Displaying publications 1 - 20 of 157 in total

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  1. Zawawi NK, Taha M, Ahmat N, Wadood A, Ismail NH, Rahim F, et al.
    Bioorg Chem, 2016 Feb;64:29-36.
    PMID: 26637946 DOI: 10.1016/j.bioorg.2015.11.006
    Newly synthesized benzimidazole hydrazone derivatives 1-26 were evaluated for their α-glucosidase inhibitory activity. Compounds 1-26 exhibited varying degrees of yeast α-glucosidase inhibitory activity with IC50 values between 8.40 ± 0.76 and 179.71 ± 1.11 μM when compared with standard acarbose. In this assay, seven compounds that showed highest inhibitory effects than the rest of benzimidazole series were identified. All the synthesized compounds were characterized by different spectroscopic methods adequately. We further evaluated the interaction of the active compounds with enzyme with the help of docking studies.
  2. Zawawi NK, Taha M, Ahmat N, Ismail NH, Wadood A, Rahim F, et al.
    Bioorg Chem, 2015 Dec;63:36-44.
    PMID: 26432614 DOI: 10.1016/j.bioorg.2015.09.004
    Biscoumarin analogs 1-18 have been synthesized, characterized by EI-MS and (1)H NMR and evaluated for α-glucosidase inhibitory potential. All compounds showed variety of α-glucosidase inhibitory potential ranging in between 13.5±0.39 and 104.62±0.3μM when compared with standard acarbose having IC50 value 774.5±1.94μM. The binding interactions of the most active analogs were confirmed through molecular docking. The compounds showed very good interactions with enzyme. All synthesized compounds 1-18 are new. Our synthesized compounds can further be studied to developed lead compounds.
  3. Zawawi NK, Taha M, Ahmat N, Wadood A, Ismail NH, Rahim F, et al.
    Bioorg Med Chem, 2015 Jul 1;23(13):3119-25.
    PMID: 26001340 DOI: 10.1016/j.bmc.2015.04.081
    A library of novel 2,5-disubtituted-1,3,4-oxadiazoles with benzimidazole backbone (3a-3r) was synthesized and evaluated for their potential as β-glucuronidase inhibitors. Several compounds such as 3a-3d, 3e-3j, 3l-3o, 3q and 3r showed excellent inhibitory potentials much better than the standard (IC50=48.4±1.25μM: d-saccharic acid 1,4-lactone). All the synthesized compounds were characterized satisfactorily by using different spectroscopic methods. We further evaluated the interaction of the active compounds and the enzyme active site with the help of docking studies.
  4. Zawawi NK, Rajput SA, Taha M, Ahmat N, Ismail NH, Abdullah N, et al.
    Bioorg Med Chem Lett, 2015 Oct 15;25(20):4672-6.
    PMID: 26330080 DOI: 10.1016/j.bmcl.2015.08.022
    Apoptotic cell death is the cause of the loss of insulin-producing β-cells in all forms of diabetes mellitus. The identification of small molecules capable of protecting cytokine-induced apoptosis could form the basis of useful therapeutic interventions. Here in, we present the discovery and synthesis of new benzimidazole derivatives, capable of rescuing pancreatic β-cells from cytokine-induced apoptosis. Three hydrazone derivatives of benzimidazole significantly increased the cellular ATP levels, reduced caspase-3 activity, reduced nitrite production and increased glucose-stimulated insulin secretion in the presence of proinflammatory cytokines. These findings suggest that these compounds may protect β-cells from the harmful effects of cytokines and may serve as candidates for therapeutic intervention for diabetes.
  5. Zawawi NK, Taha M, Ahmat N, Ismail NH, Wadood A, Rahim F
    Bioorg Chem, 2017 02;70:184-191.
    PMID: 28043716 DOI: 10.1016/j.bioorg.2016.12.009
    Thiourea derivatives having benzimidazole 1-17 have been synthesized, characterized by 1H NMR, 13C NMR and EI-MS and evaluated for α-glucosidase inhibition. Identification of potential α-glucosidase inhibitors were done by in vitro screening of 17 thiourea bearing benzimidazole derivatives using Baker's yeast α-glucosidase enzyme. Compounds 1-17 exhibited a varying degree of α-glucosidase inhibitory activity with IC50 values between 35.83±0.66 and 297.99±1.20μM which are more better than the standard acarbose (IC50=774.5±1.94μM). Compound 10 and 14 showed significant inhibitory effects with IC50 value 50.57±0.81 and 35.83±0.66μM, respectively better than the rest of the series. Structure activity relationships were established. Molecular docking studies were performed to understand the binding interaction of the compounds.
