PRELIMINARY RESEARCH REGARDING THE THERAPEUTIC USES OF URTICA DIOICA L. NOTE I. THE POLYPHENOLS EVALUATION
The use of stinging nettle leaves for the treatment of diabetes mellitus without a scientific evaluation, persuaded us to study them, in order to obtain pharmacological active extracts. According to scientific data, polyphenols are known as HMG-CoA reductase inhibitors and have potent anti-glycation activity. These compounds are the main active principles in the Urticae folium. The aim of this study was to evaluate the polyphenols’content (polyphenolcarboxilic acids = PPCA, and flavonoids) of stinging nettle leaves, harvested from culture and wild flora, originated from Racari, Dambovita district, Romania. Spectrophotometric and chromatographic methods were used. A new HPLC method for the identification and quantification of caffeic and chlorogenic acids from Urticae folium was also developed. The highest contents of polyphenolcarboxilic acids (expressed as % of chlorogenic acid) and flavonoids (expressed as % of rutin) were found in the leaves of wild nettles harvested in the month of March (4.2295% chlorogenic acid and 0.6237% rutin). The polyphenols’ content is slightly lower than the ones mentioned in the scientific literature. The content of PPCA decreases from March till September, both in wild and cultivated samples. The variation of the flavonoids’content differs with the origin of raw material (culture or spontaneus flora). The new HPLC method for polyphenols’analysis is reproductible. Rezumat Utilizarea tradiţională a produsului Urticae folium in diabet, fără o justificare stiintifica a acţiunii precum si menţionarea flavonelor si acizilor fenolcarboxilici (compusii majoritari) ca inhibitori ai HMG-CoA reductazei si ai proceselor de glicozilare si lipoxidare avansată, ne‐au determinat să abordăm cercetarea acestora, in vederea valorificării terapeutice sub formă de extracte selective. In acest scop am derulat o cercetare spectrofotometrică si cromatografică (HPLC) pentru a pune in evidenţă polifenolii prezenţi in frunzele de urzică recoltate din flora spontană si de cultură, din localitatea Răcari, judeţul Dâmboviţa. De asemenea, ne-am propus să separăm acizii cafeic si clorogenic si să-i determinăm cantitativ printr-o nouă metodă HPLC/UV.
A COMPARATIVE MORPHOLOGICAL AND CHEMICAL STUDY OF THE SEEDS FROM TRIGONELLA FOENUM GRAECUM (L.) AND T. CAERULEA (L.) SER. SPECIES
While the seeds of Trigonella foenum-graecum (L.) are relatively widely used as a spice and seasoning in food and as a traditional herbal medicinal product, those of T. caerulea have a more limited use and are rather ignored. We report on a comparative study of the surface morphology (investigated by scanning electron microscopy), of alcoholic extracts prepared from the seeds of the two species (analysed through HPLC) and of their fatty acid composition (investigated through GC, after derivatization with methanol). There are important differences in the seed morphology, the epidermis cells (macrosclereids) of T. foenum-graecum seeds are very narrow (6.4 x 8.4 μm; SD 0.8 μm and 0.8 μm) and those of T. caerulea are still narrower (4.4 x 5.2 μm; SD 0.6 and 0.5 μm, respectively). The HPLC chromatograms of the alcoholic seed extracts from the two species revealed at least seven peaks specific for T. foenum-graecum only, and three for T. caerulea only, suggesting a different chemical composition. Quercetin, myricetin and kaempferol, used as reference substances were not detected in the extracts. The qualitative and quantitative compositions of the various fatty acids do not indicate substantial differences between the two species: in the seeds from both species linoleic and linolenic (around 40% each), palmitic (around 10%) and stearic acids (2-4%) are the most important components.
Quantitation of Phytoestrogens in Legumes by HPLC
A fast, sensitive, and precise method is presented for the efficient extraction and quantitation of coumestrol, daidzein, genistein, formononetin, and biochanin A from foods by diode array reversed-phase HPLC analysis using flavone as internal standard. Acid hydrolysis during extraction of foods was chosen to convert the various phytoestrogen conjugates into their respective aglycons, facilitating HPLC analysis and allowing quantitation of total phytoestrogens as aglycons including originally present glycosides, «free» aglycons, and those conjugates which are below the detection limit in food plants. Extraction efficiencies and HPLC conditions were evaluated and optimized, leading to precision and spiking recovery values of 3-8% and 94-104%, respectively, depending on the analyte