Development of HDAC Inhibitors Exhibiting Therapeutic Potential in T-Cell Prolymphocytic Leukemia

Epigenetic targeting has emerged as an efficacious therapy for hematological cancers. The rare and incurable T-cell prolymphocytic leukemia (T-PLL) is known for its aggressive clinical course. Current epigenetic agents such as histone deacetylase (HDAC) inhibitors are increasingly used for targeted therapy. Through a structure-activity relationship (SAR) study, we developed an HDAC6 inhibitor KT-531, which exhibited higher potency in T-PLL compared to other hematological cancers. KT-531 displayed strong HDAC6 inhibitory potency and selectivity, on-target biological activity, and a safe therapeutic window in nontransformed cell lines. In primary T-PLL patient cells, where HDAC6 was found to be overexpressed, KT-531 exhibited strong biological responses, and safety in healthy donor samples. Notably, combination studies in T-PLL patient samples demonstrated KT-531 synergizes with approved cancer drugs, bendamustine, idasanutlin, and venetoclax. Our work suggests HDAC inhibition in T-PLL could afford sufficient therapeutic windows to achieve durable remission either as stand-alone or in combination with targeted drugs.

Discovery of AZD8154, a Dual PI3Kγδ Inhibitor for the Treatment of Asthma

Starting from our previously described PI3Kγ inhibitors, we describe the exploration of structure-activity relationships that led to the discovery of highly potent dual PI3Kγδ inhibitors. We explored changes in two positions of the molecules, including macrocyclization, but ultimately identified a simpler series with the desired potency profile that had suitable physicochemical properties for inhalation. We were able to demonstrate efficacy in a rat ovalbumin challenge model of allergic asthma and in cells derived from asthmatic patients. The optimized compound, AZD8154, has a long duration of action in the lung and low systemic exposure coupled with high selectivity against off-targets.

Discovery of novel N-sulfonamide-tetrahydroisoquinolines as potent retinoic acid receptor-related orphan receptor γt agonists

Cancer immunotherapy has become a research hotspot in recent years. A variety of targets were developed for small molecule immuno-oncology agents, including retinoic acid-related orphan receptor gamma t (RORγt), chemokine receptor, stimulator of interferon genes (Sting), indoleamine 2,3-dioxygenase (IDO), toll-like receptors (TLR), etc. Among them, the retinoic acid receptor-related orphan receptor γt (RORγt) has gradually attracted more attention in these years. In particular, LYC-55716 (cintirorgon), a small molecule RORγt agonist developed by Lycera, has entered the phase II clinical study. In this work, starting from compound 7, compound 28 was obtained after 4 rounds of compound design, synthesis and SAR studies, which had an EC₅₀ of 0.021 ± 0.002 μM in dual Fluorescence Resonance Energy Transfer (dual-FRET) assay and an EC₅₀ of 0.021 ± 0.002 μM in mouse Th17 cell differentiation assay. It indicated that compound 28 had excellent RORγt agonistic activity and was expected to be developed as a new type of small molecule drug for cancer immunotherapy. The molecular dynamic simulation revealed that the agonist 28 formed a strong HYF triplet intramolecular interaction to stabilize H12, which helped RORγt to form the protein-binding site and therefore made the receptor ready to recruit coactivator. When the inverse agonist s27 bound with RORγt, the steric hindrance between s27 and H479 caused the destruction of the HYF triplet, leading to the collapse of H12, thus the transcription function of RORγt was interrupted due to the failure of recruiting a coactivator molecule. The triplet HYF in RORγt and the rigidity of 28 and s27 were identified to be the structural determinants for the functional switch of RORγt.

