Carbonic anhydrase inhibition by antiviral drugs in vitro and in silico

Drug repurposing: Identification and X-ray crystallographic analyses of US-FDA approved drugs against carbonic anhydrase-II

Of all isoforms, human carbonic anhydrase II (PF00194; EC 4.2.1.1), which is mostly found in red cells, kidneys, and the eyes, plays a pivotal role in numerous physiological processes, and its dysregulation has been linked to the wide range of illnesses, such as glaucoma. Finding new inhibitors that target carbonic anhydrase II, therefore has great potential in drug discovery. Using drug repurposing approach, this study focused on the investigation of different drugs as Carbonic anhydrase II inhibitors and their structural studies using X-ray crystallography. For this purpose, 100 different drugs were evaluated for bovine and human carbonic anhydrase II inhibitory activity. Among all, two drugs, i.e. acetohexamide (1) and levosulpiride (54) were found to be active, with IC50 = 437.0 ± 0.2 and 1128 ± 0.75 μM, respectively. Mechanistic studies suggested that both drugs are competitive inhibitors of the human carbonic anhydrase II enzyme. The X-ray crystal structure analysis revealed that acetohexamide (1) interacts via terminal acetyl group with the active site residues of the carbonic anhydrase II enzyme, and showed strong hydrogen bonding with Zn, His94, His119, and Asn67. The sulfonamide group of levosulpiride was involved in strong hydrogen bonding with Zn, His94, His119, and Thr199. From in vivo studies, we found that carbonic anhydrase activity was significantly inhibited by the intraperitoneal administration of levosulpiride for up to 5 h. Our findings provide comprehensive insights for the optimization of the pharmacological profile of these drugs, and provide avenues for the exploration of different derivatives of these drugs with enhanced efficacy and fewer adverse effects.

Comprehensive insights into carbonic anhydrase inhibition: A triad of In vitro, In silico, and In vivo perspectives

Carbonic anhydrases (CAs) are zinc-dependent metalloenzymes essential for sustaining physiological balance by facilitating the reversible conversion of carbon dioxide to its hydrated form. Their biological significance, coupled with their involvement in a wide array of pathological conditions, makes them attractive targets for therapeutic intervention. This review presents a comprehensive analysis of carbonic anhydrase inhibition through an integrated triad of in vitro, In silico, and In vivo perspectives. In vitro studies provide critical insights into the mechanisms of enzyme inhibition, enabling the identification and optimization of potent inhibitors while elucidating their structure-activity relationships. In silico methodologies, including docking, molecular dynamics (MD) simulation, virtual screening, ADMET, and QSAR analyses, have emerged as invaluable tools in rational drug design, streamlining the discovery and development of isoform-specific inhibitors. Complementing these efforts, In vivo investigations validate the pharmacokinetics, pharmacodynamics, and therapeutic efficacy of CA inhibitors (CAIs) in disease models, bridging the gap between laboratory findings and clinical applications. The therapeutic relevance of CAIs extends across multiple domains, including glaucoma, epilepsy, cancer, metabolic disorders, and infectious diseases. Emerging applications, such as their potential use in combating antimicrobial resistance and modulating immune responses, further underscore their versatility. However, challenges such as achieving isoform selectivity, minimizing off-target effects, and translating preclinical findings into clinical success persist. Advances in fragment-based drug design, artificial intelligence-driven discovery, and innovative experimental techniques are poised to address these limitations, paving the way for the next generation of CAIs.

