Displaying publications 1 - 20 of 106 in total

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  1. Khan KM, Jamil W, Ambreen N, Taha M, Perveen S, Morales GA
    Ultrason Sonochem, 2014 May;21(3):1200-5.
    PMID: 24398059 DOI: 10.1016/j.ultsonch.2013.12.011
    Aldazines (Bis-Schiff bases) 1-24 were synthesized using aromatic aldehydes (heterocyclic and benzaldehydes) and hydrazine hydrate under reflux using conventional heating and/or via ultrasound irradiation using BiCl3 as catalyst. Ultrasonication conditions with cat. BiCl3 proved to be an effective, environmentally friendly synthetic procedure. This methodology is robust in the presence of electron donating and electron withdrawing groups affording desired products with high yields (>95%) in just a couple of minutes vs. hours using conventional heating.
  2. Sharma S, Pathak A, Parker R, Costa LOP, Ghai B, Igwesi-Chidobe C, et al.
    PMID: 38602844 DOI: 10.2519/jospt.2024.12406
    BACKGROUND: The Lancet Series of Low Back Pain (LBP) highlighted the lack of LBP data from low- and middle-income countries (LMICs). The study aimed to describe (1) what LBP care is currently delivered in LMICs, and (2) how that care is delivered. METHODS: An online mixed-methods study. A Consortium for LBP in LMICs (n=65) was developed with an expert panel of leading LBP researchers (>2 publications on LBP) and multidisciplinary clinicians and patient partners with five years of clinical/lived LBP experience in LMICs. Quantitative data were analyzed using descriptive statistics. Two researchers independently analyzed qualitative data using deductive and inductive coding and developed a thematic framework. FINDINGS: Forty-seven (85%) of 55 invited panel members representing 32 LMICs completed the survey (38% women; 62% men). The panel included clinicians (34%), researchers (28%), educators (6%), and patient partners (4%). Pharmacotherapies and electrophysiological agents were the most used LBP treatments. The Thematic Framework comprised of eight themes: (1) Self-management is ubiquitous; (2) Medicines are the cornerstone; (3) Traditional therapies have a place; (4) Society plays an important role; (5) Imaging use is very common; (6) Reliance on passive approaches; (7) Social determinants influence LBP care pathway; and (8) Health systems are ill-prepared to address LBP burden. INTERPRETATION: LBP care in LMICs did not consistently align with the best available evidence. Findings will help research prioritization in LMICs and guide global LBP clinical guidelines. FUNDING: The lead author's Fellowship was supported by the International Association for the Study of Pain.
  3. Salar U, Khan KM, Chigurupati S, Taha M, Wadood A, Vijayabalan S, et al.
    Sci Rep, 2017 12 05;7(1):16980.
    PMID: 29209017 DOI: 10.1038/s41598-017-17261-w
    Current research is based on the identification of novel inhibitors of α-amylase enzyme. For that purpose, new hybrid molecules of hydrazinyl thiazole substituted chromones 5-27 were synthesized by multi-step reaction and fully characterized by various spectroscopic techniques such as EI-MS, HREI-MS, 1H-NMR and 13C-NMR. Stereochemistry of the iminic bond was confirmed by NOESY analysis of a representative molecule. All compounds 5-27 along with their intervening intermediates 1-4, were screened for in vitro α-amylase inhibitory, DPPH and ABTS radical scavenging activities. All compounds showed good inhibition potential in the range of IC50 = 2.186-3.405 µM as compared to standard acarbose having IC50 value of 1.9 ± 0.07 µM. It is worth mentioning that compounds were also demonstrated good DPPH (IC50 = 0.09-2.233 µM) and ABTS (IC50 = 0.584-3.738 µM) radical scavenging activities as compared to standard ascorbic acid having IC50 = 0.33 ± 0.18 µM for DPPH and IC50 = 0.53 ± 0.3 µM for ABTS radical scavenging activities. In addition to that cytotoxicity of the compounds were checked on NIH-3T3 mouse fibroblast cell line and found to be non-toxic. In silico studies were performed to rationalize the binding mode of compounds (ligands) with the active site of α-amylase enzyme.
