Diabetes mellitus is a chronic disorder characterised by a blood glucose level persistently above normal due to loss of insulin production from the pancreas or peripheral tissues becoming resistant to insulin. Currently, treatment for diabetes accounts for 12% of the world's total health expenditure. There are a range of therapies available for the treatment of T2DM; however treatments can be expensive and associated with adverse effects. The studies conducted in this thesis investigated the ability of seaweed extracts to exert anti-diabetic activities through established pharmaceutical mechanisms. Some extracts from species of Irish seaweed were :1 able to reduce glucose diffusion, inhibit alpha glucosidase activity, inhibit DPP-4 activity, and also promote GLP-l secretion and biosynthesis in an enteroendocrine cell model. Furthermore, acute oral administration of Porphyra linearis reduced glucose excursions in normal mice. A commercial seaweed extract (Digestica®) was able to potently inhibit alpha glucosidase activity in a non-competitive manner and in concentrationdependent fashion. Digestica extracts were able to inhibit DPP-4 activity, again in a concentration-dependent manner. Digestica promoted GLP-l and GIP secretion in vitro and increased GLP-l biosynthesis in an enteroendocrine cell model. Digestica was able to prevent the induction of T2DM in a high fat fed mouse model by preventing the development of glucose intolerance and insulin resistance. Moreover, Digestica acted as a therapeutic for T2DM improving glucose tolerance and insulin sensitivity in the same animal model. Selected marine compounds commonly found in seaweeds were also investigated for their anti-diabetic effects in vitro with promising results. These studies demonstrate potent anti-diabetic effects displayed by seaweed extracts and common marine compounds both in vitro and in vivo without exhibiting cytotoxic effects showing their potential use as inexpensive treatments for T2DM, perhaps as food supplements or natural therapeutics.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:669673 |
| Date | January 2014 |
| Creators | Calderwood, Danielle |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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