The dichloromethane fraction from Mahonia bealei (Fort.) Carr. leaves exerts an anti-inflammatory effect both in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Mahonia bealei has a long history of medical use in traditional Chinese medicine for the treatment of inflammatory-associated diseases. Despite numerous phytochemical and pharmacological studies, there is a lack of systematic studies to understand the cellular and molecular mechanisms of the anti-inflammatory activity of this plant.

AIM OF STUDY: This study aimed to evaluate the anti-inflammatory activity of the dichloromethane fraction from M. bealei leaves (MBL-CH).

MATERIALS AND METHODS: RAW 264.7 cells were pretreated with different concentrations of MBL-CH for 30min prior to treatment with 1μg/ml of lipopolysaccharide (LPS). The nuclear factor κB (NF-κB) pathway and subsequent production of inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), and tumour necrosis factor (TNF)-α were investigated. Furthermore, the in vivo mouse model of LPS-induced acute lung injury (ALI) was employed to study the anti-inflammatory effects of MBL-CH.

RESULTS: Pre-treatment with MBL-CH significantly inhibited the LPS-stimulated secretion of NO, PGE2, and TNF-α into the culture medium, as well as the mRNA levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α, which were associated with a reduction in the phosphorylation of IκBα, Akt, and PI3K and inhibition of the transcriptional activity of NF-κB. Furthermore, in vivo experiments revealed that MBL-CH attenuated LPS-stimulated lung inflammation in mice.

CONCLUSION: Taken together, our findings indicate that MBL-CH attenuates LPS-stimulated inflammatory responses in macrophages by blocking NF-κB activation through interference with activation of the PI3K/Akt pathway, providing scientific evidence that the plant can be employed in traditional remedies.