. Author manuscript; available in PMC: 2012 Mar 10.

Published in final edited form as: J Med Chem. 2011 Feb 1;54(5):1244–1255. doi: 10.1021/jm1011947

Table 3.

Inhibition of Tubulin Assembly^a and Colchicine Binding^b

Group	Compound	IC₅₀ (μM) ± SD	Inhibition of colchicine binding (%) ± SD
	2	NA	-

I	3	2.3 ± 0.08	43 ± 10
	6	2.7 ± 0.1	50 ± 0.4
	8	2.7 ± 0.3	31 ± 3
	11	Not obtainable^c	29 ± 0.4
	35	2.5 ± 0.2	37 ± 5

II	15	6.5 ± 0.7	33 ± 2
	21	2.0 ± 0.1	78 ± 5
	22	3.4 ± 0.3	38 ± 4
	26	3.4 ± 0.2	52 ± 0.6
	36	3.7 ± 0.09	36 ± 4
	37	2.4 ± 0.007	69 ± 3

	CA-4	1.1 ± 0.1	99 ± 0.7

The tubulin assembly assay measured the extent of assembly of 10 μM tubulin after 20 min at 30 °C.

Tubulin: 1 sμM, [³H]Colchicine: 5 μM, Inhibitor: 5 μM. Incubation was for 10 min at 37 °C.

Partial inhibition observed and was maximal with 4 μM compound. Higher compound concentrations resulted in the same amount of inhibition observed with 4 μM, suggesting poor solubility of 11 in the reaction mixture.