Phenolic compounds extracted by acidic aqueous ethanol from berries and leaves of different berry plants.

Phenolic compounds of berries and leaves of thirteen various plant species were extracted with aqueous ethanol and analyzed with UPLC-DAD-ESI-MS, HPLC-DAD, and NMR. The total content of phenolics was consistently higher in leaves than in berries (25-7856 vs. 28-711mg/100g fresh weight). Sea buckthorn leaves were richest in phenolic compounds (7856mg/100g f.w.) with ellagitannins as the dominant compound class. Sea buckthorn berries contained mostly isorhamnetin glycosides, whereas quercetin glycosides were typically abundant in most samples investigated. Anthocyanins formed the dominating group of phenolics in most dark-colored berries but phenolic acid derivatives were equally abundant in saskatoon and chokeberry berries. Caffeoylquinic acids constituted 80% of the total phenolic content (1664mg/100g f.w.) in bilberry leaves. B-type procyanidins and caffeoylquinic acids were the major phenolic compounds in hawthorn and rowanberry, respectively. Use of leaves of some species with prunasin, tyramine and ß-p-arbutin, may be limited in food applications.

Characterization of metabolite profiles of leaves of bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.).

Leaves of bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.) are potential raw materials for food and health care products. Targeted (HPLC-DAD, HPLC-MS, and GC-FID) and nontargeted ((1)H NMR) approaches were applied to study the metabolomic profiles of these leaves. Chlorogenic acid was the major phenolic compound in bilberry leaves and arbutin in lingonberry leaves. Flavonol glycosides were another major group of phenolics in bilberry [5-28 mg/g DM (dry mass)] and lingonberry (15-20 mg/g DM) leaves. Contents of fatty acids were analyzed using GC-FID. The changes in the metabolomics profile during the season were apparent in bilberry but not lingonberry leaves. Negative correlation was found between the contents of lipids and phenolics. The consistency between the key results obtained by targeted and nontargeted analyses suggests nontargeted metabolomic analysis is an efficient tool for fast screening of various leaf materials.

1H NMR-based metabolic fingerprinting of urine metabolites after consumption of lingonberries (Vaccinium vitis-idaea) with a high-fat meal.

The use of NMR metabolomics in clinical trials is growing; however, reports of postprandial experiments in humans are scarce. The present study investigated whether consumption of lingonberries as a supplement to an oil-rich meal modifies the postprandial fingerprints of human urine. Urine samples were analysed by (1)H NMR, and untargeted multivariate analysis was applied to the data for comprehensive fingerprinting. A clear separation of postprandial lingonberry meal samples was revealed. To evaluate statistical differences, a targeted approach was applied for the informative spectral areas. Significantly (p<0.05) increased levels of polyphenol metabolites, hippuric acid and 4-hydroxyhippuric acid, and decreased creatinine and dimethylamine levels were the major explanations for the grouping of the postprandial samples after the different meals. Thus, inclusion of polyphenol-rich lingonberry powder in a rapeseed oil-rich meal modifies the metabolic profile of urine which may be used to reveal both consumption of berries and health-promoting changes in the common metabolism.