Sulfonamide-Bearing Pyrazolone Derivatives as Multitarget Therapeutic Agents: Design, Synthesis, Characterization, Biological Evaluation, In Silico ADME/T Profiling and Molecular Docking Study

The research and design of new inhibitors for the treatment of diseases such as Alzheimer's disease and glaucoma through inhibition of cholinesterases (ChEs; acetylcholinesterase, AChE and butyrylcholinesterase, BChE) and carbonic anhydrase enzymes are among the important targets. Here, a series of novel sulfonamide-bearing pyrazolone derivatives (1a-f and 2a-f) were successfully synthesized and characterized by using spectroscopic and analytical methods. The inhibitory activities of these newly synthesized compounds were evaluated both in vitro and in silico for their effect on carbonic anhydrases (hCA I and hCA II isoenzymes) and ChEs. The in vitro studies showed that these novel compounds demonstrated potential inhibitory activity, with KI values covering the following ranges: 18.03 ± 2.86-75.54 ± 4.91 nM for hCA I, 24.84 ± 1.57-85.42 ± 6.60 nM for hCA II, 7.45 ± 0.98-16.04 ± 1.60 nM for AChE, and 34.78 ± 5.88-135.70 ± 17.39 nM for BChE. Additionally, many of these compounds showed promising inhibitory activity, and some showed higher potency than reference compounds. While the in silico studies have also identified the potential binding positions of these compounds, using the crystal structures of hCA I, II, AChE and BChE receptors. The varying affinities demonstrated by these designed compounds for ChEs and hCA isoenzymes show that these compounds could hold promise as potential alternative agents for selectively inhibiting ChEs and hCAs in the treatment of diseases such as Alzheimer's disease and glaucoma.

Novel Anti-Tumor Effect of Natural Products from Aloe vera Resin and their In-Vitro/In-Silico Targeting Mechanism of Carbonic Anhydrase-II and IX

Human carbonic anhydrase (hCA) plays a vital role in the development and progression of tumors in hypoxic conditions. Herein we report the hCA-II and hCA-IX activities of natural products isolated from Aloe vera (L.) Burm.f., to know their potential in tumors. These isolated compounds (1-10) displayed varying degrees of inhibition against hCA-II and hCA-IX. All the compounds showed potent activity against hCA-IX with IC50 values in the range of 2.9-29.1 μM. While for hCA-II, compounds 1, 2, 5-10 exhibited IC50 in the range of 4.7-23.4 μM. The most effective hCA IX and II inhibitors, 2 and 5, were chosen for in vitro mechanism studies, revealing that they are competitive inhibitors. Furthermore, when tested for their cytotoxic effect on BJ (normal) cell line, all the compounds showed no cytotoxic behavior, while on Prostate cancer cells (PC-3), compounds 1, 3, 5, 7, and 9 exhibited significant antiproliferative activity. Molecular docking was also conducted within the hCA IX and hCA-II active sites to observe their binding capability. Compounds 1, 5, 7, and 9 were active against both isozymes of hCA and in the PC-3 cell line, therefore these are the best choices for further in vivo studies.

Interactions of novel 1,3-diaryltriazene-sulfamethazines with carbonic anhydrases: Kinetic studies and in silico simulations

Sulfonamides, recognized as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, are crucial in treating diverse diseases, including epilepsy, glaucoma, bacterial infections, and various pathological processes, e.g., high blood pressure, rheumatoid arthritis, ulcerative colitis, pain, and inflammation. Additionally, therapeutically, 1,3-diaryl-substituted triazenes and sulphamethazines (SM) are integral components in various drug structures, and the synthesis of novel compounds within these two categories holds substantial significance. Herein, ten 1,3-diaryltriazene-substituted sulphamethazine derivatives SM(1-10), which were created by reacting the diazonium salt of sulphamethazine with substituted aromatic amines, were synthesized and the physiologically and pharmacologically relevant human (h) isoforms hCA I and II, cytosolic isozymes, were included in the study. The synthesized compounds showed excellent inhibition versus hCAs; the 4-butoxy (SM7, KI of 5.69 ± 0.59 nM) compound exhibited a potent inhibitory effect against the hCA I compared with the reference drug acetazolamide (AAZ, KI of 116.00 ± 8.48 nM). The 4-cyano (SM4, KI of 5.87 ± 0.57 nM) compound displayed higher potency than AAZ (KI of 57.25 ± 4.15 nM) towards hCA II. Meanwhile, among the synthesized molecules, the 3,4-dimethoxy (SM9, KI of 74.98 ± 10.49 nM, SI of 9.94) compound (over hCA I) displayed a noticeable selectivity for hCA isoform II. The target compounds in the molecular docking investigation were determined to take part in various hydrophilic and hydrophobic interactions with nearby amino acids and fit nicely into the active sites of the hCAs. This research has yielded compounds displaying varying affinity toward hCA isoenzymes, ultimately serving as potent and selective hCA inhibitors. Given its substantial biological inhibitory potency, this particular derivative series is determined to hold the potential to serve as a promising lead compound against these hCAs.

