Synthesis of novel β-amino carbonyl derivatives and their inhibition effects on some metabolic enzymes

Synthesis of N-substituted 4-phenyl-2-aminothiazole derivatives and investigation of their inhibition properties against hCA I, II, and AChE enzymes

In this study, thiazole derivatives containing sulphonamide, amide, and phenyl amino groups were synthesized to protect the free amino groups of 5-methyl-4-phenyl-2-aminothiazole and 4-phenyl-2-aminothiazole. Halogenated reactions of N-protected thiazole derivatives have been investigated. LCMS, FT-IR, 1H NMR, and 13C NMR spectroscopy techniques were used to elucidate the structures of the synthesized compounds. Inhibition effects of the N-protected thiazole derivatives against human carbonic anhydrase I, II (hCA I, hCA II), and acetylcholinesterase (AChE) were investigated. The best results among the synthesized N-protected thiazole derivatives showed Ki values in the range of 46.85-587.53 nM against hCA I, 35.01-578.06 nM against hCA II, and in the range of 19.58-226.18 nM against AChE. Furthermore, in silico studies with the target enzyme of the thiazole derivatives (9 and 11), which showed the best results experimentally, have examined the binding interactions of the related compounds at the enzyme active site.

Lead modification via computational studies: Synthesis of pyrazole-containing β-amino carbonyls for the treatment of type 2 diabetes

This article describes studies on the design, synthesis, and biological evaluation of pyrazole-containing β-amino carbonyl compounds (5a-5q) as DPP-4 inhibitors and anti-diabetic agents. In contrast, mannich reactions went smoothly with bismuth nitrate (Bi (NO₃ )₃ ) catalyst in the presence of ethanol and produced pyrazole-containing β-amino carbonyl compounds in good yield. Molecular docking studies of designed derivatives with DPP-4 enzyme (PDB: 2OLE), compounds 5d, 5h, 5j, and 5k showed excellent interaction. 3D QSAR and pharmacophoric model studies were also carried out. ADMET parameters, pharmacokinetic properties, and in vivo toxicity studies further confirmed that all the designed compounds were found to have good bioavailability and were less toxic. Further, these compounds were evaluated as enzyme-based in vitro DPP-4 inhibitory activity, and 5d, 5h, 5i, 5j, and 5k exhibited IC₅₀ toward DPP-4 enzyme of 10.52, 10.41, 5.55, 4.16, and 7.5 nM, respectively. The most potent compound, 5j, was further selected for in vivo anti-diabetic activity using an STZ-induced diabetic mice model, and 5j showed a significant diabetic control effect.

Vinyl functionalized 5,6-dimethylbenzimidazolium salts: Synthesis and biological activities

A series of vinyl functionalized 5,6-dimethylbenzimidazolium salts are synthesized. All compounds were fully characterized by elemental analyses, MS, ¹ H-NMR, ¹³ C-NMR, and IR spectroscopy techniques. Enzyme inhibition is a very active area of research in drug design and development. In this study, the synthesized novel benzimidazolium salts were evaluated toward the human erythrocyte carbonic anhydrase I (hCA I), and II (hCA II) isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. They demonstrated highly potent inhibition ability against hCA I with K_i values of 484.8 ± 62.6-1389.7 ± 243.2 nM, hCA II with K_i values of 298.9 ± 55.7-926.1 ± 330.0 nM, α-glycosidase with K_i values of 170.3 ± 27-760.1 ± 269 μM, AChE with K_i values of 27.1 ± 3-77.6 ± 1.7 nM, and BChE with K_i values of 21.0 ± 5-61.3 ± 15 nM. As a result, novel vinyl functionalized 5,6-dimethylbenzimidazolium salts (1a-g) exhibited effective inhibition profiles toward studied metabolic enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly to treat some global disorders including glaucoma, Alzheimer's disease, and diabetes.

