Displaying publications 1 - 20 of 98 in total

  1. Taha M, Imran S, Rahim F, Wadood A, Khan KM
    Bioorg Chem, 2018 02;76:273-280.
    PMID: 29223804 DOI: 10.1016/j.bioorg.2017.12.001
    Inhibition of α-glucosidase is an effective strategy for controlling post-prandial hyperglycemia in diabetic patients. Beside these α-glucosidase inhibitors has been also used as anti-obesity and anti-viral drugs. Keeping in view the greater importance of α-glucosidase inhibitors here in this study we are presenting oxindole based oxadiazoles hybrid analogs (1-20) synthesis, characterized by different spectroscopic techniques including 1H NMR and EI-MS and their α-glucosidase inhibitory activity. All compounds were found potent inhibitors for the enzyme with IC50 values ranging between 1.25 ± 0.05 and 268.36 ± 4.22 µM when compared with the standard drug acarbose having IC50 value 895.09 ± 2.04 µM. Our study identifies novel series of potent α-glucosidase inhibitors and further investigation on this may led to the lead compounds. A structure activity relationship has been established for all compounds. The interactions of the active compounds and enzyme active site were established with the help of molecular docking studies.
  2. 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.
  3. Khan KM, Saad SM, Shaikh NN, Hussain S, Fakhri MI, Perveen S, et al.
    Bioorg Med Chem, 2014 Jul 1;22(13):3449-54.
    PMID: 24844756 DOI: 10.1016/j.bmc.2014.04.039
    2-Arylquinazolin-4(3H)-ones 1-25 were synthesized by reacting anthranilamide with various benzaldehydes using CuCl2·2H2O as a catalyst in ethanol under reflux. Synthetic 2-arylquinazolin-4(3H)-ones 1-25 were evaluated for their β-glucuronidase inhibitory potential. A trend of inhibition IC50 against the enzyme in the range of 0.6-198.2μM, was observed and compared with the standard d-saccharic acid 1,4-lactone (IC50=45.75±2.16μM). Compounds 13, 19, 4, 12, 14, 22, 23, 25, 15, 8, 17, 11, 21, 1, 3, 18, 9, 2, and 24 with the IC50 values within the range of 0.6-44.0μM, indicated that the compounds have superior activity than the standard. The compounds showed no cytotoxic effects against PC-3 cells. A structure-activity relationship is established.
  4. Khan KM, Naz F, Taha M, Khan A, Perveen S, Choudhary MI, et al.
    Eur J Med Chem, 2014 Mar 3;74:314-23.
    PMID: 24486414 DOI: 10.1016/j.ejmech.2014.01.001
    Thiourea derivatives (1-38) were synthesized and evaluated for their urease inhibition potential. The synthetic compounds showed a varying degree of in vitro urease inhibition with IC50 values 5.53 ± 0.02-91.50 ± 0.08 μM, most of which are superior to the standard thiourea (IC₅₀ = 21.00 ± 0.11 μM). In order to ensure the mode of inhibition of these compounds, the kinetic study of the most active compounds has been carried out. Most of these inhibitors were found to be mixed-type of inhibitors, except compounds 13 and 30 which were competitive, while compound 19 was identified as non-competitive inhibitor with Ki values between 8.6 and 19.29 μM.
  5. 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.
  6. Taha M, Ismail NH, Jaafar FM, Khan KM, Yousuf S
    PMID: 23476582 DOI: 10.1107/S1600536813004388
    In the title benzoyl-hydrazide derivative, C17H18N2O, the dihedral angle between the benzene rings is 88.45 (8)° and the azomethine double bond adopts an E conformation. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds, forming a chain along the b axis.
  7. Imran S, Taha M, Ismail NH, Kashif SM, Rahim F, Jamil W, et al.
    Chem Biol Drug Des, 2016 Mar;87(3):361-73.
