Two new cytotoxic stilbenoid dimers isolated from Cajanus cajan

Two new stilbenoid dimers, cajanstilbenoids A ( 1 ) and B ( 2 ), were isolated from the leaves of Cajanus cajan . Planar structures of these compounds were verified by NMR (1D and 2D) and high-resolution electrospray ionization mass spectroscopy (HR-ESI–MS). Absolute configurations were assigned by comparing experimental and calculated electronic CD values. The cytotoxicity of 1 and 2 against human hepatoma (HepG2), human breast adenocarcinoma (MCF-7), and human lung cancer (A549) cells were evaluated in vitro. Compound 1 showed strong cytotoxicity against all the tested cell lines (IC 50 values: 2.14–2.56 µM), whereas compound 2 showed strong toxicity only against HepG2 (IC 50 value: 5.99 µM) and A549 cells (IC 50 value: 6.18 µM).