Tribulus terrestris Cytotoxicity against Breast Cancer MCF-7 and Lung Cancer A549 Cell Lines Is Mediated via Activation of Apoptosis, Caspase-3, DNA Degradation, and Suppressing Bcl-2 Activity

Abstract

The primary objective of this research was to use flow cytometry to gain mechanistic insights into the cytotoxic effects of Tribulus terrestris extracts on breast cancer (MCF7) and lung cancer (A549) cell lines. T. terrestris was extracted using a Soxhlet apparatus in a progressive process. GC–MS was used to establish the phytochemical constituents. The amounts of phenolic compounds and flavonoids in the plant extracts were calculated using spectrophotometric analysis. The cytotoxicity of plant extracts was initially evaluated in non-malignant L929 cells, then in carcinogenic MCF-7 and A549 cell lines. Then, we performed an Annexin V assay, an anti-Bcl-2 assay, a Caspase-3 assay, and a DNA fragmentation (TUNEL) assay, using flow cytometry to investigate the underlying molecular processes. Based on the data, the methanolic extract of T. terrestris contained the highest amounts of phenolic compounds and flavonoids, with values of 169.87 µg GAE/g dwt and 160.12 µg QE/g dwt, respectively. Analysis by GC–MS revealed the presence of bioactive phytochemicals with proven cytotoxicity. Based on the MTT experiment, we determined that the IC50 values for the methanol extract’s effect on the viability of the MCF-7 and A549 cell lines were 218.19 and 179.62 µg/mL, respectively. The aqueous and methanol extracts were less cytotoxic when tested against the cancer-free L929 cell line (IC50 = 224.35 µg/mL). In both breast and lung cancer cells, the methanolic extract was found to activate caspase-3 and inhibit the Bcl-2 protein, resulting in early and late apoptosis and cell death via DNA damage. These findings point to cytotoxic effects of T. terrestris methanol extract against breast and lung cancer cell lines. Due to its potential as a source of anti-cancer chemotherapeutic medicines, T. terrestris warrants further investigation.