AMERICAN CRANBERRY PRODUCTS: PROANTHOCYANIDIN PURIFICATION AND CONCENTRATIONS
American cranberry (Vaccinium macrocarpon Ait.) phenolics have important roles within the plant; they also contribute to harvest and product quality, and have potential human health benefits. Proanthocyanidins (phenolic polymers) may aid in preventing urinary tract infections (UTIs), although literature results have been mixed. The disparity among cranberry clinical trials might be due to natural variation in proanthocyanidin, or other phytochemical content. Differences between methods for purification and analyses also contribute to the wide range of concentrations reported. In this study five common sample purification techniques were evaluated prior to phloroglucinolysis (acid catalysis of proanthocyanidins in the presence of excess phloroglucinol; using two incubation periods), followed by HPLC analysis of proanthocyanidin. An optimized purification method was then used to identify and quantify the proanthocyanidins (extension and terminal units of epigallocatechin, catechin, epicatechin, A-type trimer, A2) of commercially available cranberry products (juices, concentrates, tablets, and capsules; n=17). Both size exclusion beads were found suitable for proanthocyanidin purification, and proanthocyanidin extension and terminal units composition were contingent upon the cleanup procedure utilized. These data illustrate that purification methods should be given consideration prior to conducting any cranberry proanthocyanidin analyses, and have to be accounted for when comparing values between studies.
Jungmin Lee, and Rennaker, C. 2014. AMERICAN CRANBERRY PRODUCTS: PROANTHOCYANIDIN PURIFICATION AND CONCENTRATIONS. Acta Hort. (ISHS) 1017:363-368
condensed tannin, phenolic, polyphenolic, sample preparation