Montmorillonite K10 Clay Catalyzed Synthesis of Novel β-Aminocarbonyl Compounds and Their Biological Evaluation

An efficient and reusable green catalyst for the synthesis of β-aminocarbonyl compounds has been developed. In this new and greener approach, β-aminocarbonyl compounds (1a-1r) were obtained by Montmorillonite K10 clay catalyzed reaction of aryl amines, aliphatic/aromatic aldehydes and β-ketoesters. Molecular docking investigations were performed for all compounds (1a-1r) with the proteins PDB ID: 1JIJ and 1KZN for S. aureus and E. coli, respectively. For all compounds good to strong interactions with the active sites were observed. The biological activities of β-aminocarbonyl compounds were further assessed for their antibacterial and antioxidant activities. The results confirmed that β-aminocarbonyl compounds could be further developed into new drugs with potent antibacterial and antioxidant activities.

Crystal Structure of a Chiral Sec-Amine, 4-Chloro-N-(1-(pyridin-2-yl)ethyl)aniline

In this communication, we present the crystal structure of a secondary amine: 4-chloro-N-(1-(pyridin-2-yl)ethyl)aniline (Lb) obtained from a stepwise reduction of an imine, (E)-N-(4-chlorophenyl)-1-(pyridin-2-yl)ethan-1-imine (La) with sodium borohydride. The structure was characterized by FT-IR, 1H and 13C NMR, Mass Spectroscopy and X-ray diffraction.

Polyphenol Contents, Potential Antioxidant, Anticholinergic and Antidiabetic Properties of Mountain Mint (Cyclotrichium leucotrichum)

In the present work, antioxidant and antidiabetic potentials of mountain mint [Cyclotrichium leu-cotrichum (Stapf ex Rech. Fil.) Leblebici] was the first time appraised. In this sense, methanol (MECL) and water (WECL) extracts were obtained from aerial parts of mountain mint (Cyclotrichium leucotrichum) and studied for their antioxidant ability by several bioanalytical assays. Also, their inhibition profiles were realized toward several metabolic enzymes connected to some diseases, including butyrylcholinesterase (BChE), α-glycosidase, acetylcholinesterase (AChE), and α-amylase enzymes. Additionally, their phenolic contents were determined by putative chromatographic method of LC-MS/MS. Consequently, nineteen phenolic molecules were identified in MECL and fifteen phenolic molecules were found in WECL. Also, antioxidant effects of both extracts were studied using by the methods of 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), 2,2´-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and (ABTS•+)N,N-dimethyl-p-phenylenediamine (DMPD•+) scavenging activities, ferric (Fe3+) and cupric (Cu2+) ions and Fe3+-2,4,6-tri(2-pyridyl)-S-triazine (TPTZ) reducing capacities. MECL and WECL were found as powerful DPPH· (IC50: 23.74 and 28.85 μg/mL), ABTS•+ (IC50: 12.53 and 14.05 μg/mL) and DMPD•+ scavenging effects (IC50: 43.52 and 54.80 μg/mL). Also, both extracts demonstrated the effective inhibition effects on AChE (IC50: 69.31 and 115.51 μg/mL), BChE (IC50: 57.75 and 86.62 μg/mL), α-glycosidase (IC50: 36.47 and 62.94 μg/mL) and α-amylase (IC50: 1.01 and 3.43 μg/mL). This study will be useful for future studies to determine the antioxidant properties and enzyme inhibition profile of food, medical and industrially important plants.

Discovery of sulfadrug-pyrrole conjugates as carbonic anhydrase and acetylcholinesterase inhibitors

Human carbonic anhydrase (hCA) isoenzymes are zinc ion-containing, widespread metalloenzymes and they classically play a role in pH homeostasis maintenance. CA inhibitors suppress the CA activity and their usage has been clinically established as antiglaucoma agents, antiepileptics, diuretics, and in some other disorders. Alzheimer's disease (AD) is a slowly progressive neurodegenerative disorder and a fatal disease of the brain. An advanced method to cure AD includes the strategy to design acetylcholinesterase (AChE) inhibitors. A novel series of pyrrole-3-one derivatives containing sulfa drugs (5a-i) were determined to be highly potent inhibitors for AChE and hCA I and hCA II (inhibitory constant [K_i ] values are in the range of 6.50 ± 1.02-37.46 ± 4.12 nM, 1.20 ± 0.19-44.21 ± 1.09 nM, and 8.93 ± 1.58-46.86 ± 8.41 nM for AChE, hCA I, and hCA II, respectively). The designed compounds often show a more effective inhibition than the chemicals used as the standard. Among these compounds, 5f was the most effective compound against hCA I, and compound 5e was the most effective compound against hCA II. It was determined that compound 5c was the most effective inhibitor for AChE.