  4. Shahbaz MS, Anwar A, Saad SM, Kanwal, Anwar A, Khan KM, et al.
    Parasitol Res, 2020 Jul;119(7):2327-2335.
    PMID: 32476058 DOI: 10.1007/s00436-020-06710-7
    Acanthamoeba castellanii is a free-living amoeba which can cause a blinding keratitis and fatal granulomatous amoebic encephalitis. The treatment of Acanthamoeba infections is challenging due to formation of cyst. Quinazolinones are medicinally important scaffold against parasitic diseases. A library of nineteen new 3-aryl-6,7-dimethoxyquinazolin-4(3H)-one derivatives was synthesized to evaluate their antiamoebic activity against Acanthamoeba castellanii. One-pot synthesis of 3-aryl-6,7-dimethoxyquinazolin-4(3H)-ones (1-19) was achieved by reaction of 2-amino-4,5-dimethoxybenzoic acid, trimethoxymethane, and different substituted anilines. These compounds were purified and characterized by standard chromatographic and spectroscopic techniques. Antiacanthamoebic activity of these compounds was determined by amoebicidal, encystation, excystation and host cell cytopathogenicity in vitro assays at concentrations of 50 and 100 μg/mL. The IC50 was found to be between 100 and 50 μg/mL for all the compounds except compound 5 which did not exhibit amoebicidal effects at these concentrations. Furthermore, lactate dehydrogenase assay was also performed to evaluate the in vitro cytotoxicity of these compounds against human keratinocyte (HaCaT) cells. The results revealed that eighteen out of nineteen derivatives of quinazolinones significantly decreased the viability of A. castellanii. Furthermore, eighteen out of nineteen tested compounds inhibited the encystation and excystation, as well as significantly reduced the A. castellanii-mediated cytopathogenicity against human cells. Interestingly, while tested against human normal cell line HaCaT keratinocytes, all compounds did not exhibit any overt cytotoxicity. Furthermore, a detailed structure-activity relationship is also studied to optimize the most potent hit from these synthetic compounds. This report presents several potential lead compounds belonging to 3-aryl-6,7-dimethoxyquinazolin-4(3H)-one derivatives for drug discovery against infections caused by Acanthamoeba castellanii.
  5. Anwar A, Yi YP, Fatima I, Khan KM, Siddiqui R, Khan NA, et al.
    Parasitol Res, 2020 Jun;119(6):1943-1954.
    PMID: 32385711 DOI: 10.1007/s00436-020-06694-4
    Acanthamoeba causes diseases such as Acanthamoeba keratitis (AK) which leads to permanent blindness and granulomatous Acanthamoeba encephalitis (GAE) where there is formation of granulomas in the brain. Current treatments such as chlorhexidine, diamidines, and azoles either exhibit undesirable side effects or require immediate and prolonged treatment for the drug to be effective or prevent relapse. Previously, antifungal drugs amphotericin B, nystatin, and fluconazole-conjugated silver with nanoparticles have shown significantly increased activity against Acanthamoeba castellanii. In this study, two functionally diverse tetrazoles were synthesized, namely 5-(3-4-dimethoxyphenyl)-1H-tetrazole and 1-(3-methoxyphenyl)-5-phenoxy-1H-tetrazole, denoted by T1 and T2 respectively. These compounds were evaluated for anti-Acanthamoeba effects at different concentrations ranging from 5 to 50 μM. Furthermore, these compounds were conjugated with silver nanoparticles (AgNPs) to enhance their efficacy. Particle size analysis showed that T1-AgNPs and T2-AgNPs had an average size of 52 and 70 nm respectively. After the successful synthesis and characterization of tetrazoles and tetrazole-conjugated AgNPs, they were subjected to anti-Acanthamoeba studies. Amoebicidal assay showed that at concentration 10 μM and above, T2 showed promising antiamoebic activities between the two compounds while encystation and excystation assays reveal that both T1 and T2 have inhibited differentiation activity against Acanthamoeba castellanii. Conjugation of T1 and T2 to AgNP also increased efficacy of tetrazoles as anti-Acanthamoeba agents. This may be due to the increased bioavailability as AgNP allows better delivery of treatment compounds to A. castellanii. Human cell cytotoxicity assay revealed that tetrazoles and AgNPs are significantly less toxic towards human cells compared with chlorhexidine which is known to cause undesirable side effects. Cytopathogenicity assay also revealed that T2 conjugated with AgNPs significantly reduced cytopathogenicity of A. castellanii compared with T2 alone, suggesting that T2-conjugated AgNP is an effective and safe anti-Acanthamoeba agent. The use of a synthetic azole compound conjugated with AgNPs can be an alternative strategy for drug development against A. castellanii. However, mechanistic and in vivo studies are needed to explore further translational values.
