Synthesis carbonic anhydrase enzyme inhibition and antioxidant activity of novel benzothiazole derivatives incorporating glycine, methionine, alanine, and phenylalanine moieties

Figures & data

Scheme 1. Synthetic pathways of amino acid-benzothiazole derivatives (1–13).

Table 1. Inhibition data of hCA I, hCA II, hCA V, and hCA XIII with compounds 1–13 and the standard sulfonamide inhibitor acetazolamide (AAZ) by a stopped flow CO₂ hydrase assay.

KI (µM)^a
Comp	hCA I	hCAII	hCA V	hCA XIII
1	4.3	32.1	4.3	94.6
2	>100	74.8	65.5	>100
3	90.5	50.4	86.9	>100
4	>100	>100	>100	>100
5	>100	82.3	>100	>100
6	>100	>100	>100	>100
7	>100	>100	60.0	>100
8	89.9	>100	9.0	>100
9	71.9	>100	7.3	>100
10	7.1	>100	2.9	>100
11	>100	88.1	74.5	>100
12	>100	37.0	>100	>100
13	>100	39.1	41.2	84.9
AAZ	0.25	0.012	0.063	0.017

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

Table 2. Antioxidant activities of the synthesised amino acid-benzothiazole derivatives.

	Antioxidant activity, %
Comp. no	12.5 μg/ml	25 μg/ml	37.5 μg/ml	62.5 μg/ml	125 μg/ml
1	0	0	0	11.4	12.5
2	0	0	3.9	4.6	6.1
3	3.3	3.4	5.3	7.5	7.7
4	0	5.7	5.8	9.6	10,4
5	12.0	15.0	25.0	32.0	38.0
6	11.0	14.0	23.0	32.0	37.0
7	13.0	15.0	22.5	24.8	28.3
8	0	2.1	6.6	19.2	20.7
9	4	4.6	5.3	5.8	6.4
10	0	0	22.5	23.1	24.5
11	5	6.7	6.9	7.1	8.2
12	0	3	3.4	5.8	6.1
13	5	6.7	6.1	7.1	8.2
α-Toc.	62.9	63.4	68.4	72.8	74.0
BHA	61.1	63.0	67.5	71.0	72.4