Eleven new resin glycosides, ipoalbins XI–XXI, from Ipomoea alba seeds

Ipomoea alba L. (Convolvulaceae), an annual vine native to tropical America, is primarily cultivated for ornamental purposes. The seeds are traditionally used as laxatives in herbal medicine, and young shoots are consumed as a food source. In this study, 11 new resin glycosides, ipoalbins XI (1)-XXI (11), were isolated from the seeds of I. alba. Their structures were elucidated using spectroscopic analyses. All the compounds comprised macrolactone (jalapin-type) structures with sugar moieties that were partially acylated by organic acids, including acetic, (E)-2-methylbut-2-enoic, and 2S-methyl-3S-hydroxybutyric (2S,3S-nilic) acids. Furthermore, the cytotoxic activity of 1-11 against HL-60 human promyelocytic leukemia cells was evaluated. All tested compounds exhibited cytotoxicity; notably, three compounds (3, 7, and 11) exhibited stronger activity, with IC₅₀ values approximately two-thirds that of the positive control (cisplatin). The observed activity may vary depending on the position at which the organic acids are attached to the sugar moiety and the type of monosaccharide present.