    PMID: 26362113 DOI: 10.1111/cbdd.12666
    We report herein the synthesis, α-glucosidase inhibition and docking studies for a series of 3-15 new flavones. A simple nucleophilic substitution reaction takes place between 3'hydroxyflavone (2) with halides to afford the new flavones. Chalcone (1), 3'hydroxyflavone (2) and the newly synthesized flavones (3-15) were being evaluated for their ability to inhibit activity of α-glucosidase. Compounds 2, 3, 5, 7-10 and 13 showed good inhibitory activity with IC50 values ranging between 1.26 and 36.44 μm as compared to acarbose (IC50 = 38.25 ± 0.12 μm). Compounds 5 (5.45 ± 0.08 μm), 7 (1.26 ± 0.01 μm) and 8 (8.66 ± 0.08 μm) showed excellent inhibitory activity, and this may be due to trifluoromethyl substitution that is common for these compounds. Compound 7, a 2,5-trifluoromethyl-substituted compound, recorded the highest inhibition activity, and it is thirty times better than the standard drug. Docking studies for compound 7 suggest that both trifluoromethyl substituents are well positioned in a binding pocket surrounded by Phe300, Phe177, Phe157, Ala278, Asp68, Tyr71 and Asp214. The ability of compound 7 to interact with Tyr71 and Phe177 is extremely significant as they are found to be important for substrates recognition by α-glucosidase.
  8. Taha M, Ismail NH, Imran S, Selvaraj M, Rahim A, Ali M, et al.
    Bioorg Med Chem, 2015 Dec 1;23(23):7394-404.
    PMID: 26526743 DOI: 10.1016/j.bmc.2015.10.037
    A series of compounds consisting of 25 novel oxadiazole-benzohydrazone hybrids (6-30) were synthesized through a five-step reaction sequence and evaluated for their β-glucuronidase inhibitory potential. The IC50 values of compounds 6-30 were found to be in the range of 7.14-44.16μM. Compounds 6, 7, 8, 9, 11, 13, 18, and 25 were found to be more potent than d-saccharic acid 1,4-lactone (48.4±1.25μM). These compounds were further subjected for molecular docking studies to confirm the binding mode towards human β-d-glucuronidase active site. Docking study for compound 13 (IC50=7.14±0.30μM) revealed that it adopts a binding mode that fits within the entire pocket of the binding site of β-d-glucuronidase. Compound 13 has the maximum number of hydrogens bonded to the residues of the active site as compared to the other compounds, that is, the ortho-hydroxyl group forms hydrogen bond with carboxyl side chain of Asp207 (2.1Å) and with hydroxyl group of Tyr508 (2.6Å). The other hydroxyl group forms hydrogen bond with His385 side chain (2.8Å), side chain carboxyl oxygen of Glu540 (2.2Å) and Asn450 side-chain's carboxamide NH (2.1Å).
  9. Taha M, Ismail NH, Imran S, Wadood A, Rahim F, Khan KM, et al.
    Bioorg Chem, 2016 Jun;66:80-7.
    PMID: 27038849 DOI: 10.1016/j.bioorg.2016.03.010
    Benzothiazole analogs (1-20) have been synthesized, characterized by EI-MS and (1)H NMR, and evaluated for urease inhibition activity. All compounds showed excellent urease inhibitory potential varying from 1.4±0.10 to 34.43±2.10μM when compared with standard thiourea (IC50 19.46±1.20μM). Among the series seventeen (17) analogs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, and 18 showed outstanding urease inhibitory potential. Analogs 15 and 19 also showed good urease inhibition activity. When we compare the activity of N-phenylthiourea 20 with all substituted phenyl derivatives (1-18) we found that compound 15 showed less activity than compound 20 having 3-methoxy substituent. The binding interactions of these active analogs were confirmed through molecular docking.
  10. Salar U, Taha M, Ismail NH, Khan KM, Imran S, Perveen S, et al.
    Bioorg Med Chem, 2016 Apr 15;24(8):1909-18.
    PMID: 26994638 DOI: 10.1016/j.bmc.2016.03.020
    Thiadiazole derivatives 1-24 were synthesized via a single step reaction and screened for in vitro β-glucuronidase inhibitory activity. All the synthetic compounds displayed good inhibitory activity in the range of IC50=2.16±0.01-58.06±1.60μM as compare to standard d-saccharic acid 1,4-lactone (IC50=48.4±1.25μM). Molecular docking study was conducted in order to establish the structure-activity relationship (SAR) which demonstrated that thiadiazole as well as both aryl moieties (aryl and N-aryl) involved to exhibit the inhibitory potential. All the synthetic compounds were characterized by spectroscopic techniques (1)H, (13)C NMR, and EIMS.
