Highly Methylated 6-Hydroxyflavones and Other Flavonoids from Thymus piperella

Abstract

From the aerial parts of Thymus piperella, the free flavone aglycones 5,6-dihydroxy-7,8,4′-trimethoxyflavone (1), 5,6-dihydroxy-7,8,3′,4′-tetramethoxyflavone (2), 5,6-dihydroxy-7,3′,4′-trimethoxyflavone (3), ladanein (4) (5,6-dihydroxy-7,4′-dimethoxy-flavone), 5-hydroxy-7,4′-dimethoxyflavone (5) and apigenin (6), the flavanones naringenin (7) and eriodictyol (8), and the flavone glycosides vicenin-2 (9), apigenin-7-O-β-D-glucoside (10) and luteolin-7-O-β-D-glucoside (11), have been isolated and identified. This is the first time that 5,6-dihydroxy-7,8,4′-trimethoxyflavone has been found as a natural product.