Jump to main content
Jump to site search

Issue 1, 2018
Previous Article Next Article

Extracts from the edible seaweed, Ascophyllum nodosum, inhibit lipase activity in vitro: contributions of phenolic and polysaccharide components

Author affiliations

Abstract

A polyphenol-rich extract (PRE) from the edible seaweed, Ascophyllum nodosum, inhibited pancreatic lipase activity in an oil-based turbidimetric assay with an IC50 of 200 μg gallic acid equivalents (GAE) perassay) [∼230 μg DW] whereas the known inhibitor, Orlistat, gave an IC50 at 0.4 μg per assay. A phlorotannin-enriched fraction (TRF) purified from the PRE was more potent with an IC50 = 60 μg GAE per assay (∼65 μg DW). When the assay was started by the addition of lipase, both Orlistat and TRF were much less effective which suggests that pre-incubation of enzyme and inhibitor improved inhibition. Based on phenol content, water extracts from Ascophyllum were more potent lipase inhibitors than PRE (IC50 ∼ 150 μg GAE per assay). However, this was equivalent to ∼580 μg DW and these extracts contained polysaccharides (e.g. alginate content = 110 μg mL−1) which may also contribute to inhibition. Indeed, a polysaccharide-enriched fraction obtained by ethanol precipitation gave an IC50 of 1000 μg DW which was equivalent to 130 μg GAE and 420 μg alginate per assay. Therefore a >3 fold increase in alginate content did not markedly improve inhibition. Re-precipitation increased alginate content and reduced polyphenol content but lipase inhibition was markedly reduced (i.e. IC50 at ∼1100 μg DW per assay, 700 μg alginate and 25 μg GAE). Purifying the polysaccharide fraction by ion exchange removed all phenolics but the IC50 increased to >2500 μg DW, equivalent to >1970 μg alginate per assay. In conclusion, polysaccharides and phlorotannins may inhibit lipase in an additive fashion, with phlorotannins apparently more effective in vitro. However, interactions between these components may be important when food products containing this edible seaweed are consumed.

Graphical abstract: Extracts from the edible seaweed, Ascophyllum nodosum, inhibit lipase activity in vitro: contributions of phenolic and polysaccharide components

Back to tab navigation

Supplementary files

Publication details

The article was received on 26 Oct 2017, accepted on 08 Dec 2017 and first published on 08 Dec 2017


Article type: Paper
DOI: 10.1039/C7FO01690E
Citation: Food Funct., 2018,9, 502-510
  •   Request permissions

    Extracts from the edible seaweed, Ascophyllum nodosum, inhibit lipase activity in vitro: contributions of phenolic and polysaccharide components

    C. Austin, D. Stewart, J. W. Allwood and G. J. McDougall, Food Funct., 2018, 9, 502
    DOI: 10.1039/C7FO01690E

Search articles by author

Spotlight

Advertisements