Lingonberries (Vaccinium vitis-idaea L) and blueberries (Vaccinium corymbosum) contain discrete epicatechin anthocyanin derivatives linked by ethyl bridges

BACKGROUND: Lingonberries have been associated with a range of potential bioactivities related to their polyphenol content and composition, in particular anthocyanin and proanthocyanidin derivatives. OBJECTIVES: The objective of this study was to examine the anthocyanin composition of extracts of lingonberry and related Vaccinium berries with respect to previously unidentified anthocyanin-like components. METHODS: Extracts were prepared from lingonberries, blueberries and a commercial cranberry juice product and examined by liquid chromatography mass spectroscopic techniques (LCMSⁿ) before and after various fractionation steps. RESULTS: A range of discrete anthocyanin derivatives ethyl linked to (epi)catechin units were identified in lingonberry extracts using LC-MSⁿ methods. Analogous derivatives were detected in similar blueberry extracts, and confirmed in cranberry juices. CONCLUSIONS: Through a combination of fractionation techniques and LCMSⁿ analysis, this paper provides the first evidence that anthocyanin-epicatechin derivatives linked by ethyl bridges are present in lingonberries and in blueberries. These discrete components may be the smallest in a series of proanthocyanidin derivatives with terminal anthocyanins linked through ethyl groups which have previously been inferred in cranberries using mass spectrometric techniques.