much stronger inhibitory activity (IC50=8.86 μM) compared with positive control 5-fluorouracil (IC50=35.62 μM). Meanwhile, antioxidant activities of all the isolates were evaluated using 2,2-diphenyl-1-pikrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays, and the results showed that most of the isolates exhibited potent antioxidant activity.