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Lucidone was previously reported to exhibit anti-inflammatory activity in vitro and in vivo. In the present study, we characterized the mechanisms underlying the hepatoprotective effect of lucidone against alcohol-induced oxidative stress in vitro. Human hepatoma (HepG2) cells were pretreated with lucidone (1-10μg/mL) and then hepatotoxicity was stimulated by the addition ethanol (100mM). With response to ethanol-challenge, increased amount of alanine aminotransferase (ALT) and aspirate aminotransferase (AST) release were observed, whereas lucidone pretreatment significantly inhibited the leakage of AST and ALT in HepG2 cells without appreciable cytotoxic effects. We also found that lucidone pretreatment significantly decreased ethanol-induced nitric oxide (NO), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA), reactive oxygen species (ROS) and glutathione (GSH) depletion in HepG2 cells. Furthermore, Western blot and quantitative-PCR analyses showed that ethanol-exposure apparently down-regulated endogenous anti-oxidant hemoxygenase-1 (HO-1) expression, whereas pretreatment with lucidone significantly up-regulates HO-1 expression followed by the transcriptional activation of NF-E2 related factor-2 (Nrf-2). Interestingly, the profound up-regulation of HO-1 and Nrf-2 were observed in only ethanol-challenged cells, which evidenced that lucidone-induced induction of HO-/Nrf-2 were specific with oxidative stress. Thus, we concluded that lucidone-mediated up-regulation of phase-II enzymes and HO-1 via Nrf-2 signaling pathway may provide a pivotal mechanism for its hepatoprotective action., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Here, we investigated the anti-inflammatory activity of lucidone, a phytocompound isolated from the fruits of Lindera erythrocarpa Makino, against lipopolysaccharide (LPS)-induced acute systemic inflammation in mice. Male ICR mice were injected intraperitoneally with LPS (5 microg/kg), and the effects of pretreatment with various concentrations of lucidone (50-200 mg/kg) for 12h on the formation of nitric oxide (NO), prostaglandin-E(2) (PGE(2)) and tumor necrosis factor (TNF-alpha) were analyzed. Lucidone inhibited the production of NO, PGE(2) and TNF-alpha production in LPS-induced mice, and also induced mRNA and protein levels of inducible nitric oxide synthase (iNOS), and cyclooxigenase-2 (COX-2). The two common response elements of the iNOS and COX-2 genes are nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). NF-kappaB nuclear translocation and DNA binding were inhibited by lucidone in the LPS-induced mice. Moreover, lucidone decreased the expression and phosphorylation of c-Jun N-terminal kinase (JNK) protein thereby causing the subsequent inhibition of AP-1 activity. Finally, our results indicated that lucidone was able to block mitogen-activated protein kinases activity and its downstream signaling activation of NF-kappaB and AP-1. We thus conclude that lucidone exerts its anti-inflammatory effects in mice by inhibiting the expression of pro-inflammatory factors and their related signaling pathways., (Copyright 2009 Elsevier B.V. All rights reserved.)

The anti-inflammatory mechanism of lucidone isolated from the fruits of Lindera erythrocarpa Makino was investigated. Our data indicate that lucidone significantly inhibits the production of NO and PGE(2) autacoids in LPS-induced RAW 264.7 murine macrophage cells. Moreover, it also notably decreased the secretion of tumor necrosis factor-alpha (TNF-alpha). Consistent with these observations, the mRNA and protein expression levels of iNOS and COX-2 were also inhibited by lucidone in a dose-dependent manner. Lucidone also reduced the translocation of NF-kappaB induced by LPS, which is associated with the prevention of the degradation of I-kappaB, and subsequently decreased p65/p50 protein levels in the nucleus. Lucidone also inhibited NF-kappaB activation by impairing the binding of NF-kappaB to its cis-acting element. In addition, lucidone inhibited JNK and p38MAPKs signals, which are the most significant signals involved in NO, PGE(2) and TNF-alpha production; NF-kappaB/AP-1 activation was also inhibited by lucidone. Taken together, the anti-inflammatory activity of lucidone might be caused by the inhibition of iNOS and COX-2 expressions through downregulation of NF-kappaB and AP-1 binding.