Bilberry is a deciduous shrub growing to 50 cm, with elliptical leaves. The flowers are single on short stems. The fruits are berries, globular, dark purple, juicy and sour.
Bilberry fruits contain up to 10% tannins, anthocyanins, organic acids, and pectins. The leaves contain tannins, flavonoids, and a small amount of arbutin.
The main bioactive compounds of bilberry leaves are hydroxycinnamic acids. It was reported that the concentration of hydroxycinnamic acids were higher in the leaves than in the bilberry fruit. Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. Several studies have reported that HCs and their derivatives act as powerful antioxidants and protect biologically important molecules from oxidation.
The second significant group of phenolics is flavonoids. Quercetin-3-O-glucuronide is the most abundant flavonol and its concentration ranges from 70% to 93% of total flavonols; other flavonols in bilberry leaves are quercetin-3-O-β-galactoside (4.06%), quercetin-3-O-(4”-HMG)-α-rhamnoside (3.48%), quercetin-3-O-arabinoside (2.92%), quercetin-3-O-glucoside (0.99%), quercitrin (0.73%), and quercetin (0.03%), as well as three kaempferol glycosides (almost 1.5%).
In traditional medicine, fruits of Vaccinium myrtillus are much used as anti-diarreal while leaves are used as astringent, anti-bacterial, anti-inflammatory, and diuretic. Vaccinium myrtillus leaf infusions are traditionally used as a folk medicine treatment of diabetes. A tea made of the leaves is also a remedy for diabetes if taken for a prolonged period.
The researchers have shown that bilberry leaf tea has an antidiabetic activity, anti-hyperlipidemic activity, anti-staphylococcal activity, antioxidant, anti-neoplastic activity.
Teas from bilberry leaves
