Phytochemical profiling and molecular docking analysis of Kigelia pinnata leaves for anticancer activity

This study investigated phytochemical constituents of Kigelia pinnata leaves and evaluated their anticancer potential through molecular docking and enzymatic assessment against cyclin-dependent kinase 6 (CDK6), a key regulator of cell cycle progression. Hydroalcoholic leaf extract underwent phytochemical screening, total phenolic and flavonoid estimation and LC-MS profiling. Fifteen phytochemicals were docked against CDK6 (PDB ID: 5L2I) using GeinDock Suite v3.0 Drug-likeness, ADME and toxicity assessments were performed. The lead compound underwent MD simulations, MM-GBSA calculations, isolation, spectral characterization, MTT assay against MCF-7 cells and CDK6 enzyme inhibition assay. Total phenolic and flavonoid contents were 198.53 ± 4.12 mg GAE/g and 78.21 ± 1.96 mg QE/g respectively. Rutin showed the highest predicted docking affinity (-9.0 kcal/mol); however, kigelinone showed acceptable predicted drug-likeness (bioavailability score: 0.85), low in‑silico toxicity (LD₅₀: 1196.4 mg/kg), stable MD simulation (RMSD: 1.6-2.1 Å), MCF-7 antiproliferative activity (IC₅₀: 74.28 ± 1.43 µg/mL) and concentration-dependent CDK6 kinase inhibition in a cell free enzymatic assay (IC₅₀: 35.03 µg/mL); these findings do not establish a CDK6-specific antiproliferative mechanism in a cellular context. Kigelinone is a preliminary anticancer candidate requiring further experimental validation.