Anti-cancer activity of ethanolic leaf extract of Salvia officinalis against oral squamous carcinoma cells in vitro via caspase mediated mitochondrial apoptosis

Aim: Need for novel agents that fight oral squamous cancer is on constant demand. The current study aims in the identification of active phytochemical ingredients from Salvia officinalis leaf extract (SOLE) and evaluation for anticancer properties in oral squamous carcinoma cells. Materials and Methods: Soxhlet method was used for SOLE extraction. Phytochemical tests and thin-layer chromatography (TLC) were performed for active compounds identification. Oral squamous cancer cells (SSC-15 and SSC-25) were used to assess anticancer efficacy. MTT analysis was utilized for the viability of cells. The utilization of flow cytometry was done to assess the changes in cell cycle and apoptosis induction. Western Blotting method was used to analyze the expressions of apoptotic protein. Results: Preliminary phytochemical screening showed the presence of sterols, flavonoids, and tannins. TLC study revealed the presence of rutin in SOLE. The extract inhibited cell proliferation of SSC-15 and SSC-25 cells with GI50values of 340.7 μg/ml and 287.7 μg/ml, respectively. SOLE inhibited the migration of these cells across the endothelial membrane and induced nuclear fragmentation in cancer cells. Analysis of the cell cycle revealed SOLE to increase the sub G0/G1population in SSC-15 and SSC-25 cells. SOLE increased both early and late phase apoptosis in both oral squamous cancer cell lines. Apoptotic markers such as caspase-3, Bax and P-53 were found to be dose-dependently increased with SOLE treatment in both the tested cell lines, while the anti-apoptotic Bcl-2 protein was decreased. Conclusion: In summary, SOLE demonstrated excellent anticancer and anti-migration efficacy in oral squamous cancer cells through caspase-mediated mitochondrial apoptosis. More than one compound might be responsible for the activity, which deserves further research.