Chem. Pharm. Bull., 47(3),383-387, March 1999

Regular Articles

Dihydroisocoumarin Constituents from the Leaves of Hydrangea macrophylla var. thunbergii (2).¹⁾ : Absolute Stereostructures of Hydrangenol, Thunberginol I, and Phyllodulcin Glycosides and Isomerization Reaction at the 3-Positions of Phyllodulcin and Its Glycosides

Masayuki YOSHIKAWA,^* Tomohiko UEDA, Hiroshi SHIMODA, Toshiyuki MURAKAMI, Johji YAMAHARA, and Hisashi MATSUDA

Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
Received October 15, 1998; accepted December 10, 1998

Following the characterization of 3S-phyllodulcin, 3R- and 3S-phyllodulcin 3'-O-glucosides, and 3R- and 3S-thunberginol H 8-O-glucosides, six new dihydroisocoumarin glycosides, 3R- and 3S-hydrangenol 4'-O-apiosylglucosides, 3R- and 3S-thunberginol I 4'-O-glucosides, thunberginol I 8-O-glucoside, and 3S-phyllodulcin 8-O-glucoside, were isolated from the dried leaves of Hydrangea macrophylla var. thunbergii and their structures were determined on the basis of chemical and physicochemical evidence. In addition, isomerization reaction at the 3-positions of phyllodulcin and its glycosides was examined.

Key words thunberginol I glycoside; hydrangenol glycoside; Hydrangea macrophylla var. thunbergii; dihydroisocoumarin glycoside; dihydroisocoumarin 3-isomerization; Hydrangeae Dulcis Folium