Newcastle University eTheses >
Newcastle University >
Research Institutes >
Institute for Cell and Molecular Biosciences >
Please use this identifier to cite or link to this item:
|Title: ||Bioactive alginates and macronutrient digestion|
|Authors: ||Chater, Peter|
|Issue Date: ||2014 |
|Publisher: ||Newcastle University|
|Abstract: ||Macronutrient digestion is a major factor in health and metabolic diseases such as
obesity and diabetes and presents a huge global challenge.
Modulating macronutrient digestion with food additives and pharmaceuticals has been
shown to be a fruitful approach to the treatment of obesity (Orlistat) and diabetes
(Acarbose). Previous work has shown that bioactive agents have novel modulatory
effects on the major enzymes of digestion, and work in this lab has shown that specific
alginates can inhibit pancreatic lipase up to 70%. Alginates are now being investigated
as a potential anti-obesity agent.
The purpose of this thesis was to develop in vitro methodologies and an analytical
approach for investigating the effects of exogenous compounds on the major digestive
enzymes; -amylase, pepsin, trypsin, and lipase. A 3-step process was developed
consisting of; higher-throughput single enzyme analysis, selected enzyme kinetics and
model gut analysis.
Alginates were shown to inhibit the action of pepsin, but have no effect on trypsin
activity in vitro. The structure of alginate is key to the inhibition of pepsin, and
rheological and viscometric data suggested that this effect was due to a pH dependent
interaction between alginate and protein substrate as well as direct enzyme-inhibitor
interactions. A similar effect was observed with Fucoidan and sulphated carrageenans.
In the model gut analysis, these effects manifested as inhibition of proteolysis in the
simulated gastric phase, but not in the small-intestinal phase.
Alginates were shown to increase the activity of α-amylase during in vitro single
enzyme analysis, but have no significant affect on carbohydrate digestion in a model gut
simulation. Fat digestion in the model gut simulation was inhibited by specific
alginates, adding further weight to the potential use of alginates as a therapeutic
treatment of obesity.|
|Description: ||PhD Thesis|
|Appears in Collections:||Institute for Cell and Molecular Biosciences|
Items in eTheses are protected by copyright, with all rights reserved, unless otherwise indicated.