Andrea Angeli

Microwave-assisted extraction, HPLC analysis, and inhibitory effects on carbonic anhydrase I, II, VA, and VII isoforms of 14 blueberry Italian cultivars.

Abstract The multi-component fingerprint and the biological evaluation of plant-derived material are indispensable for the pharmaceutical field, in food quality control procedures, and in all plant-based products. We investigated the quantitative content of biologically active compounds (anthocyanins and chlorogenic acid) of microwave-assisted blueberry extracts from 14 different Italian cultivars, using validated high-performance liquid chromatography-photodiode array detector (HPLC-PDA) method and routinely instrument configuration. The carbonic anhydrase (CA, EC 4.2.1.1) inhibition profiles against several pharmacologically relevant CA isoforms of blueberry extracts and some bioactive compounds were also investigated. The various cultivars showed a highly variable content in anthocyanins and chlorogenic acid, and their CA inhibitory effects were also highly variable. Overall these data prove that antioxidant natural products found in blueberries may be useful for designing pharmacological agents in which various CAs are involved, e.g., antiobesity, antitumor, or anticonvulsants agents.

Evaluation of selenide, diselenide and selenoheterocycle derivatives as carbonic anhydrase I, II, IV, VII and IX inhibitors

A series of selenides, diselenides and organoselenoheterocycles were evaluated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors against the human (h) isoforms hCA I, II, IV, VII and IX, involved in a variety of diseases among which glaucoma, retinitis pigmentosa, epilepsy, arthritis and tumors etc. These investigated compounds showed inhibitory action against these isoforms and some of them were selective for inhibiting the cytosolic over the membrane-bound isoforms, thus making them interesting leads for the development of isoform-selective inhibitors.

Synthesis of 4-(thiazol-2-ylamino)-benzenesulfonamides with carbonic anhydrase I, II and IX inhibitory activity and cytotoxic effects against breast cancer cell lines

A series of 4-(thiazol-2-ylamino)-benzenesulfonamides was synthesized and screened for their carbonic anhydrase (CA, EC 4.2.1.1) inhibitory and cytotoxic activity on human breast cancer cell line MCF-7. Human (h) CA isoforms I, II and IX were included in the study. The new sulfonamides showed excellent inhibition of all three isoforms, with KIs in the range of 0.84-702nM against hCA I, of 0.41-288nM against hCA II and of 5.6-29.2 against the tumor-associated hCA IX, a validated anti-tumor target, with a sulfonamide (SLC-0111) in Phase I clinical trials for the treatment of hypoxic, metastatic solid tumors overexpressing CA IX. The new compounds showed micromolar inhibition of growth efficacy against breast cancer MCF-7 cell lines.

Inhibition of the α-carbonic anhydrase from Vibrio cholerae with amides and sulfonamides incorporating imidazole moieties

Abstract We discovered novel and selective sulfonamides/amides acting as inhibitors of the α-carbonic anhydrase (CA, EC 4.2.1.1) from the pathogenic bacterium Vibrio cholerae (VchCA). This Gram-negative bacterium is the causative agent of cholera and colonises the upper small intestine where sodium bicarbonate is present at a high concentration. The secondary sulfonamides and amides investigated here were potent, low nanomolar VchCA inhibitors whereas their inhibition of the human cytosolic isoforms CA I and II was in the micromolar range or higher. The molecules represent an interesting lead for antibacterial agents with a possibly new mechanism of action, although their CA inhibition mechanism is unknown for the moment.

Isatin: a privileged scaffold for the design of carbonic anhydrase inhibitors

Abstract The isatin scaffold is the constitutive fragment of several natural and synthetic bioactive molecules. Albeit several benzene sulphonamide-based carbonic anhydrase inhibitors (CAIs) have been reported, only recently isatin benzene sulphonamides have been studied and proposed as CAIs. In this study we have designed, synthesised, and evaluated the biological activity of a series of differently substituted isatin-based benzene sulphonamides which have been designed for the inhibition of carbonic anhydrase isoforms. The activity of all the synthesised compounds was evaluated towards human carbonic anhydrase I, II, IX, and XII isozymes. Our results indicate that the nature and position of substituents on the isatin ring can modulate both activity and isozyme selectivity.

Discovery of Benzenesulfonamides with Potent Human Carbonic Anhydrase Inhibitory and Effective Anticonvulsant Action: Design, Synthesis, and Pharmacological Assessment

We report two series of novel benzenesulfonamide derivatives acting as effective carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The synthesized compounds were tested against human (h) isoforms hCA I, hCA II, hCA VII, and hCA XII. The first series of compounds, 4-(3-(2-(4-substitued piperazin-1-yl)ethyl)ureido)benzenesulfonamides, showed low nanomolar inhibitory action against hCA II, being less effective against the other isoforms. The second series, 2-(4-substitued piperazin-1-yl)-N-(4-sulfamoylphenyl)acetamide derivatives, showed low nanomolar inhibitory activity against hCA II and hCA VII, isoforms involved in epileptogenesis. Some of these derivatives were evaluated for their anticonvulsant activity and displayed effective seizure protection against MES and scPTZ induced seizures in Swiss Albino mice. These sulfonamides were also found effective upon oral administration to Wistar rats and inhibited MES induced seizure episodes in this animal model of the disease. Some of the new compounds showed a long duration of action in the performed time course anticonvulsant studies, being nontoxic in subacute toxicity studies.

