Comparison of Growth in Hydrangea macrophylla var. thunbergii Grown in Different Soil pH and Quantitative Analysis of Its Sweetness-Related Constituents.

Abstract

Dried and fermented (processed) leaves of Hydrangea macrophylla Seringe var. thunbergii Makino (Hydrangeae Dulcis Folium) are currently used as a crude drug with a sweet taste for diabetic patients and as an oral refrigerant. The sweet taste of this crude drug is primarily attributed to phyllodulcin. However, there are currently no standards for the cultivation of H. macrophylla var. thunbergii and the isolation and production of the primary constituents of this crude drug. In the present study, we prepared five types of soils with different pH values (pH 7.5-5.0) and investigated the effects of these soils on the growth of this plant. The contents of phyllodulcin and its glycoside, phyllodulcin 8-O-β-D-glucopyranoside, in the leaves of plants grown in these soils were quantified. Furthermore, the correlation between the sweetness of Hydrangeae Dulcis Folium and phyllodulcin was investigated. The results showed that soils with pH ranging from 7.0 to 5.5 was not only suitable for plant growth but also increased the content of phyllodulcin and phyllodulcin 8-O-β-D-glucopyranoside in the leaves. Altogether, these findings could be useful for the development of high-quality Hydrangeae Dulcis Folium.