Muhammad Atif

University of Karachi, Karachi, Sindh, Pakistan

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Publications (7)12.99 Total impact

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    ABSTRACT: Dehydroabietic acid (DHA, 1), a natural occurring diterpene resin acid, is an abundant resin acid in conifers, representing a natural wood protectant. The aim of this study was to use microbial cell cultures as tools for modification of 1 in order to obtain value-added functional derivatives. A scaled-up biotransformation of 1 by filamentous fungus Cunninghamella elegans, Rhizopus stolonifer, Gibberella fujikuroi, and Cephalosporium aphidicola were conducted for the first time. Three hydroxylated metabolites; 1β-hydroxydehydroabietic acid (2); 15-hydroxy dehydroabietic acid (3); and 16-hydroxy dehydroabietic acid (4). The structure of the hydroxylated metabolites were elucidated by 1-D (1H, 13C) and 2-D NMR (COSY, HMBC, HMQC, NOESY) techniques and MS analyses. Dehydroabietic acid (1) and their transformed products 2-4 exhibited a promising α-Glucosidase inhibitory activity. Compound 1 showed 38 times more active than the standard α-Glucosidase inhibitor Keywords: Microbial transformation, Dehydroabietic acid, Antibacterial activities, , deoxynojirimycin. Compound 1 and its transformed
    International Journal of Pharmacy and Pharmaceutical Sciences 01/2014; · 1.59 Impact Factor
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    ABSTRACT: The fungal transformation of cedryl acetate (1) was investigated for the first time by using Cunninghamella elegans. The metabolites obtained include, 10β-hydroxycedryl acetate (3), 2α, 10β-dihydroxycedryl acetate (4), 2α-hydroxy-10-oxocedryl acetate (5), 3α,10β-dihydroxycedryl acetate (6), 3α,10α-dihydroxycedryl acetate (7), 10β,14α-dihydroxy cedryl acetate (8), 3β,10β-cedr-8(15)-ene-3,10-diol (9), and 3α,8β,10β -dihydroxycedrol (10). Compounds 1, 2, and 4 showed α-glucosidase inhibitory activity, whereby 1 was more potent than the standard inhibitor, acarbose, against yeast α-glucosidase. Detailed docking studies were performed on all experimentally active compounds to study the molecular interaction and binding mode in the active site of the modeled yeast α-glucosidase and human intestinal maltase glucoamylase. All active ligands were found to have greater binding affinity with the yeast α-glucosidase as compared to that of human homolog, the intestinal maltase, by an average value of approximately -1.4 kcal/mol, however, no significant difference was observed in the case of pancreatic amylase.
    European journal of medicinal chemistry 02/2013; 62C:764-770. · 3.27 Impact Factor
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    ABSTRACT: Microbial transformation of (20S)-20-hydroxymethylpregna-1,4-dien-3-one (1) by four filamentous fungi, Cunninghamella elegans, Macrophomina phaseolina, Rhizopus stolonifer, and Gibberella fujikuroi, afforded nine new, and two known metabolites 2-12. The structures of these metabolites were characterized through detailed spectroscopic analysis. These metabolites were obtained as a result of biohydroxylation of 1 at C-6β, -7β, -11α, -14α, -15β, -16β, and -17α positions, except metabolite 2 which contain an O-acetyl group at C-22. These fungal strains demonstrated to be efficient biocatalysts for 11α-hydroxylation. Compound 1, and its metabolites were evaluated for the first time for their cytotoxicity against the HeLa cancer cell lines, and some interesting results were obtained.
    Steroids 07/2011; 76(12):1288-96. · 2.80 Impact Factor
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    ABSTRACT: Transformation of lynestrenol (19-nor-17alpha-pregn-4-en-20-yn-17beta-ol) (1) was carried out by incubation with Cunninghamella elegans to obtain 19-nor-17alpha-pregn-4-en-20-yn-3-one-10beta,17beta-diol (2), 19-nor-17alpha-pregn-4-en-20-yn-3-one-6beta,17beta-diol (3), and 19-nor-17alpha-pregn-4-en-20-yn-3beta,6beta,17beta-triol (4). Metabolite 4 was identified as a new compound. These metabolites were structurally characterised on the basis of spectroscopic techniques.
    Natural product research 01/2010; 24(1):1-6. · 1.01 Impact Factor
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    ABSTRACT: Microbial transformation of the sesquiterpene (-)-guaiol (1) [1(5)-guaien-11-ol] was investigated using three fungi, Rhizopus stolonifer, Cunninghamella elegans, and Macrophomina phaseolina. Fungal transformation of 1 with Rhizopus stolonifer yielded a hydroxylated product, 1-guaiene-9 beta,11-diol (2). In turn, Cunninghamella elegans afforded two mono- and dihydroxylated products, 1-guaiene-3beta,11-diol (3) and 1(5)-guaiene-3beta,9 alpha,11-triol (4), while Macrophomina phaseolina produced two additional oxidative products, 1(5)-guaien-11-ol-6-one (5) and 1-guaien-11-ol-3-one (6). All metabolites were found to be new compounds as deduced on the basis of spectroscopic techniques. Compounds 1-6 were evaluated for their activity against several bacterial strains.
    Journal of Natural Products 06/2007; 70(5):849-52. · 3.29 Impact Factor
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    Z. Naturforsch. 01/2007;
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    ABSTRACT: The microbial transformation of levonorgestrel (1) by Cunningham elegans resulted in the formation of five hydroxylated metabolites, 13-ethyl-10beta, 17beta-dihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one(2), 13-ethyl-6beta,17beta-dihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one (3) 13-ethyl 6beta, 10beta, 17beta-trihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one (4) 13-ethyl-15alpha-17beta-dihydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one (5) and 13-ethyl-11alpha, 17beta-dihydroxy-18,19-dinor-17alpha-pregn-4en-20-yn-3-one. The fermentation of one with Rhizopus stolonifer, Fusarium lini and Curvularia lunata afforded compound 2 as a major metabolise. These metabolites were structurally characterized on the basis of spectroScopic techniques. Metabolite 6 was identified as a new compound. Compounds 2 2 ad 5 displayed inhibitory activity against the acetylcholinesterase ( AChE, EC. 3.1.1.7) with IC50 values of 79.2 and 24.5 microM, respectively. The metabolites 2 and 5 also showed inhibitory activity against the butyryLcholinesterase ( BChE, E.C 3.1.1.8) with IC50 values ranging between 9.4 and 309.8 microM.
    Natural Product Research 11/2006; 20(12):1074-81. · 1.03 Impact Factor

Publication Stats

24 Citations
12.99 Total Impact Points

Institutions

  • 2007–2011
    • University of Karachi
      • • International Center for Chemical and Biological Sciences
      • • HEJ Research Institute of Chemistry
      Karachi, Sindh, Pakistan
  • 2006
    • H.E.J. Research Institute of Chemistry
      Kurrachee, Sindh, Pakistan