Pregnane, coumarin and lupane derivatives and cytotoxic constituents from Helicteres angustifolia

Four natural products possessing pregnane, coumarin and lupane skeletons, along with 24 known compounds were isolated from the roots and aerial parts of the anti-tumor medicinal plant Helicteres angustifolia. Among these, two cucurbitacin derivatives exhibited significant inhibitory activity against the growth of both hepatocellular carcinoma BEL-7402 cells and malignant melanoma SK-MEL-28 cells.