24-Hydroxyoleanane-type triterpenes from the aerial parts and roots of Oxytropis falcata.

Phytochemical investigation of the aerial parts of Oxytropis falcata led to the isolation of three new 24-hydroxyoleanane-type triterpenes (1-3), seven known analogues (4-10), and two rare sesquiterpenoids (12, 13). Compounds 6 and 12 were isolated as new natural products. Triterpenes (5, 6, 8, 11) were isolated from the roots of O. falcata. The structures and relative configurations of these compounds were elucidated by spectroscopic analyses, including 1D and 2D NMR spectroscopy and mass spectrometry, and by comparison of their NMR data with those of related compounds. Single-crystal X-ray diffraction analyses confirmed the structures of 1-4, and the absolute configuration of 3 was evidenced by the incorporation of DMSO (crystallization solvent) in the crystal lattice.