Antiproliferative Effect of Okra Seed Protein Isolate against HepG2 and A549 Cell Lines

Cancer is a non-communicable disease and is one of the leading causes of mortality worldwide. While plant-derived compounds have exhibited promise in cancer therapy, the biological activity of okra seed protein isolate (OSPI) has not been extensively explored. The present study evaluates the antiproliferative effect of OSPI against human liver hepatocellular carcinoma (HepG2) and lung adenocarcinoma (A549) cancer cell lines using in vitro assays. The protein isolate exhibited cytotoxic effects by reducing A549 cell viability significantly (37.73%), with an IC₅₀ of 21.80 µg/mL, lower than that of a known chemopreventive agent, camptothecin (524.85 µg/mL). Additionally, defatted okra flour (DOF) exhibited potent activity (168.37 µg/mL), suggesting that lower doses could effectively inhibit A549 proliferation. In HepG2 cells, OSPI activated caspase 3/7, 8, and 9, indicating apoptosis via intrinsic and extrinsic pathways. Furthermore, OSPI (36.06 µg/mL) and DOF (34.68 µg/mL) elevated p53 expression in A549 cells, suggesting p53-mediated apoptosis. In addition, reactive oxygen species induction by OF further supports its pro-apoptotic potential. These findings underscore the therapeutic potential of OSPI, demonstrating its efficacy at lower doses compared to conventional therapeutics, supporting its future development as a plant-based antiproliferative agent. The study provides foundational evidence for the application of OSPI in the pharmaceutical and nutraceutical industries.