Colchicin

Colchicin is a kind of alkaloid extracted from the crom or seed of the lily family plants, Colchicum autumnale, and is naturally presented in the Liliaceae Garland and Iphigenia with the contents being 0.11% and 0.1%. It is pale yellow needle crystals. It has slight odor and bitter taste with the melting point being 157℃. It is soluble in cold water, alcohol, chloroform and formaldehyde with poor solubility in hot water and is not easily soluble in benzene and ether.

Colchicin appears as odorless or nearly odorless pale yellow needles or powder that darkens on exposure to light.

Colchicin interacts with albumin and binds to tubulin. Its association with tubulin impacts autophagic vacuole fusion with lysosomes. It inhibits tyrosine kinases and phospholipases. Colchicin may be useful for treating acute coronary syndromes. It is prescribed for treating rheumatologic conditions including familial mediterranean fever (FMF) and acute gouty arthritis.

Colchicin poisoning has a certain incubation period with symptoms often happening at 3d~6d after oral administration or injection. Symptoms include throat burning, nausea, vomiting, abdominal pain, diarrhea, watery stools, hematuria, urine retention, numbness, aching limbs, muscle cramps, hair loss, dilated pupils, and convulsion, paralysis of the central nervous system, and respiratory depression and death. In addition, it can also produce local reactions such as when the drug liquid is leaked out from the blood vessel upon injection, local tissue necrosis can occur. Poisoning is usually caused by ingestion or drug overdose.

Colchicin ameliorates the symptoms of gout and Familial Mediterranean fever. It possesses anti-inflammatory, anti-fibrotic, and cardiovascular protective effects. Colchicin was shown to exhibit anticancer properties, such as the inhibition of cancer cell migration and angiogenesis.

Colchicin undergoes some hepatic metabolism. Colchicin is partially deacetylated in the liver. Large amounts of colchicin and of its metabolites undergo enterohepatic circulation. This may explain the occurrence of a second plasma peak concentration observed 5 to 6 hours after ingestion.

The human lethal dose of colchicine is 6mg~7mg. Mouse oral-LD was 66.6mg/kg; LD50-intraperitoneal injection of mice is 3.5mg/kg. LD50-subcutaneous injection of rat is 4mg/kg.