Two new quinoline glycoalkaloids from Echinops gmelinii.

Two new glycosidic quinoline alkaloids, 1-methyl-4-methoxy-8-(beta-D-glucopyranosyloxy)-2(1H)-quinolinone (1) and 4-methoxy-8-(beta-D-glucopyranosyloxy)-2(1H)-quinolinone (2), have been isolated from the 1-butanol extract of the aerial parts of Echinops gmelinii (Compositae). Structural elucidation of the two new glycoalkaloids was based on their 1H, 13C, DEPT, HSQC, COSY, HMBC NMR spectra and high-resolution FAB-MS data. These two compounds are rare examples of quinoline alkaloidal glycosides from natural sources.