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Cranberry metabolomics : new approaches for phytochemical characterizations

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Title: Cranberry metabolomics : new approaches for phytochemical characterizations
Author: Brown, Paula Naomi
Degree Doctor of Philosophy - PhD
Program Chemistry
Copyright Date: 2011
Publicly Available in cIRcle 2012-01-03
Abstract: There is a long history of use and modern commercial importance of large (Vaccinium macrocarpon Aiton) and small cranberries (V. oxycoccus L. and V. vitis-idaea L.) in North America. While epidemiological research indicates cranberries have positive health benefits, identifying specific phytochemicals for disease prevention remains elusive. The central objective of this research was to develop phytochemical characterization tools for comparing commercially cultivated cranberries and two wild-harvested Vaccinium species. A method was developed and validated to quantify cyanidin-3-O-galactoside (C3Ga), cyanidin-3-O-glucoside (C3Gl), cyanidin-3-O-arabinoside (C3Ar), peonidin-3-O-galactoside (P3Ga) and peonidin-3-O-arabinoside (P3Ar) in cranberry fruit products. The relative standard deviation (%RSDr) of anthocyanins ranged from 1.77% to 3.31% with the method detection limit (MDL) for C3Ga, C3Gl, C3Ar, P3Ga, and P3Ar estimated at 0.018, 0.016, 0.006, 0.013, and 0.011 µg/mL, respectively. In biological replicates of V. macrocarpon cultivars, anthocyanin content (mg/g) was determined to be 7.98±5.83 in Ben Lear; 7.02±1.75 in Bergman; 6.05± 2.51 in GH1; 3.28± 1.88 in Pilgrim and 2.81 ±0.81 in Stevens. V. oxycoccus contained the five major anthocyanins with the ratio of glycosylated peonidins to cyanidins varying from V. macrocarpon. V. vitis-idaea contained no measurable glycosylated peonidins. Determination and statistical analysis of serotonin, melatonin and ascorbic acid content in the three Vaccinium species, found only vitamin C positively correlated with antioxidant activity. Metabolome comparisons made from untargeted metabolomics by ultra-fast liquid chromatography (UFLC) with time-of-flight (TOF) mass spectrometry (MS), found different pools of common metabolites extracted in methanol (7635), 70% ethanol (5832), and water (5664). Each cranberry matrix contained unique compounds; fruit=3680, product 1=3464, product 2=3500. Clustering was visualized using principal component and partial least squares discriminate analyses with application of univariate statistics to mitigate false discoveries. A significance algorithm found 1987, 716 and 1556 compounds (p-value<0.05) in methanol, 70% ethanol and water extracts, respectively. In metabolomic profiles of V. macrocarpon varietals 6481 compounds were conserved and 136 (Ben Lear), 84 (Bergman), 91 (GH1), 128 (Pilgrim) and 165 (Stevens) unique observations were made. Across the three Vaccinium species 8000-10,000 phytochemicals were detected with 4624 compounds conserved between them. Together these data establish targeted and untargeted methods for phytochemical characterization of cranberries, providing foundational chemotaxonomic knowledge and new insights into the maintenance of health in traditional North American diets.
URI: http://hdl.handle.net/2429/39867
Scholarly Level: Graduate

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