  11. Taha M, Ismail NH, Imran S, Wadood A, Rahim F, Saad SM, et al.
    Bioorg Chem, 2016 Jun;66:117-23.
    PMID: 27149363 DOI: 10.1016/j.bioorg.2016.04.006
    Twenty derivatives of 5-aryl-2-(6'-nitrobenzofuran-2'-yl)-1,3,4-oxadiazoles (1-20) were synthesized and evaluated for their α-glucosidase inhibitory activities. Compounds containing hydroxyl and halogens (1-6, and 8-18) were found to be five to seventy folds more active with IC50 values in the range of 12.75±0.10-162.05±1.65μM, in comparison with the standard drug, acarbose (IC50=856.45±5.60μM). Current study explores the α-glucosidase inhibition of a hybrid class of compounds of oxadiazole and benzofurans. These findings may invite researchers to work in the area of treatment of hyperglycemia. Docking studies showed that most compounds are interacting with important amino acids Glu 276, Asp 214 and Phe 177 through hydrogen bonds and arene-arene interaction.
  12. Imran S, Taha M, Ismail NH, Fayyaz S, Khan KM, Choudhary MI
    Bioorg Chem, 2015 Oct;62:83-93.
    PMID: 26275866 DOI: 10.1016/j.bioorg.2015.08.001
    This article describes discovery of 29 novel bisindolylmethanes consisting of thiourea moiety, which had been synthesized through three steps. These novel bisindolylmethane derivatives evaluated for their potential inhibitory activity against carbonic anhydrase (CA) II. The results for in vitro assay of carbonic anhydrase II inhibition activity showed that some of the compounds are capable of suppressing the activity of carbonic anhydrase II. Bisindoles having halogen at fifth position showed better inhibitory activity as compared to unsubstituted bisindoles. Derivatives showing inhibition activity docked to further, understand the binding behavior of these compounds with carbonic anhydrase II. Docking studies for the active compound 3j showed that nitro substituent at para position fits into the core of the active site. The nitro substituent of compound 3j is capable of interacting with Zn ion. This interaction believed to be the main factor causing inhibition activity to take place.
  13. Taha M, Ismail NH, Imran S, Rokei MQB, Saad SM, Khan KM
    Bioorg Med Chem, 2015 Aug 01;23(15):4155-4162.
    PMID: 26183542 DOI: 10.1016/j.bmc.2015.06.060
    Oxadiazole derivatives (6-28) having hydrazone linkage, were synthesized through condensation reaction between benzohydrazide 5 with various benzaldehydes. The oxadiazoles derivatives (6-28) were evaluated for their α-glucosidase inhibitory activity. The IC50 values for inhibition activity vary in the range between 2.64 ± 0.05 and 460.14 ± 3.25 μM. The IC50 values were being compared to the standard acarbose (IC50=856.45 ± 5.60 μM) and it was found that compounds 6-9, 12, 13, 16, 18, 20, 22-28 were found to be more active than acarbose, while other compounds showed no activity. Structure-activity relationship (SAR) studies suggest that oxadiazole benzohydrazones (6-28) inhibitory potential is dependent on substitution of the N-benzylidene part. Compound 18 (IC50=2.64 ± 0.05 μM), which has trihydroxy substitution at C-2', C-4', and C-5' on N-benzylidene moiety, recorded the highest inhibition activity that is three-hundred times more active than the standard drug, acarbose (IC50=856.45 ± 5.60 μM). Compound 23 (IC50=34.64 ± 0.35 μM) was found to be the most active among compounds having single hydroxyl substitution. Shifting hydroxyl from C-2' to C-4' (6) and C-3' (7) reduces inhibitory activity significantly. Compounds with chlorine substituent (compounds 16, 28, and 27) showed potent activities but lower as compared to hydroxyl analogs. Substituent like nitro or methyl groups at any position suppresses enzyme inhibition activity. This reveals the important presence of hydroxyl and halo groups to have enzyme inhibitory potential.
  14. Imran S, Taha M, Ismail NH, Fayyaz S, Khan KM, Choudhary MI
    Bioorg Chem, 2016 10;68:90-104.
