Anti-inflammatory Effects of Artemisia annua Ethanol Extract in Lipopolysaccharide-Stimulated RAW264.7 Macrophages

This study investigated the anti-inflammatory properties of an ethanol extract of Artemisia annua (AE) and its underlying molecular mechanisms in LPS-stimulated RAW264.7 macrophages. AE demonstrated no significant cytotoxicity at concentrations up to 200 μg/mL. The Griess assay showed that AE significantly and dose-dependently suppressed LPS-induced nitric oxide (NO) production, with notable inhibition at 100 and 200 μg/mL. Quantitative real-time PCR (qRT-PCR) analysis revealed that AE dose-dependently attenuated the mRNA expression of iNOS and interleukin-6 (IL-6). While the mRNA levels of cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) also decreased, this trend was not statistically significant. Western blot analysis further indicated that AE selectively inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) in a concentration- dependent manner, and also showed a tendency to reduce p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation, without significantly affecting c-Jun N-terminal kinase (JNK) signaling. These findings suggest that AE exerts its anti-inflammatory effects primarily through an ERK-mediated pathway, alongside a non-significant reduction in p38 phosphorylation. This leads to the downregulation of iNOS and COX-2 expression and subsequent inhibition of excessive NO production. Collectively, these in vitro results indicate that AE holds promise as a natural functional ingredient with anti-inflammatory potential.