Possible Interaction: Vitamin K and Ascorbate

“ Ascorbate and menadione (Apatone) in a ratio of 100:1 kills tumor cells by autoschizis.”

“At concentrations of 100 microM and higher, menadione depleted the cells of both GSH and ascorbate , and ascorbate loading partially prevented the decrease in GSH due to menadione.”

“ Menadione caused intracellular oxidation of dihydrofluorescein, which required the presence of D-glucose in the incubation medium, and was inhibited by intracellular ascorbate and desferrioxamine.”

“ Menadione increased L-arginine uptake by the cells, but inhibited endothelial nitric oxide synthase, an effect that was prevented by acute loading with ascorbate.”

“After administration of menadione and ascorbate , we found a 21-fold increase of the recovery rate relative to the pretherapy value, to within 56% of the recovery rate of the young female control.”

“Finally, while H2O2, when administered as a bolus, strongly enhances a constitutive basal NF-κB activity in TLT cells, their incubation in the presence of ascorbate and menadione results in a total abolition of such a constitutive activity.”

“The quinones 1,4-naphthoquinone (NQ), …-methyl-1,4-naphthoquinone MNQ ), 2,3-dimethoxy-5-methyl-1,4-benzoquinone (UBQ-0), 2,6-…), and 9,10-phenanthraquinone (PHQ) enhance the rate of H2O2 reduction by ascorbate , under anaerobic conditions, as detected from the … hydroxyl radical reaction with dimethyl sulfoxide.”

“The paraquinones 2,6-dimethyl-1,4-benzoquinone (DMBQ), 1,4-benzoquinone, methyl-1,4-benzoquinone, 2,6-dimethoxy-…, tetramethyl-1,4-benzoquinone, and 2,3-dimethoxy-5-methyl-1,4-benzoquinone; the paranaphthoquinones 1,4-naphthoquinone, menadione , 1,4-naphthoquinone-2-sulfonate, … enhance the anaerobic rate of ascorbate ….”

“This fraction displays low-potential properties, as it can be also oxidised by menadione in the presence of 5 mM ascorbate.”