Determination of caffeoyl quinic acids and flavonoids in Acanthopanax trifoliatus leaves by HPLC.

Extracts from the leaves of Acanthopanax trifoliatus, harvested at different seasons, were quantitatively analyzed for phenolic contents using high performance liquid chromatographic (HPLC) methods. Samples collected in winter contained high amounts of the major active components, mono and di-caffeoylquinic acid derivatives and flavonoid glycosides. It was found that January and November were the preferred periods for collecting plant material containing high amounts of caffeoyl quinic acid and flavonoid constituents.