Natural Product Polyamines That Inhibit Human Carbonic Anhydrases

Table 1

Inhibition data of human CA isozymes with simple natural product polyamines: spermine and spermidine [10] and complex natural product polyamines 1–5 and the clinically used CA inhibitor, acetazolamide.

Polyamine	𝐾𝑖 (𝜇M)^a
	CA I	CA II	CA IV	CA IX	CA XII	CA XIV
Spermine	231	84	0.010	13.3	27.6	0.86
Spermidine	1.40	1.11	0.112	1.37	44.1	1.00
1	1.76	0.41	6.72	0.20	2.81	2.12
2	0.77	0.37	9.10	0.35	3.48	2.28
3	0.86	0.35	9.08	0.27	3.50	6.96
4	0.85	0.48	>20	0.34	>20	2.72
5	0.79	0.34	7.03	0.36	4.21	1.52
Acetazolamide	0.25	0.012	0.074	0.025	0.006	0.041

aErrors in the range of ±5% of the reported value, from three determinations using a stopped-flow CO₂ anhydrase assay.