Lignans and an Abundant flavone glycoside with Free-Radical Scavenging Activity from the Roots of the Endemic Species Stachys mialhesi de Noé

Two sterols, stigmasterol (1) and β-sitosterol (2), two lignans, (+)-sesamin (3), new for the genus Stachys and (±)-paulownia (4), new in the Lamiaceae family, reported for the second time from a natural source, and one acetylated flavone glycoside isoscutellarein-7-O-(2''-O-6'''-O-acetyl-β-D-allopyranosyl-β-D-glucopyranoside (5), were isolated from the roots of Stachys mialhesi de Noé. Surprisingly, 3g of compound 5 are gathered from 5g of roots extract. The structures of compounds 1-5 were established on the basis of physical and spectroscopic analysis, and by comparison with the literature data. The free-radical-scavenging property of compound 5 was evaluated by the use of the ESR method in order to visualize the inhibition of the 1,1-diphenyl-2-1picrylhydrazyl (DPPH) free radical.