Curcumin protects liver inflammation by suppressing expression of inducible nitric oxide synthase in primary cultured rat hepatocytes

Abstract

Background: Curcumin has beneficial effects on organ metabolism. However, there is little evidence that curcumin affects inflammatory mediators, such as tumor necrosis factor (TNF)-α and nitric oxide (NO). In an inflamed liver, proinflammatory cytokines stimulate liver cells, followed by the induction of inducible NO synthase (iNOS). Excessive NO produced by iNOS is one of the factors in liver injury. Therefore, inhibiting iNOS induction for preventing liver injury is important.Objective: This study aimed to investigate liver protective effects of curcumin by examining interleukin (IL)-1β-stimulated hepatocytes.Methods: Primary cultured rat hepatocytes were treated with IL-1β in the presence or absence of curcumin. Induction of NO production and iNOS, and the signaling pathway of iNOS were analyzed.Results: Simultaneous addition of IL-1β and curcumin decreased expression levels of iNOS protein and mRNA, resulting in inhibition of NO production. Curcumin also reduced mRNA expression of TNF-α and IL-6. Curcumin inhibited two essential signaling pathways for iNOS induction, NF-κB activation and type I IL-1 receptor upregulation. Transfection experiments revealed that curcumin reduced iNOS mRNA levels at the promoter activation and mRNA stabilization steps. Delayed administration of curcumin after IL-1β addition also inhibited iNOS induction.Conclusions: Curcumin affects induction of inflammatory mediators, such as iNOS and TNF-α, in part through the inhibition of NF-κB activation in hepatocytes. Curcumin may have therapeutic potential for organ injuries, including the liver.Key words: curcumin, inducible nitric oxide synthase, liver injury, primary cultured hepatocytes, nuclear factor-κB, type I interleukin-1 receptor, tumor necrosis factor-α.

Liposome-Encapsulated Bioactive Guttiferone E Exhibits Anti-Inflammatory Effect in Lipopolysaccharide-Stimulated MH-S Macrophages and Cytotoxicity against Human Cancer Cells

“…To exclude the possibility that the observed anti-inflammatory effects could be due to cytotoxicity, samples were used only at concentrations in which cell proliferation was not affected according to the calculated IC 50 . Curcumin, a well-known inhibitor of nitric oxide production, was used as a reference compound at a single concentration of 5 μ g/mL [ 21 ]. Results are presented in Figure 5 .…”

Effect of Curcumin gel on inflammatory and anti-inflammatory biomarkers in experimental induced periodontitis in rats: a biochemical and immunological study

“…Curcumin also inhibits the expression of inducible nitric oxide synthase (iNOS) enzyme by inflammatory and epithelial cells, which may play a role in periodontal inflammation ( Nakatake et al, 2017 ; Wang et al, 2019 ). On the other hand, it has been reported Curcumin molecule bind to CXCL8 chemokine and inhibit ferroptosis in ligature-induced periodontal-diseased mice, thus, play a pivotal role in treatment of periodontitis ( Huang et al, 2023 ; Wang et al, 2023 ).…”

Mechanism underlying nephroprotective property of curcumin against sodium nitrite‐induced nephrotoxicity in male Wistar rat

“…Upon administration of curcumin before treatment with NaNO 2 , a notable change in the NO concentration was observed. Curcumin has earlier been confirmed to have an anti‐inflammatory property and the mechanism has not been unconnected with domination of nuclear factor kappa B (NF‐KB) and interleukin‐2 (IL‐2) expression which eventually results in inducible nitric oxide synthase (iNOS) inhibition hence, NO reduction (Nakatake et al., 2017; Onoda & Inano, 2000; Song et al., 2011; Zhao et al., 2015). Reduction of NaNO 2 induced increase in NO level by curcumin might not be unrelated to its widely reported anti‐inflammatory activity.…”