Description
Colcemid is a colchicine derivative that inhibits tubulin polymerization as potently as colchicine (IC
50 = 2.1 and 2.4 μM, respectively) but is less toxic. At very low (nanomolar) concentrations, colcemid suppresses microtubule dynamicity and inhibits cell migration, while at micromolar levels it blocks microtubule assembly, arresting cells in metaphase. Mitotic block by colcemid is used to synchronize cells and for karyotyping in cytogenetic studies. Prolonged exposure to colcemid can activate p53, leading to apoptosis.
Chemical Properties
Faintly Yellow Crystalline Powder
Uses
Cell synchronization agent; for chromosome visualization; to induce oocyte enucleation for somatic cell cloning.
Uses
Inhibitor of spindle fiber formation
Uses
An antimitotic agent that disrupts microtubles by binding to tubulin and preventing its polymerization. Stimulates the intrinsic GTPase activity of tubulin. Induces apoptosis in several normal and tumor cell lines and activates the JNK/SAPK signaling pathway.
Definition
ChEBI: A secondary amino compound that is (S)-colchicine in which the N-acetyl group is replaced by an N-methyl group. Isolable from the autumn crocus, Colchicum autumnale, it is less toxic than
olchicine and is used as an antineoplastic.
General Description
Colcemid is also known as demecolcine. Its generic name is
N-methyl-
N-deacetyl-colchicine. Colcemid depolymerizes microtubules and blocks mitosis at metaphase.
Biochem/physiol Actions
Often in karyotyping and cell cycle research it is desirable to increase the yield of mitotic cells in a particular phase of the cell cycle. This can be achieved in a variety of ways with the most popular being the use of a cell cycle synchronizing agent such as demecolcine. Demecolcine will arrest cells in metaphase with no remarkable effect on the biochemical events in mitotic cells or in synchronized G1 and S phase cells. White blood cells are often treated with demecolcine to arrest cells in metaphase.
Safety Profile
Poison by ingestion,
intraperitoneal, parenteral, intravenous, and
intramuscular routes. Human systemic
effects by ingestion: (skin and appendages)
hair effects. Human mutation data reported.
An experimental teratogen. Experimental
reproductive effects. When heated to
decomposition it emits toxic fumes of NOx.
Purification Methods
Colcemide is purified by chromatography on silica and eluting with CHCl3/MeOH (9:1), and by recrystallisation from EtOAc/Et2O to form yellow prisms. UV in EtOH has max 243nm ( 30,200) and 350nm ( 16,3000). [Synthesis, IR, NMR, MS: Capraro & Brossi Helv Chim Acta 62 965 1979, Beilstein 8 IV 3319.]
