Alangium lamarckii Ipecac alkaloids

Scheme 2. Biosynthesis of ipecac, Alangium, and indole alkaloids nitrogenous portion. Pathway (a) in Cephaelis ipecacuanha pathway (b) in Alangium lamarckii.

For formulas 1-71 Ipecac alkaloids, t A. lamarckii alkaloids, alkaloids from other species of Alangium, new structure, revised or established structure, 5 known but newly isolated structure. 

Emetine and Related Alkaloids.—A review on the ipecac alkaloids has ap-peared. (— )-Alangiside (208) is a terpenoidal lactam recently isolated from Alangium lamarckii Thw. (Alangiaceae). The structure was proven by chemical correlation with desacetylipecoside (209) (Scheme 13). ... 

Ipecac Alkaloids.— The stereochemistry of ipecoside (71) is known by X-ray analysis, and this has been confirmed. Feeding experiments in Cephaelis ipecacuanha have given results which demonstrate that it is not desacetylipecoside (72), as previously supposed cf. ref. 2), but desacetylisoipecoside (73), with the same stereochemistry at C-1 (= C-llb) as cephaeline (76) and emetine (75), which is the true precursor for these alkaloids. Similar results were obtained for cephaeline (76) in Alangium lamarckii On the other hand, desacetylipecoside (72), and not (73), is the precursor for ipecoside (71) (in C. ipecacu-... 

Ipecac alkaloids are derived from the amino acid tyrosine and the monoterpene secologanin and are therefore termed terpenoid-isoquinoline alkaloids. They occur in the eudicot families Alangiaceae and Rubiaceae. Two species, Psychotria ipecacuanha (Rubiaceae) and Alangium lamarckii (Alangiaceae), have been investigated in detail with respect to their metabolites and biosynthesis of their alkaloids (Fujii and Ohba, 1998). Roots and rhizomes of P. ipecacuanha are the source of cephaeline and emetine (Fig. 9), two compounds with emetic, expectorant, and amebicidal properties. 

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