Jalapinoside, a Macrocyclic Bisdesmoside from the Resin Glycosides of <i>Ipomea purga</i>, as a Modulator of Multidrug Resistance in Human Cancer Cells

The first macrocyclic bisdesmoside resin glycoside, jalapinoside (<b>4</b>), was purified by preparative-scale recycling HPLC from the MeOH-soluble extracts of <i>Ipomoea purga</i> roots, the officinal jalap. Purgic acid C (<b>3</b>), a new glycosidic acid of ipurolic acid, was identified as 3-<i>O</i>-β-d-quinovopyranoside, 11-<i>O</i>-β-d-quinovopyranosyl-(1→2)-<i>O</i>-β-d-glucopyranosyl-(1→3)-<i>O</i>-[β-d-fucopyranosyl-(1→4)]-<i>O</i>-α-l-rhamnopyranosyl-(1→2)-<i>O</i>-β-d-glucopyranosyl-(1→2)-<i>O</i>-β-d-quinovopyranoside (3<i>S</i>,11<i>S</i>)-dihydroxytetradecanoic acid. The acylating residues of this core were acetic, (+)-(2<i>S</i>)-methylbutanoic, and dodecanoic acids. The site of lactonization was defined as C-3 of the second saccharide moiety. Reversal of multidrug resistance by this noncytotoxic compound was evaluated in vinblastine-resistant human breast carcinoma cells