In vitro effects of some anaesthetic drugs on lactoperoxidase enzyme activity

In vitro effects of ketamine and bupivacaine drugs on bovine lactoperoxidase (LPO; E.C. 1.11.1.7) enzyme activity were investigated. Lactoperoxidase was purified with Amberlite CG 50 resin, CM Sephadex C-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography from skimmed bovine milk. R_z(A₄₁₂/A₂₈₀) value for the purified LPO was found to be 0.8. Inhibition or activation effects of the drugs on LPO enzyme were determined using 2,2¹-azino-bis (3-ethylbenzthiazoline-6 sulfonic acid) diammonium salt (ABTS) as a chromogenic substrate at pH = 6.0. The I₅₀ values of ketamine and bupivacaine were 0.29 mM and 0.155 mM, respectively and the K_i constants for ketamine and bupivacaine were 0.019 ± 0.031 and 0.015 ± 0.021 mM, respectively; they were non-competitive inhibitors.     

Screening of in Vitro Inhibition of Lactoperoxidase Enzyme by Methyl Benzoate Derivatives with Molecular Docking Studies

Lactoperoxidase enzyme (LPO) is secreted from salivary, mammary, and other mucosal glands including the bronchi, lungs, and nose, which had functions as a natural and the first line of defense towards viruses and bacteria. In this study, methyl benzoates were examined in LPO enzyme activity. Methyl benzoates are used as precursors in the synthesis of aminobenzohydrazides used as LPO inhibitors. For this purpose, LPO was purified in a single step using sepharose-4B-l-tyrosine-sulfanilamide affinity gel chromatography with a yield of 9.91 % from cow milk. Also, some inhibition parameters including the half maximal inhibitory concentration (IC₅₀) value and an inhibition constant (K_i) values of methyl benzoates were determined. These compounds inhibited LPO with K_i values ranging from 0.033±0.004 to 1540.011±460.020 μM. Compound 1 a (methyl 2-amino-3-bromobenzoate) showed the best inhibition (K_i=0.033±0.004 μM). The most potent inhibitor ( 1 a ) showed with a docking score of −3.36 kcal/mol and an MM-GBSA value of −25.05 kcal/mol, of these methyl benzoate derivatives ( 1 a – 16 a ) series are established H-bond within the binding cavity with residues Asp108 (distance of 1.79 Å), Ala114 (distance of 2.64 Å), and His351 (distance of 2.12 Å).     

Urease inhibitors from Hypericum oblongifolium WALL.

The bioassay-guided fractionation of H. oblongifolium has led to the isolation of potent urease inhibitors 1–3. The structures were elucidated by NMR and mass spectroscopic techniques. Compound 2 showed a potent enzyme inhibition activity (IC₅₀ 20.96?±?0.93), which is comparatively higher than that for the standard thiourea (IC₅₀ 21.01?±?0.51 μM). Compounds 1 and 3 also showed a significant activity, with IC₅₀ 37.95?±?1.93 and 138.43?±?1.23 μM, respectively. The sub crude fractions (F1, F2, F3, and F4) were tested in vitro for their urease inhibition activity. Fractions F2 and F4 showed significant activity with IC₅₀ 140.37?±?1.93 and 167.43?±?3.03 μM, respectively.     

Rat Kidney Histamine N-Methyltransferase: Purification and Partial Characterization

Abstract

Histamine N-methyltransferase (HMT, EC 2.1.1.8) was purified 8,420-fold In 44% yield from rat kidney. The basic steps in the purification included differential centrlfugation, calcium phosphate adsorption, DEAE cellulose chromatography, and affinity chromatography on an S-adenosylhomocysteine-agarose matrix. The resulting protein was homogeneous as determined by gel electrophoresis and was stable for at least five months at ?80°C. The apparent molecular weight of the enzyme was found to be 31,500 as determined by gel filtration through Sephadex G-100 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Isoelectric point of the enzyme was determined to be 5.4. The K_m's for histamine and S-adenosyl-L-methionine were 12.4 ± 1.3 μM and 10.2 ±0.5 μM, respectively. When S-adenosyl-L-methionlne was the variable substrate, the K₁'s for S-adenosyl-L-homocysteine and S-adenosyl-D-homocys-teine were 31.9 ± 3.4 μM and 32.0 ± 3.5 μM, respectively. When histamine was the variable substrate, the K₁ for S-adenosyl-L-homocysteine was 11.8 ± 0.6 μM. Comparison of physico-chemical and catalytic properties of the rat kidney and the guinea pig enzymes suggest that these proteins have similar structural and catalytic characteristics.     

