Description_x000D_ General description_x000D_ Dihydrorhodamine 123 (DHR123) is an uncharged non-fluorescent dye and a derivative of rhodamine 123 (R123). Dihydrorhodamine 123 (DHR123) is oxidized to fluorescent R123 within cells in the presence of reactive oxygen species and it localizes in mitochondria. It is an analog of 2,7-Dichlorodihydrofluorescein (DCDHF), lipophilic and diffuses through cell membrane._x000D_ Application_x000D_ Dihydrorhodamine 123 (DHR) has been used for the detection of free intracellular radicals or ROS (reactive oxygen species) in head kidney-derived macrophages. It has also been used in DHR assay in red blood cells and in oxidative burst assay in neutrophils._x000D_ Packaging_x000D_ 2, 10 mg in ampule_x000D_ Biochem/physiol Actions_x000D_ Dihydrorhodamine 123 detects superoxide ions at the single-cell level and is used for probing neutrophils superoxide generation in a respiratory burst event. It is also used for measuring oxidative stress in macrophages and human spermatozoa._x000D_ Dihydrorhodamine 123 is used for the detection of ROS (reactive oxygen species). Presence of ROS oxidizes dihydrorhodamine 123 to the fluorescent derivative rhodamine 123. The reaction happens in the presence of a peroxidase or a similar catalyst._x000D_ Substrates_x000D_ Peroxidase substrate