Plumbagin inhibits LPS-induced inflammation through the inactivation of the nuclear factor-kappa B and mitogen activated protein kinase signaling pathways in RAW 264.7 cells.
Food Chem Toxicol 2013;
64:177-83. [PMID:
24296134 DOI:
10.1016/j.fct.2013.11.027]
[Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 11/20/2013] [Accepted: 11/23/2013] [Indexed: 01/18/2023]
Abstract
Plumbagin (PL) has been reported to exhibit anti-carcinogenic, anti-inflammatory and analgesic activities, but little is known about its mechanism. In this study, we investigated the anti-inflammatory property of PL and its mechanism of action. Although no significant cytotoxicity of PL was observed over the concentration range tested, PL (2.5-7.5 μM) significantly and dose-dependently suppressed the secretion of pro-inflammatory mediators and inhibited the expression of TNF-α, IL-1β, IL-6 and iNOS in LPS-stimulated RAW 264.7 cells. Furthermore, PL consistently suppressed the activity of iNOS in LPS-induced RAW 264.7 cells. To elucidate the mechanism underlying the anti-inflammatory activity of PL, we assessed the effects of PL on the MAPK pathway and the activity and expression of NF-κB. These experiments demonstrated that PL significantly reduced the luciferase activity of an NF-κB promoter reporter and p65 nuclear translocation. The LPS-induced phosphorylation of MAP kinases was also attenuated by PL; significant changes were observed in the levels of phosphorylated ERK1/2, JNK and p38 MAPK. Additionally, MAPK inhibitors confirmed the inhibitory effect of PL on the MAPK pathway. Taken together, these data suggest that PL exerts its anti-inflammatory effects by down-regulating the expression of pro-inflammatory mediators through inhibition of NF-κB and MAPK signaling in LPS-stimulated RAW 264.7 cells.
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