In the current study, antiproliferative effects of 3 ß- hydroxyl- Olean - 12 - en - 28 - oic acid (Oleanolic acid ; OA) & 3-ß-hydroxyolean - 12-en–27, 28 dioic acid (Cincholic acid; CA); triterpene sapogenins isolated from the ethyl-acetate fraction of Lotus glaber-mill herb were evaluated against three human cancer cell lines, the liver cancer cell line( HepG-2), the colon cancer cell line (HCT-116), & the breast cancer cell line (MCF-7). The structures of isolated phytoconstituents were identified by careful analysis of 1D NMR spectra and negative ESI-MS data. Oleanolic acid & Cincholic acid displayed cytotoxic activities against the tested cell lines. Oleanolic acid has lower IC50 than Cincholic acid for both MCF-7 & HCT-116 at 27.99 & 18.66µg/ml respectively.While Cincholic acid has a lower IC50 in HEPG-2 than Oleanolic acid at 22.81µg/ml. Further investigations have shown that Oleanolic acid & Cincholic acid- induce apoptosis and cause cell cycle arrest at the G2/M phase.