Tryptophan-derived alkaloids

Alkaloids derived from L-tryptophan hold the indole nucleus in a ring system. The ring system originates in the shikimate secondary compounds building block and the anthranilic acid pathway. It is known that the shikimate block. 

Scytonemin (123) is a yellow-brovm pigment of cyanobacterial sheaths. While a plethora of cyanobacterial species with yellow-brown sheaths are described in the 

According to Proteau et al., condensation of two subunits of tryptophan and two phenylpropanoid-derived units would explain the biogenetic pathway to form the symmetrical structure of scytonemin (123) [146]. No syntheses of 123 have been reported. 

For ipobscurines, hydroxycinnamic acid conjugates of serotonin (5-hydroxytryp-tamine), see Sect. 6.6.4 for withanamides, fatty acid amides of serotonin, see Sect. 8.I.2.I. 

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Figure 9. The devil s-pepper genus contains L-tryptophan-derived alkaloids. Rauwolfia serpentina appears on flowers (Photo T. Aniszewski).

L-proline L-serine L-threonine L-tryptophan Tryptophan-derived alkaloids Phenylethylamino alkaloids Phenylisoquinoline alkaloids Amaryllidaceae alkaloids True alkaloids... 

Towers, G. H. N. and Abramowski, Z. 1983. UV-mediated genotoxicity of fura-noquinine and of certain tryptophan-derived alkaloids. Journal of Natural Products, 46 576-581. 

Selected tryptophan syntheses will first be described because tryptophan is easily converted into its decarboxylation product tryptamine. Major emphasis will be placed on tryptophan analogues with a variety of substitution patterns at the aromatic ring system. These derivatives could be of significance for producing new tryptophan derived alkaloids. 

FIGURE 1.9 The devil s pepper genus contains i-tryptophan-derived alkaloids. 

Kondo, K., Nishi, J., Ishibashi, M., Kobayashi, J., (1994). Two new tryptophan -derived alkaloids from the Okinawan marine spongQ Aplysina sp. J. Nat. Prod. 57, 1008-1011. 

Danieli, B., G. Lesma, and G. Palmisano A New Tryptophan Derived Alkaloid from Evodia rutaecarpa (Juss.) Benth. et Hook. Experientia 35, 156 (1979). 

L-Tryptophan is an indole ring containing aromatic amino acid derived via the shikimate pathway. The tryptophan-derived alkaloids are found in eight families, of which, Apocynaceae, Loganiaceae, Rubiaceae, and Nyssaceae are the best sources. The alkaloids under discussion are the Catharanthus alkaloids, namely, ajmalicine, tabersonine, catharanthine, vindoline, vinblastine, vincristine and vincamine as well as terpenoid alkaloids derived from other families, namely, yohimbine, reserpine, strychnine, brucine, and ellipticine. The above-mentioned alkaloids are pharmacologically very important and hence extremely valuable. This chapter describes various aspects of the tryptophan-derived alkaloids like occurrence, biological activity, phytochemistry, and commercial and biotechnological aspects. 

Fig. 20.2 Types of skeleton in tryptophan-derived alkaloids (Adapted frran Ref. [15])...

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