Selective Cytotoxicity and Pro‑apoptotic Activity of Stem Bark of Wrightia tinctoria (Roxb.) R. Br. in Cancerous Cells

Background: Wrightia tinctoria (Roxb.) R. Br. is a widely available shrub in India used traditionally in various ailments, including cancer. However, the anticancer activity of the bioactive fractions has not been validated scientifically. Objective: To investigate the anticancer potential of stem bark of W. tinctoria and establish its phytochemical basis. Materials and Methods: The ethanol extract and subsequent fractions, petroleum ether, ethyl acetate, n‑butanol, and aqueous were prepared by standard methods. In vitro cytotoxicity was determined in MCF‑7 (breast) and HeLa (cervical) adenocarcinoma cells, and V79 (nontumor fibroblast) cells and apoptogenic activity in MCF‑7 cells by acridine orange (AO)/ ethidium bromide (EB) staining. Additionally, the antioxidant potential was evaluated using suitable methods. High‑performance thin layer chromatography (HPTLC) analysis was performed for identification of active phytoconstituents. Results: Petroleum ether and ethyl acetate fractions were most potent with IC50 values of 37.78 and 29.69 µg/ml in HeLa and 31.56 and 32.63 µg/ml in MCF‑7 cells respectively in the sulforhodamine B assay. Comparable results were obtained in HeLa cells in 3‑(4,5‑dimethylthiazolyl‑2‑yl)‑2,5‑diphenyl tetrazolium bromide assay and interestingly, the fractions were found to be safe to noncancerous fibroblast cells. Both fractions induced significant (P < 0.05) apoptotic morphological changes observed by AO/EB staining. Moreover, extract/fractions exhibited excellent inhibition of lipid peroxidation with the ethyl acetate fraction being most active (IC50: 23.40 µg/ml). HPTLC confirmed the presence of two anti‑cancer triterpenoids, lupeol, and β‑sitosterol in active fractions. Conclusion: Extract/fractions of W. tinctoria exhibit selective cytotoxicity against cancerous cells that is mediated by apoptosis. Fractions are less toxic to noncancerous cells; hence, they can be developed as safer chemopreventive agents.