Lablab purpureus bioactive fractions as potent anticancer agents: an in vitro and in Silico study

Plant-based bioactive compounds are essential for the discovery of drugs, especially in cancer research, because they include a wide range of chemicals and are very specific to certain types of cells. In earlier research, Lablab purpureus (LP), a legume rich in nutrients and with ethnomedicinal significance, showed encouraging antioxidant and anticancer potential. However, the specific bioactive components that cause these effects are still unknown. The objective of this study was to use a bioactivity-guided approach to isolate and characterise cytotoxic fractions from LP seed methanol extract, followed by in vitro and in silico evaluation.

Column chromatography and liquid-liquid partitioning were used to separate the fractions from the LP seed methanol extract. DPPH, FRAP, and ABTS assays were performed to determine the individual fractions with high antioxidant activity. Lablab Purpureus Methanol seed extract Methanol fraction (LPMMF 1.5), was hence subjected to MTT assay against MCF-7 and A549 cells for 24, 48, and 72 h. Further, dual AO/EtBr staining was performed to evaluate apoptosis induction. FTIR and HR-LCMS analyses were performed to identify the phytocompounds in LPMMF 1.5. The identified compounds were subjected to ADME screening, molecular docking, MM-GBSA, 500 ns molecular dynamics simulations, per-residue energy decomposition, and metadynamics to evaluate their stability in binding with cancer-specific targets (PARP1, CDK2, and CCNB1).

LPMMF 1.5 had the most antioxidant activity and the strongest cytotoxicity of the tested fractions, with IC₅₀ values of 36.96 µg/ml (MCF-7) and 76.14 µg/ml (A549) at 72 h. AO/EtBr staining revealed the induction of apoptosis in treated MCF-7 and A549 cells. Picroside-1 and other bioactives were identified by HR-LCMS. In silico studies revealed that Picroside-1 formed very stable complexes with PARP1, CDK2, and CCNB1, and the docking scores of Picroside-1 were found to be better than those of standard inhibitors. MD simulations and MM-GBSA confirmed that the binding was stable and that important residues were involved. Metadynamics provided additional validation of the binding energetics.

This study identified LPMMF 1.5 as a bioactive fraction with significant antioxidant and anticancer activity. Picroside-1 emerged as a key compound, exhibiting strong affinity and stable interactions with cancer-relevant targets. These findings support its potential development as a plant-derived anticancer lead candidate.