Design, synthesis, and biological evaluation of 3-benzenesulfonamide-linked 3-hydrazinoisatin derivatives as carbonic anhydrase inhibitors.

A new series of isatin-linked benzenesulfonamide derivatives (9a-w) were synthesized using the tail approach and assayed for their inhibitory potency against four different human carbonic anhydrase (hCA) isoforms, hCA I, II, IX, and XII. Most of these synthesized compounds exhibited interesting inhibition potency against isoforms hCA I, IX, and XII in the nanomolar range and by taking the standard drug acetazolamide. The most potent compounds in the case of hCA I were 9c (435.8 nM) and 9s (956.4 nM), for hCA IX, 9a (60.5 nM), 9d (95.6 nM), 9g (92.1 nM), and 9k (75.4 nM), and for hCA XII, 9p (84.5 nM). However, these compounds showed more selectivity toward hCA IX over hCA I, II, and XII. Thus, these compounds can be further developed as potential lead molecules for the development of isoform-selective hCA IX inhibitors with further structural modifications.

6-Aminocoumarin oxime-ether/sulfonamides as selective hCA IX and XII inhibitors: Synthesis, evaluation, and molecular dynamics studies.

Carbonic anhydrase isoforms IX and XII are overexpressed in hypoxic tumor cells regulating various physiological processes such as cell proliferation, invasion, and metastasis, resulting in the onset and spread of cancer. Selective inhibition of these enzymes is a promising strategy for anticancer therapy. Coumarin derivatives were identified as selective and potent inhibitors of these isoforms. This study reports 6-aminocoumarin sulfonamide and oxime ether derivatives linked through a chloroacetyl moiety tethered to piperazine and piperidone, respectively, showing selective inhibition against human carbonic anhydrase (hCA) IX and XII with Ki ranging from 0.51 to 1.18 µM and 0.89-4.43 µM. While the sulfonamide derivative 8a exhibited submicromolar inhibition against hCA IX and XII with Ki 0.89 and 0.51 µM, the oxime ether derivatives showed lower activity than the sulfonamides, with the compound 5n inhibiting hCA IX and hCA XII with a Ki of 1.055 and 0.70 µM, respectively. The above results demonstrate the potential of these derivatives as selective, potent inhibitors of carbonic anhydrase IX and XII and provide a foundation for further optimization and development as effective anticancer agents. Further, the binding mode of the synthesized derivatives in the active site were examined using molecular docking and dynamic simulation studies.

Development of Novel Indole-3-sulfonamide-heteroaryl Hybrids as Carbonic Anhydrase Inhibitors: Design, Synthesis and in-vitro Screening.

BACKGROUND: Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the reversible hydration of carbon dioxide to bicarbonate and a proton. Inhibition of isoforms IX and XII has induced potent anticancer effects. OBJECTIVE: A series of indole-3-sulfonamide-heteroaryl hybrid (6a-y) was synthesized and screened for the inhibition of human (h) hCA isoforms I, II, IX, and XII. METHODS: The synthesis of target compounds (6a-y) was carried out in multistep starting from 5-nitro indole as starting material by using classical reported reaction conditions. The steps involved are N-Alkylation Chlorosulfonation, amination, reduction, and finally amidation reaction. RESULTS: Amongst all the compounds (6a-y) synthesized and screened, 6l was found to be active against all the screened hCA isoforms, with Ki ranging 8.03 µM, 4.15 µM, 7.09 µM, and 4.06 µM respectively. On the other hand, 6i, 6j, 6q, 6s, and 6t were highly selective against tumor-associated hCA IX, and 6u was selective against both hCA II and hCA IX with moderate inhibitory activities under the range of 100 µM. These compounds showed good activity against the tumor-associated hCA IX and might be developed as future drug leads for anticancer drug discovery. CONCLUSION: These compounds may be useful as starting points for the design and development of more selective and potent hCA IX and XII inhibitors.

Bioevaluation of quinoline-4-carbonyl derivatives of piperazinyl-benzothiazinones as promising antimycobacterial agents.

