- Logie, L.; Bacon, S.; Middleton, P.; Harthill, J.; Coats, J.; Stewart, D.; Sakamoto, K.; McDougall, G.; Rena, G., (2013) How does glucophage (metaformin) work? Investigation of the cellular action of chemical analogues., Diabetes UK Professional Conference, Manchester Central, Manchester, 13-15 March 2013.
- McDougall, G.J.; Dobson, P.; Jordan-Mahy, N., (2010) Effect of different cooking regimes on rhubarb polyphenols., Food Chemistry, 119, 758-764.
- Cameron, A.; Logie, L.; Patel, K.; Bacon, S.; Forteath, C.; Harthill, J.; Roberts, A.; Sutherland, C.D.; Stewart, D.; Viollet, B.; Sakamoto, K.; McDougall, G.; Foretz, M.; Rena, G., (In press) Investigation of salicylate hepatic responses in comparison with chemical analogues of the drug., BBA - Molecular Basis of Disease.
- McDougall, G.J.; Austin, C.; van Schayk, E.; Martin, P., (2016) Salal (Gaultheria shallon) and aronia (Aronia melanocarpa) fruits from Orkney: phenolic content, composition and effect of wine making., Food Chemistry, 205, 239-247.
- Bohn, T.; McDougall, G.J.; Alegria, A.; Alminger, M.; Arrigoni, E.; Aura, A.M.; Brito, C.; Cilla, A.; El, S.N.; Karakaya, S.; Martinez-Cuesta, M.C.; Santos, C.N., (2015) Mind the gap: deficits in our knowledge of aspects impacting the bioavailability of phytochemicals and their metabolites - a position paper focusing on carotenoids and polyphenols., Molecular Nutrition and Food Research, 59, 1307-1323.
- Macedo, D.; Tavares, L.; McDougall, G.J.; Miranda, H.V.; Stewart, D.; Ferreira, R.B.; Tenreiro, S.; Outeiro, T.F.; Santos, C.N., (2015) (Poly)phenols protect from alpha-synuclein toxicity by reducing oxidative stress and promoting autophagy., Human Molecular Genetics, 24, 1717-1732.
- Martin, P.; Wishart, J.; McDougall, G.; Brennan, R., (2015) Fruit production and polyphenol composition of salal (Gaultheria shallon), a potential new fruit for northern maritime regions., Fruits, 70, 377-383.
- Brown, E.M.; Latimer, C.; Allsopp, P.; Ternan, N.G.; McMullan, G.; McDougall, G.J.; Stewart, D.; Crozier, A.; Rowland, I.; Gill, C.I.R., (2014) In vitro and in vivo models of colorectal cancer: antigenotoxic activity of berries., Journal of Agricultural and Food Chemistry, 62, 3852-3866.
- Brown, E.M.; Nitecki, S.; Pereira-Caro, G.; McDougall, G.J.; Stewart, D.; Rowland, I.; Crozier, A.; Gill, C.I.R., (2014) Comparison of in vivo and in vitro digestion on polyphenol composition in lingonberries: potential impact on colonic health., Biofactors, 40, 611-623.
- McDougall, G.J.; Conner, S.; Pereira-Caro, G.; Gonzalez-Barrio, R.; Brown, E.M.; Verrall, S.; Stewart, D.; Moffet, T.; Ibars, M.; Lawther, R.; O'Connor, G.; Rowland, I.; Crozier, A.; Gill, C.I.R., (2014) Tracking (poly)phenol components from raspberries in ileal fluid., Journal of Agricultural and Food Chemistry, 62, 7631-7641.
- Pantidos, N.; Boath, A.; Lund, V.; Conner, S.; McDougall, G.J., (2014) Phenolic-rich extracts from the edible seaweed, Ascophyllum nodosum, inhibit alpha-amylase and alpha-glucosidase: Potential anti-hyperglycemic effects., Journal of Functional Foods, 10, 201-209.
- Pimpao, R.C.; Dew, T.; Figueira, M.E.; McDougall, G.J.; Stewart, D.; Ferreira, R.B.; Santos, C.N.; Williamson, G., (2014) Urinary metabolite profiling identifies novel colonic metabolites and conjugates of phenolics in healthy volunteers., Molecular Nutrition and Food Research, 58, 1414-1425.
- Powell, C.; Hughes, A.D.; Kelly, M.S.; Conner, S.; McDougall, G.J., (2014) Extraction and identification of antioxidant polyhydroxynaphthoquinone pigments from the sea urchin, Psammechinus miliaris., LWT - Food Science and Technology, 59, 455-460.
- Dahlawi, H.; Jordan-Mahy, N.; Clench, M.; McDougall, G.J.; Le Maitre, C.L., (2013) Polyphenols are responsible for the pro-apoptotic properties of pemegranate juice on leukemia cell lines., Food Science & Nutrition, 1, 196-208.