Aldose reductase with quinolone antibiotics interaction: In vitro and in silico approach of its relationship with diabetic complications

Aldose reductase (AR, EC1.1.1.21), a member of the aldo-keto reductase family, is critically implicated in the pathogenesis of chronic complications associated with diabetes mellitus, including neuropathy, nephropathy, and retinopathy. Hyperglycemia-induced AR overactivity results in intracellular sorbitol accumulation, NADPH depletion, and oxidative stress. Consequently, AR is recognized as a key mediator of oxidative and inflammatory signaling pathways involved in diverse human pathologies such as cardiovascular diseases, inflammatory disorders, and cancer. This has sparked renewed interest in developing novel AR inhibitors (ARIs) with enhanced therapeutic profiles. In this study, we evaluated the inhibitory potential of five quinolone antibiotics-gatifloxacin, lomefloxacin, nalidixic acid, norfloxacin, and sparfloxacin-as ARIs relevant to various physiological and pathological conditions. Through comprehensive in vitro and in silico analyses, we explored these antibiotics' binding interactions and affinities within the AR active site. Our findings reveal that these quinolones moderately inhibit AR at micromolar concentrations, with inhibition constants (KIs) ranging from 1.03 ± 0.13 μM to 4.12 ± 0.51 μM, compared to the reference drug epalrestat (KI of 0.85 ± 0.06 μM). The combined in vitro and in silico results underscore significant interactions between these drugs and AR, suggesting their potential as therapeutic agents against the aforementioned pathological conditions. Furthermore, these insights will aid in optimizing clinical dosing regimens and mitigating unexpected drug-drug interactions when these antibiotics are co-administered with other treatments.

Novel benzenesulfonamides containing a dual triazole moiety with selective carbonic anhydrase inhibition and anticancer activity

A series of sulfonamides incorporating a 1,2,3-triazolyloxime substituted 1,2,3-triazolyl moiety were conceptualized and synthesized as human carbonic anhydrase (hCA) inhibitors. The synthesized small structures, denoted 7a through 7o, exhibited moderate inhibitory effects against the tumor-associated isoforms hCA IX and hCA XII compared to the well-known hCA inhibitor acetazolamide. In contrast, these molecules demonstrated higher potency and a diverse range of selectivity against the cytosolic isoforms hCA I and hCA II. Notably, the 4-hydroxyphenyl derivative (compound 7dversus cytosolic isoforms), the 4-acetylphenyl derivative (compound 7o), and the phenyl derivative (compound 7a) emerged as the most potent and selective inhibitors in this series, with inhibition constants (K I) of 47.1, 35.9, 170.0, and 149.9 nM, respectively, against hCA I, II, IX, and XII. Further cytotoxicity assays of compounds 7a-o against cancer cell lines Hep3B and A549, as well as normal cell line L929, were conducted to assess their selectivity towards malignant cells. Compounds 7d, 7g, and 7k exhibited selective cytotoxicity towards the Hep3B cell line, with reduced selectivity towards A549, whereas compound 7j demonstrated higher selectivity for the A549 cell line. Additionally, molecular docking studies were performed to elucidate the binding modes of these compounds within the active sites of hCAs, revealing crucial interactions that underpin their significant activity and selectivity for the tumor-specific isoforms.

