Seasonal Variation of Loganin from Lonicera japonica Thunb.

Lonicerae Folium et Caulis, the folium and stem of Lonicera japonica Thunb., has been used as diuretic, stomachic, antipyretic, analgesic and anti-inflammatory agent in Korea. We isolated a main iridoid, loganin which has some important biological effects from the folium and stem of this plant. Generally, it is known that iridoid compounds have variable contents by the collecting time and a part of plant. The content of main compound is important to evaluate its quality. In order to evaluate the quality of Lonicerae Folium et Caulis, the method of quantitative determination of loganin as a reference standard compound has been developed. (omitted)