PRELIMINARY RESEARCH REGARDING URTICA URENS L. AND URTICA DIOICA L.

The leaves of Urtica urens L. (dwarf nettle, Uu) and Urtica dioica L. (Ud) are included in the European Pharmacopoeia 7th edition, as a monograph called Urticae folium (collective drug), and both are traditionally used to treat diabetes mellitus. The insufficient data regarding the chemical composition of Uu leaves led us to approach their research, and that of Ud (harvested in the same period of growth), in order to select the highest quality raw material for obtaining pharmacologically active vegetal extracts. The phytochemical analysis consisted in: specific reactions, in order to identify the main active substances; spectrophotometric methods to quantify phenolcarboxylic acids, flavonoids, total phenolic compounds, tannins, carotenoids and sterols; chromatographic analysis HPLC/UV and HPLC/MS to identify and quantify phenolcarboxylic acids and flavonoids, respectively sterols. Sterols and phenolcarboxylic acids are the main active substances in both nettle species, but higher quantities are found in Ud. The carotenoids content is low. The chromatographic results indicated, for both species, the presence of caffeic acid, chlorogenic acid, beta-sitosterol and stigmasterol. Rutin and ergosterol were present only in Ud, and campesterol only in Uu. Of these, sterols are known as peroxisome proliferator activated receptor gamma (PPAR-gamma) (can lower blood glucose), and phenolcarboxylic acids as 3-hydroxy-3-methylglutaryl coenzyme-A (HMGCoA) inhibitors (may act as hypocholesterolaemic agents).