Phenoxychromone and 4-hydroxyisoflavans from the roots of Glycyrrhiza uralensis

In an attempt to find species specific markers, a phenoxychromone (1) and eight isoflavonoids including six isoflavans (2-7) and two isoflavanones (8 and 9) were isolated from the root of Glycyrrhiza uralensis. Among the isolated phenolic compounds, glycyurelone (1), glycyurelvanins A and B (2 and 3) were found to be undescribed while others, (-)-vestitol (4), conferol A (5), glyasperin C (6), glyasperin D (7), (-)-licoisoflavanone (8), and (-)-3'-(γ,γ-dimethylallyl)kievitone (9) were previously reported. All compounds except 4 and 5 were prenylated and majority of these possess isoflavan scaffold with highly conserved stereo specificity at C-3 center. Structure elucidation was mainly based on extensive NMR, ECD and mass spectral data analysis.