- Antiarol cinnamate and africanoside, a cinnamoyl triterpene and a hydroperoxy-cardenolide from the stem bark of antiaris africana
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From the methanol extract of the stem bark of the African tree Antiaris africana Engler, two new bioactive metabolites were isolated, namely, the α-amyrin derivative 1β,11α-dihydroxy-3β-cinnamoyl-α- amyrin (antiarol cinnamate, 1) and a cardiac glycoside, 3β-O-(α-L- rhamnopyranosyl)-14β-hydroperoxy-5β-hydroxy-19-oxo-17β-card- 20(22)-enolide (africanoside, 2a), together with the known compounds-α- amyrin and its acetate, β-sitosterol and its 3-O-β-D-glucopyranoside, friedelin, ursolic and oleanolic acid, 19-norperiplogenin, strophanthidol, strophanthidinic acid, periplogenin (3a), 3-epiperiplogenin, strophanthidin (3b) and 3,3-dimethoxy-4-O-β-D-xylopyronosyl-ellagic acid. Their structures were established on the basis of their spectroscopic data and by chemical methods, while 3a was additionally confirmed by Xray crystal structure analysis. The aglycone moiety possessing a hydroperoxy group was found for the first time in cardenolides. Compounds 1 and 2a showed no activity against bacteria, fungi, and microalgae; however, the crude extract exhibited a high toxicity against Artemia salina and a selective antitumor activity against human tumor cell lines. Africanoside (2a) effected a concentration-dependent inhibition of tumor cell growth with a mean IC50 value of 5.3nM. Georg Thieme Verlag KG Stuttgart - New York.
- Vouffo, Bertin,Dongo, Etienne,Facey, Petrea,Thorn, Andrea,Sheldrick, George,Maier, Armin,Fiebig, Heinz Herbert,Laatsch, Hartmut
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p. 1717 - 1723
(2011/12/04)
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- SYNTHESIS OF CONVALLOSIDE
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The known natural diglycoside convalloside - strophanthidin 3β-O- - has been synthesized.The synthesis was carried out by the Koenigs-Knorr method via the preparation as intermediates of convallatoxin and its 2,3-isopropylidene derivative.Selectivity of glycosylation was achieved by the preliminary protection of the two OH groups in the cardenolide L-rhamnoside (convallatoxin).
- Makarevich, I. F.,Terno, I. S.
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p. 323 - 325
(2007/10/02)
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