Three new phenanthrenes, a new stilbenoid isolated from the roots of Stemona tuberosa Lour. and their cytotoxicity.

Three new phenanthrenes, stemophenanthrenes A-C (1-3), along with one new stilbenoid, isopinosylvin A (4) and a known compound methyl ferulate (5), were isolated and identified from the roots of Stemona tuberosa Lour. plants, collected in Attapu province (Laos). Their structures were elucidated by spectroscopic analysis (FT-ICR-MS, IR, UV, 1D and 2D NMR). These compounds show moderate cytotoxic activity against four cancer cell lines, KB (a human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma) and HepG2 (hepatocellular carcinoma).