Tellurides bearing benzensulfonamide as carbonic anhydrase inhibitors with potent antitumor activity

We evaluated in vitro a series of telluride containing compounds bearing the benzenesulfonamide group, as effective inhibitors of the physiologically relevant human (h) expressed Carbonic Anhydrase (CA; EC 4.2.1.1) enzymes I, II, IV VII and IX. The potent effects of such compounds against the tumor-associated hCA IX being low nanomolar inhibitors (K_I 2.2 to 2.9 nM) and with good selectivity over the ubiquitous hCA II, gave the possibility to evaluate their lethal effect in vitro against a breast cancer cell line (MDA-MB-231). Among the series, both compounds 3a and 3g induced significant toxic effects against tumor cells after 48 h incubation. Under normoxic condition 3a showed high efficacy killing over 94% of tumor cells at 1 µM, and derivative 3g reached the tumor cell viability under the 5% at 10 µM. In hypoxic condition, these two compounds showed less effective although retained excellent cancer cell killer. These unusual features make them interesting lead compounds acting as antitumor agents also in tumor types not dependent from hCA IX overexpression.

Synthesis, Molecular Docking Analysis and Biological Evaluations of Saccharide-Modified Thiadiazole Sulfonamide Derivatives

A series of saccharide-modified thiadiazole sulfonamide derivatives has been designed and synthesized by the “tail approach” and evaluated for inhibitory activity against carbonic anhydrases II, IX, and XII. Most of the compounds showed high topological polar surface area (TPSA) values and excellent enzyme inhibitory activity. The impacts of some compounds on the viability of HT-29, MDA-MB-231, and MG-63 human cancer cell lines were examined under both normoxic and hypoxic conditions, and they showed certain inhibitory effects on cell viability. Moreover, it was found that the series of compounds had the ability to raise the pH of the tumor cell microenvironment. All the results proved that saccharide-modified thiadiazole sulfonamides have important research prospects for the development of CA IX inhibitors.

Comprehensive study on potent and selective carbonic anhydrase inhibitors: Synthesis, bioactivities and molecular modelling studies of 4-(3-(2-arylidenehydrazine-1-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-1-yl) benzenesulfonamides

In this research, rational design, synthesis, carbonic anhydrases (CAs) inhibitory effects, and cytotoxicities of the 4-(3-(2-arylidenehydrazine-1-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-1-yl)benzenesulfonamides 1-20 were reported. Compound 18 (Ki = 7.0 nM) was approximately 127 times more selective cancer-associated hCA IX inhibitor over hCA I, while compound 17 (Ki = 10.6 nM) was 47 times more selective inhibitor of hCA XI over hCA II compared to the acetazolamide. Compounds 11 (CC50 = 5.2 μM) and 20 (CC50 = 1.6 μM) showed comparative tumor-specificity (TS= > 38.5; >128.2) with doxorubicin (TS > 43.0) towards HSC-2 cancer cell line. Western blot analysis demonstrated that 11 induced slightly apoptosis whereas 20 did not induce detectable apoptosis. A preliminary analysis showed that some correlation of tumor-specificity of 1-20 with the chemical descriptors that reflect hydrophobic volume, dipole moment, lowest hydrophilic energy, and topological structure. Molecular docking simulations were applied to the synthesized ligands to elucidate the predicted binding mode and selectivity profiles towards hCA I, hCA II, and hCA IX.

Design of Trehalose-Based Amide/Sulfonamide C-type Lectin Receptor Signaling Compounds

Mincle agonists have been shown to induce inflammatory cytokine production, such as tumor necrosis factor-alpha (TNF) and promote the development of a Th1/Th17 immune response that might be crucial to development of effective vaccination against pathogens such as Mycobacterium tuberculosis. As an expansion of our previous work, a library of 6,6'-amide and sulfonamide α,α-d-trehalose compounds with various substituents on the aromatic ring was synthesized efficiently in good to excellent yields. These compounds were evaluated for their ability to activate the human C-type lectin receptor Mincle by the induction of cytokines from human peripheral blood mononuclear cells. A preliminary structure-activity relationship (SAR) of these novel trehalose diamides and sulfonamides revealed that aryl amide-linked trehalose compounds demonstrated improved activity and relatively high potency cytokine production compared to the Mincle ligand trehalose dibehenate adjuvant (TDB) and the natural ligand trehalose dimycolate (TDM) inducing dose-dependent and human-Mincle-specific stimulation in a HEK reporter cell line.

