The content of procyanidin trimers of types A and B in some Vaccinium species and cultivars

The flavonoids procyanidin trimers of A and B types known as antidiabetic and antiobesic compounds [1] were detected in some Vaccinium species, their content has been determined only in blueberry/bilberry plant leaves and fruits but not in the stems. The aim of this study was to compare their content in different parts of V. myrtillus and V. corymbosum cultivars. We collected stems (60 samples) and leaves (30) of V. myrtillus and V. corymbosum cultivars 'Ama' and 'North Blue' from different locations in Estonia around the year, and estimated the concentration of bioactive polyphenols by reversed phase HPLC-MS; procyanidins were identified by their spectra and quantified using catechin as a standard. The content of oligomeric procyanidins was significantly higher in the stems than in the leaves, and a clear seasonal variability was also detected. The seasonal/geographic variation in the content of procyanidins was nearly tenfold. The concentration of type A procyanidin was drastically higher in the V. myrtillus plants than in hybrid blueberries, while the differences in procyanidin B concentrations were less prominent. The level of procyanidins A and B was rather equal in stems and leaves of V. myrtillus collected from different locations, whereas the content of A-type isomer was higher. The highest content of procyanidin A in V. myrtillus stems was more than 3000 times higher than the lowest content in the leaves of V. corymbosum cultivar 'Ama'. No clear seasonal dynamics in procyanidins content in either Vaccinium spp. stems or leaves was found, but the ratio of the highest and lowest values for stems, collected in the same location at different times was between 3 and 18, whereas the highest contents of procyanidin A in the stems of V. myrtillus were over 1% of the dry matter. Conclusion: the best sources of procyanidin trimers of type A and B are the stems of V. myrtillus . Reference: [1] Nakahara K. et al. (2001) U. S. States Patent 6,294,190 B1, September 25.