Background: Melodinus cochinchinensis (Lour.) Merr. is a medicinal plant, which is used as a folk medicine for treating meningitis and fractures. However, the anti-inflammatory activity of total alkaloid extract from M. cochinchinensis (MCTA) and its molecular mechanism are still not studied.
Purpose: The aim of this study is to investigate the main chemical constituents of MCTA and explore its anti-inflammatory potential in both in vitro and in vivo assessments.
Methods: UHPLC-ESI-HRMS/MS was applied to analyze the chemical profiling. The anti-inflammatory efficacy of MCTA was evaluated on lipopolysaccharide (LPS) induced RAW 264.7 cells and two common inflammation models in mice. The production of pro-inflammatory mediator and cytokine was tested using the ELISA method. The pathological change was analyzed by histological assessment. The expression of NF-κB, MAPKs and PPAR-γ proteins was evaluated using western blot analysis.
Results: A total of 21 monoterpenoid indole alkaloids (MIAs) were characterized by UHPLC-ESI-HRMS/MS. Aspidospermine- and quinolone-type alkaloids were found to be the major compounds. MCTA significantly decreased the production of NO, IL-1β, IL-6 and TNF-α in LPS-induced RAW 264.7 macrophages. MCTA significantly inhibited the phosphorylation of ERK1/2, JNK and p38 MAPK, suppressed the NF-κB transcriptional activation and improved the PPAR-γ expression. Moreover, the in vivo experiment exhibited that MCTA pretreatment markedly alleviated the xylene-induced ear edema and carrageenan-induced paw edema in mice and decreased the IL-1β, IL-6 and TNF-α expressions.
Conclusion: MCTA is rich in MIAs and exhibited a significant inhibitory effect on the production proinflammatory cytokines. The mechanism might be related to the inhibition of activation of NF-κB and MAPK pathways.
Keywords: Anti-inflammatory activity; Ear edema; Melodinus cochinchinensis (Lour.) Merr.; Monoterpenoid indole alkaloids; Paw edema; Signaling pathway.
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