Sweet and bitter glycosides of the Chinese plant drug, Bai-Yun-Shen (roots of Salvia digitaloides).

Abstract

From a Chinese plant drug, Bai-Yun-Shen (roots of Salvia digitaloides), a new sweet glycoside named baiyunoside (1) was isolated. The structure of the acid-unstable aglycone of 1 named baiyunol (2) was elucidated by MS and NMR spectroscopy especially by comparison with the 13C chemical shifts of β-onocerin (3). The structure of 1 was determined to be β-D-xylopyranosyl (1→2)-β-D-glucopyranoside of 2 by MS and NMR spectroscopy. Besides this sweet principle (1), several bitter iridoid glucosides were also isolated from this plant. Two of these glucosides were identified as shanzhiside methyl ester (13) and its 8-O-acetate (=acetylbarlerin, 10), respectively. A new glucoside (9) was formulated as 6-O-syringyl-8-O-acetyl shanzhiside methyl ester by the correlation with 13.