Phytochemical profiling of betel leaf extracts: Antioxidant efficacy and cytotoxic potential against oral cancer cells (Piperaceae)

Abstract

Betel leaf is a plant with traditional importance; however, its pharmacological profile remains underexplored. This study evaluated the antioxidant activity and cytotoxicity of hexane, chloroform and methanol extracts of mature betel leaf against human oral epidermoid carcinoma (KB) cells and correlated bioactivity with phytochemical composition. Extraction was performed using a Soxhlet apparatus at 65 °C for 3–4 hr. Antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle distribution by flow cytometry with propidium iodide staining. Compared to chloroform and hexane, the methanol extract exhibited significantly higher cytotoxicity against KB cells, with a half-maximal inhibitory concentration (IC₅₀) of 12.5 μg/mL and antioxidant activity (IC₅₀ = 18.5 μg/mL). The methanol extract caused dose-dependent inhibition, reaching 88.39 % at 25 μg/mL. Flow cytometry revealed that the extracts induced G2/M phase arrest, with the chloroform extract producing the highest accumulation (40.44 %). Phytochemical screening showed that the methanol extract contained phenolic acids, flavonoids and sterols, while the chloroform extract was moderately complex and hexane extract simple. These findings indicate that betel leaf extracts, particularly the methanol fraction, are promising sources of bioactive compounds with antioxidant and anticancer activities.