Three New Pentasaccharide Resin Glycosides from the Roots of Sweet Potato (Ipomoea batatas)

Three new pentasaccharide resin glycosides, batatosides III-V (1-3), were isolated from the roots of Sweet potato (Ipomoea batatas). Saponification of the crude resin glycoside mixture yielded substituents and simonic acid B. The structures of the isolated compounds (1-3) were established through spectroscopic analyses, including high field NMR spectroscopy and HR-ESI-MS, and chemical correlation. The major characteristics of 3 are the presence of three different substituents, especially the substituent of cinnamic acid was seldom. The mono-saccharides of 1-3 were proved by GC-MS and the absolute configuration of aglycone was further established as S by Mosher's method with R-methyloxyphenylacetic acid (MPA) and S-MPA.