Eight new resin glycosides, calyhedins XXIV–XXXI, from the rhizomes of Calystegia hederacea

Abstract

Eight new resin glycosides, named calyhedins XXIV ( 1 )–XXXI ( 8 ), were isolated from the rhizomes of Calystegia hederacea Wall. (Convolvulaceae), along with six known calyhedins: calyhedins II ( 9 ), III ( 10 ), IV ( 11 ), V ( 12 ), VIII ( 13 ), and XII ( 14 ). Their structures were determined from the spectroscopic data. Compounds 1 – 7 were hexa- or hepta-glycosides with macrolactone structures (jalapins), and their sugar moieties were partially acylated by five organic acids, including 2 S -methylbutyric, ( E )-2-methylbut-2-enoic, and 2 R -methyl-3 R -hydroxybutyric acids. Compounds 1 – 7 were macrolactones with 22- ( 1 , 7 ), 23- ( 2 ), 27- ( 3 – 5 ), or 28- ( 6 ) membered rings. Compound 8 was identified as an acylated glycosidic acid methyl ester, corresponding to the compound in which the lactone ring of 1 was cleaved and subsequently methylated. In addition, the cytotoxic activities of 1 – 8 , 11 , 12 , and 14 against HL-60 human promyelocytic leukemia cells and the antiviral activities of 1 – 14 and 11 previously isolated calyhedins against herpes simplex virus type 1 (HSV-1) were evaluated. Except for 1 , the other ten tested compounds exhibited cytotoxicity against HL-60 cells, with the IC 50 values of 3 , 4 , 6 , 7 , 11 , and 12 being closer to or rather lower than that of the positive control cisplatin. Additionally, all tested compounds demonstrated anti-HSV-1 activity, with seven compounds, i.e., 3 , 6 , 9 , 10 , 22 , 23 , and 24 , having EC 50 values lower than or comparable to that of the positive control acyclovir. Graphical abstract

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