(3,4-Dihydroxyphenyl)(2,3,4-trihydroxyphenyl)methanone and its derivatives as carbonic anhydrase isoenzymes inhibitors

In this study, we have synthesised (3,4-dihydroxyphenyl)(2,3,4-trihydroxyphenyl)methanone and a series of its derivatives (5, 13–16) and tested the ability of these compounds to inhibit two metalloenzyme human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes, hCA I and hCA II. The synthesised compounds showed inhibitory effect on hCA I and hCA II isozymes. The results showed that synthesised compounds (5, 13–16) demonstrated the best inhibition activity against hCA I (IC₅₀: 3.22–54.28 μM) and hCA II (IC₅₀: 18.52–142.01 μM). The compound 14 showed the highest inhibiton effect against hCA I (IC₅₀: 3.22 μM; K_i: 1.19?±?1.4 μM). On the other hand, the compound 13 showed the highest inhibiton effect against hCA II (IC₅₀: 18.52 μM; K_i: 3.25?±?1.13 μM).     

The inhibition effects of some natural products on lactoperoxidase purified from bovine milk

In this study, inhibition profiles of some natural products, which are digoxin, L‐Dopa, dopamine, isoliquiritigenin, and 1,1,2,2‐tetrakis(p‐hydroxyphenyl)ethane (Tetrakis), were investigated against bovine lactoperoxidase (LPO) enzyme. Digoxin, L‐Dopa, and dopamine are active ingredients of some drugs, which have important functions in our body, especially in cases of heart failure. Isoliquiritigenin and tetrakis are types of natural phenolic compounds, which play an important role in cancer prevention and treatment. LPO enzyme was purified from bovine milk using sepharose‐4B‐l ‐tyrosine sulfonamide affinity column chromatography. LPO is responsible for the nonimmune biological defense system and has antibacterial activity so selection of these active substances is important. The inhibition studies are performed with the ABTS substrate. Bovine LPO enzyme was effectively inhibited by phenolic molecules. K_i values of these natural products were found as 0.20 ± 0.09, 0.22 ± 0.17, 0.49 ± 0.11, 0.49 ± 0.27, and 1.20 ± 0.25 μM, respectively. Tetrakis and digoxin exhibited noncompetitive inhibition, and other molecules showed competitive inhibition.     

The influence of Al3+ ion on porcine pepsin activity in vitro

The in vitro effect of Al³⁺ ions in the concentration range 1.7·10^{? 6} M–8.7·10^{? 3} M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al³⁺ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al³⁺ ions increase the maximal velocity (V_max) and k_cat values rather than apparent affinity for substrate (K_S) implying the non-competitive nature of activation which indicated that aluminium was a non-essential activator of partial non-competitive type. The values of the equilibrium constants K_S and K_mA for dissociation of corresponding complexes were evaluated as 0.904 ± 0.083 mM and 8.56 ± 0.51 μM, respectively. Dissociation constant K_A, of activator from enzyme-activator complex calculated via kinetic and direct measurement of Al³⁺ binding data, as well as activation constant A₅₀, the activator concentration that gives a rate equal to half at a saturating concentration of activator, were found to be 8.82 ± 0.90 μM, 8.39 ± 0.76 μM, and 8.05 ± 0.48 μM respectively. Native PAGE electrophoresis shows the decrease in electrophoretic mobility of pepsin and confirms modification of the electric charge and conformational changes of pepsin caused by bound Al³⁺ on the pepsin molecule. Al³⁺ induced conformational changes of pepsin were verified by UV-VIS and IR spectra. Moreover, the absence of conformational changes in the haemoglobin molecule in the presence of Al³⁺ ions confirms that the obtained activation is a consequence of conformational changes caused only in the pepsin molecule.     