Naphthoquinones and anthraquinones: Exploring their impact on acetylcholinesterase enzyme activity

The identification of novel acetylcholinesterase inhibitors holds significant relevance in the treatment of Alzheimer's disease (AD), the prevailing form of dementia. The exploration of alternative inhibitors to the conventional acetylcholinesterase inhibitors is steadily gaining prominence. Quinones, categorized as plant metabolites, represent a specific class of compounds. In this study, the inhibitory effects of various naphthoquinone derivatives, along with anthraquinone and its derivatives, on the acetylcholinesterase (AChE) enzyme were investigated for this purpose. An in vitro investigation was conducted to examine the effects of these compounds in order to clarify the possible mechanism of inhibition in the interaction between the enzyme and chemicals. In addition, an in silico investigation was carried out to understand the conceivable inhibitor binding process to the enzyme's active site. The acquired outcomes corroborated the in vitro results. The AChE enzyme was found to be effectively inhibited by both naphthoquinones and anthraquinones, with inhibition constant (KI) values ranging from 0.014 to 0.123 μM (micormolar). The AChE enzyme was inhibited differently by this quinone and its derivatives. Although derivatives of naphthoquinone and anthraquinone exhibited a competitive inhibitory effect, derivatives of anthraquinone exhibited a noncompetitive inhibition effect. Furthermore, because it had the lowest KI value of any of these substances, 1,5-dihydroxyanthraquinone (1c) was shown to be the most potent inhibitor. The findings will add to the body of knowledge on the creation of fresh, potent, and successful treatment approaches.

Phytochemical analysis, antioxidant, anticancer, and antibacterial potential of Alpinia galanga (L.) rhizome

Alpinia galanga (L.) Willd. (A. galanga) is extremely significant and is utilized extensively in traditional medicine throughout many nations. This study aimed to determine the chemical composition of A. galanga rhizome extract (AgRE) and to evaluate its antioxidant, anticancer, and antibacterial activities. The total phenolic content (TPC) and total flavonoid content (TFC) of AgRE were determined. The antioxidant activity, cytotoxic capability, and antibacterial of were assessed, as well as anti-apoptotic genes. Molecular docking (MD) was used to assess the binding affinity of the most enriched constituents in AgRE toward the active sites of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and p53 tumor suppressor protein (TP53). Gas chromatography-mass spectrometry (GC-MS) analysis demonstrated that AgRE is a rich source of turmerone. AgRE had moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging properties, with the half-maximal inhibitory concentration (IC50) values of 79.34 ± 1.78 and 88.94 ± 2.28 μg/ml, respectively. AgRE preferentially reduced the viability of a subset of malignant MCF-7 and HepG2 cell lines, with IC50 of 125.35 ± 4.28 and 182.49 ± 3.19 μg/ml, respectively. AgRE exhibited considerable antimicrobial activity against all bacterial strains, with MIC values ranging from 7.81 ± 1.53 to 62.5 ± 3.28 μg/ml. The MD results revealed that ethyl-4-(2-methylpropyl)-benzene had the greatest binding energy with NADPH oxidase, with a Glide score of -6848 kcal/mol, followed by 2-methoxy-phenol (-5111 kcal/mol). Taken together, we report the interesting antioxidant, antibacterial, and anticancer properties of AgRE, which warrant further investigation. AgRE is a promising natural resource that could be used to combat complicated diseases such as cancer and bacterial infections.

