Anti-inflammatory Potential of Artemisia capillaris and Its Constituents in LPS-induced RAW264.7 Cells

Artemisia capillaris has been widely used as an alternative therapy for treating obesity and atopic dermatitis. It has been used as a hepatoprotactant. It is also used for ameliorating inflammatory reactions. Although there are several investigations on other Artemisia species, there is no systematic study describing the role of A. capillaris MeOH extract, its solvent soluble fractions, or derived anti-inflammatory principal components in regulating inflammatory conditions. Therefore, the objective of this study was to elucidate anti-inflammatory mechanisms of A. capillaris. Results revealed that MeOH extract of A. capillaris could decrease LPS-stimulated NO secretion. Of tested fractions, CH₂Cl₂, EtOAc, and n-BuOH strongly inhibited NO release from RAW264.7 cells. Bioactive mediators derived from CH₂Cl₂ and n-BuOH fractions elicited potent anti-inflammatory actions and strikingly abrogated LPS-triggered NO accumulation in RAW264.7 cells. Of particular interest, capillin and isoscopoletin possessed the most potent NO suppressive effects. Western blot analysis validated the molecular mechanism of NO inhibition and showed that capillin and isoscopoletin significantly down-regulated iNOS and COX-2 protein expression. Taken together, our results provide the first evidence that MeOH extract, CH₂Cl₂, EtOAc, and n-BuOH fractions from A. capillaris and its derived lead candidates can potently suppress inflammatory responses in macrophages by hampering NO release and down-regulating iNOS and COX-2 signaling.

Pulegone Exhibits Anti-inflammatory Activities through the Regulation of NF-κB and Nrf-2 Signaling Pathways in LPS-stimulated RAW 264.7 cells

Pulegone is a naturally occurring organic compound obtained from essential oils from a variety of plants. The aim of this study was to investigate the anti-inflammatory effects through the inhibitory mechanism of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPK) pathways and the activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase (HO)-1 pathways in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Results revealed that pulegone significantly inhibited NO production as well as iNOS and COX-2 expressions. Meanwhile, western blot analysis showed that pulegone down-regulated LPS-induced NF-κB and MAPKs activation in RAW 264.7 cells. Furthermore, the selected compound suppressed LPS-induced intracellular ROS production in RAW 264.7 cells, while the expression of stress response gene, HO-1, and its transcriptional activator, Nrf-2 was upregulated upon pulegone treatment. Taking together, these findings provided that pulegone inhibited the LPS-induced expression of inflammatory mediators via the down-regulation iNOS, COX-2, NF-κB, and MAPKs signaling pathways as well as up-regulation of Nrf-2/HO-1 indicating that pulegone has a potential therapeutic and preventive application in various inflammatory diseases.

Luteolin 5-O-glucoside from Korean Milk Thistle, Cirsium maackii, Exhibits Anti-Inflammatory Activity via Activation of the Nrf2/HO-1 Pathway

Luteolin 5-O-glucoside is the major flavonoid from Korean thistle, Cirsium maackii. We previously reported the anti-inflammatory activities of luteolin 5-O-glucoside in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. In this study, we determined the anti-inflammatory mechanisms of luteolin 5-O-glucoside through the inhibition of nitric oxide (NO) production in vitro and in vivo. Results revealed that luteolin 5-O-glucoside dose-dependently inhibited NO production and expression of iNOS and COX-2 in LPS-induced RAW 264.7 cells. Luteolin 5-O-glucoside also significantly inhibited the translocation of NF-κB, the activation of MAPKs, and ROS generation in LPS-induced RAW 264.7 cells. In addition, protein expressions of Nrf-2 and HO-1 were also upregulated by luteolin 5-O-glucoside treatment. Moreover, luteolin 5-O-glucoside inhibited λ-carrageenan-induced mouse paw edema by 65.34% and 48.31% at doses of 50 and 100 mg/kg body weight, respectively. These findings indicate potential anti-inflammatory effect of luteolin 5-O-glucoside particularly by downregulating NF-κB and upregulating HO-1/Nrf-2 pathway.