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Ganoderma lucidum has been reported to be associated with suppressed motility, invasion and metastasis of several types of cancers, but its mechanism of action remains unclear. In our previous study, lucidenic acids A, B, C and N were isolated from a new strain of G.lucidum and all of them were found to have potential anti-invasive activity on phorbol-12-myristate-13-acetate (PMA)-induced HepG(2) cells by suppressing the matrix metalloproteinase (MMP)-9 activity. Here, the lucidenic acid B (LAB) was used to explore its mechanisms underlying MMP-9 expression of HepG(2) cells. The results showed that the LAB suppressed PMA-induced MMP-9 activity in a dose-dependent transcriptional level. The suppression of PMA-induced MMP-9 expression of HepG(2) cells by LAB was through inactivating phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. The treatment of mitogen-activated protein kinase kinase (MEK) inhibitors (PD98059 and U0126) and LAB to HepG(2) cells could result in a synergistic reduction on the MMP-9 expression along with an inhibition on cell invasion. Moreover, LAB also strongly inhibited PMA-stimulated nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1) DNA-binding activities of HepG(2) cells in dose-dependent manners. A dose-dependent inhibition on protein levels of NF-kappaB, c-Jun and c-Fos in nuclear by LAB treatment was further observed. In conclusion, we demonstrated that the anti-invasive effects of the LAB on the PMA-induced HepG(2) cells might be through inhibiting the phosphorylation of ERK1/2 and reducing AP-1 and NF-kappaB DNA-binding activities, leading to downregulation of MMP-9 expression.

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Berberine, a main protoberberine component of Coptidis Rhizoma, was studied for the mechanism of its inhibitory effects on the tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity and lipid peroxidation in rat liver. In the preliminary study, berberine expressed an antioxidant property by its capacity for quenching the free radicals of 1,1-diphenyl-2-picrylhydrazyl (DPPH). Further investigations were conducted using t-BHP-induced cytotoxicity in rat primary hepatocytes and hepatotoxicity in rats to evaluate the antioxidative bioactivity of berberine. The results in rat primary hepatocytes demonstrated that berberine, at the concentrations of 0.01-1.0 mM, significantly decreased the leakage of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT), and the formation of malondialdehyde (MDA) induced by 30 min treatment of t-BHP (1.5 mM). Berberine also attenuated the t-BHP-induced depletion of glutathione (GSH) and induced a high level of DNA repair synthesis. The in vivo study showed that the intraperitoneal pretreatment with berberine (0.5 and 5 mg/kg) for 5 days before a single dose of t-BHP (0.1 mmol/kg) significantly lowered the serum levels of hepatic enzyme markers (ALT and aspartate aminotransferase) and reduced oxidative stress in the liver. The histopathological evaluation of the livers revealed that berberine reduced the incidence of liver lesions, including hepatocyte swelling, leukocyte infiltrations, and necrosis induced by t-BHP. These results lead us to speculate that berberine may play a chemopreventive role via reducing oxidative stress in living systems.

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A trypsin inhibitor (ACTI) was isolated and purified from the seeds of Acacia confusa by gel filtration, and trypsin-Sepharose 4B column affinity chromatography. The molecular weight of ACTI was found to be 21,000 +/- 1,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino acid composition analysis. ACTI contained four half-cystine and no methionine residues, and was rich in aspartic acid, glutamic acid, glycine, leucine, and lysine residues. The native trypsin inhibitor was composed of two polypeptide chains, and it inhibited trypsin and alpha-chymotrypsin stoichiometrically at the molar ratio of 1:1 and 2:1, respectively. The amino-terminal sequence analysis of the A. confusa trypsin inhibitor A and B chains revealed a more extensive homology with Acacia elata and silk tree trypsin inhibitors, and a less extensive homology with Kunitz soybean trypsin inhibitor.

Chronic infection of hepatitis C virus (HCV) leads to hepatic fibrosis and subsequently cirrhosis, although the underlying mechanisms have not been established. Previous studies have indicated that the binding of HCV E2 protein and CD81 on the surface of hepatic stellate cells (HSCs) lead to the increased protein level and activity of matrix metallopeptidase (MMP) 2, indicating that E2 may involve in the HCV-induced fibrosis. This study was designed to investigate the involvement of HCV E2 protein in the hepatic fibrogenesis. Results showed that E2 protein may promote the expression levels of α-smooth muscle actin (α-SMA) and collagen α(I). Furthermore, several pro-fibrosis or pro-inflammatory cytokines, including transforming growth factor (TGF)-β1, connective tissue growth factor (CTGF), interleukin (IL)-6 and IL-1β, were significantly increased in E2 transfected-HSC cell lines, while the expression of MMP-2 are also considerably increased. Moreover, the significant increases of CTGF and TGF-β1 in a stable E2-expressing Huh7 cell line were also observed the same results. Further molecular studies indicated that the impact of E2 protein on collagen production related to higher production of ROS and activated Janus kinase (JAK)1, JAK2 and also enhance the activation of ERK1/2 and p38, while catalase and inhibitors specific for JAK, ERK1/2, and p38 abolish E2-enhanced expression of collagen α(I). Taken together, this study indicated that E2 protein involve in the pathogenesis of HCV-mediated fibrosis via an up-regulation of collagen α(I) and oxidative stress, which is JAK pathway related.