University of Medicine and Pharmacy „Carol Davila“, Faculty of Pharmacy, Bucharest, RomaniaObjective: phytochemical characterization of Urtica
dioica L. leaves and the selection of the raw materials
with the highest content of sterols and carotenoids, in
order to obtain pharmacologically active extracts.
Material and methods. The leaves were harvested for
a period of 7 months (March – September) from Racari
Village, Dambovita County, Romania, in 2010. The batches
were codified as B1 (March), B2 (April), B3 (May),
B4 (June), B5 (July), B6 (August), B7 (September). In
order to confirm the identity of the leaves, macroscopic,
microscopic and qualitative exams were undertaken.
The sterols (free and glycosidic sterols) were assessed
spectrophotometrically, based on the formation of
dehydration products with multiple conjugated double
bonds in the presence of concentrated sulfuric acid and
ferric chloride (catalyst). The carotenoids content were
determined, before and after their release from esteric
forms, by assessing the absorbance at λ = 460 nm.
Results. The morphological and anatomical aspects
concur with scientific literature. The leaves are thin
and complete, with a triangular and pubescent lamina
(L=0.5 to 10 cm, l=0.3 to 5 cm).The margin is serate and
the apex is acuminate. The upper surface is dark green
and the lower surface is light green. In all batches, the
microscopic exam shows the following specific anatomical
elements: subulate hairs and stinging hairs, secretory
trichomes with bicellular heads and unicellular stalks,
cluster-crystals of calcium oxalate. The active principles
identified in the qualitative examination are: sterols,
carotenoids, coumarines, flavonoids (except batch B4),
polyphenolcarboxilic acids, tannins, proanthocyanidins,
mucilages. The carotenoids determination indicates
that the highest content of free and esteric forms are
found in leaves harvested in June and July, respectively.
Glycosidic sterols are prevailing. The leaves content of
glycosidic sterols is increases with maturity of the plant.
The highest content of free sterols was determined in
samples harvested in May.
Conclusions. The leaves of Urtica dioca L. represent
a complex source of active principles. The selected batch
was B3. The selection of the batch was based on the total
amount of carotenoids and sterols