  6. Zaman K, Rahim F, Taha M, Wadood A, Shah SAA, Ahmed QU, et al.
    Sci Rep, 2019 11 05;9(1):16015.
    PMID: 31690793 DOI: 10.1038/s41598-019-52100-0
    Here in this study regarding the over expression of TP, which causes some physical, mental and socio problems like psoriasis, chronic inflammatory disease, tumor angiogenesis and rheumatoid arthritis etc. By this consideration, the inhibition of this enzyme is vital to secure life from serious threats. In connection with this, we have synthesized twenty derivatives of isoquinoline bearing oxadiazole (1-20), characterized through different spectroscopic techniques such as HREI-MS, 1H- NMR and 13C-NMR and evaluated for thymidine phosphorylase inhibition. All analogues showed outstanding inhibitory potential ranging in between 1.10 ± 0.05 to 54.60 ± 1.50 µM. 7-Deazaxanthine (IC50 = 38.68 ± 1.12 µM) was used as a positive control. Through limited structure activity relationships study, it has been observed that the difference in inhibitory activities of screened analogs are mainly affected by different substitutions on phenyl ring. The effective binding interactions of the most active analogs were confirmed through docking study.
  7. Zaman K, Rahim F, Taha M, Ullah H, Wadood A, Nawaz M, et al.
    Bioorg Chem, 2019 08;89:103024.
    PMID: 31176853 DOI: 10.1016/j.bioorg.2019.103024
    Despite of many diverse biological activities exhibited by benzimidazole scaffold, it is rarely explored for the urease inhibitory potential. For that purpose, benzimidazole analogues 1-19 were synthesized and screened for in vitro urease inhibitory potential. Structures of all synthetic analogues were deduced by different spectroscopic techniques. All analogues revealed inhibition potential with IC50 values of 0.90 ± 0.01 to 35.20 ± 1.10 μM, when compared with the standard thiourea (IC50 = 21.40 ± 0.21 μM). Limited SAR suggested that the variations in the inhibitory potentials of the analogues are the result of different substitutions on phenyl ring. In order to rationalize the binding interactions of most active compounds with the active site of urease enzyme, molecular docking study was conducted.
  8. Zaman K, Rahim F, Taha M, Wadood A, Adnan Ali Shah S, Gollapalli M, et al.
    Bioorg Chem, 2019 08;89:102999.
    PMID: 31151055 DOI: 10.1016/j.bioorg.2019.102999
    Isoquinoline analogues (KA-1 to 16) have been synthesized and evaluated for their E. coli thymidine phosphorylase inhibitory activity. Except compound 11, all other analogs showed outstanding thymidine inhibitory potential ranging in between 4.40 ± 0.20 to 69.30 ± 1.80 µM when compared with standard drug 7-Deazaxanthine (IC50 = 38.68 ± 4.42 µM). Structure Activity Relationships has been established for all compounds, mainly based on substitution pattern on phenyl ring. All analogs were characterized by various spectroscopic techniques such as 1H NMR, 13C NMR and EI-MS. The binding interactions of isoquinoline analogues with the active site of TP enzyme, the molecular docking studies were performed. Furthermore, the angiogenic inhibitory potentials of isoquinoline analogues (KA-1-9, 14, 12 and 16) were determined in the presence of standard drug Dexamethasone based on percentage inhibitions at various concentrations. Herein this work analogue KA-12, 14 and 16 emerged with most potent angiogenic inhibitory potentials among the synthesized analogues.
  9. Zaman K, Rahim F, Taha M, Sajid M, Hayat S, Nawaz M, et al.
    Bioorg Chem, 2021 10;115:105199.
    PMID: 34329995 DOI: 10.1016/j.bioorg.2021.105199
    Synthesis of quinoline analogs and their urease inhibitory activities with reference to the standard drug, thiourea (IC50 = 21.86 ± 0.40 µM) are presented in this study. The inhibitory activity range is (IC50 = 0.60 ± 0.01 to 24.10 ± 0.70 µM) which displayed that it is most potent class of urease inhibitor. Analog 1-9, and 11-13 emerged with many times greater antiurease potential than thiourea, in which analog 1, 2, 3, 4, 8, 9, and 11 (IC50 = 3.50 ± 0.10, 7.20 ± 0.20, 1.30 ± 0.10, 2.30 ± 0.10, 0.60 ± 0.01, 1.05 ± 0.10 and 2.60 ± 0.10 µM respectively) were appeared the most potent ones among the series. In this context, most potent analogs such as 1, 3, 4, 8, and 9 were further subjected for their in vitro antinematodal study against C. elegans to examine its cytotoxicity under positive control of standard drug, Levamisole. Consequently, the cytotoxicity profile displayed that analogs 3, 8, and 9 were found with minimum cytotoxic outline at higher concentration (500 µg/mL). All analogs were characterized through 1H NMR, 13C NMR and HR-EIMS. The protein-ligand binding interaction for most potent analogs was confirmed via molecular docking study.
