M Iqbal Choudhary

King Abdulaziz University, Djidda, Makkah, Saudi Arabia

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Publications (711)987.76 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Pyridyl-benzimidazole analogues 1–11 with variable substituent on phenyl ring of phenacyl moiety were synthesized and evaluated for their urease inhibitory activity. The compounds exhibited urease inhibition with IC50 between 19.22 and 77.31 µM. Compounds 4 (IC50 = 19.22 ± 0.49 µM) showed a urease inhibition comparable to thiourea (IC50 = 21.00 ± 0.01 µM) and twofold more active than acetohydroxamic acid (IC50 = 42.00 ± 1.26 µM) (standards), respectively. Moreover, compounds 5 (IC50 = 21.55 ± 0.36 µM), 1 (IC50 = 24.37 ± 0.41 µM), 7 (IC50 = 25.44 ± 0.19 µM), 6 (IC50 = 27.62 ± 0.25 µM), 3 (IC50 = 31.32 ± 0.75 µM), 8 (40.88 ± 0.36 µM) and 9 (41.22 ± 0.42 µM) also exhibited excellent activities when compared to the standards. Compounds 2 (IC50 = 65.46 ± 0.75 µM), 10 (68.99 ± 0.33 µM) and 11 (77.31 ± 0.51 µM) showed a moderate activity. The size of the substituents and their electron donating or withdrawing affects as well as their position on phenyl apparently modulates the enzyme inhibitory activity.
    Medicinal Chemistry Research 10/2014; 23(10). · 1.61 Impact Factor
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    ABSTRACT: Compounds 1–30 showed varying degree of α-glucosidase inhibition with IC50 values ranging between 187 and 420 μM. Compounds 1, 2, 3, 6, 8, 12, and 4 (IC50 = 187.7 ± 3.05, 203.4 ± 4.0, 240.7 ± 1.9, 252.9 ± 3.9, 285.2 ± 6.3, 399.07 ± 1.2, and 420.36 ± 5.6 μM, respectively) were found to be more active than standard acarbose (IC50 = 906 ± 6.3 μM). The synthetic compounds were also tested for urease inhibition. Compounds 5 (IC50 = 19.6 ± 1.0 μM) and 1 (IC50 = 21.6 ± 0.6 μM) showed better activity than standard drug thiourea (IC50 = 21.8 ± 1.6 μM). The crystal structures of compounds 15 and 16 are also reported.
    Medicinal Chemistry Research 08/2014; · 1.61 Impact Factor
  • Yahia Nasser Mabkhot, Assem Barakat, Sammer Yousuf, M. Iqbal Choudhary, Wolfgang Frey, Taibi Ben Hadda, Mohammad S. Mubarak
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    ABSTRACT: A series of 15 novel compounds incorporating the thieno[2,3-b]thiophene moiety were synthesized. The chemical structures of these compounds were deduced from elemental analyses, 1H-NMR, 13C-NMR, and ESI-mass spectral data. The enzyme inhibition potential of these compounds was evaluated, in vitro, against β-glucuronidase, xanthine oxidase, and -chymotripsin enzymes. The cytotoxicity was evaluated by a cell viability assay utilizing the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Among the compounds tested, compound 3 was the most potent β-glucuronidase inhibitor with an IC50 value of 0.9±0.0138 μM; it was much more active than the standard, D-saccharic acid 1-4- lactone (IC50 = 45.75±2.16 μM). Compound 12, on the other hand, was the most potent as a xanthine oxidase inhibitor with an IC50 of 14.4±1.2 μM. With the characterization of their mechanism of action and with further testing, these compounds could be useful candidates as anticancer drugs. In addition, the newly synthesized products were subjected to POM Analyses to get insights on the degree of their toxicity.
