Three undescribed solalodine-type glycoalkaloids, named solanigrinoside A-C (1-3), and six known compounds (4-9) were isolated from the whole plants of Solanum nigrum. Their structures were elucidated based on analysis of HR-ESI-MS, 1D- and 2D-NMR spectral data, and comparison with those reported in literatures. The solanigrinoside A-C (1-3), solasodine (4), and 3-acetoxysolasodine (5) exhibited cytotoxic effects against LU-1, Hep-G2, and MCF-7 cells with IC50 values in range from 4.6 mu M to 56.2 mu M. Compound 2 showed the significant cytotoxic activity with corresponding IC50 values of 5.7 mu M, 7.9 mu M, and 4.6 mu M, respectively.