Malachite green (hemioxalate)

Malachite green hemioxalate (MCCK1) is a triphenylmethane dye which can be used to detect the release of phosphate in enzymatic reactions. Malachite green hemioxalate has antibacterial activity, which is attributed to inhibition of intracellular enzymes, insertion into DNA and/or interaction with cell membranes. Malachite green hemioxalate is also a potent and selective inhibitor of IKBKE, and inhibits its downstream targets such as IκBα, p65 and IRF3. Malachite green hemioxalate exhibits antitumor activity in vitro and in vivo^[1][2][3]. IC50 & Target:IKBKE^[3] In Vitro:Malachite green hemioxalate (5 μM; treated for 12 h) inhibits the growth of pCMV-3B-Myc-IKBKE stably transfected NIH3T3 cells, while having no significant effect on pCMV-3B transfected NIH3T3 cells^[13,14,25].
Malachite green hemioxalate (2-5 μM) can effectively inhibit the phosphorylation of MBP by IKBKE in a dose-dependent manner in an in vitro kinase assay using MBP as a substrate^[2].
Malachite green hemioxalate (2.5 μM; treated for 2 h) significantly reduces the luciferase activities of NF-κB and IFN-β reporter genes in HEK293 cells transfected with reporter plasmids fused with NF-κB and IFN-β promoters and the luciferase gene^[2].
Malachite green hemioxalate (0.1-2.5 μM; treated for 2 h) significantly decreases the activation/phosphorylation levels of p65, IκBα, and IRF3 in a dose-dependent manner in HeLa cells expressing myc - tagged IKBKE^[2].
Malachite green hemioxalate (1-5 μM; treated for 72 h) has a significant inhibitory effect on cell lines with high IKBKE expression, resulting in a low cell viability, while having a weak inhibitory effect on cell lines with low IKBKE expression, resulting in a high cell viability in various cancer cell lines including breast, ovarian, lung, and colorectal cancer cell lines^[2].
Malachite green hemioxalate (5 μM; treated for 48 h) shows that cell lines with high IKBKE expression have a higher apoptosis rate and a higher level of cleaved PARP in various cancer cell lines including breast, ovarian, lung, and colorectal cancer cell lines through Annexin V/PI flow cytometry and WB detection^[2].
The crystal of Malachite green hemioxalate is vivid shiny emerald green and the solution is a similar colour at pH 2. The colour changes with increasing pH to blue and above pH 6 the leucoform precipitates. This colour change has been used in the colorimetric determination of phosphates. If living tissue is added immediately there is no precipitation even through the pH remains neutral, and the solution is stable for at least 24 h^[1].
The leaves of ryegrass^[1]
1. Sections are cut from fresh leaf tissue with a hand-held razor blade and fixed in 1% glutaraldehyde with 0.1% Malachite green hemioxalate for 30 min. The sections are then infiltrated with 1% osmium tetroxide for 10 min, washed and mounted in water.
2. Sections from fresh leaf tissue are stained with a saturated solution of Sudan B Black in 70% ethanol for 5 min, washed in 70% ethanol and mounted in glycerol.
Sections are viewed with a X100 oil planapochromatic objective and X6.3 eyepiece.
Observation with an optical microscope.
In Vivo:Malachite green hemioxalate (MCCK1) (10 mg/kg; intraperitoneal injection; every other day; 6 weeks) significantly inhibits the growth of tumors derived from cancer cells with high IKBKE expression, while having no significant inhibitory effect on the growth of tumors derived from cancer cells with low IKBKE expression in NOD/SCID nude mouse models inoculated with human colon cancer cells or ovarian cancer cells^[2].
Female and male B6C3F1 mice and Fischer 344 rats are fed up to 1200 ppm Malachite green hemioxalate for 28 days to determine the toxicity and metabolism of the dyes. Hepatocyte vacuolization is present in rats administered Malachite green hemioxalate. Malachite green hemioxalate is metabolized to primary and secondary arylamines in the tissues of rodentse for the adverse effects associated with exposure to malachite green^[3].