Planta Med 2008; 74 - PB141
DOI: 10.1055/s-0028-1084486

Two cycloartane-type glycosides from the roots of Astragalus glycyphyllos

J Linnek 1, AC Mitaine-Offer 1, T Miyamoto 2, MA Lacaille-Dubois 1
  • 1Laboratoire de Pharmacognosie, Unité de Molécules d'Intérêt Biologique, UMIB UPRES- EA 3660, Faculté de Pharmacie, Université de Bourgogne, 7, Bd. Jeanne d'Arc, BP 87900, 21079 Dijon Cedex, France
  • 2Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812–8582, Japan

The genus Astragalus is the largest one in the Fabaceae family. Several species are used in traditional medicine for the treatment of diabetes mellitus, nephritis, and leukemia [1]. Chemical studies on Astragalus saponins have provided oleanane-type and cycloartane-type triterpenoid glycosides that exhibited cytotoxic, immunostimulatory, hepatoprotective, or antiviral activities [2]. In the field of our ongoing search for triterpene saponins from Astragalus genus [3,4], a phytochemical investigation of A. glycyphyllos, an endemic plant in France, was carried out. The n-butanol fraction from the methanol extract of the roots was submitted to several solid/liquid preparative chromatographic methods such as flash, VLC, MPLC over silica gel and reversed phase RP18. Two known cycloartane-type glycosides called Askenoside C and Askenoside F previously isolated from A. taschendicus [5,6] were now isolated from A. glycyphyllos. Although saponins have already been found in A. glycyphyllos [7,8], we isolated for the first time triterpenoid glycosides from the cycloartane-type from this plant.

The structures were established mainly by 600MHz 1D and 2D NMR techniques (COSY, TOCSY, NOESY, HSQC, HMBC) and mass spectrometry as 3-O-[α-L-arabinopyranosyl-(1→2)-β-D-xylopyranosyl]-20(R)-3β,6α,16β,24(R),25-pentahydroxycycloartane (Askenoside C) and 3-O-[α-L-arabinopyranosyl-(1→2)-β-D-xylopyranosyl]-25-O-β-D-glycopyranosyl-20(R)-3β,6α,16β,24(R),25-pentahydroxycycloartane (Askenoside F).

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