Triterpenoidal Saponins Acylated with Two Monoterpenic Acids from Gleditsia sinensis

Abstract

The isolation and characterization of three new oleanane-type triterpenoidal saponins, called gleditsiosides E-G, along with two known ones, from the anomalous fruits of Gleditsia sinensis LAM. are described. Their structural details were unambiguously determined by using a combination of modern NMR techniques, including distortionless enhancement by polarization transfer (DEPT), double-quantum filtered ¹H-¹H correlated spectroscopy (DQF-COSY), homonuclear hartmann-hahn (HOHAHA), ¹H-¹³C heteronuclear correlation (HETCOR), heteronuclear multiple-bond connectivity (HMBC) and rotating-frame overhauser enhancement spectroscopy (ROESY) experiments as well as some chemical methods. The five bisdesmosidic triterpenoidal saponins consisting of the same sugar sequence were all acylated with two different or identical monoterpenic acids to the C-2 and C-3 positions of rhamnose moiety.