Cytotoxic dibenzocyclooctadiene lignans from Kadsura coccinea

Three new dibenzocyclooctadiene lignans, kadusurain A–C (1–3), together with two known compounds kadsuphilin A (4) and B (5), were isolated from an EtOAc fraction of the 80 % acetone extract of Kadsura coccinea (Lem.) A. C. Smith. Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy. Anti-proliferative effect of isolated compounds was evaluated against four human tumor cell lines (A549, HCT116, HL-60, and HepG2), and it was found that compound 1 exhibited significant antiproliferative effects with IC₅₀ values ranging from 1.05 to 12.56 μg/ml.