    Bioorganic & Medicinal Chemistry. 08/2014;
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    ABSTRACT: Oxadiazoles and thiadiazoles 1-37 were synthesized and evaluated for the first time for their α-glucosidase inhibitory activities. As a result, fifteen of them 1, 4, 5, 7, 8, 13, 17, 23, 25, 30, 32, 33, 35, 36 and 37 were identified as potent inhibitors of the enzyme. Kinetic studies of the most active compounds (oxadiazoles 1, 23 and 25, and thiadiazoles 35 and 37) were carried out to determine their mode of inhibition and dissociation constants Ki. The most potent compound of the oxadiazole series (compound 23) was found to be a non-competitive inhibitor (Ki=4.36±0.017μM), while most potent thiadiazole 35 was identified as a competitive inhibitor (Ki=6.0±0.059μM). The selectivity and toxicity of these compounds were also studied by evaluating their potential against other enzymes, such as carbonic anhydrase-II and phosphodiesterase-I. Cytotoxicity was evaluated against rat fibroblast 3T3 cell line. Interestingly, these compounds were found to be inactive against other enzymes, exhibiting their selectivity towards α-glucosidase. Inhibition of α-glucosidase is an effective strategy for controlling post-prandial hyperglycemia in diabetic patients. α-Glucosidase inhibitors can also be used as anti-obesity and anti-viral drugs. Our study identifies two novel series of potent α-glucosidase inhibitors for further investigation.
    Bioorganic & medicinal chemistry. 07/2014;
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    ABSTRACT: In a previous study, we evaluated the maternal and fetal safety of antimalarial herb Artemisia annua with artemisinin yield of 1.09%. Here, we attempted to ascertain the contraceptive claim of A. annua. Sexually matured female Wistar rats (180–220 g) were allotted into four study groups of six rats each. The control group received normal saline, while the A. annua-treated groups received 100, 200 and 300 mg/kg of A. annua for 2 weeks, followed by mating with proven fertile males (1:1). The rats were allowed to carry the pregnancy to term. At birth and weaning periods, selected reproductive outcome and fertility indices were determined. The results showed that A. annua significantly reduced litter size, reproductive outcome and fertility indices compared with the control ( p < 0.05). These results imply that A. annua could serve as a prospective contraceptive agent in addition to its antimalarial activity.
    Natural Product Research 07/2014; · 1.03 Impact Factor
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    ABSTRACT: A variety of zwitterionic adducts were synthesized by using means green chemistry method. The products contain the biologically active barbituric acid moiety embedded in zwitterion products. Both features are pharmaceutically relevant. The chemical structures were deduced by 1H-, 13C-, NMR and HRMS spectral analysis, and X-Ray diffraction techniques. In vitro evaluation for the antioxidant activities were carried out towards the inhibition of nitric oxide (NO) radical, known to regulate a mechanism of signals for various cellular functions. NO also play an important role as a mediator of various pathological conditions responsible for cellular damages such as strokes, cancers, diabetes, chronic heart failure and inflammatory disease and various neurodegenerative disorders. All tested compounds were found to be more potent nitric oxide scavengers as compared to standard drug ascorbic acid (IC50 = 618±2.0 µM). Compounds 4c and e exhibiting several hundred fold more activity against nitric oxide radical with IC50 values of 69±1.66 and 70.1±0.89 µM respectively, as compared to standard drug ascorbic acid (IC50 = 618±2.0 µM).
    European Journal of Medicinal Chemistry 07/2014; 84:146-154. · 3.50 Impact Factor
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    ABSTRACT: AimsThe emergence of multi-drug resistant (MDR) Staphylococcus aureus is a challenge for the treatment of infections. We report here the antimicrobial potential of artonin I against MDR S. aureus, its mechanism of reversal of resistance and synergistic effects by combinational therapy.Methods and ResultsArtonin I, a flavonoid obtained from Morus mesozygia Stapf., inhibited the bacterial efflux pump and induced depolarization of the cell membrane. To study the dose-dependent production of reactive oxygen species in MDR cells by artonin I, lucigenin chemiluminescence assay was employed. Reversal of multi-drug resistance by artonin I, in combination with antibiotics, was measured by a fractional inhibitory concentration index assay. The effect of artonin I on ultra-structural features was studied by microscopy. Artonin I increased the penetration of ethidium bromide by blocking the efflux mechanism. It also helped anionic probe DiBAC4(3) to bind with the lipid rich cellular components by causing depolarization of the cell membrane. Artonin I reversed multi-drug resistance and increased the susceptibility of existing antibiotics by lowering their minimum inhibitory concentrations (MICs).Conclusions Artonin I was identified both as a new antibacterial agent and as a helper molecule to potentiate the action of otherwise inactive antibiotics.This article is protected by copyright. All rights reserved.
