Optimization of extraction procedure and determination by high performance liquid chromatography of flavonols and phenolic acids from Hypericum Perforatum L.

Hypericum perforatum is a medicinal plant which has been known in traditional medicine as an antiinflammatory and healing agent. Nowadays the use of Hypericum extracts is concerned mainly with antidepressive applications. In the present work, HPLC – RP- C18 column chromatography with photodiode array detection was applied for the determination of the derivatives of cinnamic and benzoic acid (e.g., caffeic, chlorogenic, ferulic, sinapic, gallic acids) (Fig.1.) and flavonols - quercetine derivatives (quercetine, rhamnetine, quercitrin, mirycetine, keampferol and rutin) in Hypericum Perforatum. Phenolic compounds were extracted from the sample matrix with ethanol and ethanolwater mixture in different ratios solvent (3:7; 8:2; v/v) at 30°C and 60°C in water-bath shaker and by ultrasonic extraction and then analyzed before and after acid and basic hydrolysis. The total amount of studied flavonols and phenolic acids were compared with the total flavonoids content (TFC) and with total polyphenols content (TPC). UV-Vis spectrometry was used to investigate methods for qualitative and quantitative determination of these compounds

The influence of pH and selected cations on the spectrofluorometric determination of oxytetracycline hydrochloride

The spectrofluorometric method for the oxytetracycline hydrochloride in pure and in veterinary products Tetrox and Oxymed 50 determination is described. The influence of pH solution and presence selected cations on fluorescence intensity were studied too. It was ascertained that the highest fluorescence intensity take place at pH=9. Moreover, the quenching of fluorescence intensity was observed at presence Ca2+, Al3+ and Fe3+ in contrast to Mg2+ which caused increasing of intensity. The obtained recovery (97.23±0.12% for Tetrox and 95.21±0.10% for Oxymed 50) values meet the European Pharmacopoeia requirement. Moreover, the relative standard deviation (RSD) was below 0.23% confirmed high precise of the method. The statistical test (t-Student and F-Snedecor) used for comparison spectrofluorometric and chromatographic methods pointed that they are comparable in respect of precision but not of accuracy