Synthesis and in vitro carbonic anhydrases and acetylcholinesterase inhibitory activities of novel imidazolinone-based benzenesulfonamides

New imidazolinone-based benzenesulfonamides 3a-e and 4a-e were synthesized in three steps and their chemical structures were confirmed by 1 H NMR (nuclear magnetic resonance), 13 C NMR, and high-resolution mass spectrometry. The benzenesulfonamides used were sulfacetamide (3a, 4a), sulfaguanidine (3b, 4b), sulfanilamide (3c, 4c), sulfadiazine (3d, 4d), sulfamerazine (3e), and sulfathiazole (4e). The compounds were evaluated against carbonic anhydrase (CA) and acetylcholinesterase (AChE) enzymes to obtain possible drug candidate/s. The lead compounds of the series were 3a and 4a against human CA (hCA) I, whereas 3d and 4a were leads against hCA II in terms of Ki values. Series 4 includes more effective CAs inhibitors than series 3 (except 3d). Series 4 compounds having a nitro group (except 4d) were 3.3-4.8 times more selective inhibitors than their corresponding analogues 3a-d in series 3, in which hydrogen was located in place of the nitro group, by considering Ki values against hCA II. Compounds 3c and 4c, where the sulfanilamide moiety is available, were the leads in terms of AChE inhibition with the lowest Ki values. The use of secondary sulfonamides was a more effective modification on CA inhibition, whereas the primary sulfonamide was the effective substitution in terms of AChE inhibitory potency.

3-Functionalised benzenesulphonamide based 1,3,4-oxadiazoles as selective carbonic anhydrase XIII inhibitors: Design, synthesis and biological evaluation

A new series of benzenesulphonamide linked-1,3,4-oxadiazole hybrids (6a-s) has been synthesized and tested for their carbonic anhydrase inhibition against human (h) carbonic anhydrase (CA) isoforms hCA I, II, IX, and XIII. Fluorescence properties of some of the synthesized molecules were studied. Most of the molecules exhibited significant inhibitory power, comparable or better than the standard drug acetazolamide (AAZ) on hCA XIII. Out of 19 tested molecules, compound 6e (75.8 nM) was 3 times more potent than AAZ (250.0 nM) against hCA I, whereas compound 6e (15.4 nM), 6g (16.2 nM), 6h (16.4 nM) and 6i (17.0 nM) were found to be more potent than AAZ (17.0 nM) against isoform hCA XIII. It is anticipated that these compounds could be taken as the potential leads for the development of selective hCA XIII isoform inhibitors with improved potency.

Unique Molecular Interaction with the Histone Deacetylase 6 Catalytic Tunnel: Crystallographic and Biological Characterization of a Model Chemotype

Histone deacetylase 6 (HDAC6) is involved in multiple regulatory processes, ranging from cellular stress to intracellular transport. Inhibition of aberrant HDAC6 activity in several cancers and neurological diseases has been shown to be efficacious in both preclinical and clinical studies. While selective HDAC6 targeting has been pursued as an alternative to pan-HDAC drugs, identifying truly selective molecular templates has not been trivial. Herein, we report a structure-activity relationship study yielding TO-317, which potently binds HDAC6 catalytic domain 2 (Ki = 0.7 nM) and inhibits the enzyme function (IC50 = 2 nM). TO-317 exhibits 158-fold selectivity for HDAC6 over other HDAC isozymes by binding the catalytic Zn2+ and, uniquely, making a never seen before direct hydrogen bond with the Zn2+ coordinating residue, His614. This novel structural motif targeting the second-sphere His614 interaction, observed in a 1.84 Å resolution crystal structure with drHDAC6 from zebrafish, can provide new pharmacophores for identifying enthalpically driven, high-affinity, HDAC6-selective inhibitors.