Multifunctional 5,6-dimethoxybenzo[d]isothiazol-3(2H)-one-N-alkylbenzylamine derivatives with acetylcholinesterase,monoamine oxidases and β-amyloid aggregation inhibitory activities as potential agents against Alzheimer’s disease

A series of 5,6-dimethoxybenzo[d]isothiazol-3(2H)-one-N-alkylbenzylamine derivatives were designed, synthesized and evaluated as potential multifunctional agents for the treatment of Alzheimer’s disease (AD). The in vitro assays indicated that most of these derivatives were selective AChE inhibitors with good multifunctional properties. Among them, compounds 11b and 11d displayed comprehensive advantages, with good AChE (IC₅₀?=?0.29?±?0.01?μM and 0.46?±?0.02?μM, respectively), MAO-A (IC₅₀?=?8.2?±?0.08?μM and 7.9?±?0.07?μM, respectively) and MAO-B (IC₅₀?=?20.1?±?0.16?μM and 43.8?±?2.0% at 10?μM, respectively) inhibitory activities, moderate self-induced Aβ_1–42 aggregation inhibitory potency (35.4?±?0.42% and 48.0?±?1.53% at 25?μM, respectively) and potential antioxidant activity. In addition, the two representative compounds displayed high BBB permeability in vitro. Taken together, these multifunctional properties make 11b and 11d as a promising candidate for the development of efficient drugs against AD.     

Effects of Melatonin on Carbonic Anhydrase from Human Erythrocytes In Vitro and from Rat Erythrocytes In Vivo

The in vitro effects of melatonin (N-acetyl-5-methoxytryptamine) on human carbonic anhydrase isozymes (HCA-I and HCA-II) from human erythrocytes and in vivo effects on rat erythrocytes carbonic anhydrase (CA) were determined. Human erythrocyte carbonic anhydrase isozymes were purified by haemolysate preparation and Sepharose-4B-L tyrosine-sulfanilamide affinity gel chromatography. The HCA-I enzyme, having a specific activity of 7337.5?EU/mg protein, was purified 843-fold with a yield of 60% and the HCA-II enzyme, having a specific activity of 17067?EU/mg protein, was purified 1962-fold with a yield of 22.7%. For in vitro experiments, the enzyme activity was minimal at 2×10-4?M melatonin concentration and increased above this concentration. Ten mg?kg-1 melatonin was administered intraperitoneally and showed a stimulatory effect on the enzyme. Time-dependent in vivo studies were conducted for melatonin in Sprague–Dawley type rats. It was found that CA activity in the rat erythrocytes was decreased by the melatonin after 1 and 3 hours to 2500±500.0 and 1875±239.4 respectively which were statistically significant (p<0.05) differences to the control (2660±235.8). However, CA activity was restored to its normal level after 6?h (2666±235.7) (p>0.05) probably due to metabolism of the melatonin. The findings indicate that melatonin may be pharmacologically useful in some diseases.     

Design,synthesis, and urease inhibition studies of some 1,3,4-oxadiazoles and 1,2,4-triazoles derived from mandelic acid

Some new structural type inhibitors of urease, i.e. 2,5-disubstituted-1,3,4-oxadiazoles (4a–e) and 4,5-disubstituted-1,2,4-triazole-3-thiones (5a–e) were synthesized in two steps from mandelic acid hydrazides (2a–e) and aryl isothiocyantes. The hydrazides in turn were synthesized from mandelic acid via esterification. Compounds 4a–e and 5a–e were evaluated against jack bean urease. Compounds 4d, 5b, and 5d were found to be more potent, with IC₅₀ values of 16.1?±?0.12?µM, 18.9?±?0.188?µM, and 16.7?±?0.178?µM, respectively, when compared to the standard (thiourea; IC₅₀?=?21.0?±?0.011?µM). These compounds may be subjected to further investigations for the development of antiulcer drugs.     

Purification and characterization of dihydropyrimidine dehydrogenase enzyme from sheep liver and determination of the effects of some anaesthetic and antidepressant drugs on the enzyme activity

Dihydropyrimidine dehydrogenase (DPD, E.C. 1.3.1.2) was purified from sheep liver with a yield of 16.7%, purification fold of 407.5 and specific activity of 0.705?EU/mg proteins. The purification procedure consisted of ammonium sulphate fractionation, DEAE ion exchange chromatography and 2′,5′-ADP Sepharose-4B affinity chromatography. The molecular weight determined by SDS-PAGE and was found 111?kDa. Optimum pH, ionic strength temperature and stable pH were determined as 8.0, 0.9?mM, 50?°C and 6.0, respectively. The kinetic parameters (K_m and V_max) of the enzyme were determined with NADPH as 22.97?μM and 0.17?EU/mL, respectively. The same parameters were determined with uracil as 17.46?μM and 0.14?EU/mL, respectively. Additionally, in vitro inhibitory effects of some antidepressant drugs including escitalopram, fluoxetine, mirtazapine, haloperidol and some anaesthetic drugs including propofol and lidocaine were investigated against DPD. In addition, IC₅₀ values for each active drug obtained for escitalopram, fluoxetine, mirtazapine, haloperidol, propofol and lidocaine were determined as 1736.11, 13.24, 86.65, 99.03, 0.21 and 15.07?μM, respectively.     

