Moringa oleifera inhibit neuroinflammation in LPS activated BV2 microglia

Abstract

Moringa oleifera has been used for centuries to treat a variety of inflammatory disorders. In this study, we evaluated the effects of a crude extract and some bioactives isolated from M. oleifera in LPS‐activated BV2 microglia. Neuroinflammation was induced with LPS (100 ng/ml) in the presence or absence of test substances. After 24 h, levels of nitrite, TNFα, IL‐6, and PGE2 were determined in cell supernatants using specific immunoassays. Expression of cyclooxygenase‐2 (COX‐2) and inducible nitric oxide (iNOS) protein expressions were determined using western blots. Bioactivity guided fractionation of an ethanol extract of the leaves of M. oleifera yielded five compounds. Three of the compounds were identified by MS‐NMR as rutin (F50‐3), quercetin (F50‐4) and kaempferol (F50‐5). To determine the effects of the isolated compounds on NF‐κB transactivation, a reporter gene assay was carried out in HEK 293 cells stimulated with TNFα. Results show that the crude extract (150 and 200μg/ml) produced significant (p˂0.05) reduction in nitrite, PGE2, TNFα and IL6 production. Isolated compounds F50‐3, F50‐4 and F50‐5 (15.26, 4.2 and 3.6μg/ml) produced significant reduction in COX‐2 and iNOS protein expressions in LPS stimulated BV‐2 cells. These compounds also inhibited TNFα‐stimulated NF‐κB transcriptional activation in HEK 293 cells. These results suggest that Moringa oleifera leaves contain compounds that inhibit neuroinflammation in LPS activated microglia.