Monoterpenoid indole alkaloids from the bark of Melodinus henryi.

Four new alkaloids, melodinines W₁-W₄ (1-4), together with twenty one known alkaloids (5-25) were isolated from Melodinus henryi. The structures with absolute configurations were elucidated by extensive MS and NMR spectroscopic methods, as well as the single crystal X-ray diffraction and ECD calculations. All compounds were evaluated for their cytotoxicities to five human cancer cell lines. Many compounds showed certain cytotoxicities to five human cancer cell lines with an IC₅₀ range of 1.4-29.4 μM.