Synthesis of novel sulfonamide derivatives containing pyridin-3-ylmethyl 4-(benzoyl)piperazine-1-carbodithioate moiety as potent PKM2 activators

Pyruvate kinase M2 isoform (PKM2) plays a key role in cancer progression through both metabolic and non-metabolic functions, thus it is recognized as a potential target for cancer diagnosis and treatment. In this study, we discovered a sulfonamide-dithiocarbamate compound 8a as a novel PKM2 activator from a random screening of an in-house compound library. Then, a series of lead compound 8a analogs were designed and synthesized for screening as potent PKM2 activators. Among them, compound 8b (AC50 = 0.136 µM) and 8k (AC50 = 0.056 µM) showed higher PKM2 activation activities than positive control NZT (AC50 = 0.228 µM), and they (IC50 < 1 µM) exhibited more significant anti-proliferative activities against human tumor cell lines than NZT (IC50 > 10 µM). Especially, compound 8k inhibited the proliferation of multiple cancer cells, but showed little toxicity on normal cells. In addition, we found that compound 8k inhibit the colony formation of MCF7 cells. Western blot analysis demonstrated that 8k could reduce PKM2 nuclear localization and block the downstream signaling pathway of PKM2, resulting in suppression of tumor cell proliferation. Overall, compound 8k may be a promising candidate for further mechanistic investigation of PKM2 and cancer therapy.

Discovery of N-(3,4-Dimethylphenyl)-4-(4-isobutyrylphenyl)-2,3,3a,4,5,9b-hexahydrofuro[3,2-c]quinoline-8-sulfonamide as a Potent Dual MDM2/XIAP Inhibitor

Murine double minute 2 (MDM2) and X-linked inhibitor of apoptosis protein (XIAP) are important cell survival proteins in tumor cells. As a dual MDM2/XIAP inhibitor reported previously, compound MX69 has low potency with an IC50 value of 7.5 μM against an acute lymphoblastic leukemia cell line EU-1. Herein, we report the structural optimization based on the MX69 scaffold, leading to the discovery of a 25-fold more potent analogue 14 (IC50 = 0.3 μM against EU-1). We demonstrate that 14 maintains its mode of action by dual targeting of MDM2 and XIAP through inducing MDM2 protein degradation and inhibiting XIAP mRNA translation, respectively, which resulted in cancer cell growth inhibition and cell death. The results strongly suggest that the scaffold based on 14 is promising for further optimization to develop a new therapeutic agent for leukemia and possibly other cancers where MDM2 and XIAP are dysregulated.

New sulphonamide pyrolidine carboxamide derivatives: Synthesis, molecular docking, antiplasmodial and antioxidant activities

Carboxamides bearing sulphonamide functionality have been shown to exhibit significant lethal effect on Plasmodium falciparum, the causative agent of human malaria. Here we report the synthesis of thirty-two new drug-like sulphonamide pyrolidine carboxamide derivatives and their antiplasmodial and antioxidant capabilities. In addition, molecular docking was used to check their binding affinities for homology modelled P. falciparum N-myristoyltransferase, a confirmed drug target in the pathogen. Results revealed that sixteen new derivatives killed the parasite at single-digit micromolar concentration (IC₅₀ = 2.40–8.30 μM) and compounds 10b, 10c, 10d, 10j and 10o scavenged DPPH radicals at IC₅₀s (6.48, 8.49, 3.02, 6.44 and 4.32 μg/mL respectively) comparable with 1.06 μg/mL for ascorbic acid. Compound 10o emerged as the most active of the derivatives to bind to the PfNMT with theoretical inhibition constant (K_i = 0.09 μM) comparable to the reference ligand pyrazole-sulphonamide (K_i = 0.01 μM). This study identifies compound 10o, and this series in general, as potential antimalarial candidate with antioxidant activity which requires further attention to optimise activity.