    PMID: 27474804 DOI: 10.1016/j.bioorg.2016.07.011
    In this study, 45 bisindolylmethanes having sulfonamide moiety had been synthesized through 3 steps. In vitro assay for inhibition of carbonic anhydrase showed that some of the compounds having sulfonamide moiety are capable of inhibiting carbonic anhydrase II. Bisindoles having halogens at fifth position showed better inhibitory activity as compared to unsubstituted bisindoles. The results obtained from in vitro inhibitory activity were subjected through 3D QSAR and docking studies to identify important features contributing to the activity and further improve the structure. Pharmacophore studies suggest that bisindolylmethane moiety is contributing significantly towards the inhibition activity. Docking studies showed that compounds having nitro substituent (5g and 5i) were found to be able interact with Zn(2+) ion, Thr199, His94, His96, and His119, which interferes with the ZnOHThr199Glu106 hydrogen bond network. Bulky nitro substituent at ortho position for compound 5g prevents the compound from interacting with other residues like Thr199 and Thr200. Methyl substituent at ortho position for Compound 5i induces less steric hindrance effect, thus allowing second oxygen atom of sulfonamide to interact with Thr199 (2.51Å). Hydrogen bonding between NH on indole ring with Glu69 might have increased stability of ligand-receptor complex.
  15. Salar U, Taha M, Khan KM, Ismail NH, Imran S, Perveen S, et al.
    Eur J Med Chem, 2016 Oct 21;122:196-204.
    PMID: 27371923 DOI: 10.1016/j.ejmech.2016.06.037
    3-Thiazolylcoumarin derivatives 1-14 were synthesized via one-pot two step reactions, and screened for in vitro α-glucosidase inhibitory activity. All compounds showed inhibitory activity in the range of IC50 = 0.12 ± 0.01-16.20 ± 0.23 μM as compared to standard acarbose (IC50 = 38.25 ± 0.12 μM), and also found to be nontoxic. Molecular docking study was carried out in order to establish the structure-activity relationship (SAR) which demonstrated that electron rich centers at one and electron withdrawing centers at the other end of the molecules showed strong inhibitory activity. All the synthesized compounds were characterized by spectroscopic techniques such as EI-MS, HREI-MS, (1)H NMR and (13)C NMR. CHN analysis was also performed.
  16. Taha M, Ismail NH, Ali M, Rashid U, Imran S, Uddin N, et al.
    Bioorg Chem, 2017 04;71:192-200.
    PMID: 28228228 DOI: 10.1016/j.bioorg.2017.02.005
    The high potential of quinoline containing natural products and their derivatives in medicinal chemistry led us to discover a novel series of compounds 6-23 based on the concept of molecular hybridization. Most of the synthesized analogues exhibited potent leishmanicidal potential. The most potent compound (23, IC50=0.10±0.001μM) among the series was found ∼70 times more lethal than the standard drug. The current series 6-23 conceded in the development of fourteen (14) extraordinarily active compounds against leishmaniasis. In silico analysis were also performed to probe the mode of action while all the compounds structure were established by NMR and Mass spectral analysis.
  17. Salar U, Khan KM, Taha M, Ismail NH, Ali B, Qurat-Ul-Ain, et al.
    Eur J Med Chem, 2017 Jan 05;125:1289-1299.
    PMID: 27886546 DOI: 10.1016/j.ejmech.2016.11.031
    Current study is based on the biology-oriented drug synthesis (BIODS) of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl carboxylate derivatives 1-26, by treating metronidazole with different aryl and hetero-aryl carboxylic acids in the presence of 1,1'-carbonyl diimidazole (CDI) as a coupling agent. Structures of all synthetic derivatives were confirmed with the help of various spectroscopic techniques such as EI-MS, (1)H -NMR and (13)C NMR. CHN elemental analyses were also found in agreement with the calculated values. Synthetic derivatives were evaluated to check their β-glucuronidase inhibitory activity which revealed that except few derivatives, all demonstrated good inhibition in the range of IC50 = 1.20 ± 0.01-60.30 ± 1.40 μM as compared to the standard d-saccharic acid 1,4-lactone (IC50 = 48.38 ± 1.05 μM). Compounds 1, 3, 4, 6, 9-19, and 21-24 were found to be potent analogs and showed superior activity than standard. Limited structure-activity relationship is suggested that the molecules having electron withdrawing groups like NO2, F, Cl, and Br, were displayed better activity than the compounds with electron donating groups such as Me, OMe and BuO. To verify these interpretations, in silico study was also performed, a good correlation was observed between bioactivities and docking studies.
