Phenolic extract of Macrotyloma uniflorum triggers caspase 3–mediated apoptosis and HDAC modulation in PC3 prostate cancer cells

• Phenolics acids from M. uniflorum inhibit prostate cancer cells HDAC7 • Induce apoptotic cell death and G0/G1 arrest • Show potent cytotoxicity in PC3 cells. • Reduce HDAC7 and increase the expression of caspase-3 (Pro-apoptotic protein). • Provide a natural, safe epigenetic treatment for prostate cancer Prostate cancer is a major global health issue, disproportionately affecting older adults and those with genetic or socio-economic risk factors. HDAC inhibitors show promise but are restricted by toxicity and insufficient target specificity. This study, investigated phenol-rich extracts of Macrotyloma uniflorum (horse gram) for their potential to inhibit HDAC7, a class II HDAC associated with prostate cancer progression. Total phenolics in M. uniflorum seeds measured 258.34 ± 2.16 mg/g, expressed as gallic acid equivalents (GAE).The extracts exerted dose-dependent cytotoxic effects on prostate cancer cell lines (PC3, LNCaP, DU145), with the highly aggressive, androgen-independent PC3 cells showing the greatest sensitivity (IC₅₀ = 681.75 µg/mL). The extract induced dose-dependent cytotoxicity, apoptosis, and G0/G1 cell cycle arrest. Western blot revealed decreased HDAC7 protein levels and increased cleaved caspase-3, indicating caspase-3-mediated HDAC7 downregulation. Global or overall HDAC activity was modulated, reflecting epigenetic effects. Phenolic extract from Macrotyloma uniflorum induces caspase-3–dependent apoptosis, cell cycle arrest, and HDAC modulation in PC3 cells. These results support its potential as an epigenetic anticancer agent and warrant further isoform-specific HDAC studies. The graphical abstract presents the following findings: A) Phytochemical analysis of Macrotyloma uniflorum seeds, commonly known as Black Kulthi (or Kuthi), involves grinding the seeds into fine particles. Phenolic compounds are then extracted and separated using rotary evaporation. After drying, the dry weight is calculated to estimate the total phenolic content and identified the compound via GC-MS as well as HPLC, B) The results illustrate a cell-based test conducted on PC3 prostate cancer cell lines. The IC 50 value is calculated, and cell morphology is examined for apoptotic bodies using fluorescence microscopy. AnnexinV/PI apoptosis assays are performed via flow cytometry, followed by cell cycle analysis. Finally, HDAC7 and caspase 3 expression levels are assessed through Western blot analysis in PC3 cell lines.