Vaccinium corymbosum Lam. (highbush blueberry) was introduced in the Romanian culture for its fruit production. After the harvest of the fruits, its leaves can be used as substitute for the leaves of the indigenous one (Myrtilli folium). Several comparative phytochemical and pharmacological studies of the leaves were done in order to evaluate its phytotherapeutic features.
At present Myrtilli folium is used against diarrhoea and for its hypoglycaemic effects.
The substances analysed quantitatively and qualitatively were the following ones: flavones, proanthocyanins, tannins and phenolic glycosides. In addition, the diuretic, saluretic, anti-inflammatory and hypoglycaemic actions of the 1:1 hydroalcoholic extract obtained from dried leaves was tested.
The analysed V. corymbosum leaves have a higher content of active principles (twice - three times higher) than the leaves of V.myrtillus: 3.68/1.50% flavones, 16.20/3.96 proantho-cyanins and 18.60/10.43% tannins, while the phenolic glycosides are not present (in both species). Qualitatively, the active principles were alike for both species.
The diuretic index of the leaf extract of V. corymbosum administered p.o. is higher than the extract of. V. myrtillus: I.D. = 1.48/1.20; the saluretic index shows the same characteristics: Na+1.66/K+0.98 / Na+1.04/K+1.10.
By the phagocytary activation test and by infiltrating a local inflammatory in the muscle, the anti-inflammatory effect of V. corymbosum Lam.proved to be superior to the V. myrtillus one.
The extract and the powder obtained from the leaves lack toxic features (D.L.50ł5.0 g/kg).
The leaf extract of V. corymbosum. decreases glycaemia in the case of diabetes-induced animals with 15.8%, while the leaf extract of V. mytrillus decreases it with 31.6%.