  6. Simau FA, Ahmed U, Khan KM, Khan NA, Siddiqui R, Alharbi AM, et al.
    Parasitol Res, 2024 Jan 31;123(2):117.
    PMID: 38294565 DOI: 10.1007/s00436-024-08131-2
    The free living Acanthamoeba spp. are ubiquitous amoebae associated with potentially blinding disease known as Acanthamoeba keratitis (AK) and a fatal central nervous system infection granulomatous amoebic encephalitis (GAE). With the inherent ability of cellular differentiation, it can phenotypically transform to a dormant cyst form from an active trophozoite form. Acanthamoeba cysts are highly resistant to therapeutic agents as well as contact lens cleaning solutions. One way to tackle drug resistance against Acanthamoeba is by inhibiting the formation of cysts from trophozoites. The biochemical analysis showed that the major component of Acanthamoeba cyst wall is composed of carbohydrate moieties such as galactose and glucose. The disaccharide of galactose and glucose is lactose. In this study, we analyzed the potential of lactase enzyme to target carbohydrate moieties of cyst walls. Amoebicidal assessment showed that lactase was ineffective against trophozoite of A. castellanii but enhanced amoebicidal effects of chlorhexidine. The lactase enzyme did not show any toxicity against normal human keratinocyte cells (HaCaT) at the tested range. Hence, lactase can be used for further assessment for development of potential therapeutic agents in the management of Acanthamoeba infection as well as formulation of effective contact lens disinfectants.
  7. Jamil W, Perveen S, Shah SA, Taha M, Ismail NH, Perveen S, et al.
    Molecules, 2014 Jun 25;19(7):8788-802.
    PMID: 24968334 DOI: 10.3390/molecules19078788
    Phenoxyacetohydrazide Schiff base analogs 1-28 have been synthesized and their in vitro β-glucouoronidase inhibition potential studied. Compounds 1 (IC50=9.20±0.32 µM), 5 (IC50=9.47±0.16 µM), 7 (IC50=14.7±0.19 µM), 8 (IC50=15.4±1.56 µM), 11 (IC50=19.6±0.62 µM), 12 (IC50=30.7±1.49 µM), 15 (IC50=12.0±0.16 µM), 21 (IC50=13.7±0.40 µM) and 22 (IC50=22.0±0.14 µM) showed promising β-glucuronidase inhibition activity, better than the standard (D-saccharic acid-1,4-lactone, IC50=48.4±1.25 µM).
  8. Imran S, Taha M, Ismail NH, Khan KM, Naz F, Hussain M, et al.
    Molecules, 2014;19(8):11722-40.
    PMID: 25102118 DOI: 10.3390/molecules190811722
    In an effort to develop new antibacterial drugs, some novel bisindolylmethane derivatives containing Schiff base moieties were prepared and screened for their antibacterial activity. The synthesis of the bisindolylmethane Schiff base derivatives 3-26 was carried out in three steps. First, the nitro group of 3,3'-((4-nitrophenyl)-methylene)bis(1H-indole) (1) was reduced to give the amino substituted bisindolylmethane 2 without affecting the unsaturation of the bisindolylmethane moiety using nickel boride in situ generated. Reduction of compound 1 using various catalysts showed that combination of sodium borohydride and nickel acetate provides the highest yield for compound 2. Bisindolylmethane Schiff base derivatives were synthesized by coupling various benzaldehydes with amino substituted bisindolylmethane 2. All synthesized compounds were characterized by various spectroscopic methods. The bisindolylmethane Schiff base derivatives were evaluated against selected Gram-positive and Gram-negative bacterial strains. Derivatives having halogen and nitro substituent display weak to moderate antibacterial activity against Salmonella typhi, S. paratyphi A and S. paratyphi B.
