Valorization of Moringa oleifera pericarp via semi-synthetic sugar-based enone derivatives with anticancer potential: phytochemical isolation, cytotoxic evaluation, and dual EGFR/CAIX targeting

Abstract

Abstract Moringa oleifera pericarp, an underutilized agro-waste, was investigated as a potential source of anticancer agents. In this study, bioassay-guided fractionation of the pericarp extract led to the identification of the ethyl acetate fraction as the most active fraction, showing notable antioxidant, antimicrobial, and cytotoxic activities. Subsequent purification afforded three compounds: 4-( α -L-rhamnopyranosyloxy)-benzaldehyde ( M 1 ), 4-( α -L-rhamnopyranosyl) benzyl alcohol ( M 2 ), and 4-(hydroxymethyl) phenol-1- O - β -D-glucopyranosyl-(1''→3')- O - α -L-rhamnopyranoside ( M 3 ). The major constituent, M 2 , was semi-synthetically modified by Steglich esterification with cinnamic acid and crotonic acid to yield two sugar-based enone derivatives, S1 M2 and S2 M2 . Structural elucidation was performed using IR, MS, and NMR spectroscopy. The cytotoxic activity of the isolated and semi-synthesized compounds was evaluated against HepG2 and HCT116 cancer cell lines, and selectivity was assessed using normal WI-38 fibroblasts. Among the tested compounds, S2 M2 exhibited the most potent cytotoxicity, with IC 50 values of 5.97 ± 0.19 µM and 11.52 ± 0.37 µM against HepG2 and HCT116 cells, respectively, together with favorable selectivity. In addition, S2 M2 showed strong inhibitory activity against epidermal growth factor receptor tyrosine kinase (EGFR-TK) and carbonic anhydrase IX (CAIX), with IC 50 values of 0.40 ± 0.008 µM and 0.27 ± 0.01 µM, respectively. Molecular docking and 100-ns molecular dynamics simulations supported the stable binding of S2 M2 within the active sites of EGFR-TK and CAIX, and MM-GBSA calculations confirmed its favorable binding free energy. Structure–activity relationship analysis suggested that the α , β -unsaturated carbonyl moiety significantly contributed to the observed anticancer activity. These findings highlight M. oleifera pericarp as a promising source of bioactive glycosylated phenolic scaffolds and identify S2 M2 as a potential dual-target anticancer lead for further development.