  10. Yeye EO, Kanwal, Mohammed Khan K, Chigurupati S, Wadood A, Ur Rehman A, et al.
    Bioorg Med Chem, 2020 06 01;28(11):115467.
    PMID: 32327353 DOI: 10.1016/j.bmc.2020.115467
    Thirty-three 4-amino-1,2,4-triazole derivatives 1-33 were synthesized by reacting 4-amino-1,2,4-triazole with a variety of benzaldehydes. The synthetic molecules were characterized via1H NMR and EI-MS spectroscopic techniques and evaluated for their anti-hyperglycemic potential. Compounds 1-33 exhibited good to moderate in vitro α-amylase and α-glucosidase inhibitory activities in the range of IC50 values 2.01 ± 0.03-6.44 ± 0.16 and 2.09 ± 0.08-6.54 ± 0.10 µM as compared to the standard acarbose (IC50 = 1.92 ± 0.17 µM) and (IC50 = 1.99 ± 0.07 µM), respectively. The limited structure-activity relationship suggested that different substitutions on aryl part of the synthetic compounds are responsible for variable activity. Kinetic study predicted that compounds 1-33 followed mixed and non-competitive type of inhibitions against α-amylase and α-glucosidase enzymes, respectively. In silico studies revealed that both triazole and aryl ring along with different substitutions were playing an important role in the binding interactions of inhibitors within the enzyme pocket. The synthetic molecules were found to have dual inhibitory potential against both enzymes thus they may serve as lead candidates for the drug development and research in the future studies.
  11. Ullah H, Rahim F, Taha M, Uddin I, Wadood A, Shah SAA, et al.
    Bioorg Chem, 2018 08;78:58-67.
    PMID: 29533215 DOI: 10.1016/j.bioorg.2018.02.020
    We have synthesized oxadiazole derivatives (1-16), characterized by 1H NMR, 13C NMR and HREI-MS and screened for thymidine phosphorylase inhibitory potential. All derivatives display varied degree of thymidine phosphorylase inhibition in the range of 1.10 ± 0.05 to 49.60 ± 1.30 μM when compared with the standard inhibitor 7-Deazaxanthine having an IC50 value 38.68 ± 1.12 μM. Structure activity relationships (SAR) has been established for all compounds to explore the role of substitution and nature of functional group attached to the phenyl ring which applies imperious effect on thymidine phosphorylase activity. Molecular docking study was performed to understand the binding interaction of the most active derivatives with enzyme active site.
  12. Tajudeen Bale A, Mohammed Khan K, Salar U, Chigurupati S, Fasina T, Ali F, et al.
    Bioorg Chem, 2018 09;79:179-189.
    PMID: 29763804 DOI: 10.1016/j.bioorg.2018.05.003
    Despite of a diverse range of biological activities associated with chalcones and bis-chalcones, they are still neglected by the medicinal chemist for their possible α-amylase inhibitory activity. So, the current study is based on the evaluation of this class for the identification of new leads as α-amylase inhibitors. For that purpose, a library of substituted chalcones 1-13 and bis-chalcones 14-18 were synthesized and characterized by spectroscopic techniques EI-MS and 1H NMR. CHN analysis was carried out and found in agreement with the calculated values. All compounds were evaluated for in vitro α-amylase inhibitory activity and demonstrated good activities in the range of IC50 = 1.25 ± 1.05-2.40 ± 0.09 µM as compared to the standard acarbose (IC50 = 1.04 ± 0.3 µM). Limited structure-activity relationship (SAR) was established by considering the effect of different groups attached to aryl rings on varying inhibitory activity. SMe group in chalcones and OMe group in bis-chalcones were found more influential on the activity than other groups. However, in order to predict the involvement of different groups in the binding interactions with the active site of α-amylase enzyme, in silico studies were also conducted.
