Assay of flavonoid aglycones with HPLC in four species of genus Hypericum

Abstract

Hypericum plants are widely used in phytotherapy in many countries. A number of plants of this genus have exhibited various pharmacological activities attributed to their flavonoid content. The present paper describes a reverse-phase HPLC method developed for the assay of 7 flavonoid aglycones (quercetin, myricetin, isorhamnetin, rhamnetin, kaempferol, luteolin and apigenin) in polar extracts of four Hypericum species from UK, Hypericum androsaemum, L., Hypericum ericoides, Arechav, Hypericum x moserianum (Hypericum calycinum x Hypericum patulum) Andre and Hypericum olympicum, L. The identity of detected flavonoids was confirmed by comparing their retention times with those of corresponding standards. The content of detected flavonoids varied from 816.69 (mg/Kg fresh wt.) in Hypericum moserianum to 6726.52 (mg/Kg fresh wt.) in Hypericum olympicum. Quercetin and apigenin were present in all the species while myricetin and kaempferol were detected only in H. moserianum.