N-Methylcolchicine

In vitro genotoxicity of nitroimidazoles as a tool in the search of new trypanocidal agents.[Pubmed:31271593]

Mem Inst Oswaldo Cruz. 2019;114:e190017.

BACKGROUND: Only benznidazole (Bnz) (1) and nifurtimox (Nfx) (2) are licensed for the treatment of Chagas disease although their safety and efficacy profile are far from ideal. Farmanguinhos from Fiocruz has developed seven nitroimidazole compounds (4-10) analogs of megazol (3). OBJECTIVES: To evaluate whether the genotoxic effect of 3 was abolished in the seven nitroimidazoles (4-10) analogs using the in vitro alkaline comet assay (CA) and the in vitro cytokinesis-block micronucleus assay (CBMN) in whole human blood cells (WHBC) and correlate this effect with their trypanocidal activity using bloodstream trypomastigote forms of Trypanosoma cruzi. METHODS: The toxicity of 3-10 to WHBC in the in vitro CA was determined using the fluorescein diacetate/ethidium bromide assay. DNA damage in the in vitro CA was evaluated according to tail size in four classes (0-3) and methyl methane-sulfonate (MMS) was used as a positive control. The cytotoxicity of 3-10 to WHBC in the CBMN was measured using the cytokinesis-block proliferation index and the replication index. The number of the micronucleate cells in 2,000 binucleate cells by experimental group was determined. Mitomycin C and N-deacetyl-N-Methylcolchicine were used as positive controls. FINDINGS: Compound 3 showed a significant DNA strand break effect through the in vitro CA and highly significant clastogenic and/or aneugenic effect in the CBMN. Compounds 5, 6, 8, 9 and 10 showed negative results in the CBMN and positive results in the in vitro CA, while the inverse effect was observed for 4 and 7. MAIN CONCLUSIONS: Compound 10 was the most promising to proceed with the development as a drug candidate in the treatment of Chagas disease showing absence of chromosomal cytogenetic damage and high activity against T. cruzi, about two times higher than 3 and the clinical drug 1.

Assembly of microtubules at the tip of growing axons.[Pubmed:2872595]

Nature. 1986 Jun 19-25;321(6072):788-90.

The growth of axons in the developing nervous system depends on the elongation of the microtubules that form their principal longitudinal structural element. It is not known whether individual microtubules in the axon elongate at their proximal ends, close to the cell body, and then move forward into the lengthening axon, or whether tubulin subunits are transported to the tip of the axon and assembled there onto the free ends of microtubules. The former possibility is supported by studies of slow axonal transport in mature nerves from which it has been deduced that microtubule assembly occurs principally at the neuronal cell body. By contrast, the polarity of microtubules in axons, which have their 'plus' or 'fast-growing' ends distal to the cell body, suggests that assembly occurs at the growing tip, or growth cone, of the axon. We have addressed this question by topically applying Colcemid (N-desacetyl-N-Methylcolchicine), and other drugs which alter microtubule stability, to different regions of isolated nerve cells growing in tissue culture. We find that the sensitivity to these drugs is greatest at the growth cone by at least two orders of magnitude, suggesting that this is a major site of microtubule assembly during axonal growth.

Mechanism of action of colchicine. I. Effect of colchicine and its analogs on the reversed passive Arthus reaction and the carrageenan-induced hindpaw edema in the rat.[Pubmed:125325]

J Pharmacol Exp Ther. 1975 Jul;194(1):154-8.

Colchicine and N-desacetyl-N-Methylcolchicine suppressed both the reversed passive Arthus reaction and the carrageenan-induced edema in the rat. Colchicine, 2-desmethyl-colchicine glucoside and trimethylcolchicine acid had no effect on either model of inflammation. The ability or inability of these compounds to suppress the development of experimental inflammation correlated with their antimitotic activities. The findings lend support to the hypothesis that the anti-inflammatory and the antimitotic effects of colchicine may depend on the same basic, biophysical mechanism of action, i.e., the disruption of the microtubules.

Colcemid sensitivity of fission yeast and the isolation of colcemid-resistant mutants.[Pubmed:5436084]

Science. 1970 Apr 24;168(3930):485-7.

Cell division of the fission yeast, Schizosaccharomyces pombe, is reversibly inhibited by the antimitotic agent Colcemid (N-deacetyl-N-Methylcolchicine) in nutrient medium. Cell growth continiues until all cells become nonseparating cell doublets in a V configuration. Mutants have been isolated capable of uninhibited growth in the presence of concentrations of Colcemid mycostatic for the parent strain.