  9. Ikram HM, Rasool N, Zubair M, Khan KM, Abbas Chotana G, Akhtar MN, et al.
    Molecules, 2016 Jul 27;21(8).
    PMID: 27472312 DOI: 10.3390/molecules21080977
    The present study describes several novel 2,5-biaryl-3-hexylthiophene derivatives (3a-i) synthesized via a Pd(0)-catalyzed Suzuki cross-coupling reaction in moderate to good yields. The novel compounds were also analyzed for their anti-thrombolytic, haemolytic, and biofilm inhibition activities. In addition, the anti-tumor activity was also evaluated in vitro for newly-synthesized compounds, where 3-hexyl-2,5-bis(4-(methylthio)phenyl)thiophene exhibited the best anti-tumor activity against 4T1 cells with IC50 value of 16 μM. Moreover, 2,5-bis(4-methylphenyl)-3-hexylthiophene showed the highest activity against MCF-7 cells with an IC50 value of 26.2 μM. On the other hand, the compound 2,5-bis(4-chloropheny)-3-hexylthiophene exhibited excellent biofilm inhibition activity. Furthermore, the compound 2,5-bis(3-chloro-4-fluorophenyl)-3-hexylthiophene also exhibited better anti-thrombolytic and hemolytic activity results as compared to the other newly-synthesized compounds.
  10. Taha M, Alshamrani FJ, Rahim F, Hayat S, Ullah H, Zaman K, et al.
    Molecules, 2019 Oct 23;24(21).
    PMID: 31652777 DOI: 10.3390/molecules24213819
    A new class of triazinoindole-bearing thiosemicarbazides (1-25) was synthesized and evaluated for α-glucosidase inhibitory potential. All synthesized analogs exhibited excellent inhibitory potential, with IC50 values ranging from 1.30 ± 0.01 to 35.80 ± 0.80 µM when compared to standard acarbose (an IC50 value of 38.60 ± 0.20 µM). Among the series, analogs 1 and 23 were found to be the most potent, with IC50 values of 1.30 ± 0.05 and 1.30 ± 0.01 µM, respectively. The structure-activity relationship (SAR) was mainly based upon bringing about different substituents on the phenyl rings. To confirm the binding interactions, a molecular docking study was performed.
  11. Aziz AN, Taha M, Ismail NH, Anouar el H, Yousuf S, Jamil W, et al.
    Molecules, 2014 Jun 19;19(6):8414-33.
    PMID: 24950444 DOI: 10.3390/molecules19068414
    Schiff bases of 3,4-dimethoxybenzenamine 1-25 were synthesized and evaluated for their antioxidant activity. All the synthesized compounds were characterized by various spectroscopic techniques. In addition, the characterizations of compounds 13, 15 and 16 were supported by crystal X-ray determinations and their geometrical parameters were compared with theoretical DFT calculations at the B3LYP level of theory. Furthermore, the X-ray crystal data of two non-crystalline compounds 8 and 18 were theoretically calculated and compared with the practical values of compounds 13, 15, 16 and found a good agreement. The compounds showed good DPPH scavenging activity ranging from 10.12 to 84.34 μM where compounds 1-4 and 6 showed stronger activity than the standard n-propyl gallate. For the superoxide anion radical assay, compounds 1-3 showed better activity than the standard.
  12. Babatunde O, Hameed S, Salar U, Chigurupati S, Wadood A, Rehman AU, et al.
    Mol Divers, 2021 Mar 01.
