Polyphenols Isolated from Xanthoceras sorbifolia Husks and Their Anti-Tumor and Radical-Scavenging Activities

Xanthoceras sorbifolia Bunge. is used in traditional medicine in North China. To evaluate the anti-tumor and radical-scavenging activities of X. sorbifolia husks polyphenols and determine their structure-activity relationships, 37 polyphenols 1-37 were obtained by bioassay-guided fractionation. Two new compounds 1-2, and compounds 5, 6, 8, 9, 11, 14-17, 21-25, 27-29, 31, 33, 34, 36, and 37 were isolated from the genus Xanthoceras for the first time. Compounds 1-37 did not show strong cytotoxicity against the four tested tumor cell lines (A549, HepG2, MGC-803, and MFC) compared to paclitaxel and under the conditions tested in the anti-tumor assay, but compounds 3, 4, 7, 8, 10, 18-20, 25, 26, 29, 30, 32, and 35 exhibited stronger radical-scavenging activity than ascorbic acid in a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt assay. This was the first report on the anti-tumor and radical-scavenging activities of the polyphenols isolated from X. sorbifolia husks. Overall, the present study contributed valuable information concerning X. sorbifolia husks use in medicine and pharmacology.