Abstract:A new natural halogen-containing stilbene derivative was isolated from the leaves of Cajanus cajan (L.) Millsp. and identified as 3-O-(3-chloro-2-hydroxyl-propanyl)-longistylin A by comprehensive spectroscopic and chemical analysis, and named cajanstilbene H (1). It is the first halogen-containing stilbene derivative found from plants. In human mesenchymal stem cells (hMSC) from bone marrow, 1 did not promote cell proliferation, but distinctly enhanced osteogenic differentiation of hMSC in time-and dose-dependent manners. In six human cancer cell lines, 1 showed a moderate inhibitory effect on cell proliferation, with IC50 values of 21.42-25.85 μmol·L −1 .

Two new stilbenoids cajanotone and cajanamide A (1-2), together with another six known ones (3-8) and four known dihydroflavones (9-12), have been isolated from the leaves of Cajanus cajan. Their structures were elucidated based on spectroscopic studies. A possible pathway to the new compounds 1 and 2 has been proposed. In vitro cytotoxicities of selected compounds against cancer cell lines HepG2, MCF-7 and A549 have been evaluated. Compounds 7 and 8 show strong cytotoxity against all the tested cell lines (with IC 50 values in the range of 3.5 -6.0 µ M), and compounds 1 and 3 showed strong to moderate activity against the three cell lines.