Cranberry (Vaccinium macrocarpon) oligosaccharides decrease biofilm formation by uropathogenic Escherichia coli. (August 2015) - Sun, Jiadong
Highlights: A phenolic-free fraction was purified from American cranberry ( Vaccinium macrocarpon ). Constituents of the fraction were predominantly composed of oligosaccharides with various degrees of polymerisation. Glycosyl composition and linkage analyses and NMR data revealed mainly xyloglucan and arabinan residues. The oligosaccharide constituents reduced biofilm formation by uropathogenic E. coli by over 50%. Cranberry oligosaccharides may play a role in its preventive effects against urinary tract infections. Abstract: The preventive effects of the American cranberry ( Vaccinium macrocarpon ) against urinary tract infections are supported by extensive studies which have primarily focused on its phenolic constituents. Herein, a phenolic-free carbohydrate fraction (designated cranf1b-F2) was purified from cranberry fruit using ion exchange and size exclusion chromatography. MALDI-TOF-MS analysis revealed that the cranf1b-F2 constituents are predominantly oligosaccharides possessing various degrees of polymerisation and further structural analysis (by GC–MS and NMR) revealed mainly xyloglucan and arabinan residues. In antimicrobial assays, cranf1b-F2 (at 1.25 mg/mL concentration) reduced biofilm production by the uropathogenic Escherichia coli CFT073 strain by over 50% but did not inhibit bacterial growth. Cranf1b-F2 (ranging from 0.625 to 10 mg/mL) also inhibited biofilm formation of the non-pathogenic E. coli MG1655 strain up to 60% in a concentration-dependent manner. These results suggest that cranberry oligosaccharides, in addition to its phenolic constituents, may play a role in its preventive effects against urinary tract infections.