Two New Dolabrane Diterpenes from the Chinese Mangrove Ceriops tagal

Two new dolabrane diterpenes, tagalenes J and K (1 and 2), together with eleven known analogues (3 - 13), were isolated from the ethanolic extract of the Chinese mangrove Ceriops tagal. The structures of these compounds were determined by extensive spectroscopic analysis, including 1D-, 2D-NMR and HR-ESI-MS, as well as the comparison with data in the literatures. Cytotoxicities of isolated compounds against MCF-7, SW480, HepG2, HeLa, PANC-1, and A2058 cancer cell lines were also evaluated. Compound 4 exhibited weak cytotoxic activity against SW480, HeLa, and PANC-1 cell lines with IC₅₀ values of 27.7, 22.2, and 17.6 μm, respectively.