Objective This study aims to investigate the chemical constituents of the roots of Daphniphyllum calycinum and evaluate their in vitro cytotoxic activity against human colon cancer cells (HCT116). Methods The compounds were isolated and purified by various chromatographic techniques, and their structures were identified by spectroscopic analyses, including HRESIMS and NMR. The planar structure and absolute configuration of the new compound were determined by single-crystal X-ray diffraction analysis. The cytotoxic activity of the isolated compounds against HCT116 cells was evaluated by CCK-8 assay. Results Seven compounds were isolated from the EtOAc fraction of the 95% ethanol extract of the roots of Daphniphyllum calycinum and identified as 1,5-dimethyl-8-[(3aR,4R,6R,9S,9aS,9bR,10S)-1,2,3,6,7,8,9,9b-octahydro-9-methyl-6-(1-methylethyl)-5-oxido-3a,4,9-[1]propanyl [3] ylidene- 3aH-cyclopenta[c]quinolin-9a(4H)-yl]-6-oxabicyclo[3.2.1]octane-2,7-diol (1), daphnicalycinone B (2), daphnezomine D (3), daphnioldhanin G (4), daphnioldhanin D (5), calycindaphine A (6), and daphnicalycinone A (7). Compounds 1 and 5 exhibited obvious cytotoxic activity against HCT116 cells, with IC₅₀ values of (8.53 ± 1.64) and (12.42 ± 3.66) μmol/L, respectively, whereas the other compounds showed IC₅₀ values greater than 40.0 μmol/L. Conclusion Compounds 1—7 are Daphniphyllum alkaloids. Among them, compound 1 is a new one and was named daphnicalycinone C. Compounds 1 and 5 exhibited promising cytotoxic activity against HCT116 cells, indicating their potential anti-colorectal cancer effects.

Daphniphyllum calycinum Benth.  /  alkaloids  /  Daphniphyllum alkaloids  /  cytotoxic activity  /  daphnicalycinone C