Determination of Structure and Cytotoxicity of Ten Undescribed Steroidal Glycosides from Allium cristophii × A. macleanii ‘Globemaster’

Abstract

‘Globemaster’ is an ornamental hybrid cultivar whose parent plants are Allium cristophii and A. macleanii. The chemical constituents of ‘Globemaster’ bulbs have not yet been examined; thus, a systematic phytochemical investigation was undertaken herein. A series of chromatographic separations of the MeOH extract of ‘Globemaster’ bulbs afforded 27 steroidal glycosides (1–27), which are classified into 23 spirostanol glycosides (1–8 and 11–25), two furostanol glycosides (9 and 26), a pregnane glycoside (10), and a cholestane glycoside (27). The structures of the hitherto undescribed compounds (1–10) were determined from the two-dimensional NMR spectroscopic data and hydrolysis. The cytotoxicity of the isolated compounds (1–27) toward HL-60 human promyelocytic leukemia cells, A549 human adenocarcinoma lung cancer cells, and SBC-3 human small-cell lung cancer cells was evaluated. Compounds 8, 22, 23, 24, and 26 exhibited cytotoxicity toward all cell lines in a dose-dependent manner, with IC50 values in the 1.3–49 µM range.