A new dimeric phenylpropanoid and cytotoxic norditerpene constituents from Podocarpus nakaii.

A new dimeric phenylpropanoid namely podonaka A (1), along with the 13 known compounds including diterpenes (2 and 3), norditerpenes (4 and 5), benzenoids (6-10), steroids (11 and 12), chalcone (13), and megastigmane (14), was isolated from the EtOH extract of Podocarpus nakaii Hayata. The structure of 1 was elucidated on the basis of spectroscopic analysis including 1D and 2D NMR and MS techniques. Biological evaluation showed that norditerpenes, inumakilactone B (4), and podolactone E (5) have potent cytotoxic activities against Daoy, WiDr, KB, and HeLa tumor cell lines. Moreover, low dosage of 5 may induce early apoptosis in KB cells before 12 h.