    PMID: 33650031 DOI: 10.1007/s11030-021-10196-5
    A variety of dihydroquinazolin-4(1H)-one derivatives (1-37) were synthesized via "one-pot" three-component reaction scheme by treating aniline and different aromatic aldehydes with isatoic anhydride in the presence of acetic acid. Chemical structures of compounds were deduced by different spectroscopic techniques including EI-MS, HREI-MS, 1H-, and 13C-NMR. Compounds were subjected to α-amylase and α-glucosidase inhibitory activities. A number of derivatives exhibited significant to moderate inhibition potential against α-amylase (IC50 = 23.33 ± 0.02-88.65 ± 0.23 μM) and α-glucosidase (IC50 = 25.01 ± 0.12-89.99 ± 0.09 μM) enzymes, respectively. Results were compared with the standard acarbose (IC50 = 17.08 ± 0.07 μM for α-amylase and IC50 = 17.67 ± 0.09 μM for α-glucosidase). Structure-activity relationship (SAR) was rationalized by analyzing the substituents effects on inhibitory potential. Kinetic studies were implemented to find the mode of inhibition by compounds which revealed competitive inhibition for α-amylase and non-competitive inhibition for α-glucosidase. However, in silico study identified several important binding interactions of ligands (synthetic analogues) with the active site of both enzymes.
  13. Seraj F, Kanwal, Khan KM, Khan A, Ali M, Khalil R, et al.
    Mol Divers, 2021 Feb;25(1):143-157.
    PMID: 31965436 DOI: 10.1007/s11030-019-10032-x
    Novel ibuprofen derivatives 1-19 including ibuprofen hydrazide 1, and substituted thiourea derivatives 2-19 were synthesized and characterized by EI-MS, FAB-MS, HREI-MS, HRFAB-MS, 1H-, and 13C-NMR spectroscopic techniques. The synthetic molecules 1-19 were examined for their in vitro urease inhibition and were found to display a diversified degree of inhibitory potential in the range of IC50 = 2.96-178 μM as compared to the standard thiourea (IC50 = 21.32 ± 0.22 μM). Out of nineteen, thirteen derivatives 2-4, 6, 7, 9, 11-15, 17, and 18 demonstrated remarkable inhibitory activity with IC50 values of 2.96 ± 1.11 to 16.1 ± 1.07 μM, compound 5 exhibited moderate inhibition with IC50 value of 37.3 ± 0.41 μM, whereas, compounds 1, 8, and 10 demonstrated weak inhibition against urease enzyme. Almost all structural features are participating in the activity; however, limited structure-activity relationship was discussed on the basis of different structural features, i.e., different functional groups and their positions at aryl part. In addition, molecular docking study was performed in order to understand the ligands binding interactions with the active site of urease enzyme.
  14. Abid O, Imran S, Taha M, Ismail NH, Jamil W, Kashif SM, et al.
    Mol Divers, 2021 May;25(2):995-1009.
    PMID: 32301032 DOI: 10.1007/s11030-020-10084-4
    The β-glucuronidase, a lysosomal enzyme, catalyzes the cleavage of glucuronosyl-O-bonds. Its inhibitors play a significant role in different medicinal therapies as they cause a decrease in carcinogen-induced colonic tumors by reducing the level of toxic substances present in the intestine. Among those inhibitors, bisindole derivatives had displayed promising β-glucuronidase inhibition activity. In the current study, hydrazone derivatives of bisindolymethane (1-30) were synthesized and evaluated for in vitro β-glucuronidase inhibitory activity. Twenty-eight analogs demonstrated better activity (IC50 = 0.50-46.5 µM) than standard D-saccharic acid 1,4-lactone (IC50 = 48.4 ± 1.25 µM). Compounds with hydroxyl group like 6 (0.60 ± 0.01 µM), 20 (1.50 ± 0.10 µM) and 25 (0.50 ± 0.01 µM) exhibited the most potent inhibitory activity, followed by analogs with fluorine 21 (3.50 ± 0.10 µM) and chlorine 23 (8.20 ± 0.20 µM) substituents. The presence of hydroxyl group at the aromatic side chain was observed as the main contributing factor in the inhibitory potential. From the docking studies, it was predicted that the active compounds can fit properly in the binding groove of the β-glucuronidase and displayed significant binding interactions with essential residues.
  15. Salar U, Khan KM, Chigurupati S, Syed S, Vijayabalan S, Wadood A, et al.
    Med Chem, 2019;15(1):87-101.