- Dincheva, I.; Badjakov, I.; Kondakova, V.; Dobson, P.; McDougall, G.; Stewart, D., (2013) Identification of the phenolic components in Bulgarian raspberry cultivars by LC-ESI-MSn., International Journal of Agricultural Science Research, 3, 127-137.
- Josuttis, M.; Verrall, S.; Stewart, D.; Kruger, E.; McDougall, G.J., (2013) Genetic and environmental effects on tannin composition in strawberry (Fragaria x ananassa) cultivars grown in different European locations., Journal of Agricultural and Food Chemistry, 61, 790-800.
- Juedtz, K.; Aberdein, N.; Stewart, D.; McDougall, G.J., (2013) Sequential extraction of black currant residues produce anthocyanin-rich extracts containing anthocyanin dimers., Journal of Berry Research, 3, 53-64.
- Mahbub, A.; Le Maitre, C.L.; Haywood-Small, S.L.; McDougall, G.J.; Cross, N.A., (2013) Differential effects of polyphenols on proliferation and apoptosis in human myeloid and lymhoid leukemia cell lines., Anti-Cancer Agents in Medicinal Chemistry, 13, 1601-1613.
- Tavares, L.R.; Figueira, I.; McDougall, G.J.; Vieira, H.L.A.; Stewart, D.; Alves, P.M.; Ferreira, R.B.; Santos, C.N., (2013) Neuroprotective effects of digested polyphenols from wild blackberry species., European Journal of Nutrition, 52, 225-236.
- Vepsalainen, S.; Koivisto, H.; Pekkarinen, E.; Makinen, P.; Dobson, G.; McDougall, G.J.; Stewart, D.; Haapasalo, A.; Karjalainen, R.O.; Tanila, H.; Hiltunen, M., (2013) Anthocyanin-enriched bilberry and blackcurrant extracts modulate amyloid precursor protein processing and alleviate behavioral abnormalities in the APP/PS1 mouse model of Alzheimer's disease., Journal of Nutritional Biochemistry, 24, 360-370.
- Boath, A.S.; Grussu, D.; Stewart, D.; McDougall, G.J., (2012) Berry polyphenols inhibit digestive enzymes: a source of potential health benefits?, Food Digestion, 3, 1-7.
- Boath, A.S.; Stewart, D.; McDougall, G.J., (2012) Berry components inhibit alpha-glucosidase in vitro: synergies between acarbose and polyphenols from black currant and rowanberry., Food Chemistry, 135, 929-936.
Current research interests
There is increasing evidence that non-nutrient components of fruit and vegetables (FAV) may have key roles in providing the health benefits associated with diets rich in FAV. The main thrust of my research examines the possibility that phytochemicals in plant foods can influence human health. The focus has been on soft fruit, particularly on polyphenols in berries, as there is already evidence for the effectiveness of these components from other foods and beverages and berries are a particularly rich and palatable source.
My research has four main overlapping and interdependent areas:
- Establishment of bioactivities relevant to human health for berry polyphenols
- Analysis of the composition of polyphenols in bioactive extracts to confirm structure-activity relationships for effectiveness and to assess the stability and bioavailability of active components in the human body
- Development of high through-put methods to analyse the inheritance of bioactive polyphenols in berries, to link the ‘health' phenotype to the genotype of The James Hutton Institute’s elite germplasm collection.
- Assess environmental influences on the accumulation of levels of bioactive components.
To accrue evidence that berry phytochemicals have bioactivities that can influence human health or mitigate disease progression, I have initiated collaborations with a range of biomedical experts who have relevant model systems for cardiovascular health, neurodegeneration, diabetes, and cancers. These model systems range from in vitro enzyme screens, ex vitro cell or tissue studies to animal or human trials. I also developed key in-house screens and assays. In each case, extracts with closely defined compositions have been used and the studies include analysis of the metabolic fate of the components to define the mechanisms of action and the candidate active ingredients. In human trials, bioavailability studies of the levels of metabolites in blood, urine and faeces have been completed.
Through these studies, I have confirmed that different polyphenol components from berries can have different effects in different model systems and that overall efficacy is often decided by a combination of bioactivity, stability and longevity/bioavailability in the system. These cross-disciplinary collaborations have led to close associations particularly with the University of Ulster and the University of Dundee. These approaches are currently being applied to studies on Alzheimer’s disease through the EU-funded BrainHealthFood project.
Along with Ilka Abreu and Sean Connor, I have established novel MS based methods for following polyphenol diversity. This has enabled us to begin to link polyphenol inheritance to the genetic maps being developed for raspberry and blackcurrant by the Genetics Programme (with Rex Brennan and Julie Graham). Through this approach, we hope to enable accelerated breeding of improved varieties with elevated levels of healthy components. Importantly, I have also directed research to establish if environmental conditions influence polyphenol levels, which has informed us that certain genetic markers are consistently associated with enhanced polyphenol content across years with widely differing climatic conditions. The high-through-put methods developed have been employed to track the diversity of polyphenols from growing berries under different agronomic conditions, in different latitudes or after different processing methods with collaborators from across Europe (ClimaFruit Project). These areas form part of the new programme of work planned for the Scottish Government.