  13. Taha MM, Sheikh BY, Salim LZ, Mohan S, Khan A, Kamalidehghan B, et al.
    Cell Mol Biol (Noisy-le-grand), 2016 May 30;62(6):97-101.
    PMID: 27262811
    Nigella sativa is also known for its properties as a traditional herbal healing for many ailments. In this study, the anticancer properties of thyomquinone (TQ), the active ingredient of N. sativa, were studied using ovarian cancer cell line (Caov-3 cells). The anti-proliferative activity of TQ was determined using MTT and the apoptosis was investigated using Flowcytometry and Annexin-V Assays. Multiparameteric cytotoxicity bioassays were used to quantify the changes in cell permeability and mitochondrial membrane potential. Reactive oxygen species (ROS) and apoptosis-involved cell markers were examined to verify cell death mechanism. The MTT-assay showed that TQ induces anti-proliferative activity on Caov-3 with an IC50 of 6.0±0.03 μg/mL, without any cytotoxic activity towards WRL-68 normal hepatocytes. A significant induction of early phase of apoptosis was shown by annexin-V analysis. Treatment of Caov-3 cells with TQ induces decreases in plasma membrane permeability and mitochondrial membrane potential. Visible decrease in the nuclear area was also observed. A significant decrease is observed in Bcl-2 while Bax is down-regulated. TQ-triggered ROS-mediated has found to be associated with Hsp70 dysregulation, an indicator of oxidative injury. We found that TQ induced anti-cancer effect involves intrinsic pathway of apoptosis and cellular oxidative stress. Our results considered collectively indicated that thyomquinone may be a potential agent for ovarian cancer drug development.
  14. Taha MA, Ravindran J
    Med J Malaysia, 2003 Mar;58 Suppl A:9-18.
    PMID: 14556346
    When a doctor is required to go to court, he does so with some amount of trepidation. The degree of trepidation increases in direct proportion as to whether he is required to be a witness or a defendant. The practice of medicine on the other hand requires the patient to have full confidence and open out his secrets to the doctor. If you hold back vital information, the diagnosis may be entirely different to the disease that you have. Lawyers who enter hospitals may also do so with some trepidation, maybe even more so than doctors who enter courts, as their lives are at stake. There is a perception that medico-legal matters are on the rise. We may put forward a few reasons for this: 1. A better educated and increasingly assertive public with greater awareness of the medical and legal systems; 2. Rising expectations of medical results; 3. Commercialization of medical care with erosion of the doctor-patient trust relationship. This paper will discuss the reasons for and the ways to address medical errors as well as explore the reasons for defensive medicine. The argument is put forward that public education programs on the risks inherent in some of the new advances in treatment modalities and surgery and professional education programs on the need for obtaining the patient's informed consent to such treatment is needed. Public advocacy programs to demonstrate the problems in medicine and the delivery of health care resulting from strict cost containment limitations should be carried out. There is also the need to enhance the level and quality of medical education for all physicians, including improved clinical training experiences. Doctors' must manage their clinical affairs in a professional manner without being dictated to by the legal system. However, it would be wise to take note of the views expressed by learned counsel and judges in their courts. The middle road is always the best and we must never be extreme in our viewpoints. We must always remember the patient is why we are here and the patient must never suffer in the process while we formulate our responses to the medico-legal challenges that lie ahead.
  15. Taha M, Ismail NH, Lalani S, Fatmi MQ, Atia-Tul-Wahab, Siddiqui S, et al.
    Eur J Med Chem, 2015 Mar 6;92:387-400.
    PMID: 25585009 DOI: 10.1016/j.ejmech.2015.01.009
    In an effort to design and synthesize a new class of α-glucosidase inhibitor, we synthesized benzothiazole hybrid having benzohydrazide moiety (5). Compound 5 was reacted with various substituted aryl aldehyde to generate a small library of compounds 6-35. Synthesis of compounds was confirmed by the spectral information. These compounds were screened for their α-glucosidase activity. They showed a varying degree of α-glucosidase inhibition with IC50 values ranging between 5.31 and 53.34 μM. Compounds 6, 7, 9-16, 19, 21-30, 32-35 showed superior activity as compared to standard acarbose (IC50 = 906 ± 6.3 μM). This has identified a new class of α-glucosidase inhibitors. The predicted physico-chemical properties indicated the drug appropriateness for most of these compounds, as they obey Lipinski's rule of five (RO5). A hybrid B3LYP density functional theory (DFT) was employed for energy, minimization of 3D structures for all synthetic compounds using 6-311 + G(d,p) basis sets followed by molecular docking to explore their interactions with human intestinal C- and N-terminal domains of α-glucosidase. All compounds bind to the prospective allosteric site of the C- terminal domain, and consequently, may be considered as mixed inhibitors. It was hypothesized that both the dipole moment and H-bond interactions govern the biological activation of these compounds.