Dynamics of small molecule-enzyme interactions: Novel benzenesulfonamides as multi-target agents endowed with inhibitory effects against some metabolic enzymes

In contemporary medicinal chemistry, employing a singular small molecule to concurrently multi-target disparate molecular entities is emerging as a potent strategy in the ongoing battle against metabolic disease. In this study, we present the meticulous design, synthesis, and comprehensive biological evaluation of a novel series of 1,2,3-triazolylmethylthio-1,3,4-oxadiazolylbenzenesulfonamide derivatives (8a-m) as potential multi-target inhibitors against human carbonic anhydrase (EC.4.2.1.1, hCA I/II), α-glycosidase (EC.3.2.1.20, α-GLY), and α-amylase (EC.3.2.1.1, α-AMY). Each synthesized sulfonamide underwent rigorous assessment for inhibitory effects against four distinct enzymes, revealing varying degrees of hCA I/II, a-GLY, and a-AMY inhibition across the tested compounds. hCA I was notably susceptible to inhibition by all compounds, demonstrating remarkably low inhibition constants (KI) ranging from 42.20 ± 3.90 nM to 217.90 ± 11.81 nM compared to the reference standard AAZ (KI of 439.17 ± 9.30 nM). The evaluation against hCA II showed that most of the synthesized compounds exhibited potent inhibition effects with KI values spanning the nanomolar range 16.44 ± 1.53-70.82 ± 4.51 nM, while three specific compounds, namely 8a-b and 8d, showcased lower inhibitory potency than other derivatives that did not exceed that of the reference drug AAZ (with a KI of 98.28 ± 1.69 nM). Moreover, across the spectrum of synthesized compounds, potent inhibition profiles were observed against diabetes mellitus-associated α-GLY (KI values spanning from 0.54 ± 0.06 μM to 5.48 ± 0.50 μM), while significant inhibition effects were noted against α-AMY, with IC50 values ranging between 0.16 ± 0.04 μM and 7.81 ± 0.51 μM) compared to reference standard ACR (KI of 23.53 ± 2.72 μM and IC50 of 48.17 ± 2.34 μM, respectively). Subsequently, these inhibitors were evaluated for their DPPH· and ABTS+· radical scavenging activity. Moreover, molecular docking investigations were meticulously conducted within the active sites of hCA I/II, α-GLY, and α-AMY to provide comprehensive elucidation and rationale for the observed inhibitory outcomes.

Some pyrroles as inhibitors of the pentose phosphate pathways enzymes: An in vitro and molecular docking study

Glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) are pentose phosphate pathway enzymes. Compounds with a heterocyclic pyrrole ring system containing this atom can be derivatized with various functional groups into highly effective bioactive agents. In this study, pyrrole derivatives on these enzyme's activity were investigated. The IC50 values of different concentrations of pyrrole derivatives for G6PD were found in the range of 0.022-0.221 mM Ki values 0.021 ± 0.003-0.177 ± 0.021 and for 6PGD IC50 values 0.020-0.147, mM Ki values 0.013 ± 0.002-0.113 ± 0.030 mM. The 2-acetyl-1-methylpyrrole (1g) showed the best inhibition value for G6PD and 6PGD enzymes. In addition, in silico molecular docking experiments were performed to elucidate how these pyrrole derivatives (1a-g) interact with the binding sites of the target enzymes. The study's findings on pyrrole derivatives could be used to create innovative therapeutics that could be a treatment for many diseases, especially cancer manifestations.

Identification, crystallization, and first X-ray structure analyses of phenyl boronic acid-based inhibitors of human carbonic anhydrase-II