I have also been involved in studies that correlate the metabolic and molecular changes associated with aspects of food quality. For example, through close working with Mark Taylor and Rob Hancock and collaborators from the University of Colorado, we correlated changes in metabolite profiles and gene expression in coloured and non-coloured potato tuber tissues.
With industrial and University partners, I have applied our analytical capacities to solve problems associated with berry flavour, juice manufacture and the effects of processing and cooking on bioactive components from diverse sources such as seaweeds and oats (see Quoats project).
I have also applied expertise in cell wall chemistry and biochemistry to studies on potato flavour and texture led by Mark Taylor within PPFQ. We are assessing the genetic and biochemical basis of potato tuber texture by comparing differences in textural properties between Solanum tuberosum and Solanum phureja varieties. These varieties have consistent year-on-year differences in texture and cooking properties, which are correlated with differences in cell wall structure and cohesiveness. We have identified that these differences are mainly associated with subtle differences in pectin structure and localisation which directly influence cell-to-cell adhesion. Indeed, microarray analysis has identified candidate genes involved in pectin methylation and decoration whose expression has subsequently been manipulated to provide evidence for their involvement in the textural traits.
This work has involved collaborations with British Universities including Bath, Glasgow, Ulster, Dundee, Reading, Abertay, Queen Margaret, Newcastle, Sheffield Hallam, Strathclyde, Aberystwyth, University of the Highlands and Islands and St Andrews. International collaborations are in place with scientists from Universities and Research Institutes in, for example, Germany, Italy, Bulgaria, Spain, Norway, Sweden, Denmark, France, Holland, Ireland, Portugal, USA and New Zealand. We also have a number of research partners in UK and European companies.
- Grussu, D., Stewart, D., McDougall, G.J. 2011. Berry polyphenols inhibit α-amylase in vitro: Identifying active components in rowanberry and raspberry. Journal of Agricultural and Food Chemistry (in press).
- Nwosu, F., Morris, J., Lund, V.A, Stewart, D., Ross, H.A., McDougall, G.J. 2011. Anti-proliferative and potential anti-diabetic effects of phenolic-rich extracts from edible marine algae. Food Chemistry 126, 1006–1012
- McDougall, G.J., Dobson, P. and Jordan-Mahy, N. 2010. Effect of different cooking regimes on rhubarb polyphenols. Food Chemistry 119, 758-764
- Stushnoff, C., Ducreux, L.J.M., Hancock, R.D., Hedley, P.E., Holm, D., McDougall, G.J., McNicol, J.W., Morris, J., Morris, W.L., Sungurtas, J., Verrall, S.R., Zuber, T. and Taylor, M.A. 2010. Flavonoid profiling and transcriptome analysis reveals new gene-metabolite correlations in tubers of Solanum tuberosum L. Journal of Experimental Botany 61, 1225-1238.
- Whitson, J., McDougall, G.J., Ross, H.A., Lund, V., Hamilton, C.A., Dominiczak, A.F. and Stewart, D. 2010. Bioactive berry components: potential modulators of health benefits. Functional Plant Science and Biotechnology 4, 34-38.
- McDougall, G.J., Kulkarni, N.N. and Stewart, D. 2009. Berry polyphenols inhbit pancreatic lipase actvity in vitro. Food Chemistry 115, 193-199.
- Weaver, J., Briscoe, T., Hou, M., Goodman, C., Kata, S., Ross, H.A., McDougall, G.J., Stewart, D. and Riches, A. 2009. Strawberry polyphenols are equally cytotoxic to tumourigenic and normal human breast and prostate cell lines. International Journal of Oncology 34, 777-786.
- Cameron, A.R., Anton, S., Melville, L., Houston, N.P., Dayal, S., McDougall, G.J., Stewart, D. and Rena, G. 2008. Black tea polyphenols mimic insulin/insulin-like growth factor-1 signalling to the longevity factor FOXO1a. Aging Cell 7, 69-77.
- McDougall, G.J., Ross, H.A., Ikeji, M. and Stewart, D. 2008. Berry extracts exert different antiproliferative effects against cervical and colon cancer cells grown in vitro. Journal of Agricultural and Food Chemistry 56, 3016-3023.
- McDougall, G.J., Martinussen, I. and Stewart, D. 2008. Towards fruitful metabolomics: High throughput analyses of polyphenol composition in berries using direct infusion mass spectrometry. Journal of Chromatography B 871, 362-369.
- Coates, E.M., Popa, G., Gill, C.I.R., McCann, M.J., McDougall, G.J., Stewart, D. and Rowland, I. 2007. Colon-available raspberry polyphenols exhibit anti-cancer effects on in vitro models of colon cancer. Journal of Carcinogenesis 6, 1-13.
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