  18. Iqbal S, Saleem M, Azim MK, Taha M, Salar U, Khan KM, et al.
    Bioorg Chem, 2017 06;72:89-101.
    PMID: 28390994 DOI: 10.1016/j.bioorg.2017.03.014
    Discovery and development of carbonic anhydrase inhibitors is crucial for their clinical use as antiepileptic, diurectic and antiglaucoma agents. Keeping this in mind, we have synthesized carbohydrazones 1-27 and evaluated them for their in vitro carbonic anhydrase inhibitory potential. Out of twenty-seven compounds, compounds 1 (IC50=1.33±0.01µM), 2 (IC50=1.85±0.24µM), 3 (IC50=1.37±0.06µM), and 9 (IC50=1.46±0.12µM) have showed carbonic anhydrase inhibition better than the standard drug zonisamide (IC50=1.86±0.03µM). Moreover, compounds 4 (IC50=2.32±0.04µM), 5 (IC50=3.96±0.35µM), 7 (IC50=2.33±0.02µM), and 8 (IC50=2.67±0.01µM) showed good inhibitory activity. Cheminformatic analysis has shown that compounds 1 and 2 possess lead-like properties. In addition, kinetic and molecular docking studies were also performed to investigate the binding interaction between carbohydrazones and carbonic anhydrase enzyme. This study has identified a novel and potent class of carbonic anhydrase inhibitors with the potential to be investigated further.
  19. Baharudin MS, Taha M, Imran S, Ismail NH, Rahim F, Javid MT, et al.
    Bioorg Chem, 2017 06;72:323-332.
    PMID: 28505547 DOI: 10.1016/j.bioorg.2017.05.005
    Natural products are the main source of motivation to design and synthesize new molecules for drug development. Designing new molecules against β-glucuronidase inhibitory is utmost essential. In this study indole analogs (1-35) were synthesized, characterized using various spectroscopic techniques including 1H NMR and EI-MS and evaluated for their β-glucuronidase inhibitory activity. Most compounds were identified as potent inhibitors for the enzyme with IC50 values ranging between 0.50 and 53.40μM, with reference to standard d-saccharic acid 1,4-lactone (IC50=48.4±1.25μM). Structure-activity relationship had been also established. The results obtained from docking studies for the most active compound 10 showed that hydrogen bond donor features as well as hydrogen bonding with (Oε1) of nucleophilic residue Glu540 is believed to be the most importance interaction in the inhibition activity. It was also observed that hydroxyl at fourth position of benzylidene ring acts as a hydrogen bond donor and interacts with hydroxyl (OH) on the side chain of catalysis residue Tyr508. The enzyme-ligand complexed were being stabilized through electrostatic π-anion interaction with acid-base catalyst Glu451 (3.96Å) and thus preventing Glu451 from functioning as proton donor residue.
  20. Taha M, Baharudin MS, Ismail NH, Selvaraj M, Salar U, Alkadi KA, et al.
    Bioorg Chem, 2017 04;71:86-96.
    PMID: 28160943 DOI: 10.1016/j.bioorg.2017.01.015
    Novel sulfonamides having oxadiazole ring were synthesized by multistep reaction and evaluated to check in vitro β-glucuronidase inhibitory activity. Luckily, except compound 13, all compounds were found to demonstrate good inhibitory activity in the range of IC50=2.40±0.01-58.06±1.60μM when compared to the standard d-saccharic acid 1,4-lactone (IC50=48.4±1.25μM). Structure activity relationship was also presented. However, in order to ensure the SAR as well as the molecular interactions of compounds with the active site of enzyme, molecular docking studies on most active compounds 19, 16, 4 and 6 was carried out. All derivatives were fully characterized by 1H NMR, 13C NMR and EI-MS spectroscopic techniques. CHN analysis was also presented.
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