Inhibition of platelet aggregation by colchicine, thiocolchicine, and their phenolic and glucosidic congeners

Inhibition of platelet aggregation by colchicine, thiocolchicine, O-demethylated and 3-glucosidic congeners was measured in vitro. 2- And 3-demethylated analogs of colchicine and thiocolchicine were found to be as potent as colchicine and thiocolchicine, respectively, whereas 1-demethylated compounds were found to be considerably less active. Both glucosides, colchicoside and thiocolchicoside, were not very active in this assay. 2,3-Didemethylcolchicine, which is much less toxic than colchicine, showed similar inhibitory effects on platelet aggregation as colchicine.