Human carbonic anhydrases (hCAs) play a central role in various physiological processes in the human body. HCAs catalyze the reversible hydration of CO2 into HCO3-, and hence maintains the fluid and pH balance. Overexpression of CA II is associated with diseases, such as glaucoma, and epilepsy. Therefore, CAs are important clinical targets and inhibition of different isoforms, especially hCA II is used in treatment of glaucoma, altitude sickness, and epilepsy. Therapeutically used CA inhibitors (CAI) are sulfonamide-based, such as acetazolamide, dichlorphenamide, methazolamide, ethoxzolamide, etc. However, they exhibit several undesirable effects such as numbness, tingling of extremities, malaise, metallic taste, fatigue, renal calculi, and metabolic acidosis. Therefore, there is an urgent need to identify safe and effective inhibitors of the hCAs. In this study, different phenyl boronic acids 1-5 were evaluated against bovine (bCA II) and hCA II. Among all, compound 1 (4-acetylphenyl boronic acid) was found to be active against bCAII and hCA II with IC50 values of 246 ± 0.48 and 281.40 ± 2.8 μM, respectively, while the remaining compounds were found in-active. Compound 1 was identified as competitive inhibitor of hCA II enzyme (Ki = 283.7 ± 0.002 μM). Additionally, compound 1 was found to be non-toxic against BJ Human fibroblast cell line. The X-ray crystal structure for hCA II in-complex with compound 1 was evaluated to a resolution of 2.6 Å. In fact, this the first structural analysis of a phenyl boron-based inhibitor bound to hCA II, allowing an additional structure-activity analysis of the compounds. Compound 1 was found to be directly bound in the active site of hCA II by interacting with His94, His119, and Thr199 residues. In addition, a bond of 3.11 Å between the zinc ion and coordinated boron atom of the boronic acid moiety of compound 1 was also observed, contributing to binding affinity of compound 1 for hCA II. PDB ID: 8IGF.

Protective effects of esculetin against doxorubicin-induced toxicity correlated with oxidative stress in rat liver: In vivo and in silico studies

Doxorubicin (DOX) is widely used in cancer treatment but the dose-related toxicity of DOX on organs including the liver limit its use. Therefore, there is great interest in combining DOX with natural compounds with antioxidant properties to reduce toxicity and increase drug efficacy. Esculetin is a natural coumarin derivative with biological properties encompassing anti-inflammatory and antioxidant activities. In light of these properties, this study was meticulously crafted to investigate the potential of esculetin in preventing doxorubicin (DOX)-induced hepatotoxicity in Sprague-Dawley rats. The rats were divided into a total of six groups: control group, DOX group (administered DOX at a cumulative dose of 5 mg/kg intraperitoneally every other day for 2 weeks), E50 group (administered 50 mg/kg of esculetin intraperitoneally every day), E100 group (administered 100 mg/kg of esculetin intraperitoneally every day) and combined groups (DOX + E50 and DOX + E100) in which esculetin was administered together with DOX. The treatments, both with DOX alone and in combination with E50, manifested a reduction in catalase (CAT mRNA) levels in comparison to the control group. Notably, the enzymatic activities of superoxide dismutase (SOD), CAT, and glutathione peroxidase (GPx) witnessed significant decreases in the liver of rats treated with DOX. Moreover, DOX treatment induced a statistically significant elevation in malondialdehyde (MDA) levels, coupled with a concurrent decrease in glutathione (GSH) levels. Additionally, molecular docking studies were conducted. However, further studies are needed to confirm the hepatoprotective properties of esculetin and to precisely elucidate its mechanisms of action.

Novel spiroindoline derivatives targeting aldose reductase against diabetic complications: Bioactivity, cytotoxicity, and molecular modeling studies

Despite significant developments in therapeutic strategies, Diabetes Mellitus remains an increasing concern, leading to various complications, e.g., cataracts, neuropathy, retinopathy, nephropathy, and several cardiovascular diseases. The polyol pathway, which involves Aldose reductase (AR) as a critical enzyme, has been focused on by many researchers as a target for intervention. On the other hand, spiroindoline-based compounds possess remarkable biological properties. This guided us to synthesize novel spiroindoline oxadiazolyl-based acetate derivatives and investigate their biological activities. The synthesized molecules' structures were confirmed herein, using IR, NMR (1H and 13C), and Mass spectroscopy. All compounds were potent inhibitors with KI constants spanning from 0.186 ± 0.020 μM to 0.662 ± 0.042 μM versus AR and appeared as better inhibitors than the clinically used drug, Epalrestat (EPR, KI: 0.841 ± 0.051 μM). Besides its remarkable inhibitory profile compared to EPR, compound 6k (KI: 0.186 ± 0.020 μM) was also determined to have an unusual pharmacokinetic profile. The results showed that 6k had less cytotoxic effect on normal mouse fibroblast (L929) cells (IC50 of 569.58 ± 0.80 μM) and reduced the viability of human breast adenocarcinoma (MCF-7) cells (IC50 of 110.87 ± 0.42 μM) more than the reference drug Doxorubicin (IC50s of 98.26 ± 0.45 μM and 158.49 ± 2.73 μM, respectively), thus exhibiting more potent anticancer activity. Moreover, molecular dynamic simulations for 200 ns were conducted to predict the docked complex's stability and reveal significant amino acid residues that 6k interacts with throughout the simulation.

