Alfalfa (Medicago sativa L.) Flavonoids. 1. Apigenin and Luteolin Glycosides from Aerial Parts

Nine flavones and adenosine have been identified in aerial parts of alfalfa, and their structures were established by spectral (FABMS and NMR) techniques. Five of the identified compounds, including apigenin 7-O-[β-d-glucuronopyranosyl(1→2)-O-β-d-glucuronopyranosyl]-4‘-O-β-d-glucuronopyranoside, apigenin 7-O-[2-O-feruloyl-β-d-glucuronopyranosyl(1→2)-O-β-d-glucuronopyranosyl]-4‘-O-β-d-glucuronopyranoside, apigenin 7-O-{2-O-feruloyl-[β-d-glucuronopyranosyl(1→3)]-O-β-d-glucuronopyranosyl(1→2)-O-β-d-glucuronopyranoside}, apigenin 7-O-{2-O-p-coumaroyl-[β-d-glucuronopyranosyl(1→3)]-O-β-d-glucuronopyranosyl(1→2)-O-β-d-glucuronopyranoside}, and luteolin 7-O-[2-O-feruloyl-β-d-glucuronopyranosyl(1→2)-O-β-d-glucuronopyranosyl]-4‘-O-β-d-glucuronopyranoside, have not been reported before in the plant kingdom. Additionally, five known compounds, including apigenin 7-O-β-d-glucuronopyranoside, apigenin 4‘-O-β-d-glucuronopyranoside, apigenin 7-O-[β-d- glucuronopyranosyl(1→2)-O-β-d-glucuronopyranoside], luteolin 7-O-β-d-glucuronopyranoside, and adenosine, were identified. Keywords: Medicago sativa; flavone glucuronides; acylated flavones; adenosine