Discovery of carbon-11 labeled sulfonamide derivative: A PET tracer for imaging brain NLRP3 inflammasome

We report herein the discovery of a positron emission tomography (PET) tracer for the (NOD)-like receptor protein 3 (NLRP3). Our recent medicinal chemistry campaign on developing sulfonamide-based NLRP3 inhibitors led to an analog, 1, with a methoxy substituent amenable to labeling with carbon-11. PET/CT imaging studies indicated that [¹¹C]1 exhibited rapid blood-brain barrier (BBB) penetration and moderate brain uptake, as well as blockable uptake in the brain. [¹¹C]1, thus suggesting the potential to serve as a useful tool for imaging NLRP3 inflammasome in living brains.

Discovery of new phenyl sulfonyl-pyrimidine carboxylate derivatives as the potential multi-target drugs with effective anti-Alzheimer's action: Design, synthesis, crystal structure and in-vitro biological evaluation

Alzheimer's disease (AD) is multifactorial, progressive neurodegeneration with impaired behavioural and cognitive functions. The multitarget-directed ligand (MTDL) strategies are promising paradigm in drug development, potentially leading to new possible therapy options for complex AD. Herein, a series of novel MTDLs phenylsulfonyl-pyrimidine carboxylate (BS-1 to BS-24) derivatives were designed and synthesized for AD treatment. All the synthesized compounds were validated by ¹HNMR, ¹³CNMR, HRMS, and BS-19 were structurally validated by X-Ray single diffraction analysis. To evaluate the plausible binding affinity of designed compounds, molecular docking study was performed, and the result revealed their significant interaction with active sites of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The synthesized compounds displayed moderate to excellent in vitro enzyme inhibitory activity against AChE and BuChE at nanomolar (nM) concentration. Among 24 compounds (BS-1 to BS-24), the optimal compounds (BS-10 and BS-22) displayed potential inhibition against AChE; IC₅₀ = 47.33 ± 0.02 nM and 51.36 ± 0.04 nM and moderate inhibition against BuChE; IC₅₀ = 159.43 ± 0.72 nM and 153.3 ± 0.74 nM respectively. In the enzyme kinetics study, the compound BS-10 displayed non-competitive inhibition of AChE with Ki = 8 nM. Respective compounds BS-10 and BS-22 inhibited AChE-induced Aβ_1-42 aggregation in thioflavin T-assay at 10 μM and 20 μM, but BS-10 at 10 μM and 20 μM concentrations are found more potent than BS-22. In addition, the aggregation properties were determined by the dynamic light scattering (DLS) and was found that BS-10 and BS-22 could significantly inhibit self-induced as well as AChE-induced Aβ_1-42 aggregation. The effect of compounds (BS-10 and BS-22) on the viability of MC65 neuroblastoma cells and their capability to cross the blood-brain barrier (BBB) in PAMPA-BBB were further studied. Further, in silico approach was applied to analyze physicochemical and pharmacokinetics properties of the designed compounds via the SwissADME and PreADMET server. Hence, the novel phenylsulfonyl-pyrimidine carboxylate derivatives can act as promising leads in the development of AChE inhibitors and Aβ disaggregator for the treatment of AD.

Quarternary α-cyanobenzylsulfonamides: A new subclass of CAA fungicides with excellent anti-Oomycetes activity

A bioisosteric carboxamide - sulfonamide replacement explored during the optimization of an insecticide lead compound led to the surprising discovery of a formerly unknown subclass of the Carboxylic Acid Amide (CAA) fungicides, which is the very first CAA fungicide group without a carboxamide function. In this paper we present invention pathway, racemic and stereoselective synthesis routes, structure-activity relationship studies as well as resistance profile of this novel family of fungicides.

