Inhibition survey with phenolic compounds against the δ- and η-class carbonic anhydrases from the marine diatom thalassiosira weissflogii and protozoan Plasmodium falciparum

Figures & data

Figure 1. Metal ion coordination in the different CA families: (A) α-, γ - and δ-CAs (in the α- and δ-classes the coordinating residues are from the same monomer, whereas in γ -CAs the third His is from an adjacent monomer). (B) β-CAs (ζ -CAs possess a Cd(II) bound within the active site and show analogue coordination pattern). (C) η-CAs.

Table 1. Kinetic parameters for the CO₂ hydration reaction catalysed by the human cytosolic isozymes hCA I and II (α-class CAs), TweCAδ and PfCA measured at 20 °C^14,18.

Enzyme	Species	Class	Activity level	Kcat (s^−1)	kcat/km (M^−1 × s^−1)	KI AAZ (nM)
hCA I	Human	α	Moderate	2.0 × 10^5	5.0 × 10^7	250
hCA II	Human	α	Very high	1.4 × 10^6	1.5 × 10^8	12
TweCAδ	T. weissflogii	δ	Moderate	1.3 × 10^5	3.3 × 10^7	83
PfCA	P. falciparum	η	Moderate	3.8 × 10^5	7.2 × 10^7	366

Figure 2. Structures of phenolic compounds 1–22.

Table 2. Inhibition data of TweCAδ and PfCA with phenols 1–22 and the standard sulphonamide inhibitor acetazolamide (AAZ) by a stopped flow CO₂ hydrase assay²⁷.

Cmpd	R	KI (µM)^a
		TweCAδ	PfCA	CA I^b	CA II^b
1	H	52.3	68.1	10.2	5.5
2	2-OH	4.5	1.4	>100	5.5
3	3-OH	48.2	26.9	>100	9.4
4	4-OH	34.9	21.0	10.7	0.1
5	2,4-diOH	2.0	0.83	>100	>100
6	3-NH2	65.4	78.7	4.9	4.7
7	4-NH2	17.6	33.8	>100	>100
8	4-NHCOCH3	7.9	26.4	10.0	6.2
9	4-CN	56.9	36.9	>100	0.1
10	2-COOH	0.95	0.72	9.9	7.1
11	4-COOH	1.4	0.90	9.8	10.6
12	4-CH2OH	35.9	47.1	68.9	95.3
13	3-NH2-4-Cl	>100	>100	6.3	4.9
14	4-NH2-2-Cl	>100	>100	57.8	57.5
15	2,5-diF	30.7	41.3	>100	>100
16	3,5-diF	21.0	32.7	38.8	33.9
17	2,4,6-triF	13.8	22.8	>100	>100
18	4-COOH-2-OH	4.9	1.6	1.1	0.5
19	2-COOH-3-OH	2.7	2.5	5.7	5.2
20	2-COOH-4-OH	0.81	0.62	4.2	4.1
21	4-(CHCHCOOH)	14.5	5.7	1.1	1.3
22	2-OH-4-(CHCHCOOH)	5.9	11.2	2.4	1.6
AAZ	–	0.08	0.36	0.25	0.01

^a Mean from 3 different assays, by a stopped flow technique (errors were in the range of ± 5–10% of the reported values)

^b Data from ref.³³

Table 3. Selectivity index (SI) for target CA over the off-target hCA I and II.

Cmpd	R	SI
		I/TweCA	II/TweCA	I/PfCA	II/ PfCA
1	H	0.2	0.1	0.1	0.08
2	2-OH	>22.2	1.2	71.4	3.9
3	3-OH	>2.0	0.2	>3.7	0.3
4	4-OH	0.3	<0.01	0.5	<0.01
5	2,4-diOH	>50	>50	>100	>100
6	3-NH2	0.07	0.07	0.06	0.05
7	4-NH2	>5.6	>5.6	>2.9	>2.9
8	4-NHCOCH3	1.2	0.8	0.4	0.2
9	4-CN	>1.7	<0.01	>2.7	<0.01
10	2-COOH	10.4	7.4	13.7	9.8
11	4-COOH	7.0	7.5	10.9	11.8
12	4-CH2OH	1.9	2.6	1.4	2.0
13	3-NH2-4-Cl	<0.06	<0.05	<0.06	<0.05
14	4-NH2-2-Cl	<0.6	<0.5	<0.6	<0.6
15	2,5-diF	>3.2	>3.2	>2.4	>2.4
16	3,5-diF	1.8	1.6	1.1	1.0
17	2,4,6-triF	>7.2	>7.2	>4.3	>4.3
18	4-COOH-2-OH	0.2	0.1	0.6	0.3
19	2-COOH-3-OH	2.1	1.9	2.3	2.1
20	2-COOH-4-OH	5.2	5.0	6.8	6.2
21	4-(CHCHCOOH)	0.07	0.09	0.2	0.2
22	2-OH-4-(CHCHCOOH)	0.4	0.3	0.2	0.1
AAZ	–	3.1	0.1	0.7	0.03

Del Prete S, Vullo D, De Luca V, et al. Biochemical characterization of the δ-carbonic anhydrase from the marine diatom Thalassiosira weissflogii. TweCA. J Enzyme Inhib Med Chem 2014;29:906–11. Dec

 PubMed Web of Science ®Google Scholar

Del Prete S, De Luca V, De Simone G, et al. Cloning, expression and purification of the complete domain of the eta-carbonic anhydrase from Plasmodium falciparum. J Enzyme Inhib Med Chem 2016;31:54–9.

 PubMed Web of Science ®Google Scholar

(a) Vermelho AB, da Silva Cardoso V, Ricci Junior E, et al. Nanoemulsions of sulfonamide carbonic anhydrase inhibitors strongly inhibit the growth of Trypanosoma cruzi. J Enzyme Inhib Med Chem 2018;33:139–46.

 PubMed Web of Science ®Google Scholar

(b) Nocentini A, Carta F, Tanc M, et al. Deciphering the mechanism of human carbonic anhydrases inhibition with sulfocoumarins: computational and experimental studies. Chemistry 2018;24:7840–44.

 PubMed Web of Science ®Google Scholar

(c) Awadallah FM, Bua S, Mahmoud WR, et al. Inhibition studies on a panel of human carbonic anhydrases with N1-substituted secondary sulfonamides incorporating thiazolinone or imidazolone-indole tails. J Enzyme Inhib Med Chem 2018;33:629–38.

 PubMed Web of Science ®Google Scholar

(a) Bilginer S, Unluer E, Gul HI, et al. Carbonic anhydrase inhibitors. Phenols incorporating 2- or 3-pyridyl-ethenylcarbonyl and tertiary amine moieties strongly inhibit Saccharomyces cerevisiae β-carbonic anhydrase. J Enzyme Inhib Med Chem 2014;29:495–9.

 PubMed Web of Science ®Google Scholar

(b) Supuran CT, Clare BW. Carbonic anhydrase inhibitors. Part 57. Quantum chemical QSAR of a group of 1,3,4-thiadiazole and 1,3,4-thiadiazoline disulfonamides with carbonic anhydrase inhibitory properties. Eur J Med Chem 1999;34:41–50.

 Web of Science ®Google Scholar