    PMID: 30179139 DOI: 10.2174/1573406414666180903162243
    BACKGROUND: Despite many side effects associated, there are many drugs which are being clinically used for the treatment of type-II diabetes mellitus (DM). In this scenario, there is still need to develop new therapeutic agents with more efficacy and less side effects. By keeping in mind the diverse spectrum of biological potential associated with coumarin and thiazole, a hybrid class based on these two heterocycles was synthesized.

    METHOD: Hydrazinyl thiazole substituted coumarins 4-20 were synthesized via two step reaction. First step was the acid catalyzed reaction of 3-formyl/acetyl coumarin derivatives with thiosemicarbazide to form thiosemicarbazone intermediates 1-3, followed by the reaction with different phenacyl bromides to afford products 4-20. All the synthetic analogs 4-20 were characterized by different spectroscopic techniques such as EI-MS, HREI-MS, 1H-NMR and 13C-NMR. Stereochemical assignment of the iminic double bond was carried out by the NOESY experiments. Elemental analysis was found in agreement with the calculated values.

    RESULTS: Compounds 4-20 were screened for α-amylase inhibitory activity and showed good activity in the range of IC50 = 1.829 ± 0.102-3.37 ± 0.17 µM as compared to standard acarbose (IC50 = 1.819 ± 0.19 µM). Compounds were also investigated for their DPPH and ABTS radical scavenging activities and displayed good radical scavenging potential. In addition to that molecular modelling study was conducted on all compounds to investigate the interaction details of compounds 4- 20 (ligands) with active site (receptor) of enzyme.

    CONCLUSION: The newly identified hybrid class may serve as potential lead candidates for the management of diabetes mellitus.

  16. Aftab MF, Afridi SK, Mughal UR, Karim A, Haleem DJ, Kabir N, et al.
    J. Chem. Neuroanat., 2017 04;81:1-9.
    PMID: 28093241 DOI: 10.1016/j.jchemneu.2017.01.001
    Diabetes is associated with neurodegeneration. Glycation ensues in diabetes and glycated proteins cause insulin resistance in brain resulting in amyloid plaques and NFTs. Also glycation enhances gliosis by promoting neuroinflammation. Currently there is no therapy available to target neurodegenration in brain therefore, development of new therapy that offers neuroprotection is critical. The objective of this study was to evaluate mechanistic effect of isatin derivative URM-II-81, an anti-glycation agent for improvement of insulin action in brain and inhibition of neurodegenration. Methylglyoxal induced stress was inhibited by treatment with URM-II-81. Also, Ser473 and Ser9 phosphorylation of Akt and GSK-3β respectively were restored by URM-II-81. Effect of URM-II-81 on axonal integrity was studied by differentiating Neuro2A using retinoic acid. URM-II-81 restored axonal length in MGO treated cells. Its effects were also studied in high fat and low dose streptozotocin induced diabetic mice where it reduced RBG levels and inhibited glycative stress by reducing HbA1c. URM-II-81 treatment also showed inhibition of gliosis in hippocampus. Histological analysis showed reduced NFTs in CA3 hippocampal region and restoration of insulin signaling in hippocampii of diabetic mice. Our findings suggest that URM-II-81 can be developed as a new therapeutic agent for treatment of neurodegenration.
  17. Jamil W, Shaikh J, Yousuf M, Taha M, Khan KM, Shah SAA
    J Biomol Struct Dyn, 2022;40(23):12723-12738.
