Synergistic combinatorial anticancer potential of Tamoxifen with Naringin and Diosmetin in MCF-7 breast cancer cells and their liposomal delivery.

Breast cancer continues to remain a significant issue due to resistance to endocrine therapies, including tamoxifen. Naringin and Diosmetin (natural flavonoids) have anticancer effects that may synergistically enhance therapeutic efficacy when used with Tamoxifen. However, their inadequate solubility and bioavailability require the formulation of specialised delivery systems. This research aimed to determine the synergistic anticancer potential of dual (Tamoxifen + Naringin, Tamoxifen + Diosmetin) and triple (Tamoxifen + Naringin + Diosmetin) combinations, followed by evaluation of their liposomal co-delivery as a formulation strategy. The MTT test evaluated cytotoxic activities in breast cancer cell lines (MCF-7, T47D). IC₅₀ values were obtained for Tamoxifen (9.38 ± 1.87 µM), Naringin (12.34 ± 1.23 µM), and Diosmetin (22.7 ± 1.76 µM). The combination index study showed a more significant synergism when Tamoxifen was combined with Naringin than with Diosmetin. Protein expression analysis revealed significant downregulation of Bcl-2 (p < 0.01) and Bcl-xL (p < 0.01) and upregulation of cleaved caspase-3 (p < 0.01) in the combination-treated groups. Liposomal formulations were developed and characterized based on the identified synergistic effects of combinations and showing particle sizes ranging from 150 to 210 nm, with a PDI of less than 0.3. Zeta potential readings ranging from − 19 to − 29 mV indicated stability, whereas FE-SEM pictures revealed a spherical shape. In vitro release conformed to the Higuchi kinetics for both dual and triple liposomal delivery systems (r² ≥ 0.98). The findings reveal that dual and triple combinations of Tamoxifen with flavonoids synergistically improve cytotoxicity, decrease anti-apoptotic signaling, and activate caspase-dependent pathways. Therefore, the results indicate the synergistic biological effects of Tamoxifen–flavonoid combinations and suggest that nanocarrier-based co-delivery may serve as a beneficial formulation approach for future therapeutic development.