Antioxidant properties and colonic degradation of Moringa oleifera phenolics by HPLC-triple detection

Moringa oleifera is a typical officinal plant that is widely used in the supplementary and pharmaceutical industries as a natural ingredient because of its bioactive compounds. This study analyzed the main bioactive compounds in Moringa oleifera extracts (MOLE), particularly caffeoylquinic acid and quercetin derivatives, using high performance liquid chromatography-diode array detector-high resolution mass spectroscopy (HPLC-CAD-HRMS). An in vitro fecal batch fermentation was used to analyze the colonic catabolism of phenolic compounds. Compounds with the highest antioxidant capacity (3-caffeoylquinic acid and quercetin derivatives) were degraded within the first 2 h, whereas the concentration of vitexin derivatives gradually decreased during the 24 h of fermentation. The results were validated by kinetic reactivity analysis using 2,2-diphenyl-1-picrylhydrazyl assay (DPPH) and redox properties measured using cyclic voltammetry. Notably, the correlation between electron transfer capacity and microbial degradation was observed, suggesting that electrochemical behavior can provide insights into the bioaccessibility and transformation of MOLE compounds during fermentation. These findings highlight the potential of MOLE in nutraceutical and pharmaceutical applications. • Fermentation revealed rapid degradation of antioxidants in MOLE, except apigenins. • 3-caffeoylquinic acid and quercetin derivatives degraded in the first 2 h. • Electrochemical properties are correlated with the bioavailability of antioxidants. • This study shows potential supplementary and pharmaceutical applications of MOLE.