The effect of sumac (Rhus coriaria L.) supplementation on glycemic indices: A systematic review and meta-analysis of controlled clinical trials

BACKGROUND & AIMS

Rhus coriaria L. (Sumac) is a popular spice/herb with several biological functions owing to its antioxidant and insulin-like activities. Many clinical trials have indicated the potent anti-diabetic property of sumac but the results on few glycemic indices were inconclusive. Hence, this systematic review and meta-analysis were aimed to investigate sumac supplementation effect on glycemic indices.

METHODS

Systematically searched was performed by two independent reviewers using online databases including: PubMed, Scopus, web of science, EMBASE from inception until November 2020. Data were pooled using a random-effects model and weighted mean difference (WMD) with 95 % confidence intervals (CI).

RESULTS

A total of 6 potentially relevant clinical trials met the inclusion criteria with total of 278 participants. Random-effects meta-analysis suggested no significant effects on the levels of fasting blood glucose [-7.08 mg/dl, 95 % CI: -14.85 to 0.70,P = 0.07, I² = 59.8 %], glycosylated hemoglobin (HbA1c) [-0.48 %, 95 % CI: -1.01 to -0.04, P = 0.07, I² = 0.0 %], homeostatic model assessment for insulin resistance (HOMA-IR) [-0.97, 95 % CI: -1.96 to 0.02, P = 0.05, I² = 83.8 %], and insulin [-2.94 Hedges' g, 95 % CI: -6.67 to 0.80, P = 0.12, I² = 83.1 %] following supplementation with sumac powder.

CONCLUSION

This meta-analysis showed no significant effects on any glycemic indices following supplementation with sumac powder.

Design, synthesis, molecular docking, and some metabolic enzyme inhibition properties of novel quinazolinone derivatives

3-Amino-2-ethylquinazolin-4(3H)-one (3) was synthesized in two steps from the reaction of amide (2), which was obtained from the treatment of methyl anthranilate (1) with propionyl chloride, with hydrazine. From the reaction of 3-amino-2-ethylquinazolin-4(3H)-one (3) with various aromatic aldehydes, novel benzylidenaminoquinazolin-4(3H)-one (3a-n) derivatives were synthesized. The structures of the novel molecules were characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy (¹ H-NMR and ¹³ C-NMR), and high-resolution mass spectroscopy. The novel compounds were tested against some metabolic enzymes, including α-glucosidase (α-Glu), acetylcholinesterase (AChE), and human carbonic anhydrases I and II (hCA I and II). The novel compounds showed K_i values in the range of 244-988 nM for hCA I, 194-900 nM for hCA II, 30-156 nM for AChE, and 215-625 nM for α-Glu. The binding affinities of the most active compounds were calculated as -7.636, -6.972, -10.080, and -8.486 kcal/mol for hCA I, hCA II, AChE, and α-Glu enzymes, respectively. The aromatic ring of the quinazoline moiety plays a critical role in the inhibition of the enzymes.

