Two New Acylated Tridesmosidic Saponins from Astragalus armatus |
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| Authors: | Nabil Semmar Miyamoto Tomofumi Yassine Mrabet Marie‐Aleth Lacaille‐Dubois |
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| Institution: | 1. Laboratoire de Pharmacognosie, Unité de Molécules d'Intérêt Biologique (UMIB), UPRES‐EA 3660, Faculté de Pharmacie, Université de Bourgogne, 7 Bd Jeanne D'Arc, BP87900, F‐21079 Dijon Cedex (phone: +33‐380‐393229;2. fax: +33‐380‐393300);3. Institut Supérieur des Sciences Biologiques Appliquées de Tunis (ISSBAT), 1006 Tunis, Tunisia;4. Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812‐8582, Japan |
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| Abstract: | Two new tridesmosidic glycosides of (3β,6α,16β,20R,24S)‐20,24‐epoxycycloartane‐3,6,16,25‐tetrol (=cycloastragenol), armatosides I and II ( 1 and 2 , resp.), were isolated from the roots of Astragalus armatus (Fabaceae) as well as the known bidesmosidic glycosides of cycloastragenol, trigonoside II ( 3 ) and trojanoside H ( 4 ). Their structures were elucidated as (3β,6α,16β,20R,24S)‐3‐O‐(2,3‐di‐O‐acetyl‐β‐D ‐xylopyranosyl)‐20,24‐epoxy‐25‐O‐β‐D ‐glucopyranosyl‐6‐O‐β‐D ‐xylopyranosylcycloartane‐3,6,16,25‐tetrol ( 1 ), and (3β,6α,16β,20R,24S)‐3‐O‐(2‐O‐acetyl‐β‐D ‐xylopyranosyl)‐20,24‐epoxy‐25‐O‐β‐D ‐glucopyranosyl‐6‐O‐β‐D ‐xylopyranosylcycloartane‐3,6,16,25‐tetrol ( 2 ). These structures were established by extensive NMR and MS analyses and by comparison with literature data. |
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| Keywords: | Astragalus armatus Tridesmosidic saponins Armatosides I and II Saponins Cycloastragenol |
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