HPLC-DAD and TLC-densitometry for quantification of hypericin in Hypericumperforatum L. extracts

Hypericum perforatum L. is a spontaneous perennial herbaceous plant. widely distributed in Europe, Asia, Northern Africa, and North America. The dried flowers or dried aerial parts are used to prepare the drug Hyperici Herba or St. John's Wort. Nowadays this drug is largely used as a natural antidep ressant; hypericin and hypericin-like substances are considered the main ac tive ingredients. In this work the hypericin and pseudohy-pericin content o f hydroalcoholic extracts both of Hyperici Herba and of Hypericum perforatu m L. dried flowers were measured by two techniques, TLC-densitometry with f luorescence detection and reversed-phase HPLC-DAD (diode-array detection). The quantitative data obtained by applying these techniques were compared a nd the identification of the main flavonoid constituents was performed by H PLC-DAD for characterization of the extracts. The quantitative data obtained by use of the two techniques were in good ag reement and statistical analysis of the findings was indicative of the equi valence of the techniques.