Recent advances in the medicinal chemistry of carbonic anhydrase inhibitors

Carbonic anhydrase (CA, EC 4.2.1.1) is an enzyme and a very omnipresent zinc metalloenzyme which catalyzed the reversible hydration and dehydration of carbon dioxide and bicarbonate; a reaction which plays a crucial role in many physiological and pathological processes. Carbonic anhydrase is present in human (h) with sixteen different isoforms ranging from hCA I-hCA XV. All these isoforms are widely distributed in different tissues/organs and are associated with a range of pivotal physiological activities. Due to their involvement in various physiological roles, inhibitors of different human isoforms of carbonic anhydrase have found clinical applications for the treatment of various diseases including glaucoma, retinopathy, hemolytic anemia, epilepsy, obesity, and cancer. However, clinically used inhibitors of CA (acetazolamide, brinzolamide, dorzolamide, etc.) are not selective causing the undesirable side effects. One of the major hurdles in the design and development of carbonic anhydrase inhibitors is the lack of balanced isoform selectivity which thrived to new chemotypes. In this review, we have compiled the recent strategies of various researchers related to the development of carbonic anhydrase inhibitors belonging to different structural classes like pyrimidine, pyrazoline, selenourea, isatin, indole, etc. This review also summarizes the structure-activity relationships, analysis of isoform selectivity including mechanistic and in silico studies to afford ideas and to provide focused direction for the design and development of novel isoform-selective carbonic anhydrase inhibitors with therapeutic implications.

Synthesis, molecular docking, and biological activities of new cyanopyridine derivatives containing phenylurea

A new class of cyanopyridine derivatives (10a-e and 11a-e) containing the phenylurea unit was synthesized and tested against some metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glycosidase (α-Gly). The new cyanopyridine derivatives showed K_i values in the range of 40.73 ± 6.54 to 87.05 ± 16.98 µM against AChE, 29.17 ± 4.88 to 124.03 ± 22.43 µM against BChE, and 3.66 ± 0.93 to 26.33 ± 5.05 µM against α-Gly. These inhibition effects were compared with standard enzyme inhibitors like tacrine (for AChE and BChE) and acarbose (for α-Gly). Also, these cyanopyridine derivatives with the best inhibition score were docked into the active site of the indicated metabolic enzymes. Finally, molecular docking calculations were made to compare the biological activities of the compounds against AChE (-8.81 kcal/mol for molecule 11d), BChE (-3.52 kcal/mol for molecule 11d), and α-Gly (-2.98 kcal/mol for molecule 11a). After molecular docking calculations, the ADME/T analysis was performed to examine the future drug use properties of the new cyanopyridine derivatives containing phenylurea.

Phytochemical screening, anti-oxidant activity and α-amylase inhibition study using different extracts of loquat (Eriobotrya japonica) leaves

Diabetes Mellitus is an endocrine disorder which causes insulin deficiency. Medicinal plants are documented to be efficacious in the management of the disease. The current research set to determine the phytochemicals present, anti-oxidant activity and investigate the potency of Eriobotrya japonica against α-amylase inhibition. The leaves of the plant were extracted sequentially. The different extracts were evaluated for the presence of phytochemicals and their potential anti-oxidant and α-amylase inhibition activity. Methanol with the highest polarity, gave the highest yield of 20% and hexane with the lowest polarity have the lowest yield of 2.09%. This trend resembled that observed for the total flavanoid and total phenolic content analysis which gave values of 0.3822 mg QAE/mg and 3.810 mg GAE/mg respectively for methanolic and hexane extracts. The extracts of methanol recorded higher DPPH free radical scavenging activity of 87% and gave the lowest IC₅₀ of 0.5336 which was below that of ascorbic acid used as a control. Hexane extract had a higher α-amylase inhibitory activity of 24% at 1 μg/ml as compared to other extracts. Generally hexane extracts of Eriobotrya japonica exhibits mild inhibitory activity against α-amylase enzyme which is recommended than the conventional therapy which maximally inhibits the enzyme causing major side effects. The results obtained herein support the use of the plant as an anti-diabetic agent at higher concentrations.

