- Studies on the constituents of Actinostemma lobatum MAXIM. V. Structures of Lobatosides B,E,F and G, the dicrotalic acid esters of bayogenin bisdesmosides isolated from the herb
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The structures of lobatosides B, E, F and G, the dicrotalic acid esters of bayogenin bisdesmosides isolated from the herb of Actinostemma lobatum MAXIM. (Cucurbitaceae), were determined on the basis of chemical and spectral evidence.Lobatoside B is the dicrotalic acid (3-hydroxy-3-methylglutaric acid ) ester of 3-O-2)-β-D-glucopyranosyl>bayogenin 28-2)-α-L-arabinopyranosyl> ester.Dicrotalic acid is linked at one end to the C6-hydroxyl group of the terminal β-D-glucopyranosyl group in the C3-linked sugar moiety, and at the other end to the C4-hydroxyl group of the α-L-rhamnopyranosyl group in the ester-linked sugar moiety to form a macrocyclic structure (cyclic bisdesmoside).Lobatosides E, F and G are cyclic bisdesmosides of bayogenin similar to lobatoside B, but different in the numbers and species of the component sugars and positions of the ester linkages of the dicrotalic acid.Keywords - Actinostemma lobatum; Cucurbitaceae; lobatoside; bayogenin glycoside; cyclic bisdesmoside; dicrotalic acid; NOE difference spectrum; decoupling difference spectrum.
- Fujioka, Toshihiro,Iwamoto, Masayo,Iwase, Yukiko,Hachiyama, Shizuko,Okabe, Hikaru,et al.
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p. 2355 - 2360
(2007/10/02)
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