Design,synthesis and preliminary activity evaluation of novel 3-amino-2-hydroxyl-3-phenylpropanoic acid derivatives as aminopeptidase N/CD13 inhibitors

Aminopeptidase N (APN/CD13) over expressed on tumour cells, plays a critical role in tumour invasion, metastasis and tumour angiogenesis. In this article, we described the design, synthesis and preliminary activity studies of novel 3-amino-2-hydroxyl-3-phenylpropanoic acid derivatives as APN inhibitors. The in vitro enzymatic inhibitions on APN from porcine kidney showed that compound 7e had the most potent inhibitory activity against APN with the IC₅₀ value to 1.26?±?0.01 μM, which is better than that of bestatin (IC₅₀?=?2.55?±?0.11 μM). In addition, compound 7e also showed better inhibitory activity against APN on human ovary clear cell carcinoma cell ES-2 than bestatin with the IC₅₀ value to 30.19?±?1.02 μM versus 60.61?±?0.1 μM. Compound 7e could be used as the lead compound in the future for anti-cancer agent research.     

Urease and Serine Protease inhibitory alkaloids from Isatis tinctoria

Phytochemical investigations on the alkaloidal fraction of the whole plant of the Isatis tinctoria led to the isolation of the alkaloids 1-6., 3′-Hydroxyepiglucoisatisin (3), Epiglucoisatisin (2) were found to be potent urease inhibitors in a concentration-dependent manner with IC₅₀ values 25.63 ± 0.74, 37.01 ± 0.41 and 31.72 ± 0.93, 47.33 ± 0.31 μM against Bacillus pasteurii & Jack bean urease, respectively. Compounds 3 and 2 also showed potent inhibitory potential against α-chymotrypsin with IC₅₀ values of 23.40 ± 0.21 and 27.45 ± 0.23 μM, respectively.     

Design,synthesis and evaluation of vilazodone-tacrine hybrids as multitarget-directed ligands against depression with cognitive impairment

Depression, a severe mental disease, is greatly difficult to treat and easy to induce other neuropsychiatric symptoms, the most frequent one is cognitive impairment. In this study, a series of novel vilazodone-tacrine hybrids were designed, synthesized and evaluated as multitarget agents against depression with cognitive impairment. Most compounds exhibited good multitarget activities and appropriate blood-brain barrier permeability. Specifically, compounds 1d and 2a exhibited excellent 5-HT_1A agonist activities (1d, EC₅₀?=?0.36?±?0.08?nM; 2a, EC₅₀?=?0.58?±?0.14?nM) and 5-HT reuptake inhibitory activities (1d, IC₅₀?=?20.42?±?6.60?nM; 2a, IC₅₀?=?22.10?±?5.80?nM). In addition, they showed moderate ChE inhibitory activities (1d, AChE IC₅₀?=?1.72?±?0.217?μM, BuChE IC₅₀?=?0.34?±?0.03?μM; 2a, AChE IC₅₀?=?2.36?±?0.34?μM, BuChE IC₅₀?=?0.10?±?0.01?μM). Good multitarget activities with goodt blood-brain barrier permeability of 1d and 2a make them good lead compounds for the further study of depression with cognitive impairment.     

