Planta Med 2016; 82(S 01): S1-S381
DOI: 10.1055/s-0036-1596863
Abstracts
Georg Thieme Verlag KG Stuttgart · New York

α-Glucosidase inhibitors from Phyllanthus amarus and Phyllanthus urinaria

BTD Trinh
1   Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
,
D Staerk
1   Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
,
AK Jäger
1   Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
› Author Affiliations
Further Information

Publication History

Publication Date:
14 December 2016 (online)

 
 

    Phyllanthus amarus Schum. Thonn. and Phyllanthus urinaria L. (Phyllanthaceae) are indigenous medicinal plants having folk reputation in Vietnam as hypoglycemic agents. All parts of the plants are used. The present study was carried out to identify the α-glucosidase inhibitors from water extracts of P. amarus and P. urinaria. These extracts showed IC50 values of 34.9 ± 1.5 and 14.6 ± 4.6 µg/mL against the digestive enzyme α-glucosidase.

    The extracts was fractionated into a 96 well microplate by analytical-scale HPLC (C18, acetonitrile gradient), followed by α-glucosidase inhibitory assessment of each well [1]. Biochromatograms constructed from the assays allowed identification of active constituents, which were subsequently isolated using preparative-scale HPLC. Their structures were elucidated as corilagin, repandusinic acid A, and mallotinin based on NMR and HR-ESIMS data. IC50 of these compounds were 1.70 ± 0.03, 6.10 ± 0.10, and 3.76 ± 0.15µM, respectively. Kinetics analysis revealed that corilagin displayed a mixed type mode of inhibition with K i and K i′ values of 2.37 ± 0.90 and 2.61 ± 0.61µM, respectively, whereas repandusinic acid A and mallotinin competitively inhibited α-glucosidase with K i values of 4.01 ± 0.47 and 0.65 ± 0.11µM, respectively.

    Corilagin, repandusinic acid A, and mallotinin were potent α-glucosidase inhibitors contributing significantly to the inhibitory effect observed for the water extracts of P. amarus and P. urinaria.

    Acknowledgements: Binh T.D. Trinh is thankful to Vietnam Ministry of Education and Training for a scholarship and Son V. Dang for assistance in verifying collected plants. HPLC equipment used for obtaining high-resolution α-glucosidase and α-amylase inhibition profiles was obtained via a grant from The Carlsberg Foundation.

    Keywords: Type 2 diabetes, α-glucosidase, high-resolution inhibition profile, Vietnamese plants, Phyllanthus.

    References:

    [1] Schmidt JS, Lauridsen MB, Dragsted LO, Nielsen J, Staerk D. Development of a bioassay-coupled HPLC-SPE-ttNMR platform for identification of α-glucosidase inhibitors in apple peel (Malus × domestica Borkh.). Food Chem 2012; 135: 1692 – 1699


    #

    No conflict of interest has been declared by the author(s).