Edible seaweed as future functional food: Identification of α-glucosidase inhibitors by combined use of high-resolution α-glucosidase inhibition profiling and HPLC-HRMS-SPE-NMR

Bingrui Liu; Kenneth T Kongstad; Stefanie Wiese; Anna K Jäger; Dan Staerk

doi:10.1016/j.foodchem.2016.02.001

Edible seaweed as future functional food: Identification of α-glucosidase inhibitors by combined use of high-resolution α-glucosidase inhibition profiling and HPLC-HRMS-SPE-NMR

Food Chem. 2016 Jul 15:203:16-22. doi: 10.1016/j.foodchem.2016.02.001. Epub 2016 Feb 2.

Authors

Bingrui Liu¹, Kenneth T Kongstad¹, Stefanie Wiese², Anna K Jäger¹, Dan Staerk³

Affiliations

¹ Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
² Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
³ Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. Electronic address: ds@sund.ku.dk.

PMID: 26948583
DOI: 10.1016/j.foodchem.2016.02.001

Abstract

Crude chloroform, ethanol and acetone extracts of nineteen seaweed species were screened for their antioxidant and α-glucosidase inhibitory activity. Samples showing more than 60% α-glucosidase inhibitory activity, at a concentration of 1 mg/ml, were furthermore investigated using high-resolution α-glucosidase inhibition profiling combined with high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy (HR-bioassay/HPLC-HRMS-SPE-NMR). The results showed Ascophyllum nodosum and Fucus vesicolosus to be rich in antioxidants, equaling a Trolox equivalent antioxidant capacity of 135 and 108 mM Troloxmg(-1) extract, respectively. HR-bioassay/HPLC-HRMS-SPE-NMR showed the α-glucosidase inhibitory activity of A. nodosum, F. vesoculosus, Laminaria digitata, Laminaria japonica and Undaria pinnatifida to be caused by phlorotannins as well as fatty acids - with oleic acid, linoleic acid and eicosapentaenoic acid being the most potent with IC50 values of 0.069, 0.075 and 0.10 mM, respectively, and showing a mixed-type inhibition mode.

Keywords: Antioxidant capacity; Edible seaweed; Functional food; HPLC–HRMS–SPE–NMR; High-resolution inhibition profile; α-Glucosidase inhibition.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Antioxidants / isolation & purification*
Benzothiazoles / chemistry
Chromatography, High Pressure Liquid / methods
Functional Food*
Glycoside Hydrolase Inhibitors / isolation & purification*
Magnetic Resonance Spectroscopy / methods
Mass Spectrometry
Plant Extracts / chemistry
Seaweed / chemistry*
Seaweed / classification
Solid Phase Extraction / methods
Substrate Specificity
Sulfonic Acids / chemistry
alpha-Glucosidases / metabolism*

Substances

Antioxidants
Benzothiazoles
Glycoside Hydrolase Inhibitors
Plant Extracts
Sulfonic Acids
2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid
alpha-Glucosidases