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AMP-activated protein kinase (AMPK) plays an important role in inflammation in various cells and increases the phagocytic ability of macrophages. In this study, we found that sauchinone increased the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC), a downstream target of AMPK, in mouse peritoneal macrophages. Sauchinone increased macrophage phagocytosis of fluorescent Escherichia coli, which was blocked by compound C, an AMPK inhibitor. Sauchinone also increased the phosphorylation of p38 mitogen activated protein kinase (MAPK) in cultured macrophages in a concentration-dependent fashion, which was not blocked by compound C. However, the increase of sauchinone-induced phagocytosis was prevented by SB203580. An inhibitor of the upstream kinase TGF-beta-activated kinase (TAK1), (5z)-7-oxozeaenol, abolished the phosphorylation of ACC and p38 MAPK. Systemic administration of sauchinone to mice led to increased phosphorylation of AMPK and p38 MAPK in the lung, and enhanced phagocytosis of fluorescent E. coli in bronchoalveolar lavage fluid as compared with control mice. These results suggest sauchinone to be a useful adjunctive treatment for bacterial infection., (Copyright © 2014 Elsevier B.V. All rights reserved.)

We investigated the anti-inflammatory effects of sauchinone, a lignan isolated from Saururus chinensis, and the underlying mechanism in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. To assess the effects of sauchinone on LPS-induced macrophages activation, we measured the production of tumor necrosis factor (TNF)-alpha and macrophage inflammatory protein (MIP)-2, and activation of mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated kinase (ERK) 1/2, c-Jun amino terminal kinases and p38 mitogen-activated protein kinase, and NF-kappaB activation in RAW264.7 cells. Sauchinone decreased the production of TNF-alpha, but not MIP-2 production in RAW264.7 cells stimulated with LPS. Sauchinone also decreased c-Raf-MEK1/2-ERK1/2 phosphorylation and NF-kappaB activation in RAW264.7 cells stimulated with LPS. Our results show that sauchinone inhibits LPS-induced TNF-alpha expression in macrophages by suppression of NF-kappaB activation via ERK1/2 pathway, which may constitute anti-inflammatory effects of sauchinone., ((c) 2010. Published by Elsevier B.V. All rights reserved.)

A high performance liquid chromatography method coupled with diode array detection (HPLC-DAD) was developed for simultaneous determination of five major active flavonoids, two aristolactams and four main lignans in Saururus chinensis, namely rutin (1), isoquercitrin (2), quercetin-3-O-beta-d-glucopyranosyl (1-->4)-alpha-l-rhamnoside (3), quercitrin (4), quercetin (5), aristolactam A II (6), sauristolactam (7), dihydroguaiaretic acid (8), sauchinone (9), licarin A (10) and licarin B (11). The analysis was performed on an Agilent Eclipse XDB C(18) column (4.6mmx150mm, 5microm) with gradient elution of 0.4% aqueous phosphoric acid and acetonitrile. The detection wavelengths were 280 and 360nm. All calibration curves showed good linearity (r(2)>0.9991) within test ranges. The method was reproducible with intra- and inter-day variation less than 3.2%. The recovery of the assay was in the range of 95.1-103.9%. The validated method was successfully applied for the analysis of the eleven bioactive compounds in seven samples from different harvesting seasons and significant variations were revealed. The results indicated that the developed method can be used as a suitable quality control method for S. chinensis and it should be harvested in August (fruiting period) for Jiangsu cultivation regions, taking the yield into consideration, with the highest amounts of lignans, relative higher amounts of flavonoids and lower amounts of aristolactams., (Copyright 2009 Elsevier B.V. All rights reserved.)

Natural products and their derivatives have historically been an invaluable a source of therapeutic agents. In this report, we demonstrated the anti-inflammatory activity of saurolactam, a compound isolated from the aerial portions of the Chinese lizard, Saururus chinensis. In RAW264.7 macrophage cells, saurolactam significantly inhibited the lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 and, consequently, inhibited the release of NO and prostaglandin E2. Moreover, real-time PCR and multiplex cytokine assays showed that saurolactam (10 microM) significantly inhibited the LPS-induced mRNA and protein expression levels of pro-inflammatory genes, including interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha. Finally, western blot analysis showed that saurolactam dose-dependently inhibited LPS-induced extracellular signal-regulated kinase (ERK)/mitogen-activated protein (MAP) kinase activation and nuclear factor (NF)-kappaB translocation into the nucleus. The inhibitory activity of saurolactam on the activation of NF-kappaB was confirmed by a NF-kappaB luciferase reporter gene assay. In conclusion, we propose that the in vitro anti-inflammatory activity of saurolactam is produced by blocking ERK/MAP kinase and NF-kappaB activation., (Copyright 2009 Elsevier B.V. All rights reserved.)

Iron-overload disorders cause hepatocyte injury and inflammation by oxidative stress, possibly leading to liver fibrosis and hepatocellular carcinoma. This study investigated the efficacy of sauchinone, a bioactive lignan, in preventing iron-induced liver injury and explored the mechanism of sauchinone's activity. To create iron overload, mice were injected with phenylhydrazine, and the effects on hepatic iron and histopathology were assessed. Phenylhydrazine treatment promoted liver iron accumulation and ferritin expression, causing hepatocyte death and increased plasma arachidonic acid (AA). Sauchinone attenuated liver injury (EC(50)=10 mg/kg) and activated AMPK in mice. Treatment of hepatocytes with iron and AA simulated iron overload conditions: iron + AA synergistically amplified cytotoxicity, increasing H(2)O(2) and the mitochondrial permeability transition. Sauchinone protected hepatocytes from iron + AA-induced cytotoxicity, preventing the induction of mitochondrial dysfunction and apoptosis (EC(50)=1 microM), similar to the result using metformin. Sauchinone treatment activated LKB1, which led to AMPK activation: these events contributed to cell survival. Evidence of cytoprotection by LKB1 and AMPK activation was revealed in the reversal of sauchinone's restoration of the mitochondrial membrane potential by either dominant negative mutant AMPKalpha or chemical inhibitor. In conclusion, sauchinone protects the liver from toxicity induced by iron accumulation, and sauchinone's effects may be mediated by LKB1-dependent AMPK activation.

In our search for NF-kappaB inhibitors from natural resources, we have previously identified two structurally related dilignans, manassantin A and B as specific inhibitors of NF-kappaB activation from Saururus chinensis. However, their molecular mechanism of action remains unclear. We here demonstrate that manassantins A and B are potent inhibitors of NF-kappaB activation by the suppression of transciptional activity of RelA/p65 subunit of NF-kappaB. These compounds significantly inhibited the induced expression of NF-kappaB reporter gene by LPS or TNF-alpha in a dose-dependent manner. However, these compounds did not prevent the DNA-binding activity of NF-kappaB assessed by electrophoretic mobility shift assay as well as the induced-degradation of IkappaB-alpha protein by LPS or TNF-alpha. Further analysis revealed that manassantins A and B dose-dependently suppressed not only the induced NF-kappaB activation by overexpression of RelA/p65, but also transactivation activity of RelA/p65. Furthermore, treatment of cells with these compounds prevented the TNF-alpha-induced expression of anti-apoptotic NF-kappaB target genes Bfl-1/A1, a prosurvival Bcl-2 homologue, and resulted in sensitizing HT-1080 cells to TNF-alpha-induced cell death. Similarly, these compounds also suppressed the LPS-induced inducible nitric oxide synthase expression and nitric oxide production. Taken together, manassantins A and B could be valuable candidate for the intervention of NF-kappaB-dependent pathological condition such as inflammation and cancer.