  16. Taha M, Ismail NH, Jamil W, Rashwan H, Kashif SM, Sain AA, et al.
    Eur J Med Chem, 2014 Sep 12;84:731-8.
    PMID: 25069019 DOI: 10.1016/j.ejmech.2014.07.078
    4-Methylbenzimidazole 1-28 novel derivatives were synthesized and evaluated for their antiglycation and antioxidant activities. Compounds 1-7 and 11 showed excellent activities ranged 140-280 μM, better than standard drug rutin (294.46 ± 1.50 μM). Compound 1-28 were also evaluated for DPPH activities. Compounds 1-8 showed excellent activities, ranging 12-29 μM, better than standard drug n-propylgallate (IC50 = 30.30 ± 0.40 μM). For superoxide anion scavenging activity, compounds 1-7 showed better activity than standard n-propylgallate (IC50 = 106.34 ± 1.6 μM), ranged 82-104 μM. These compounds were found to be nontoxic to THP-1 cells.
  17. Taha M, Shah SA, Sultan S, Ismail NH, Yousuf S
    Acta Crystallogr Sect E Struct Rep Online, 2014 Feb 01;70(Pt 2):o131.
    PMID: 24764858 DOI: 10.1107/S1600536813034636
    The title phenyl-hydrazine derivative, C16H16N2O4, has a crystallographically imposed centre of symmetry. Except for the methyl group, all non-H atoms are almost coplanar (r.m.s. deviation = 0.0095 Å). Intra-molecular O-H⋯N hydrogen bonds are observed, generating S(6) graph-set ring motifs.
  18. Taha M, Naz H, Rasheed S, Ismail NH, Rahman AA, Yousuf S, et al.
    Molecules, 2013;19(1):1286-301.
    PMID: 24451249 DOI: 10.3390/molecules19011286
    A series of 4-methoxybenzoylhydrazones 1-30 was synthesized and the structures of the synthetic derivatives elucidated by spectroscopic methods. The compounds showed a varying degree of antiglycation activity, with IC50 values ranging between 216.52 and 748.71 µM, when compared to a rutin standard (IC50=294.46±1.50 µM). Compounds 1 (IC50=216.52±4.2 µM), 3 (IC50=289.58±2.64 µM), 6 (IC50=227.75±0.53 µM), 7 (IC50=242.53±6.1) and 11 (IC50=287.79±1.59) all showed more activity that the standard, and these compounds have the potential to serve as possible leads for drugs to inhibit protein glycation in diabetic patients. A preliminary SAR study was performed.
  19. Taha M, Ismail NH, Jamil W, Yousuf S, Jaafar FM, Ali MI, et al.
    Molecules, 2013 Sep 05;18(9):10912-29.
    PMID: 24013406 DOI: 10.3390/molecules180910912
    2,4-Dimethylbenzoylhydrazones 1-30 were synthesized by condensation reactions of 2,4-dimethylbenzoylhydrazide with various aromatic aldehydes and characterized. The assigned structures of compounds 10, 15 and 22 were further supported by single-crystal X-ray diffraction data. The synthesized compounds were evaluated for their in vitro DPPH radical scavenging activity. They exerted varying degree of scavenging activity toward DPPH radical with IC₅₀ values between 25.6-190 µM. Compounds 1, 4, 2, 3, 7, and 6 have IC₅₀ values of 25.6, 28.1, 29.3, 29.8, 30.0 and 30.1 µM respectively, showing better activity than an n-propyl gallate standard (IC₅₀ value = 30.30 µM). For super oxide anion scavenging activity compounds 1, 2 and 3 with IC₅₀ values of 98.3, 102.6, and 105.6, respectively, also showed better activity than the n-propyl gallate standard (IC₅₀ value = 106.34 µM).
  20. Taha M, Ismail NH, Jaafar FM, Aziz AN, Yousuf S
    PMID: 23634042 DOI: 10.1107/S1600536813005692
    In the title compound, C16H16N2O3·H2O, the dihedral angle between the benzene rings is 30.27 (7)°. In the crystal, the components are linked by N-H⋯O, O-H⋯O and C-H⋯O inter-actions into a three-dimensional network.
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