Preparation of hypericin enriched St. John's wort extracts

Abstract

Results of solid phase extraction (SPE) of St. John' s Wort extracts were described. In order to obtain the extract the air-dried plant material of Hypericum perforatum L. (cultivar Yantar) grown in the Central Botanical Garden of NAS of Belarus was used. Analysis of the St. John's wort extract solutions was carried out by electronic absorption spectroscopy. It was shown the influence of the nature of the solvent on the spectral characteristics of the ex tract. The sorbent Waters Sep-Pak S18®Vac RC was used for solid-phase extraction. The methanol solutions of different concentrations were used as an eluent system. For SPE metanol fractions absorption and fluorescence spectra were registered. It is shown that the main part of hypericin was eluted with 80% methanol. The values of quantum yields were calculated. These results suggest that solid phase extraction on the non-polar sorbent is a promising way to increase the content of the hypericin in the St. John's Wort extracts.