Anti-Inflammatory Effects of Hydroethanolic Extract from Ehretia asperula on Lipopolysaccharide-Stimulated RAW264.7 Macrophages

Ehretia asperula is a medicinal plant of the Ehretiaceae family used to treat inflammatory disorders, but the underlying mechanisms are not fully elucidated. The anti-inflammatory potential was determined based on enzyme cyclooxygenase-2 (COX-2) inhibition, which showed that the 95% ethanol extract (95ECH) was most effective with a half-maximal inhibitory concentration (IC50) value of 34.09 mu g/mL. The effects of 95ECH on phagocytosis, NO production, gene, and protein expression of the cyclooxygenase 2/prostaglandin E2 (COX-2/PGE2) and inducible nitric oxide synthase/ nitric oxide (iNOS/NO) pathways in lipopolysaccharide (LPS)-induced RAW264.7 cells were examined using the neutral red uptake and Griess assays, reverse-transcriptase polymerase chain reactions (RTPCR), and enzyme-linked immunosorbent assays (ELISA). The results showed that 95ECH suppressed phagocytosis and the NO production in activated macrophage cells (p < 0.01). Conversely, 95ECH regulated the expression levels of mRNAs for cytokines tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 beta (IL-1 beta) as well as the corresponding proteins. In addition, PGE2 production was inhibited in a dose-dependent manner by 95ECH, and the expression of iNOS and COX-2 mRNAs was decreased in activated macrophage cells, as expected. Therefore, 95ECH from E. asperula leaves contains potentially valuable compounds for use in inflammation management.