Potential antioxidant and cytotoxic activities of areca nut (Areca catechu Linn.) extract in human oral squamous cell carcinoma and keratinocyte cells

Objectives: Areca (betel, Areca catechu) nuts have been reported to show high contents of phenolic and flavonoid compounds with associated antioxidant activity. This study was undertaken to assess the anticancer potential of areca nut extract on human squamous carcinoma (HSC)-3, HSC-2, and human keratinocyte (HaCat) cancer cell lines, and to elucidate the mechanism of its action. Methods: In this study, the areca nut extract was prepared in 96% ethanol and analyzed for the total phenolic and flavonoid content, 2,2-diphenyl-1- picrylhydrazyl (DPPH) assay, and 5-(3-carboxymethoxyphenyl)-2-(4,5-dimenthylthiazoly)-3-(4-sulfophenyl)tetrazolium inner salt assay. Results: The indicated total phenolic content of the areca nut extract was 80.3 mg tannic acid equivalent/g and total flavonoid content 238.5 mg catechin equivalent/g. The extract showed good scavenging activity against DPPH radical (efficient concentration 15.95±0.84 μg/ml). The extract showed higher toxicity on HSC-3 than HSC-2 cells, IC₅₀ was 164.06 μg/ml in HSC-3 versus 629.50 μg/ml in HSC-2. The extract had no cytotoxic effect on HaCat cells. Conclusions: The antioxidant activity of the areca nut extract might be associated with the presence of high content of phenolic and flavonoid compounds. The extract showed selective cytotoxicity against HSC-3 and HSC-2 cells but not on HaCat cells. Instead, the extract induced high rate of proliferation in HaCat cells.