In this study, we compared selected silymarin components, such as quercetin (QE), 2,3-dehydrosilybin (DHS) and silybin (SB), with the anti-inflammatory drug indomethacin (IND) in terms of their wound healing potential. In view of the fact that pathological cutaneous wound healing is associated with persistent inflammation, we studied their anti-inflammatory activity against inflammation induced by bacterial lipopolysaccharide (LPS). We investigated the regulation of crucial pro-inflammatory transcription factors-nuclear factor kappa-B (NF-κB) and activator protein 1 (AP-1)-as well as the expression of downstream inflammatory targets by Western blotting, real-time PCR (RT-PCR), electrophoretic mobility shift assay (EMSA), and/or enzyme-linked immunosorbent assay (ELISA) in vitro using primary normal human dermal fibroblasts (NHDF). We demonstrated the greater ability of DHS to modulate the pro-inflammatory cytokines production via the NF-κB and AP-1 signaling pathways when compared to other tested substances. The prolonged exposure of LPS-challenged human dermal fibroblasts to DHS had both beneficial and detrimental consequences. DHS diminished interleukin-6 (IL-6) and interleukin-8 (IL-8) secretion but induced the significant upregulation of IL-8 mRNA associated with NF-κB and AP-1 activation. The observed conflicting results may compromise the main expected benefit, which is the acceleration of the healing of the wound via a diminished inflammation.

• Klíčová slova
• NF-κB, cytokines, fibroblasts, inflammation, skin wound healing,
• MeSH
• antiflogistika farmakologie   MeSH
• chemokiny metabolismus   MeSH
• cytokiny metabolismus   MeSH
• dermatitida farmakoterapie   genetika   metabolismus   patologie   MeSH
• exprese genu MeSH
• fibroblasty účinky léků   metabolismus   MeSH
• hojení ran účinky léků   MeSH
• lidé MeSH
• lipopolysacharidy imunologie   MeSH
• messenger RNA genetika   metabolismus   MeSH
• NF-kappa B metabolismus   MeSH
• proliferace buněk účinky léků   MeSH
• silymarin farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiflogistika MeSH
• chemokiny MeSH
• cytokiny MeSH
• lipopolysacharidy MeSH
• messenger RNA MeSH
• NF-kappa B MeSH
• silymarin MeSH

Quercetin and dehydrosilybin are polyphenols which are known to behave like uncouplers of respiration in isolated mitochondria. Here we investigated whether the effect is conserved in whole cells. Following short term incubation, neither compound uncouples mitochondrial respiration in whole H9c2 cells below 50μM. However, following hypoxia, or long term incubation, leak (state IV with oligomycin) oxygen consumption is increased by quercetin. Both compounds partially protected complex I respiration, but not complex II in H9c2 cells following hypoxia. In a permeabilised H9c2 cell model, the increase in leak respiration caused by quercetin is lowered by increased [ADP] and is increased by adenine nucleotide transporter inhibitor, atractyloside, but not bongkrekic acid. Both quercetin and dehydrosilybin dissipate mitochondrial membrane potential in whole cells. In the case of quercetin, the effect is potentiated post hypoxia. Genetically encoded Ca++ sensors, targeted to the mitochondria, enabled the use of fluorescence microscopy to show that quercetin decreased mitochondrial [Ca++] while dehydrosilybin did not. Likewise, quercetin decreases accumulation of [Ca++] in mitochondria following hypoxia. Fluorescent probes were used to show that both compounds decrease plasma membrane potential and increase cytosolic [Ca++]. We conclude that the uncoupler-like effects of these polyphenols are attenuated in whole cells compared to isolated mitochondria, but downstream effects are nevertheless apparent. Results suggest that the effect of quercetin observed in whole and permeabilised cells may originate in the mitochondria, while the mechanism of action of cardioprotection by dehydrosilybin may be less dependent on mitochondrial uncoupling than originally thought. Rather, protective effects may originate due to interactions at the plasma membrane.

• MeSH
• buněčné linie MeSH
• digitonin farmakologie   MeSH
• fluorescenční mikroskopie MeSH
• konfokální mikroskopie MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• mitochondriální ADP/ATP-translokasy metabolismus   MeSH
• quercetin farmakologie   MeSH
• silymarin farmakologie   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dehydrosilybin MeSH Prohlížeč
• digitonin MeSH
• mitochondriální ADP/ATP-translokasy MeSH
• quercetin MeSH
• silymarin MeSH
• vápník MeSH

2,3-dehydrosilybin (DHS) is a minor flavonolignan component of Silybum marianum seed extract known for its hepatoprotective activity. Recently we identified DHS as a potentially cardioprotective substance during hypoxia/reoxygenation in isolated neonatal rat cardiomyocytes. This is the first report of positive inotropic effect of DHS on perfused adult rat heart. When applied to perfused adult rat heart, DHS caused a dose-dependent inotropic effect resembling that of catecholamines. The effect was apparent with DHS concentration as low as 10 nM. Suspecting direct interaction with β-adrenergic receptors, we tested whether DHS can trigger β agonist-dependent gene transcription in a model cell line. While DHS alone was unable to trigger β agonist-dependent gene transcription, it enhanced the effect of isoproterenol, a known unspecific β agonist. Further tests confirmed that DHS could not induce cAMP accumulation in isolated neonatal rat cardiomyocytes even though high concentrations (≥ 10 μM) of DHS were capable of decreasing phosphodiesterase activity. Pre-treatment of rats with reserpine, an indole alkaloid which depletes catecholamines from peripheral sympathetic nerve endings, abolished the DHS inotropic effect in perfused hearts. Our data suggest that DHS causes the inotropic effect without acting as a β agonist. Hence we identify DHS as a novel inotropic agent.

• MeSH
• buněčné linie MeSH
• kardiomyocyty fyziologie   MeSH
• kardiotonika farmakologie   MeSH
• kontrakce myokardu účinky léků   MeSH
• krysa rodu Rattus MeSH
• ostropestřec mariánský MeSH
• potkani Wistar MeSH
• reserpin farmakologie   MeSH
• rostlinné přípravky farmakologie   MeSH
• silibinin MeSH
• silymarin farmakologie   MeSH
• srdce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kardiotonika MeSH
• reserpin MeSH
• rostlinné přípravky MeSH
• silibinin MeSH
• silymarin MeSH