10.

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

Souheila Laggoune, Ignacio Brouard, Francisco Leon, Claude-Alain Calliste, Jean-luc Duroux, Jaime Bermejo, Zahia Kabouche and Ahmed Kabouche

Laboratoire d’Obtention de Substances Thérapeutiques (L.O.S.T), Université Mentouri - Constantine, Route de Ain El Bey, 25000 Constantine, Algérie

Instituto de Productos Naturales y Agrobiologı´a-C.S.I.C.-Instituto Universitario de Bio-Orga´nica ‘‘Antonio Gonza´lez’’, Universidad de La Laguna, Av. Astrofı´sico F. Sa´nchez 3, 38206 La Laguna, Tenerife, Spain

Laboratoire de Biophysique, UPRES EA-1085, Biomolécules et cibles cellulaires tumorales Faculté´ de Pharmacie, 2 rue du Dr. Marcland, 87025 Limoges Cedex, France

Abstract: 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.

Keywords: Stachys mialhesi; Lamiaceae; lignans, free radical scavenging activity; ESR.