Studies on the Constituents of Amaranthus caudatus Leaves: Isolation and Structure Elucidation of New Triterpenoid Saponins and Ionol-Derived Glycosides

The isolation of seven triterpenoid saponins ( 1 − 7 ) is reported, among them three new natural products ( 1 − 3 ), together with three new ionol-derived glycosides ( 8 − 10 ) from the MeOH extract of the leaves of Amaranthus caudatus (Amaranthaceae). All structures were elucidated by spectroscopic methods, including the concerted application of one-dimensional ( 1 H, TOCSY, 13 C, and 13 C DEPT NMR) and two-dimensional NMR techniques (DQF−COSY, HSQC, HMBC, ROESY). A comparative study of seeds and leaves has been also carried out.