    Journal of Applied Microbiology 07/2014; · 2.20 Impact Factor
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    ABSTRACT: C16H18N2O3, triclinic, P1 (no. 2), a = 8.7144(8) Å, b = 9.2142(9) Å, c = 9.6953(9) Å, a = 78.859(2)°, b = 74.822(2)°, g = 89.031(2)°, V = 736.7 Å3, Z = 2, Rgt(F) = 0.0588, wRref(F2) = 0.1867, T = 273 K.
    Zeitschrift für Kristallographie 06/2014; 229. · 1.24 Impact Factor
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    ABSTRACT: A series of thiobarbituric acid derivatives 1-27 were synthesized and evaluated for their urease inhibitory potential. Exciting results were obtained from the screening of these compounds 1-27. Compounds 5, 7, 8, 11, 16, 17, 22, 23 and 24 showed excellent urease inhibition with IC50 values 18.1±0.52, 16.0±0.45, 16.0±0.22, 14.3±0.27, 6.7±0.27, 10.6±0.17, 19.2±0.29, 18.2±0.76 and 1.61±0.18μM, respectively, much better than the standard urease inhibitor thiourea (IC50=21±0.11μM). Compound 3, 4, 10, and 26 exhibited comparable activities to the standard with IC50 values 21.4±1.04 and 21.5±0.61μM, 22.8±0.32, 25.2±0.63, respectively. However the remaining compounds also showed prominent inhibitory potential The structure-activity relationship was established for these compounds. This study identified a novel class of urease inhibitors. The structures of all compounds were confirmed through spectroscopic techniques such as EI-MS and (1)H NMR.
    Bioorganic & medicinal chemistry. 06/2014;
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    ABSTRACT: We report here a new class of compounds, quinoline derivatives, as potential inhibitors of in vitro bovine serum albumin-methylglyoxal glycation. Among compounds 1-19, compound 14 was found to be the most active analog with IC50 of 282.98 ± 8.4 µM, Compounds 12 (IC50 = 661.78 ± 8.7 µM) and 15 (IC50 = 629.43 ± 7.85 7 µM) were also identified as good inhibitors, in comparison to the standard inhibitor, rutin (IC50 = 294.50 ± 1.5 µM). When evaluated for antioxidant activity through in vitro DPPH radical scavenging assay, compounds 3 (IC50 = 2.19 ± 0.27 µM), 6 (IC50 = 7.35 ± 2.27 µM), 11 (IC50 = 8.96 ± 0.56 µM), and 12 (IC50 = 10.11 ± 2.03 µM), and 15 (IC50 = 7.01 ± 3.87 µM) were found to be more active than the standard i.e. gallic acid (IC50 = 23.34 ± 0.43 µM). These compounds were also evaluated for cytotoxicity against rat fibroblast cell line (3T3 cell line). All compounds were found to be non-toxic in cellular model. This study identifies quinoline derivatives as a new class of inhibitors of protein glycation in vitro, along with antioxidant and non-toxic nature. This makes them interesting leads for further studies.
