The lindenane-type sesquiterpenoid chlojaponilactone B (1), isolated from Chloranthus japonicus, has been reported to possess anti-inflammatory properties. The present study aimed to further explore the molecular mechanisms underlying the anti-inflammatory activity of 1. RNA-seq analyses revealed the significant changes in the expression levels of genes related to multiple inflammatory pathways upon treatment of lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages with 1. Real time PCR (RT-PCR) and Western blotting were used to confirm the modulations in the expression of essential molecules related to inflammatory responses. Compound 1 inhibited toll like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) activation upon LPS stimulation, influencing the expression of NF-κB and pro-inflammatory mediators. Molecular docking studies showed that 1 bound to TLR4 in a manner similar to that of TAK-242, a TLR4 inhibitor. Moreover, our results showed that 1 suppressed inflammatory responses by inhibiting TLR4 and subsequently decreasing reactive oxygen species (ROS) generation, downregulating the NF-κB, thus reducing the expression of the pro-inflammatory cytokines iNOS, NO, COX-2, IL-6 and TNF-α; these effects were similar to those of TAK-242. We proposed that 1 should be considered as a potential anti-inflammatory compound in future research.
Cinnamomum camphora (Linn.) Presl has been widely used in traditional Chinese medicine for a variety of purposes. Our previous study indicated the antibacterial mechanism of the essential oil (EO) from C. camphora leaves; however, its anti-inflammatory activity and the underlying mechanism have not been clearly demonstrated. Thus, the present study investigated its anti-inflammatory property. Our data revealed that EO significantly decreased the release of nitric oxide (NO) and the mRNA expression of inducible NO synthase (iNOS) in lipopolysaccharide (LPS)-induced BV2 microglial cells. EO also attenuated LPS-induced increase in the mRNA expression and secretion of inflammatory cytokines including interleukin-6 (IL-6), IL-18, IL-1β and tumor necrosis factor-α (TNF-α). Furthermore, the metabolic profiles of LPS-induced BV2 microglial cells treated with or without EO were explored. Thirty-nine metabolites were identified with significantly different contents, including 21 upregulated and 18 downregulated ones. Five pathways were enriched by shared differential metabolites. Compared with the control cells, the glucose level was decreased, while the lactate level was increased, in the culture supernatant from LPS-stimulated cells, which were reversed by EO treatment. Moreover, compared to the LPS-treated group, the activities of phosphofructokinase (PFK) and pyruvate kinase (PK) in EO group were decreased. In summary, the current study demonstrated that EO from C. camphora leaves acts as an anti-inflammatory agent, which might be mediated through attenuating the glycolysis capacity of microglial cells.
Background: Cinnamomum camphora (Linn.) Presl has been widely used in traditional Chinese medicine for a variety of purposes. Our previous study indicated the antibacterial mechanism of the essential oil (EO) from C. camphora; however, the anti-inflammatory activity of EO and its underlying mechanism have not been clearly demonstrated. The present study aims to evaluate the anti-inflammatory principle and mechanism of EO.Methods: The anti-inflammatory activity of EO was evaluated in lipopolysaccharide (LPS)-induced BV2 microglial cells. Nitric oxide (NO) production was measured by NO assay kit. The mRNA expression levels of inducible NO synthase (iNOS), interleukin-6 (IL-6), IL-18 and IL-1β were examined by real time-PCR (RT-PCR). The secretion of pro-inflammatory cytokines in cell supernatants, including IL-6, IL-18 and IL-1β, were assessed by ELISA kits. Furthermore, the metabolic profile of BV2 microglial cells treated with or without EO was explored by GC-MS-based metabolomics analysis. Phosphofructokinase (PFK) and pyruvate kinase (PK) activities were detected by commercial kits.Results: EO significantly decreased the release of NO and the mRNA expression of iNOS in LPS-induced BV2 microglial cells. EO also attenuated LPS-induced increase in the mRNA expression and secretion of inflammatory cytokines including IL-6, IL-18 and IL-1β. 39 metabolites were identified with significantly different contents, including 21 upregulated and 18 downregulated ones, in the metabolomics analysis. Five pathways were enriched by shared differential metabolites. Additionally, compared with the control group, the glucose level was decreased, while the lactate level was increased, in the culture supernatant of LPS-induced BV2 microglia cells, which were reversed by EO treatment. Besides, compared to the LPS-treated group, the activities for PK and PFK in EO group were decreased by 17.59% and 18.23%, respectively.Conclusions: The EO from C. camphora acts as an anti-inflammatory agent, which might be mediated through attenuating the glycolysis capacity of microglial cells.
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