Calysepins I-VII, Hexasaccharide Resin Glycosides from Calystegia sepium and Their Cytotoxic Evaluation.

Seven new hexasaccharide resin glycosides, named calysepins I-VII ( 1 - 7 ), with 27-membered rings, were obtained from the aerial parts of Calystegia sepium . Their structures with absolute configuration were established on the basis of spectroscopic data interpretation analysis and the use of chemical methods. They were defined as hexasaccharides composed of one d-quinovose, four d-glucose, and one l-rhamnose unit, and their sugar moieties were partially acylated by (2 S ) - methylbutanoic acid in 1 - 7 and (2 R ,3 R )-nilic acid in 1 - 5 and 7 , which mainly differed at the positions of acylation. Additionally, calysepin IV ( 4 ) exhibited cytotoxicity against A549 cells with an IC 50 value of 5.2 μM.