Synthesis,in vitro α-glucosidase inhibitory potential and molecular docking study of thiadiazole analogs

α-Glucosidase is a catabolic enzyme that regulates the body’s plasma glucose levels by providing energy sources to maintain healthy functioning. 2-Amino-thiadiazole (1–13) and 2-amino-thiadiazole based Schiff bases (14–22) were synthesized, characterized by ¹H NMR and HREI-MS and screened for α-glucosidase inhibitory activity. All twenty-two (22) analogs exhibit varied degree of α-glucosidase inhibitory potential with IC₅₀ values ranging between 2.30 ± 0.1 to 38.30 ± 0.7 μM, when compare with standard drug acarbose having IC₅₀ value of 39.60 ± 0.70 μM. Among the series eight derivatives 1, 2, 6, 7, 14, 17, 19 and 20 showed outstanding α-glucosidase inhibitory potential with IC₅₀ values of 3.30 ± 0.1, 5.80 ± 0.2, 2.30 ± 0.1, 2.70 ± 0.1, 2.30 ± 0.1, 5.50 ± 0.1, 4.70 ± 0.2, and 5.50 ± 0.2 μM respectively, which is many fold better than the standard drug acarbose. The remaining analogs showed good to excellent α-glucosidase inhibition. Structure activity relationship has been established for all compounds. The binding interactions of these compounds were confirmed through molecular docking.     

Chemical Investigation of Marine-Derived Fungus Aspergillus flavipes for Potential Anti-Inflammatory Agents

The marine fungus, Aspergillus flavipes (MTCC 5220), was isolated from the pneumatophore of a mangrove plant Acanthus ilicifolius found in Goa, India. The crude extract of A. flavipes was found to show anti-inflammatory activity. It blocked interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production in lipopolysaccharide (LPS)-activated THP-1 cells with IC₅₀ of 2.69±0.5 μM and 6.64±0.4 μM, respectively. The chemical investigation led to the isolation of optically inactive 4β-[(1E)-propen-1-yl]cyclopentane-1β,2β-diol ( 1 ) along with a new optically active diastereoisomeric compound, 4β-[(1E)-propen-1-yl]cyclopentane-1β,2α-diol ( 2 ). In addition, the fungus also produced known compounds (+)-terrein ( 3 ), butyrolactone I ( 4 ) and butyrolactone II ( 5 ) in high yields. Among these, (+)-terrein ( 3 ) exhibited IL-6 and TNF-α inhibition activity with IC₅₀ of 8.5±0.68 μM and 15.76±0.18 μM, respectively, while butyrolactone I ( 4 ) exhibited IC₅₀ of 12.03±0.85 μM (IL-6) and 43.29±0.76 μM (TNF-α) inhibition activity with low toxicity to host cells in LPS stimulated THP-1 cells. This is the first report of the isolation and characterization of 4β-[(1E)-propen-1-yl]cyclopentane-1β,2α-diol ( 2 ). The structures of all the isolated compounds were elucidated on the basis of extensive detailed NMR spectroscopic data. Anti-inflammatory activity of the fungi A. flavipes is presented here for the first time, which was due to (+)-terrein and butyrolactone I, as the major constituents and they can be further explored in the therapeutic area.     

Synthesis,and In Vitro and In Silico α-Glucosidase Inhibitory Studies of 5-Chloro-2-Aryl Benzo[d]thiazoles

Twenty-five derivatives of 5-chloro-2-aryl benzo[d]thiazole (1–25) were synthesized and evaluated for their α-glucosidase (S. cerevisiae EC 3.2.1.20) inhibitory activity in vitro. Among them eight compounds showed potent activity with IC₅₀ values between 22.1 ± 0.9 and 136.2 ± 5.7 μM, when compared with standard acarbose (IC₅₀ = 840 ± 1.73 μM). The most potent compounds 4, 9, and 10 showed IC₅₀ values in the range of 22.1 ± 0.9 to 25.6 ± 1.5 μM. Compounds 2, 5, 11, and 19 showed IC₅₀ values within the range of 40.2 ± 0.5 to 60.9 ± 2.0 μM. Compounds 1 and 3 were also found to be good inhibitors with IC₅₀ values 136.2 ± 5.7 and 104.8 ± 9.9 μM, respectively. Their activities were compared with α-glucosidase inhibitor drug acarbose (standard) (IC₅₀ = 840 ± 1.73 μM). The remaining compounds were inactive. Structure-activity relationships (SAR) have also been established. Kinetics studies indicated compounds 2, 3, 10, 19, and 25 to be non-competitive, while 1, 5, 9, and 11 as competitive inhibitors of α-glucosidase enzyme. All the active compounds (1–5, 9–11, and 19) were also found to be non-cytotoxic, in comparison to the standard drug i.e., doxorubicin (IC₅₀ = 0.80 ± 0.12 μM) in MTT assay. Furthermore, molecular interactions of active compounds with the enzyme binding sites were predicted through molecular modeling studies.     