    Medicinal chemistry (Shariqah (United Arab Emirates)). 05/2014;
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    ABSTRACT: Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower level of acetylcholine (ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase (AChE) and butyrylcholinesterase (BChE) are considered to be primary regulators of the ACh level in brain. Evidence showed that AChE activity decreases in AD, while activity of BChE doesn't change or even elevate in advanced AD, which suggests a key involvement of BChE in ACh hydrolysis during AD symptoms. Therefore, inhibiting the activity of BChE may be an effective way to control AD associated disorders. In this regard, a series of quinoxaline derivatives 1-17 was synthesized and biologically evaluated against cholinesterases (AChE and BChE) and as well as against a-chymotrypsin and urease. The compounds 1-17 were found to be selective inhibitor for BChE, as no activity was found against other enzymes. Among the series, compounds 6 (IC50 = 7.7 ± 1.0 μM) and 7 (IC50 = 9.7 ± 0.9 μM) were found to be the most active inhibitors against BChE. Their IC50 values are comparable to the standard, galantamine (IC50 = 6.6 ± 0.38 µM). Their considerable BChE inhibitory activity, make them selective candidates for the development of BChE inhibitors. Structure-activity relationship (SAR) of this new class of selective BChE inhibitors has been discussed.
    Medicinal chemistry (Shariqah (United Arab Emirates)). 05/2014;
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    ABSTRACT: Synthesis of 1,1 󸀠 -(3,4-diphenylthieno[2,3-b]thiophene-2,5-diyl)diethanone (4) is reported here. The structure of compound4was deduced by 1 H-NMR, 13 C-NMR, FT-IR, MS, microanalysis, and single-crystal X-ray diffraction. Compound crystallizes in the monoclinic space groupP21/nwitha= 9.3126(7)˚ A,b= 9.5867(7)˚ A,c= 20.2811(15)˚ A,𝛼=90∘ , 𝛽= 95.436(2) ∘ , 𝛾=90∘ , V= 1802.5(2)˚ A 3 ,andZ= 4. The molecules are packed in crystal structure by weak intermolecular C10–H10A⋅⋅⋅S1 hydrogen bonding interactions. Compound 4can be a useful intermediate for the synthesis of diphenylthieno[2,3-b]thiophene. Compound4was foundtobeactiveagainstGram-positivebacteria(Bacillus subtilisandStaphylococcus pneumoniae) and Gram-negative bacteria (Escherichia coli) and also was found to be active against fungi (Aspergillus fumigatusandCandida albicans).
    Journal of Chemistry 05/2014; 504860:1-5. · 0.48 Impact Factor
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    ABSTRACT: In our effort directed toward the discovery of new anti-diabetic agent for the treatment of diabetes, a library of biscoumarin derivative 1-18 was synthesized and evaluated for α-glucosidase inhibitory potential. All eighteen (18) compounds displayed assorted α-glucosidase activity with IC50 values 16.5-385.9 μM, if compared with the standard acarbose (IC50 = 906 ± 6.387 μM). In addition, molecular docking studies were carried out to explore the binding interactions of biscoumarin derivatives with the enzyme. This study has identified a new class of potent α-glucosidase inhibitors.
    European journal of medicinal chemistry. 05/2014; 81C:245-252.
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    ABSTRACT: Two new natural triterpenes, lantaninilic acid and lantoic acid, along with the known triterpenes lantadene A, and oleanolic, ursolic, betulinic, lantanolic, and camaric acid, were obtained from the aerial parts of Lantana camara through bioassay-guided isolation, monitoring the in vitro antileishmanial activity against promastigotes of Leishmania major. Oleanolic acid (3), ursolic acid (4), lantadene A (5), and lantanilic acid (7) showed significant leishmanicidal activities with IC50 values of 53.0, 12.4, 20.4, and 21.3 μM, respectively. The IC50 value of ursolic acid (4; 12.4 μM) was found to be comparable with that of the standard drugs, pentamidine (IC50 15.0 μM) and amphotericin B (IC50 0.31 μM). The in vitro activities of L. camara and its constituents against promastigotes of Leishmania major are reported here for the first time.
