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DOI: 10.1055/s-0028-1084457
Alkaloids and saponins from twigs and leaves of Abuta grandifolia (Mart.) Sandw
Abuta grandifolia (syn. Cocculus grandifolius (Mart.)) is used through South America as an antimalarial drug and is claimed to possess miscellaneous properties. The species is also traditionally used as an ingredient in curare arrow-poisons [1]. Chemical investigation of the ethyl acetate and methanol extracts of the twigs and leaves of A. grandifolia collected in French Guyana, furnished three tropoloisoquinoleines, imerubrine, pareirubrines A and B, one isoquinoleine, stepharine, and eight oleanane-type saponins. Two of the latter compounds are new bidesmosidic glycosides of oleanolic and their structures were established by means of spectral data, particularly 2D NMR and MS-MS experiments as 3-O-β-D-glucopyranosyl(1->2)-β-D-glucopyranosyl oleanolic acid 28-O-β-D-xylopyranosyl(1->6)-β-D-glucopyranosyl ester and 3-O-β-D-glucopyranosyl(1->2)-β-D-glucopyranosyloleanolic acid 28-O-α-L-arabinopyranosyl(1->6)-β-D-glucopyranosyl ester.
The characterization of oleanolic and hederagenin saponins with glucuronic acid, could explain the significant antimicrobial activity of the ethanol extract of A. grandifolia as reported in the literature [2].
Menispermaceae species are well-known to contain alkaloids and those are extensively analyzed with regard to curare composition but, curiously two species only were studied for their saponin content [3,4], which could favourize alkaloid solubilisation and cell permeation. This is the first isolation of these saponins from the family Menispermaceae and the first report on saponins from Abuta genus.
References:
1. Grenand P., Moretti C., Jacquemin H., Prévost M-F. (2004) Pharmacopées traditionnelles en Guyane. IRD éditions. Paris.
2. Kloucek, P. et al. (2007)J. Ethnopharm. 111:427–429; Mongelli, E. et al. (1995) Rev. Arg. Microbiologia 27:199–203.
3. Plaza, A. et al. (2003)J. Nat. Prod. 66:1606–1610.
4. Jayasinghe, L. et al. (2003) Phytochemistry 62:563–567; Jayasinghe, U.L.B. et al. (2005) Nat. Prod. Res. 19:245–251.