The quinoline moiety remains a privileged antitubercular (anti-TB) pharmacophore, whereas 8-nitrobenzothiazinones are emerging potent antimycobacterial agents with two investigational candidates in the clinical pipeline. Herein, we report the synthesis and bioevaluation of 30 piperazinyl-benzothiazinone-based quinoline hybrids as prospective anti-TB agents. Preliminary evaluation revealed 24/30 compounds exhibiting substantial activity (minimum inhibitory concentration [MIC] = 0.06-1 µg/ml) against Mycobacterium tuberculosis (Mtb) H37Rv. Cytotoxicity analysis against Vero cells found these to be devoid of any significant toxicity, with the majority displaying a selectivity index of >80. Furthermore, potent nontoxic compounds, when screened against clinical isolates of drug-resistant Mtb strains, demonstrated equipotent inhibition with MIC values of 0.03-0.25 µg/ml. A time-kill study identified a lead compound exhibiting concentration-dependent bactericidal activity, with 10× MIC completely eliminating Mtb bacilli within 7 days. Along with acceptable aqueous solubility and microsomal stability, the optimum active compounds of the series manifested all desirable traits of a promising antimycobacterial candidate.

Design and development of novel series of indole-3-sulfonamide ureido derivatives as selective carbonic anhydrase II inhibitors.

Indole is a privileged moiety with a wide range of bioactivities, making it a popular scaffold in drug design and development studies as well as in synthetic chemistry. Here, novel urea derivatives of indole, containing sulfonamide at position-3 of indole, were synthesized using a well-known tail approach, as carbonic anhydrases (CAs; EC 4.2.1.1) inhibitors. All the newly synthesized molecules were screened for their CA-inhibitory activity against four clinically relevant isoforms of human-origin carbonic anhydrase (hCA), that is, hCA I, hCA II, hCA IX, and hCA XII. These compounds were specifically active against hCA II, more than against hCA I, hCA IX, and hCA XII. Derivative 6l was found to be most active, with a Ki value of 7.7 µM against hCA II.

New 3-(1H-benzo[d]imidazol-2-yl)quinolin-2(1H)-one-based triazole derivatives: Design, synthesis, and biological evaluation as antiproliferative and apoptosis-inducing agents.

A series of 1,2,3-triazole derivatives based on the quinoline-benzimidazole hybrid scaffold was designed, synthesized, and screened against a panel of NCI-60 humanoid cancer cell lines for in vitro cytotoxicity evaluation, which revealed that compound Q6 was the most potent cytotoxic agent with excellent GI50 , TGI, and LC50 values on multiple cancer cell lines. Q6 was tested further on the BT-474 breast cancer line to evaluate the mechanism of action. Preliminary screening studies based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay revealed that compound Q6 had an excellent antiproliferative effect against human breast cancer cells, BT-474, with IC50 values of 0.59 ± 0.01 µM. The detailed study based on the acridine orange/ethidium bromide staining (AO/EB) and the 4',6-diamidino-2-phenylindole (DAPI) assay suggested that the antiproliferative activity shown was due to the induction of apoptosis on exposure to Q6. Further, DCFDA staining showed the generation of reactive oxygen species, altering the mitochondrial potential and leading to the initiation of apoptosis. This was further supported by JC-1 staining, indicating that this scaffold can contribute to the development of more potent derivatives.

Design and synthesis of benzenesulfonamide-linked imidazo[2,1-b][1,3,4]thiadiazole derivatives as carbonic anhydrase I and II inhibitors.

A novel series of imidazothiadiazole-linked benzenesulfonamide derivatives (5a-t) was synthesized and subjected for screening against the four physiologically and pharmacologically relevant human carbonic anhydrase (hCA) isoforms: hCA I, II, VA, and IX. The compounds selectively inhibited hCA I and II over hCA VA and IX. Furthermore, among the two cytosolic isoforms, hCA II was more effectively inhibited as compared with hCA I. The most active compounds were 5o with K i = 0.246 µM and 5p with K i = 0.376 µM against hCA II, whereas compound 5f showed good inhibition against both hCA I and II with K i = 0.493 and 0.4 µM, respectively. This class of underexplored sulfonamides may be used to design isoform-selective CA inhibitors targeting enzymes of medicinal chemistry interest.