    Chemistry & Biodiversity 05/2014; 11(5):709-18. · 1.81 Impact Factor
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    ABSTRACT: Biotransformation of melengestrol acetate (MGA, 17α-acetoxy-6-methyl-16-methylenepregna-4,6-diene-3,20-dione) (1) was investigated for the first time by using fungal cultures. Incubation of compound 1 with Cunninghamella blakesleeana yielded a new major metabolite, 17α-acetoxy-11β-hydroxy-6-methyl-16-methylenepregna-4,6-diene-3,20-dione (2). The metabolite 2 was purified by using HPLC, followed by characterization through (1)H- and (13)C-NMR and other spectroscopic techniques. Single crystal X-ray diffraction analysis was used to deduce the three dimensional structures of melengestrol acetate (1) and metabolite 2 for the first time. T-cell proliferation assay was employed to evaluate the immunosuppressant effect of compounds 1 and 2 with IC50 = 0.5±0.07 and 0.6±0.08 μg/mL, respectively. The results indicated that these compounds possess six-fold more potent T-cell proliferation inhibitory activity as compared to the standard prednisolone (IC50< 3.1 μg/mL). Both compounds were found to be non-toxic in a 3T3 (mouse fibroblast) cell-based cytotoxicity assay. This finding of potent anti-inflammatory activity of compounds 1 and 2 can lead the way to develop new immunosuppressant compounds for clinical application.
    Steroids 04/2014; · 2.80 Impact Factor
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    ABSTRACT: Diethylamine catalyzed tandem Knoevenagel-Michael reactions have been aimed out in aqueous medium as an efficient, greener and cost effective process for the simple one-pot synthesis of bis -dimedone derivatives. Reaction of substituted aromatic aldehyde (1 equiv.) and dimedone (2 equiv.), in the presence of aqueous diethylamine medium at room temperature provide bis -dimedone derivatives 3a-n in excellent yields (87 – 95%) within a very short reaction time (15–60 min). All the bis -dimedone derivatives were obtained in high purity and the products were fully characterized by physical and spectroscopic data. The structures of compounds 3b,c were elucidated by single crystal X-ray diffraction technique. Compound 3b crystallizes in the monoclinic space group P 21/n with a = 10.2895(9) ÅÅ, b = 18.0995(15) ÅÅ, c = 15.8615(13) ÅÅ, α = 90∘, β = 107.975(2)∘, γ = 90∘, V = 2809.8(4) Å3Å3, and Z = 4. The compound of 3c crystallizes in the monoclinic space group P 21/n with a = 10.2816(16) ÅÅ, b = 18.080(3) ÅÅ, c = 15.637(2)ÅÅ, α = 90∘, β = 107.076(4)°,γ = 90∘, V = 2778.6(7)ÅÅ3, and Z = 4. The use of inexpensive, eco-friendly and readily available reagents, easy work-up, and high purity products makes the procedure a convenient and robust method for the synthesis of tandem Knoevenagel-Michael adducts.
    Arabian Journal of Chemistry 04/2014; · 2.27 Impact Factor
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    ABSTRACT: 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.
    Bioorganic & medicinal chemistry. 04/2014;
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    ABSTRACT: Synthesis of 1,1'-(3,4-diphenylthieno[2,3-b]thiophene-2,5-diyl)diethanone (4) is reported here. The structure of compound 4 was deduced by 1H-NMR, 13C-NMR, FT-IR, MS, microanalysis, and single-crystal X-ray diffraction. Compound crystallizes in the monoclinic space group P21/n with a = 9.3126(7) ˚ A, b = 9.5867(7) ˚ A, c = 20.2811(15) ˚ A, 𝛼 = 90∘, 𝛽 = 95.436(2)∘, 𝛾 = 90∘, V = 1802.5(2) ˚A3, and Z = 4.The molecules are packed in crystal structure by weak intermolecular C10–H10A ⋅ ⋅ ⋅ S1 hydrogen bonding interactions. Compound 4 can be a useful intermediate for the synthesis of diphenylthieno[2,3-b]thiophene. Compound 4 was found to be active against Gram-positive bacteria (Bacillus subtilis and Staphylococcus pneumoniae) and Gram-negative bacteria (Escherichia coli) and also was found to be active against fungi (Aspergillus fumigatus and Candida albicans).
