Acacia catechu ethanolic seed extract triggers apoptosis of SCC-25 cells

Background: Acacia catechu Willd (Fabaceae), commonly known as catechu, cachou, and black cutch, has been studied for its hepatoprotective, antipyretic, antidiarrheal, hypoglycemic, anti-inflammatory, immunomodulatory, antinociceptive, antimicrobial, free radical scavenging, and antioxidant activities. Objective: We evaluated the cytotoxic activity of ethanol extract of A. catechu seed (ACS) against SCC-25 human oral squamous carcinoma cell line. Methods: Cytotoxic effect of ACS extract was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, using concentrations of 0.1-1000 μ g/mL for 24 h. A. catechu ethanol seed extract was treated SCC-25 cells with 25 and 50 μ g/mL. At the end of treatment period, apoptotic marker gene expressions such as caspase 8, 9, Bcl-2, Bax, and cytochrome c were evaluated by semiquantitative reverse transcription-polymerase chain reaction. Morphological changes of ACS treated SCC-25 cells was evaluated by acridine orange/ethidium bromide (AO/EB) dual staining. Nuclear morphology and DNA fragmentation was evaluated by propidium iodide (PI) staining. Results: A. catechu ethanol seed extract treatment caused cytotoxicity in SCC-25 cells with an IC₅₀value of 100 μ g/mL. Apoptotic markers caspases 8 and 9, cytochrome c, Bax gene expressions were significantly increased upon ACS extract treatment indicate the apoptosis induction in SCC-25 cells. This treatment also caused significant downregulation of Bcl-2 gene expression. Staining with AO/EB and PI shows membrane blebbing, and nuclear membrane distortion further confirms the apoptosis induction by ACS treatment in SCC-25 cells. Conclusion: The ethanol seed extracts of A. catechu was found to be cytotoxic at lower concentrations and induced apoptosis in human oral squamous carcinoma SCC-25 cells.