New Acetylated Flavone O-Sophorosides from Carduus nutans ssp. leiophyllus

Apigenin 7-O-sophoroside, chrysoeriol 7-O-sophoroside, and four new flavonoids 1–4 were observed in leaves of Carduus nutans ssp. leiophyllus (Petrovic) Stoj. & Stef. (syn. C. thoermeri Weinm.). The structures of the new compounds were determined using UV and NMR spectroscopy and mass spectrometry as luteolin 7-O-[2′′-O-(4′′′-O-acetyl)-β-D-glucopyranosyl]-β-D-glucopyranoside (carduleioside A, 1), chrysoeriol 7-O-[2′′-O-(4′′′-O-acetyl)-β-D-glucopyranosyl]-β-D-glucopyranoside (carduleioside B, 2), apigenin 7-O-[2′′-O-(2′′′-O-acetyl)-β-D-glucopyranosyl]-β-D-glucopyranoside (carduleioside C, 3), and apigenin 7-O-[2′′-O-(6′′′-O-acetyl)-β-D-glucopyranosyl]-β-D-glucopyranoside (carduleioside D, 4). Compounds 1 and 2 inhibited the activity of monoamine oxidases A and B.