Synthesis of nitrogen, phosphorus, selenium and sulfur-containing heterocyclic compounds - Determination of their carbonic anhydrase, acetylcholinesterase, butyrylcholinesterase and α-glycosidase inhibition properties

Sulfur-containing pyrroles (1-3), tris(2-pyridyl)phosphine(selenide) sulfide (4-5) and 4-benzyl-6-(thiophen-2-yl)pyrimidin-2-amine (6) were synthesized and characterized by elemental analysis, IR and NMR spectra. In this study, the synthesized compounds of nitrogen, phosphorus, selenium and sulfur-containing heterocyclic compounds (1-6) were evaluated against the human erythrocyte carbonic anhydrase I, and II isoenzymes, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glycosidase enzymes. The synthesized heterocyclic compounds showed IC₅₀ values in range of 33.32-60.79 nM against hCA I, and 37.05-66.64 nM against hCA II closely associated with various physiological and pathological processes. On the other hand, IC₅₀ values were found in range of 13.13-22.21 nM against AChE, 0.54-31.22 nM against BChE, and 13.51-26.55 nM against α-glycosidase as a hydrolytic enzyme. As a result, nitrogen, phosphorus, selenium and sulfur-containing heterocyclic compounds (1-6) demonstrated potent inhibition profiles against indicated metabolic enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly in the treatment of some global disorders including glaucoma, Alzheimer's disease and diabetes.

Synthesis and antioxidant activities of phenol derivatives from 1,6-bis(dimethoxyphenyl)hexane-1,6-dione

Starting from the compound (3,4-dimethoxyphenyl)(2-(3,4-dimethoxyphenyl)cyclopent-1-en-1-yl)methanone (4), two diols and three tetrol derivatives were synthesised. Morover, from the reactions of 1,3-dimethoxybenzene and 1,4-dimethoxybenzene with adipoyl chloride, fifteen new along with nine known compounds were obtained. For the characterizations of compounds, spectroscopic methods such as NMR including DEPT, COSY, HMQC and HMBC experiments and X-ray diffraction were used. The antioxidant activities of novel synthesized seventeen molecules were investigated by analytical methods like ABTS^•+ and DPPH^• scavenging. Also, reducing power these molecules were investigated by Fe³⁺, Cu²⁺, and [Fe³⁺-(TPTZ)₂]³⁺. Some of the molecules record powerful antioxidant profile when compared to putative standards. The inhibition effects of the phenols compounds against AChE and BChE activities were analysed. Also, these phenols were found as effective inhibitors for AChE, hCA I, hCA II, and BChE with K_is in the range of 122.95 ± 18.41-351.31 ± 69.12 nM for hCA I, 62.35 ± 9.03-363.17 ± 180.1 nM for hCA II, 134.57 ± 3.99-457.43 ± 220.10 nM for AChE, and 27.06 ± 9.12-72.98 ± 9.53 nM for BChE, respectively.

A Novel Ag-N-Heterocyclic Carbene Complex Bearing the Hydroxyethyl Ligand: Synthesis, Characterization, Crystal and Spectral Structures and Bioactivity Properties

In this study, a novel silver N-heterocyclic carbene (Ag-NHC) complex bearing hydroxyethyl substituent has been synthesized from the hydroxyethyl-substituted benzimidazolium salt and silver oxide by using in-situ deprotonation method. A structure of the Ag-NHC complex was characterized by using UV-Vis, FTIR, 1H-NMR and 13C-NMR spectroscopies and elemental analysis techniques. Also, the crystal structure of the novel complex was determined by single-crystal X-ray diffraction method. In this paper, compound 1 showed excellent inhibitory effects against some metabolic enzymes. This complex had Ki of 1.14 0.26 µM against human carbonic anhydrase I (hCA I), 1.88±0.20 µM against human carbonic anhydrase II (hCA I), and 10.75±2.47 µM against α-glycosidase, respectively. On the other hand, the Ki value was found as 25.32±3.76 µM against acetylcholinesterase (AChE) and 41.31±7.42 µM against butyrylcholinesterase (BChE), respectively. These results showed that the complex had drug potency against some diseases related to using metabolic enzymes.

Experimental and DFT mechanistic insights into one-pot synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones under catalysis of DBU-based ionic liquids

Kinetic impacts of two DBU-based ionic liquids in the three-component synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and the mechanism of the reaction were investigated by DFT calculations.