Hexasaccharide resin glycosides from the jalap roots as modulators of multidrug resistance in MCF-7 cancer cell line

The root of the plant Ipomoea purga, a morning glory native to Mexico and belonging to the medicinal herb complex known as "raiz de Jalapa" had never been phytochemically studied as a drug for the treatment of gastrointestinal disorders. Previous investigation of the aerial parts have led to the isolation of resin glycosides, derivatives of operculinic acid A and B as well as ester-typed dimmers of pentasaccarides showing the capatibility of modulating the multidrug resistance phenotype in MCF-7 cancer cell line. The objective of this work was to isolate and elucidate the structure of the major constituents of the MeOH soluble extract from the root of I. purga. Thereby, HPLC analysis of an insoluble fraction led to the isolation and purification of three new resin glycosides derived of purgic acid A: a hexasacharide composed of one D-fucose, two D-glucose, two D-quinovose and one L-ramnose units. These glicolipids are the first examples of intact resin glycosides with purgic acid A core. Their structures were established through the analysis of their NMR spectroscopy and mass spectrometry data. The capability of these compounds as modulators of multidrug resistance in MCF-7 cancer cell line was tested; results provided additional evidence to support the potential of noncytotoxic resin glycosides as inhibitory substrates of P-glycoprotein for overcoming cross drug resistance in combinatorial cancer therapy. Acknowledgment. This research was partially supported by DGAPA, UNAM (IN212813).CONACyT (220535). E.Bautista received posdoctoral scholarships from DGAPA.