Enhancing Chemotherapy Efficacy: Examining the Combination Effect of Terfezia boudieri Water Extract with First-Line Drugs Against Cancer Cell Lines

Background: Previous studies on Terfezia boudieri water extract (TWE) have demonstrated its anti-cancer potential. Our main aim in this study was to investigate the outcome of dual treatment with T. boudieri water extract and well-established chemotherapeutic agents. Methods: The antioxidant activity of TWE and total phenolic content were measured, and High-performance liquid chromatography (HPLC) was carried out. MTT assays and Chou-Talalay’s combination index (CI) were used to examine the combination effects of TWE with Tamoxifen (Tam), Xeloda (Xel), or Nexavar (Nex) on MCF-7, a breast cancer cell line, HCT-116, a colon cancer cell line, and HepG2, a liver cancer cell line respectively. Results: Antioxidant activity was determined to be 68.3% with a total phenolic content of 6.51 mg GAE/g. TWE was found to contain two main polyphenols: catechin (188.1 mg/l) and protocatechuic acid (4.37 mg/l). As per the MTT assay TWE had a clear cytotoxic effect on all cell lines and demonstrated a potential for enhancing cytotoxic effects at specific concentrations when combined with any of the chemotherapeutic agents utilized, with the most striking effect observed in HepG2 cells treated with 12 mg/ml of TWE and 25 µM of Nex, followed by MCF-7 cells treated with 50 mg/ml of TWE and 100 µM Tam, and finally HCT-116 cells treated with 25 mg/ml of TWE and 50 µM Xel. Conclusion: Overall, the data clearly demonstrate the cytotoxic effect of TWE on all three cancer cell lines, MCF-7, HCT-116 and HepG2, as well as a potential to increase this effect combined with other chemotherapeutic agents.