Biochemical evaluation and ligand binding studies on glycerophosphodiester phosphodiesterase from Staphylococcus aureus using STD-NMR spectroscopy and molecular docking analysis

Glycerophosphodiester phosphodiesterase (GDPD) is a highly conserved enzyme in both prokaryotic and eukaryotic organisms. It catalyses the hydrolysis of various glycerophosphodiesters into glycerol-3-phosphate and corresponding alcohols, which serve as building blocks in several biosynthetic pathways. This enzyme is a well-known virulence factor in many pathogenic bacteria, including Staphylococcus aureus, and is thus considered a potential drug target. In this study, competent E. coli BL21(DE3)pLysS expression cells were used to express the GDPD enzyme from vancomycin-resistant Staphylococcus aureus (VRSA), which was then purified using size exclusion and anion exchange chromatography. The hydrolytic activity of GDPD was evaluated on the non-physiological substrate bis(p-nitrophenyl) phosphate (BpNPP), which indicated functional activity of the enzyme. 79 drugs were evaluated for their inhibitory potential against GDPD enzyme by the colorimetric assay. Out of 79 drugs, 13 drugs, including tenofovir (1), adenosine (2), clioquinol (11), bromazepam (12), lamotrigine (13), sulfadiazine (14), azathioprine (15), nicotine (16), sitagliptin PO4 (17), doxofylline (18), clindamycin phosphate (19), gentamycin sulphate (20), and ceftriaxone sodium (21) revealed varying degrees of inhibitory potential with IC50 values in the range of 400 ± 0.007-951 ± 0.016 µM. All drugs were also evaluated for their binding interactions with the target enzyme by saturation transfer difference (STD-NMR) spectroscopy. 10 drugs demonstrated STD interactions and hence, showed binding affinity with the enzyme. Exceptionally, tenofovir (1) was identified to be a better inhibitor with an IC50 value of 400 ± 0.007 µM, as compared to the standard EDTA (ethylenediaminetetraacetic acid) (IC50 = 470 ± 0.008 µM). Moreover, molecular docking studies have identified key interactions of the ligand (tenofovir) with the binding site residues of the enzyme.

The effects of morin and methotrexate on pentose phosphate pathway enzymes and GR/GST/TrxR enzyme activities: An in vivo and in silico study

In this study, the mechanisms by which the enzymes glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione-S-transferase (GST), and thioredoxin reductase (TrxR) are inhibited by methotrexate (MTX) were investigated, as well as whether the antioxidant morin can mitigate or prevent these adverse effects in vivo and in silico. For 10 days, rats received oral doses of morin (50 and 100 mg/kg body weight). On the fifth day, a single intraperitoneal injection of MTX (20 mg/kg body weight) was administered to generate toxicity. Decreased activities of G6PD, 6PGD, GR, GST, and TrxR were associated with MTX-related toxicity while morin treatment increased the activity of the enzymes. The docking analysis indicated that H-bonds, pi-pi stacking, and pi-cation interactions were the dominant interactions in these enzyme-binding pockets. Furthermore, the docked poses of morin and MTX against GST were subjected to molecular dynamic simulations for 200 ns, to assess the stability of both complexes and also to predict key amino acid residues in the binding pockets throughout the simulation. The results of this study suggest that morin may be a viable means of alleviating the enzyme activities of important regulatory enzymes against MTX-induced toxicity.