Formazan dehydrogenation

Tetrazolium selenazole salts (perbromides). preparation, by dehydrogenation of formazans, 255... 

Verdrazyls, e.g., 210, are a class of cyclic free radicals, with characteristic ESR spectra and intense colors. They represent a special case of oxidation of formazans and can be obtained from the methylation of and simultaneous or subsequent dehydrogenation of formazans.359-361 Ver-... 

Dehydrogenation with iV-bromosuccinimide transforms the formazans of oxidized polysaccharides into their tetrazolium derivatives. In an alkaline medium, these colorless or cream-colored compounds readily revert to the bright-red formazans, as with the simple tetrazolium compounds. The formazans of oxidized, soluble polysaccharides (for example, dextran, or soluble starch) yield soluble tetrazolium derivatives, and those of oxidized, insoluble polysaccharides (for example, cellulose, or xylan) give insoluble compounds. 

The cell viability was evaluated by measuring mitochondrial dehydrogenize activity with MTT assay. This assay measures the cell activity, proliferation rate and cell viability. The yellow tetrazolium MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) is reduced to insoluble purple formazan granules by all living, metabolically active cells. The precipitated formazan was dissolved in isopropanol, and the absorbance was read at 595 nm. Absorbance values that are lower than the control cells indicate a reduction in the cell activity and viability. Conversely, a higher absorbance rate indicates an increase in cell viability/ proliferation. 

---