    Journal of Chemistry 04/2014; 2014:5. · 0.48 Impact Factor
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    ABSTRACT: Biotransformation of the anabolic steroid dianabol (1) by suspended-cell cultures of the filamentous fungi Cunninghamella elegans and Macrophomina phaseolina was studied. Incubation of 1 with C. elegans yielded five hydoxylated metabolites 2-6, while M. phaseolina transformed compound 1 into polar metabolites 7-11. These metabolites were identified as 6β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (2), 15α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (3), 11α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (4), 6β,12β,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (5), 6β,15 α,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (6), 17β-hydroxy-17α-methylandrost-1,4-dien-3,6-dione (7), 7β,17β,-dihydroxy-17α-methylandrost-1,4-dien-3-one (8), 15β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (9), 17β-hydroxy-17α-methylandrost-1,4-dien-3,11-dione (10), and 11β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (11). Metabolite 3 was also transformed chemically into diketone 12 and oximes 13, and 14. Compounds 6 and 12-14 were identified as new derivatives of dianabol (1). The structures of all transformed products were deduced on the basis of spectral analyses. Compounds 1-14 were evaluated for β-glucuronidase enzyme inhibitory activity. Compounds 7, 13, and 14 showed a strong inhibition of β-glucuronidase enzyme, with IC50 values between 49.0 and 84.9 μM.
    Steroids 04/2014; · 2.80 Impact Factor
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    ABSTRACT: This manuscript describes the protein anti-glycation activity of thirty-three (33) benzothiazoles, out of which twenty-seven were newly synthesized benzothiazoles. Compound 1 (IC50= 187 ± 2.6 µM) was found to be the most active, while compounds 2 (IC50= 219 ± 3.6 µM), 3 (IC50= 224 ± 1.9 µM), 4 (IC50= 223 ± 3.3 µM), 5 (IC50= 238 ± 2.2 µM), 7 (IC50= 266 ± 5.4 µM), 17 (IC50= 226 ± 1.6 µM) and 18 (IC50= 274 ± 3.6 µM) were significantly active, when compared with the standard rutin (IC50= 294 ± 1.5 µM). This study identified potential inhibitors of methylglyoxal mediated glycation of proteins.
    Medicinal chemistry (Shāriqah (United Arab Emirates)) 03/2014; · 1.64 Impact Factor

Publication Stats

3k Citations
987.76 Total Impact Points


  • 2012–2014
    • King Abdulaziz University
      • Department of Biochemistry
      Djidda, Makkah, Saudi Arabia
    • University of Ibadan
      Ibadan, Oyo, Nigeria
    • Université de Dschang
      • Department of Biochemistry
      Dschang, West Region, Cameroon
    • Balochistan University of Information Technology, Engineering and Management Sciences
      Shālkot, Balochistān, Pakistan
    • University of Calabar
      • Department of Biochemistry
      Calabar, Cross River, Nigeria
  • 2011–2014
    • King Saud University
      • Department of Chemistry
      Ar Riyāḑ, Ar Riyāḑ, Saudi Arabia
    • University of Malakand
      Dīr, North-West Frontier Province, Pakistan
    • Federal Urdu University of Arts, Science and Technology
      • Department of Chemistry
      Karachi, Sindh, Pakistan
  • 1988–2014
    • University of Karachi
      • • International Center for Chemical and Biological Sciences
      • • Dr. Panjwani Center for Molecular Medicine and Drug Research
      • • HEJ Research Institute of Chemistry
      Kurrachee, Sindh, Pakistan
    • Pennsylvania State University
      • Department of Chemistry
      University Park, MD, United States
  • 2013
    • Abdul Wali Khan University Mardan
      • Department of Chemistry
      Mardan, North-West Frontier Province, Pakistan
    • University of Uyo
      • Faculty of Pharmacy
