γ-Sitosterol from Acacia nilotica L. induces G2/M cell cycle arrest and apoptosis through c-Myc suppression in MCF-7 and A549 cells.

BACKGROUND

Acacia nilotica is widely distributed in Asia. In India, it occupies an important place in the indigenous system of medicine against anti-inflammatory, antioxidant, cancers, and/or tumors.

OBJECTIVE

The purpose of this study is to investigate the inhibitory effect of Acacia nilotica leaves extract and γ-Sitosterol on cell proliferation, the apoptotic effect and cell cycle arrest in breast and lung cancer cells.

METHODS

GC-MS and HPLC were used to determine the chemical constituents of this extract and γ-Sitosterol respectively. Human MCF-7 and A549 cell lines were treated with Acacia nilotica extract and γ-Sitosterol. Cell viability was determined by MTT assay. Cell proliferation was determined by BrdU incorporation assay. Apoptosis was detected by cell morphologic observation through AO/EtBr staining, cell cycle analysis, and immunoblot analysis on the expression of protein associated with cell cycle arrest.

RESULTS

Experimental results of bioactive compound analysis indicate that γ-Sitosterol, bioactive ingredients of Acacia nilotica extract. The IC(50) value of extract on MCF-7 and A549 cancer cells was 493.3±15.2 and 696.6±11.5 μg/ml, respectively. Acacia nilotica extract and γ-Sitosterol were inhibited the cell proliferation by 54.34±1.8 and 42.18±3.9% for MCF-7 and 58.26±1.5 and 44.36±3.05% for A549 cells. The percentage of apoptotic cells observed in the MCF-7 and A549 cell lines were increased to 42.46 and 36.8% of extract; 46.68 and 43.24% for γ-Sitosterol respectively. Flow cytometric analysis results demonstrate that cells were arrested at the G2/M phase and decrease the c-Myc expression.

CONCLUSIONS

This study demonstrates in vitro results, which support the ethnomedical use of γ-Sitosterol against cancer. Experimental results of this study suggest that γ-Sitosterol exerts potential anticancer activity through the growth inhibition, cell cycle arrest and the apoptosis on cancer cells.