Discovery of cyclic sulfonamide derivatives as potent inhibitors of SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) continues to spread worldwide, with 25 million confirmed cases and 800 thousand deaths. Effective treatments to target SARS-CoV-2 are urgently needed. In the present study, we have identified a class of cyclic sulfonamide derivatives as novel SARS-CoV-2 inhibitors. Compound 13c of the synthesized compounds exhibited robust inhibitory activity (IC50 = 0.88 μM) against SARS-CoV-2 without cytotoxicity (CC50 > 25 μM), with a selectivity index (SI) of 30.7. In addition, compound 13c exhibited high oral bioavailability (77%) and metabolic stability with good safety profiles in hERG and cytotoxicity studies. The present study identified that cyclic sulfonamide derivatives are a promising new template for the development of anti-SARS-CoV-2 agents.

A New Inhibitor of ADAM17 Composed of a Zinc-Binding Dithiol Moiety and a Specificity Pocket-Binding Appendage

A disintegrin and metalloproteinase 17 (ADAM17) is a zinc-dependent enzyme that catalyzes the cleavage of the extracellular domains of various transmembrane proteins. ADAM17 is regarded as a promising drug target for the suppression of various diseases, including cancer metastasis. We synthesized a new ADAM17 inhibitor, SN-4, composed of a zinc-binding dithiol moiety and an appendage that specifically binds to a pocket of ADAM17. We show that SN-4 inhibits the ability of ADAM17 to cleave tumor necrosis factor α (TNF-α) in vitro. This activity was reduced by the addition of zinc, indicating the importance of the zinc chelating dithiol moiety. Inhibition of TNF-α cleavage by SN-4 in cells was also observed, and with an IC50 of 3.22 µM, SN-4 showed slightly higher activity than the well-studied ADAM17 inhibitor marimastat. Furthermore, SN-4 was shown to inhibit cleavage of CD44 by ADAM17, but not by ADAM10, and to suppress cell invasion. Molecular docking showed good fitting of the specificity pocket-binding group and one SH of SN-4 and hinted at possible means of structural optimization. This study provides clues for the development of potent and selective ADAM17 inhibitors.

Synthesis and evaluation of a UMI-77-based fluorescent probe for selective detecting Mcl-1 protein and imaging in living cancer cells

Development of efficient fluorescent probes for detecting the overexpressed Mcl-1 protein in living cells is imperative for the diagnosis and treatment of cancers. In this paper, a new UMI-77 based fluorescent probe (DNSH), was synthesized and characterized. DNSH bound to the hydrophobic pockets of Mcl-1 protein tightly and the binding affinity was 20-fold higher than that of previous developed Mcl-1 probe. DNSH exhibited specific fluorescence response to Mcl-1 protein rather than other proteins. In the presence of Mcl-1 protein, fluorescence emission of DNSH can be switched on. Furthermore, fluorescence colocalization experiment demonstrated that DNSH can be successfully used for imaging mitochondrial Mcl-1 protein in human prostate cancer cells without a washing process. These results showed that DNSH may find useful applications in biological research such as tracking Mcl-1 protein in living biological specimens.

Screening of benzenesulfonamide in combination with chemically diverse fragments against carbonic anhydrase by differential scanning fluorimetry

The differential scanning fluorimetry (DSF) screening of 5.692 fragments in combination with benzenesulfonamide (BSA) against bovine carbonic anhydrase (bCA) delivered >100 hits that either caused, on their own, a significant thermal shift (ΔTm, °C) in the protein melting temperature or significantly influenced the thermal shift observed for BSA alone. Three hits based on 1,2,3-triazole moiety represent the periphery of the recently reported potent inhibitors of hCA II, IX and XII which were efficacious in vivo. Such a re-discovery of suitable BSA periphery essentially validates the new fragment-based approach to the discovery of future CAIs. Structures of other validated fragment hits are reported.

