Cellular and in-vitro models to assess antioxidant activities of seaweed extracts and the potential use of the extracts as ingredients

Seaweeds contain a range of antioxidant compounds such as polyphenols, carotenoids, sulphated polysaccharides and vitamins and have the potential to be used as ingredients in neutraceuticals. The antioxidant activity of crude 60% methanol extracts prepared from five Irish seaweeds, Ascophyllum nodosum, Laminaria hyperborea, Pelvetia canaliculata, Fucus vesiculosus and Fucus serratus were examined using in-vitro assays and a cell model system to determine the antioxidant activity of the extracts and their ability to protect against H2O2 and tert-BOOH-induced DNA damage and alterations in cellular antioxidant status in the human adenocarcinoma, Caco-2 cell line. To optimise the extraction of antioxidant compounds from seaweeds, an accelerated solvent extraction (ASE®) was used in combination with food grade solvents. The antioxidant activity of these extracts against H2O2 and tert-BOOH-induced DNA damage and alterations in cellular antioxidant status was also assessed. Extracts that exhibited the highest antioxidant activity, A. nodosum (100% water and 80% ethanol extracts) and F. vesiculosus (60% ethanol extract) were selected as ingredients for incorporation into fluid milk and yogurt at concentrations of 0.25% and 0.5%. The addition of the seaweed extracts to milk and yogurt did not affect the pH or shelf-life properties of the products. Seaweed addition did however significantly influence the colour properties of the milk and yogurt. Yellowness values were significantly higher in yogurts containing F. vesiculosus at both concentrations and A. nodosum (80% ethanol) at the 0.5% concentration. In milk, the F. vesiculosus (60% ethanol) and A. nodosum (80% ethanol) at both the 0.25% and the 0.5% concentrations had higher greenness and yellowness values than the milk containing A. nodosum (100% water). Sensory analysis revealed that appearance and flavour governed the overall acceptability of yogurts with the control yogurt, and yogurts containing A. nodosum (100% water) were the most preferred samples by panellists. However, in the milk trial the perception of a fishy taste was the determining factor in the negative perception of milk. The unsupplemented control and the milk containing A. nodosum (100% water) at a concentration of 0.5% were the most overall accepted milk samples by the sensory panellists. The antioxidant activity of the extracts in milk and yogurt remained stable during storage as determined by the in-vitro assays. Seaweed supplemented milk and yogurt were also subjected to an in-vitro digestion procedure which mimics the human digestive system. The milk and yogurt samples and their digestates were added to Caco-2 cells to investigate their antioxidant potential however neither the undigested or digested samples protected against H2O2-induced DNA damage in Caco-2 cells.

Functional educational characterisation of the utility of embalming fluids for anatomical education and research

Human cadavers have long been used to teach human anatomy and are increasingly used in other disciplines. Different embalming techniques have been reported in the literature; however there is no clear consensus on the opinion of anatomists on the utility of embalmed cadavers for the teaching of anatomy. To this end, we aimed to survey British and Irish anatomy teachers to report their opinions on different preservation methods for the teaching of anatomy. In this project eight human cadavers were embalmed using formalin, Genelyn, Thiel and Imperial College London- Soft Preserving (ICL-SP) techniques to compare different characteristics of these four techniques. The results of this thesis show that anatomy teachers consider hard-fixed cadavers not to be the most accurate teaching model in comparison to the human body, although it still serves as a useful teaching method (Chapter 2). In addition, our findings confirm that joints of cadavers embalmed using ICL-SP solution faithfully mimics joints of an unembalmed cadaver compared to the other techniques (Chapter 3). Embalming a human body prevents the deterioration in the quality of images and our findings highlight that the influence of the embalming solutions varied with the radiological modality used (Chapter 4). The method developed as part of this thesis enables anatomists and forensic scientists to quantify the decomposition rate of an embalmed human cadaver (Chapter 5). Formalin embalming solution showed the strongest antimicrobial abilities followed by Thiel, Genelyn and finally by ICL-SP (Chapter 6). The overarching viewpoint of this set of studies show that it is inaccurate to state that one embalming technique is ultimately the best. The value of each technique differs based on the requirement of the particular education or research area. Hence we highlight how different embalming techniques may be better suited to certain fields of study.