Vibsane-type diterpenes from leaves and twigs of Viburnum odoratissimum.

Seven new vibsane-type diterpenes, vibsanols C-H (1-6) and vibsanin X (7), together with seven analogues, were isolated from the leaves and twigs of Viburnum odoratissimum. The structures of the new compounds were elucidated by extensive spectroscopic methods. All the new compounds were detected for their cytotoxicity. Compound 1 showed significant cytotoxicity against all the tested cell lines (HL-60, SMMC-7721, A-594, MCF-7, and SW-480), with IC50 values of 3.35, 4.41, 5.18, 11.30, and 3.70 µM, respectively. Compounds 4 and 5 also displayed significant cytotoxicity against hepatocellular carcinoma SMMC-7721 cell line, with IC50 values of 3.69 and 3.52 µM, respectively.