Vaccinium myrtillus L., Ericaceae, (bilberry) leaves are traditionally used in southeastern Europe for
the treatment of diabetes. In the present study, the variation of the phytochemical
composition, as well as antiradical and tyrosinase-inhibiting activity of 11 bilberry
populations from Croatia (5) and Montenegro (6) was investigated, considering their
use for cosmetic purposes. Content of phenols, flavonoids and phenolic acids, as well
as antiradical and enzyme inhibiting activity of leaf extracts were determined spectrophotometrically.
The content of the most abundant flavonoid, hyperoside, was determined using HPLC
with DAD detection. Furthermore, the content of selected metals (K, Ca, Mn, Fe, Cu,
Zn, Br, Rb, Sr) was determined using TXRF. A significant quantitative variability
of total phenols (386.8–133.9 mg/g), flavonoids (83.1–12.0 mg/g) and phenolic acids
112.4–38.0 mg/g) was recorded. The extracts displayed excellent antiradical activity
(IC50 between 120.8–11.1 mg/g) and somewhat weaker anti-tyrosinase activity (IC50 between 400.3–170.9 mg/g). The hyperoside content in the extracts varied between
73.1 and 5.7 mg/g. There was no statistically significant correlation between the
content and area of origin. However, the chromatograms of extracts from Montenegro
could be easily distinguished from the Croatian ones by the presence of an additional
peak in chromatogram, which, according to its UV spectrum, represents a quercetin
derivative. The observed activities of bilberry leaf extracts suggest that they might
be used in cosmetic products. However, before the development of such products, a
detailed analysis of plant material is advisable in order to select the populations
with the highest activity.