      Uyo, Akwa Ibom State, Nigeria
    • Alexandria University
      • Department of Chemistry
      Alexandria, Alexandria, Egypt
    • Universiti Teknologi MARA
      • Faculty of Applied Sciences
      Shah Alam, Selangor, Malaysia
  • 2002–2013
    • H.E.J. Research Institute of Chemistry
      Kurrachee, Sindh, Pakistan
    • Leibniz Universität Hannover
      • Institute of Organic Chemistry
      Hannover, Lower Saxony, Germany
    • The University of Winnipeg
      • Department of Chemistry
      Winnipeg, Manitoba, Canada
  • 2010–2011
    • University of Peradeniya
      • Department of Chemistry
      Kandy, Central Province, Sri Lanka
    • University of Azad Jammu and Kashmir
      • Department of Chemistry
      Muzaffarābād, Azad Kashmir, Pakistan
  • 2009–2011
    • Trakya University
      Adrianoupolis, Edirne, Turkey
    • Bangladesh Council of Scientific & Industrial Research
      Mujib City, Dhaka, Bangladesh
  • 2005–2011
    • University of Yaounde I
      • Faculty of Sciences
      Yaoundé, Centre Province, Cameroon
    • Universita degli studi di Ferrara
      • Department of Chemical and Pharmaceutical Sciences
      Ferrara, Emilia-Romagna, Italy
    • Uzbekistan Academy of Sciences
      Toshkent, Toshkent Shahri, Uzbekistan
    • Aga Khan University Hospital, Karachi
      • Department of Medicine
      Kurrachee, Sindh, Pakistan
    • University of the Philippines Diliman
      • Institute of Chemistry
      Diliman, Central Luzon, Philippines
  • 2008–2010
    • University of Peshawar
      • • Institute of Chemical Sciences
      • • Department of Pharmacy
      Peshāwar, North West Frontier Province, Pakistan
    • Kohat University of Science and Technology
      Кохат, North-West Frontier Province, Pakistan
    • Veterinary Research Institute, Khartoum, Sudan
      Al Kharţūm, Khartoum State, Sudan
    • University of Vermont
      • Department of Chemistry
      Burlington, VT, United States
  • 2006–2010
    • Quaid-i-Azam University
      • Department of Chemistry
      Islāmābād, Islamabad Capital Territory, Pakistan
    • Gomal University
      • Department of Chemistry
      Dera Ismāīl Khān, North West Frontier Province, Pakistan
    • The Islamia University of Bahawalpur
      • Department of Chemistry
      Bahāwalpur, Punjab, Pakistan
    • Al-Farabi Kazakh National University
      Almaty, Almaty Qalasy, Kazakhstan
  • 2005–2010
    • University of Tuebingen
      • Institute of Inorganic Chemistry
      Tübingen, Baden-Württemberg, Germany
  • 2004–2010
    • Tribhuvan University
      • Institute of Forestry
      Kantipura, Central Region, Nepal
  • 1999–2010
    • The University of Calgary
      • Department of Chemistry
      Calgary, Alberta, Canada
  • 2008–2009
    • Beni Suef University
      • Faculty of Pharmacy
      Beni Suef, Banī Suwayf, Egypt
    • University of Douala
      • Faculty of Sciences
      Douala, Littoral Region, Cameroon
  • 1996–2009
    • Gazi University
      • Faculty of Pharmacy
      Ankara, Ankara, Turkey
  • 1995–2009
    • University of Jordan
      • Department of Chemistry
      Amman, Amman, Jordan
  • 2007–2008
    • Bielefeld University
      • Organische Chemie
      Bielefeld, North Rhine-Westphalia, Germany
    • Institute of Medical Research and Studies on Medicinal Plants
      Jaúnde, Centre Region, Cameroon
  • 2005–2008
    • University of Yaoundé II
      Jaúnde, Centre Region, Cameroon
  • 2002–2006
    • University of Dhaka
      • Department of Chemistry
      Dhaka, Dhaka Division, Bangladesh
  • 1988–1994
    • Cornell University
      Ithaca, New York, United States
  • 1993
    • Chulalongkorn University
      • Department of Chemistry
      Bangkok, Bangkok, Thailand