Structural Characterization and Bioactivity of Cranberry Oligosaccharides

Complex carbohydrates from plant sources, such as the fruits of cranberry (Vaccinium macrocarpon Aiton), promote human health in a variety of ways. Cranberry products are recognized to have biological activities including antioxidant and antimicrobial properties. In addition, several clinical trials and in vitro analyses have assessed the ability of cranberry products and extracts to aid in the treatment of urinary tract infections via prevention of adhesion of bacteria to uroepithelial cells. A complete understanding of carbohydrate function relies on a thorough elucidation of the chemical structure. Several methods have been used in the structural elucidation of cranberry oligosaccharides, including methods of derivatization followed by analysis using gas chromatography-mass spectrometry (GC-MS). In this manner, the identity, quantity, ring structure, and linkage position of glycosyl units within two cranberry oligosaccharides were investigated through hydrolysis of the oligomers and subsequent GC-MS analysis of derivatized monomers. A complete structure was then assigned through the compilation of data, including analysis of 1D and 2D NMR spectra, yielding novel hepta- and octasaccharides. Cranberry extracts enriched with oligosaccharides were assessed for antimicrobial activity and the ability to prevent adhesion of P- fimbriated Escherichia coli to uroepithelial cells. This presentation outlines techniques applied in the structure elucidation of cranberry complex carbohydrates and discusses the biological activity of cranberry oligosaccharides.