Anti-Inflammatory Properties and Potential Bioactive Components from Moringa oleifera Leaves Revealed by Affinity Ultrafiltration LC–MS and Molecular Docking

Moringa oleifera leaf, a popular medicinal and edible plant in Kenya communities, exhibits good anti-inflammatory effects. In present study, its anti-inflammatory mechanisms were first illustrated by evaluating the in vitro inhibition on COX-2, the levels of the pro-inflammatory cytokines (IL-1β, IL-6, PGE2, TNF-α) in the RAW 264.7 cells after treatment with the M. oleifera leaf extracts (MOLEs). Meanwhile, affinity ultrafiltration LC–MS (UF-LC/MS) with COX-2 was conducted, and 15 phytochemicals exerting differential affinities with the COX-2 were quickly fhished out and identified. Besides, the further structure–activity relationship analysis indicated that quercetin and kaempferol flavonoid glycosides, especially those quercetin flavonoids with acetylated glycosyl side chain, contributed to the potential antioxidant and anti-inflammatory components in MOLEs. Furthermore, molecular docking simulations revealed competitive binding effects of the number of hydrogen bonds and binding energies, which were in good agreement with the enrichment factors between the bioactive components and COX-2. To conclude, the present study proved M. oleifera as a potential natural remedy for inflammation and would provide valuable information on its further exploration as functional foods or other healthcare products.