New antitumor compounds from Carya cathayensis.

A new lignan (7R,8S,8'R)-4,4',9-trihydroxy-7,9'-epoxy-8,8'-lignan, and three new phenolics, carayensin-A, carayensin-B, and carayensin-C, together with 13 known compounds were isolated from the shells of Carya cathayensis. Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. All the compounds were evaluated for cytotoxicity against several human tumor types including human colorectal cancer cell lines (HCT-116, HT-29), human lung cancer cell line (A549), and human breast cancer cell line (MCF-7). The compounds 1, 5, 6, and 16 are considered to be potential as antitumor agents, which could significantly inhibit the cancer cell growth in a dose-dependent manner.