Synthesis of new series of thiazol-(2(3H)-ylideneamino)benzenesulfonamide derivatives as carbonic anhydrase inhibitors

Human carbonic anhydrase I and II isoenzymes (hCA I and II) are important metabolic enzymes. In this study, a new series of thiazol-(2(3H)-ylideneamino)benzenesulfonamide derivatives were synthesized and also some inhibition parameters including IC50 (hydratese) and inhibition constant values (Ki , esterase) were determined. All studied compounds exhibited potent inhibition against these enzymes. They inhibited carbonic anhydrases (CAs) with the IC50 values of 113 to 395.8 nM (Ki  = 77.38-319.59 nM) for hCA I and 91.9 to 516 nM (Ki  = 62.79-425.89 nM) for hCA II. Among the compounds, 5c was found to be the most active one (Ki : 77.38 nM) for hCA I and 5g was found for hCA II with the value of 62.79 nM.

Novel benzofuran-based sulphonamides as selective carbonic anhydrases IX and XII inhibitors: synthesis and in vitro biological evaluation

Pursuing on our efforts toward searching for efficient hCA IX and hCA XII inhibitors, herein we report the design and synthesis of new sets of benzofuran-based sulphonamides (4a,b, 5a,b, 9a-c, and 10a-d), featuring the zinc anchoring benzenesulfonamide moiety linked to a benzofuran tail via a hydrazine or hydrazide linker. All the target benzofurans were examined for their inhibitory activities toward isoforms hCA I, II, IX, and XII. The target tumour-associated hCA IX and XII isoforms were efficiently inhibited with KIs spanning in ranges 10.0-97.5 and 10.1-71.8 nM, respectively. Interestingly, arylsulfonehydrazones 9 displayed the best selectivity toward hCA IX and XII over hCA I (SIs: 39.4-250.3 and 26.0-149.9, respectively), and over hCA II (SIs: 19.6-57.1 and 13.0-34.2, respectively). Furthermore, the target benzofurans were assessed for their anti-proliferative activity, according to US-NCI protocol, toward a panel of sixty cancer cell lines. Only benzofurans 5b and 10b possessed selective and moderate growth inhibitory activity toward certain cancer cell lines.

Synthesis of calix[4]azacrown substituted sulphonamides with antioxidant, acetylcholinesterase, butyrylcholinesterase, tyrosinase and carbonic anhydrase inhibitory action

A series of novel calix[4]azacrown substituted sulphonamide Schiff bases was synthesised by the reaction of calix[4]azacrown aldehydes with different substituted primary and secondary sulphonamides. The obtained novel compounds were investigated as inhibitors of six human (h) isoforms of carbonic anhydrases (CA, EC 4.2.1.1). Their antioxidant profile was assayed by various bioanalytical methods. The calix[4]azacrown substituted sulphonamide Schiff bases were also investigated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes, associated with several diseases such as Alzheimer, Parkinson, and pigmentation disorders. The new sulphonamides showed low to moderate inhibition against hCAs, AChE, BChE, and tyrosinase enzymes. However, some of them possessed relevant antioxidant activity, comparable with standard antioxidants used in the study.

Aspartic peptidase of Phialophora verrucosa as target of HIV peptidase inhibitors: blockage of its enzymatic activity and interference with fungal growth and macrophage interaction

Phialophora verrucosa causes several fungal human diseases, mainly chromoblastomycosis, which is extremely difficult to treat. Several studies have shown that human immunodeficiency virus peptidase inhibitors (HIV-PIs) are attractive candidates for antifungal therapies. This work focused on studying the action of HIV-PIs on peptidase activity secreted by P. verrucosa and their effects on fungal proliferation and macrophage interaction. We detected a peptidase activity from P. verrucosa able to cleave albumin, sensitive to pepstatin A and HIV-PIs, especially lopinavir, ritonavir and amprenavir, showing for the first time that this fungus secretes aspartic-type peptidase. Furthermore, lopinavir, ritonavir and nelfinavir reduced the fungal growth, causing remarkable ultrastructural alterations. Lopinavir and ritonavir also affected the conidia-macrophage adhesion and macrophage killing. Interestingly, P. verrucosa had its growth inhibited by ritonavir combined with either itraconazole or ketoconazole. Collectively, our results support the antifungal action of HIV-PIs and their relevance as a possible alternative therapy for fungal infections.