Heterologous expression,purification, and biochemical characterization of a greenbug (Schizaphis graminum) acetylcholinesterase encoded by a paralogous gene (ace‐1)

Acetylcholinesterase is a critical enzyme in the regulation of cholinergic neurotransmission in insects. To produce Schizaphis graminum acetylcholinesterase‐1 for structure–function analysis, we constructed a recombinant baculovirus to infect Sf9 cells, which secreted the soluble protein at a final concentration of 4.0 mg/L. The purified enzyme had an apparent M_r of 70 and 130 kDa in the reducing and nonreducing SDS‐polyacrylamide gels, respectively, indicating that it formed a dimer via an intermolecular disulfide bond. The fresh enzyme had a specific activity of 245 U/mg, which stabilized at a lower level (115 U/mg) in storage. The Michaelis constant and maximum velocity were 88.3 ± 9.6 μM and 133.2 ± 1.6 U/mg for acetylthiocholine iodide, 113.9 ± 12.5 μM and 106.4 ± 3.0 U/mg for acetyl(β‐methyl)thiocholine iodide, 68.9 ± 7.8 μM and 76.7 ± 1.0 U/mg for propionylthiocholine iodide, and 201.1 ± 21.0 μM and 4.4 ± 0.1 U/mg for S‐butyrylthiocholine iodide, respectively. The IC₅₀ values (5 min, room temperature) of ethopropazine, BW284C51, carbaryl, eserine, malaoxon, and paraoxon were 102, 1.66, 0.94, 0.20, 0.061, 0.016 μM, respectively. The bimolecular reaction constants (k_i) were (6.50 ± 0.40) × 10⁴ for carbaryl, (1.00 ± 0.16) × 10⁵ for eserine, (4.70 ± 0.13) × 10⁵ for malaoxon, and (9.06 ± 0.23) × 10⁵ M^?1 min^?1 for paraoxon. The enzyme was also inhibited by one of its products, choline, at concentrations higher than 20 mM, suggesting that choline bound to an anionic site and regulated the enzymatic activity. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:51–59, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20311     

In vitro effects of some drugs on human erythrocyte glutathione reductase

The effects of ketotifen, meloxicam, phenyramidol–HCl and gadopentetic acid on the enzyme activity of GR were studied using human erythrocyte glutathione reductase (GR) enzymes in vitro. The enzyme was purified 209-fold from human erythrocytes in a yield of 19% with 0.31?U/mg. The purification procedure involved the preparation of haemolysate, ammonium sulphate precipitation, 2′′,5′-ADP Sepharose 4B affinity chromatography and Sephadex G-200 gel filtration chromatography. Purified enzyme was used in the in vitro studies. In the in vitro studies, IC₅₀ values and K_i constants were 0.012?mM and 0.0008?±?0.00021?mM for ketotifen; 0.029?mM and 0.0061?±?0.00127?mM for meloxicam; 0.99?mM and 0.4340?±?0.0890?mM for phenyramidol–HCl; 138?mM and 28.84?±?4.69?mM for gadopentetic acid, respectively, showing the inhibition effects on the purified enzyme. Phenyramidol–HCl showed competitive inhibition, whereas the others showed non-competitive inhibition.     

2,5-Disubstituted thiadiazoles as potent β-glucuronidase inhibitors; Synthesis,in vitro and in silico studies

Twenty-five thiadiazole derivatives 1–25 were synthesized from methyl 4-methoxybenzoate via hydrazide and thio-hydrazide intermediates, and evaluated for their potential against β-glucuronidase enzyme. Most of the compounds including 1 (IC₅₀ = 26.05 ± 0.60 μM), 2 (IC₅₀ = 42.53 ± 0.80 μM), 4 (IC₅₀ = 38.74 ± 0.70 μM), 5 (IC₅₀ = 9.30 ± 0.29 μM), 6 (IC₅₀ = 6.74 ± 0.26 μM), 7 (IC₅₀ = 18.40 ± 0.66 μM), and 15 (IC₅₀ = 18.10 ± 0.53 μM) exhibited superior activity potential than the standard d-saccharic acid-1,4-lactone (IC₅₀ = 48.4 ± 1.25 μM). Molecular docking studies were conducted to correlate the in vitro results and to identify possible mode of interaction with enzyme active site.