Discovery of New Potential Anti-Infective Compounds Based on Carbonic Anhydrase Inhibitors by Rational Target-Focused Repurposing Approaches.

In academia, compound recycling represents an alternative drug discovery strategy to identify new pharmaceutical targets from a library of chemical compounds available in house. Herein we report the application of a rational target‐based drug‐repurposing approach to find diverse applications for our in‐house collection of compounds. The carbonic anhydrase (CA, EC 4.2.1.1) metalloenzyme superfamily was identified as a potential target of our compounds. The combination of a thoroughly validated docking screening protocol, together with in vitro assays against various CA families and isoforms, allowed us to identify two unprecedented chemotypes as CA inhibitors. The identified compounds have the capacity to preferentially bind pathogenic (bacterial/protozoan) CAs over human isoforms and represent excellent hits for further optimization in hit‐to‐lead campaigns.

Synthesis and carbonic anhydrase I, II, VII, and IX inhibition studies with a series of benzo[d]thiazole-5- and 6-sulfonamides

Abstract A series of benzo[d]thiazole-5- and 6-sulfonamides has been synthesized and investigated for the inhibition of several human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoforms, using ethoxzolamide (EZA) as lead molecule. 2-Amino-substituted, 2-acylamino- and halogenated (bromo-and iodo-derivatives at the heterocyclic ring) compounds led to several interesting inhibitors against the cytosolic hCA I, II and VII, as well as the transmembrane, tumor-associated hCA IX isoforms. Several subnanomolar/low nanomolar, isoform-selective sulfonamide inhibitors targeting hCA II, VII and IX were detected. The sharp structure–activity relationship for CA inhibition with this small series of derivatives, with important changes of activity observed even after minor changes in the scaffold or at the 2-amino moiety, make this class of scarcely investigated sulfonamides of particular interest for further investigations.

Design, synthesis and biological evaluation of N-(5-methyl-isoxazol-3-yl/1,3,4-thiadiazol-2-yl)-4-(3-substitutedphenylureido) benzenesulfonamides as human carbonic anhydrase isoenzymes I, II, VII and XII inhibitors

Abstract A series of N-(5-methyl-isoxazol-3-yl/1,3,4-thiadiazol-2-yl)-4-(3-substitutedphenylureido) benzenesulfonamide derivatives has been designed, synthesized and screened for their in vitro human carbonic anhydrase (hCA; EC 4.2.1.1) inhibition potential. These newly synthesized sulfonamide compounds were assessed against isoforms hCA I, II, VII and XII, with acetazolamide (AAZ) as a reference compound. The majority of these compounds were found quite weak inhibitor against all tested isoforms. Compound 15 showed a modest inhibition potency against hCA I (Ki = 73.7 μM) and hCA VII (Ki = 85.8 μM). Compounds 19 and 25 exhibited hCA II inhibition with Ki values of 96.0 μM and 87.8 μM, respectively. The results of the present study suggest that, although the synthesized derivatives have weak inhibitory potential towards all investigated isoforms, some of them may serve as lead molecules for the further development of selective inhibitors incorporating secondary sulfonamide functionalities, a class of inhibitors for which the inhibition mechanism is poorly understood.

New anticancer drug candidates sulfonamides as selective hCA IX or hCA XII inhibitors

In this study, new 4-[3-(aryl)-5-substitutedphenyl-4,5-dihydro-1H-pyrazole-1-yl]benzensulfonamides (19-36) were synthesized and evaluated their cytotoxic/anticancer and CA inhibitory effects. According to results obtained, the compounds 34 (4-[5-(2,3,4-trimethoxyphenyl)-3-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-yl] benzensulfonamide, Potency-Selectivity Expression (PSE) = 141) and 36 (4-[5-(3,4,5-trimethoxyphenyl)-3-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-yl]benzensulfonamide, PSE = 54.5) were found the leader anticancer compounds with the highest PSE values. In CA inhibitory studies, the compounds 36 and 24 (4-[5-(3,4,5-trimethoxyphenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-yl]benzensulfonamide) were found the leader CA inhibitors depending on selectivity ratios. The compound 36 was a selective inhibitor of hCA XII isoenzyme (hCA I/hCA XII = 1250 and hCA II/hCA XII = 224) while the compound 24 was a selective inhibitor of hCA IX isoenzyme (hCA I/hCA IX = 161 and hCA II/hCA IX = 177). The compounds 24, 34, and 36 can be considered to develop new anticancer drug candidates.