    PMID: 34514955 DOI: 10.1080/07391102.2021.1975565
    This study reports synthesis of flavone hydrazide Schiff base derivatives with diverse functionalities for the cure of diabetic mellitus and their a-glucosidase inhibitor and in silico studies. In this regard, Flavone derivatives 1-20 has synthesized and characterized by various spectroscopic techniques. These compounds showed significant potential towards a-glucosidase enzyme inhibition activity and found to be many fold better active than the standard Acarbose (IC50 = 39.45 ± 0.11 µM). The IC50values ranges 1.02-38.1 µM. Among these, compounds 1(IC50 = 4.6 ± 0.23 µM), 2(IC50 = 1.02 ± 0.2 µM), 3(IC50 = 7.1 ± 0.11 µM), 4(IC50 = 8.3 ± 0.34 µM), 5(IC50 = 7.4 ± 0.15 µM), 6(IC50 = 8.5 ± 0.27 µM) and 18 (IC50 = 1.09 ± 0.26 µM) showed highest activity. It was revealed that the analogues having -OH substitution have higher activity than their look likes. The molecular docking analysis revealed that these molecules have high potential to interact with the protein molecule and have high ability to bind with the enzyme. Furthermore, in silico pharmacokinetics, physicochemical studies were also performed for these derivatives. The bioavailability radar analysis explored that of all these compounds have excellent bioavailability for five (5) descriptors, however, the sixth descriptor of instauration is slightly increased in all compounds.Communicated by Ramaswamy H. Sarma.
  18. Taha M, Ismail S, Imran S, Almandil NB, Alomari M, Rahim F, et al.
    J Biomol Struct Dyn, 2022 Nov;40(18):8232-8247.
    PMID: 33860726 DOI: 10.1080/07391102.2021.1910072
    In search of potent urease inhibitor indole analogues (1-22) were synthesized and evaluated for their urease inhibitory potential. All analogues (1-22) showed a variable degree of inhibitory interaction potential having IC50 value ranging between 0.60 ± 0.05 to 30.90 ± 0.90 µM when compared with standard thiourea having IC50 value 21.86 ± 0.90 µM. Among the synthesized analogues, the compounds 1, 2, 3, 5, 6, 8, 12, 14, 18, 20 and 22 having IC50 value 3.10 ± 0.10, 1.20 ± 0.10, 4.60 ± 0.10, 0.60 ± 0.05, 5.30 ± 0.20, 2.50 ± 0.10, 7.50 ± 0.20, 3.90 ± 0.10, 3.90 ± 0.10, 2.30 ± 0.05 and 0.90 ± 0.05 µM respectively were found many fold better than the standard thiourea. All other analogues showed better urease interaction inhibition. Structure activity relationship (SAR) has been established for all analogues containing different substituents on the phenyl ring. To understand the binding interaction of most active analogues with enzyme active site docking study were performed.Communicated by Ramaswamy H. Sarma.
  19. Taha M, Rahim F, Zaman K, Anouar EH, Uddin N, Nawaz F, et al.
    J Biomol Struct Dyn, 2023 Mar;41(5):1649-1664.
    PMID: 34989316 DOI: 10.1080/07391102.2021.2023640
    We have synthesized benzo[d]oxazole derivatives (1-21) through a multistep reaction. Alteration in the structure of derivatives was brought in the last step via using various substituted aromatic aldehydes. In search of an anti-Alzheimer agent, all derivatives were evaluated against acetylcholinesterase and butyrylcholinesterase enzyme under positive control of standard drug donepezil (IC50 = 0.016 ± 0.12 and 4.5 ± 0.11 µM) respectively. In case of acetylcholinesterase enzyme inhibition, derivatives 8, 9 and 18 (IC50 = 0.50 ± 0.01, 0.90 ± 0.05 and 0.3 ± 0.05 µM) showed very promising inhibitory potentials. While in case of butyrylcholinesterase enzyme inhibition, most of the derivatives like 6, 8, 9, 13, 15, 18 and 19 (IC50 = 2.70 ± 0.10, 2.60 ± 0.10, 2.20 ± 0.10, 4.25 ± 0.10, 3.30 ± 0.10, 0.96 ± 0.05 and 3.20 ± 0.10 µM) displayed better inhibitory potential than donepezil. Moreover, derivative 18 is the most potent one among the series in both inhibitions. The binding interaction of derivatives with the active gorge of the enzyme was confirmed via a docking study. Furthermore, the binding interaction between derivatives and the active site of enzymes was correlated through the SAR study. Structures of all derivatives were confirmed through spectroscopic techniques such as 1H-NMR, 13C-NMR and HREI-MS, respectively.Communicated by Ramaswamy H. Sarma.
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