Silybum marianum (milk thistle) is a medicinal plant used for the treatment of various liver disorders. This study examined whether the main flavonolignans from S. marianum (i.e. silybin, silychristin, silydianin) and their 2,3-dehydro derivatives (i.e. 2,3-dehydrosilybin, 2,3-dehydrosilychristin, 2,3-dehydrosilydianin) activate the Nrf2 pathway, which regulates the expression of genes encoding many cytoprotective enzymes, including NAD(P)H:quinone oxidoreductase 1 (NQO1). After 48h of exposure, 2,3-dehydrosilydianin at concentrations of 25μM and higher significantly elevated the activity of NQO1 in murine hepatoma Hepa1c1c7 cells. In contrast, other tested compounds at non-cytotoxic concentrations had a mild or negligible effect on the NQO1 activity. Using a luciferase reporter assay, 2,3-dehydrosilydianin was found to significantly activate transcription via the antioxidant response element in stably transfected human AREc32 reporter cells. Moreover, 2,3-dehydrosilydianin caused the accumulation of Nrf2 and significantly induced the expression of the Nqo1 gene at both the mRNA and protein levels in Hepa1c1c7 cells. We found that 2,3-dehydrosilydianin also increased to some extent the expression of other Nrf2 target genes, namely of the heme oxygenase-1 gene (Hmox1) and the glutamate-cysteine ligase modifier subunit gene (Gclm). We conclude that 2,3-dehydrosilydianin activates Nrf2 and induces Nrf2-mediated gene expression in Hepa1c1c7 cells.

• MeSH
• exprese genu účinky léků   MeSH
• faktor 2 související s NF-E2 metabolismus   MeSH
• glutamátcysteinligasa genetika   metabolismus   MeSH
• hemoxygenasa-1 genetika   metabolismus   MeSH
• lidé MeSH
• membránové proteiny genetika   metabolismus   MeSH
• molekulární struktura MeSH
• myši MeSH
• NAD(P)H dehydrogenasa (chinon) genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• ostropestřec mariánský chemie   MeSH
• silymarin farmakologie   MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The natural flavonoid quercetin is known to activate the transcription factor Nrf2, which regulates the expression of cytoprotective enzymes such as heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). In this study, a novel semisynthetic flavonoid 7-O-galloylquercetin (or quercetin-7-gallate, 3) was prepared by direct galloylation of quercetin, and its effect on the Nrf2 pathway was examined. A luciferase reporter assay showed that 7-O-galloylquercetin, like quercetin, significantly activated transcription via the antioxidant response element in a stably transfected human AREc32 reporter cell line. In addition, 7-O-galloylquercetin caused the accumulation of Nrf2 and induced the expression of HO-1 at both the mRNA and protein levels in murine macrophage RAW264.7 cells. The induction of HO-1 by 7-O-galloylquercetin was significantly suppressed by N-acetyl-l-cysteine and SB203580, indicating the involvement of reactive oxygen species and p38 mitogen-activated protein kinase activity, respectively. HPLC/MS analyses also showed that 7-O-galloylquercetin was not degalloylated to quercetin, but it was conjugated with glucuronic acid and/or methylated in RAW264.7 cells. Furthermore, 7-O-galloylquercetin was found to increase the protein levels of Nrf2 and HO-1, and also the activity of NQO1 in murine hepatoma Hepa1c1c7 cells. Taken together, we conclude that 7-O-galloylquercetin increases Nrf2 activity and induces Nrf2-dependent gene expression in RAW264.7 and Hepa1c1c7 cells.

• MeSH
• biotransformace účinky léků   MeSH
• enzymová indukce účinky léků   MeSH
• faktor 2 související s NF-E2 metabolismus   MeSH
• hemoxygenasa-1 biosyntéza   MeSH
• hmotnostní spektrometrie MeSH
• inhibitory proteinkinas farmakologie   MeSH
• lidé MeSH
• metabolom účinky léků   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• myši MeSH
• NAD(P)H dehydrogenasa (chinon) metabolismus   MeSH
• nádorové buněčné linie MeSH
• quercetin chemická syntéza   chemie   farmakologie   MeSH
• RAW 264.7 buňky MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• reportérové geny MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH