Griffipavixanthone (GPX) is a dimeric xanthone which was isolated in a systematic investigation of Garcinia oblongifolia Champ. In this study, we investigate the effect of GPX on cell proliferation and apoptosis on human Non-small-cell lung cancer (NSCLC) cells in vitro and determine the mechanisms of its action. GPX inhibited the growth of H520 cells in dose- and time-dependent manners, with I...

There is a requirement for cellular defense against excessive peroxynitrite generation to protect against DNA strand breaks and mutations and against interference with protein tyrosine-based signaling and other protein functions due to formation of 3-nitrotyrosine. Here, we demonstrate a role of selenium-containing enzymes catalyzing peroxynitrite reduction using glutathione peroxidase (GPx) as...

Cellular glutathione peroxidase (GPx-1), a selenocysteine-containing enzyme, plays a central role in protecting cells from oxidative injury. GPx-1 is ubiquitously expressed in eukaryotic cells where it reduces hydrogen and lipid peroxides to alcohols. Adenosine, which is released from stressed or injured cells, protects against ischemia/reperfusion injury and apoptosis. In this study, we hypoth...

In contrast to neutrophils or B-lymphocytes, cells of the monocytic lineage like rat macrophages, human peripheral blood monocytes and Mono Mac 6 cells contain a strong inhibitor of 5-lipoxygenase (5-LO) activity, which scavenges hydroperoxides and inhibits 5-LO activity in broken-cell preparations in the absence of exogenously added thiols. Chromatographic purification of the inhibitor from th...

Metastasis causes a large number of deaths among esophageal cancer patients. The activation of RAF family proteins elevates tumor metastasis and proliferation. In screen targeting the RAF protein, we identified that Griffipavixanthone (GPX), a dimeric xanthone isolated from Garcinia esculenta, is a B-RAF and C-RAF inhibitor against esophageal cancer cells. Using wound healing, transwell migrati...

Cytosolic glutathione peroxidase (GPX-1) is an important antioxidant enzyme that scavange hydrogen peroxide in mammalian cells. The level of GPX-1 activity in Japanese monkey (Macaca fuscata) tissues was determined and it was found to be high in the liver, kidney, and adrenal gland followed by the small intestine. We also cloned the GPX-1 cDNA that included the whole protein-coding region. The ...

BACKGROUND Preliminary studies indicated decreased glutathione peroxidase (GPX) activity in blood of ewes on scrapie-afflicted farms. Other studies have shown decreased GPX activity in brain of prion-infected mice and in prion-infected cells in vitro. The aim of this study was to examine the GPX activity in blood as well as the distribution of GPX-activity levels from ewes on farms in scrapie-a...

Although its concentration is generally not known, glutathione peroxidase-1 (GPx-1) is a key enzyme in the removal of hydrogen peroxide (H2O2) in biological systems. Extrapolating from kinetic results obtained in vitro using dilute, homogenous buffered solutions, it is generally accepted that the rate of elimination of H2O2 in vivo by GPx is independent of glutathione concentration (GSH). To ex...

This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type...

Glutathione peroxidases (GPx) and glutathione S-transferases (GST) are essential enzymes of the cellular defense system. The aim of this work was the identification of GPx transcript in a freshwater bivalve, Unio tumidus, and the effects of Aroclor 1254 on GPx and pi-class GST (pi-GST) expression pattern. The GPx full-length coding sequence was obtained by reverse transcription PCR using degene...