Terpenoids terpenoid indole alkaloids

Catharanthus roseus, biosynthesis of terpenoid indole alkaloids in, 49, 222 (1997) Celastraceae alkaloids, 16, 215 (1977)... 

L-tyrosine Tyrosine-derived alkaloids Indole alkaloids Quinoline alkaloids /3-carboline alkaloids Pyrroloindole alkaloids Ergot alkaloids Iboga alkaloids Corynanthe alkaloids Aspidosperma alkaloids Protoalkaloids Terpenoid indole alkaloids True alkaloids... 

Geerlings A, Martinez-Lozano Ibanez M, Memelink J, van der Heijden R, Verpoorte R (2000) The strictosidine 6-D-glucosidase gene from Catharanthus roseus is regulated coordinately with other terpenoid-indole alkaloid biosynthetic genes and the encoded enzyme is located in the endoplasmic reticulum. J Biol Chem 275 3051-3056... 

More than 3000 terpenoid indole alkaloids are recognized, making this one of the major groups of alkaloids in plants. They are found mainly in... 

Further variants on the terpenoid indole alkaloid skeleton (Figure 6.82) are found in ibogaine from Tabemanthe iboga, vincamine from Vinca minor, and ajmaline from Rauwolfia serpentina. Ibogaine is simply a C9 Iboga type alkaloid, but is of interest as an experimental drug to treat heroin addiction. In a number of European countries, vincamine is used clinically as a vasodilator to increase cerebral blood flow in cases of senility, and ajmaline for cardiac arrhythmias. Ajmaline... 

Of biochemical interest is the presence of quite significant amounts (up to 5%) of the iridoid glycoside loganin (see page 188) in the fruit pulp of Strychnos nux-vomica. This compound is, of course, an intermediate in the biosynthesis of strychnine and other terpenoid indole alkaloids. 

Some of the most remarkable examples of terpenoid indole alkaloid modifications are to be found in the genus Cinchona (Rubiaceae), in the alkaloids quinine, quinidine, cinchonidine,... 

Verpoorte R, van der Heijden R and Moreno PRH (1997) Biosynthesis of terpenoid indole alkaloids in Catharanthus roseus cells. The Alkaloids, Chemistry and Pharmacology (ed Cordell GA) Vol 49. Academic, San Diego, pp 221-299. 

Terpenoid Indole Alkaloids.—Important recent work has defined strictosidine (97) as a key intermediate in the biosynthesis of terpenoid indole alkaloids with both 3a- and 3/3-configurations. Some of this work, published earlier in preliminary form (cf. Vol. 9, p. 18), is now available in a full paper.26 In addition to those alkaloids examined earlier, strychnine, gelsemine, vincadifformine, isoreserpiline, aricine, isoreserpinine, and ajmaline have been shown to derive from strictosidine (data are also included for ajmalicine, for catharanthine, and for vindoline which had been reported earlier). 

Cathenamine (100) has been identified as an early intermediate in terpenoid indole alkaloid biosynthesis (cf. Vol. 8, p. 27). It has also been isolated from Guettarda eximia. Another alkaloid, 4,21-dehydrogeissoschizine (99), has now been isolated from this plant it is readily converted into (100) in alkaline solution.29 On incubation with an enzyme preparation from Catharanthus roseus cell cultures in the presence of NADPH at pH 7, (99) was converted into ajmalicine (102), 19-ep/-ajmalicine (103), and tetrahydroalstonine (104), which are the normal products with this enzyme preparation. In the absence of NADPH, cathenamine (100) accumulated.30 The reaction to give (100) proceeded linearly with time, and was dependent on the concentration of protein and substrate. No conversion occurred in the absence of enzyme. 

The biosynthesis of terpenoid indole alkaloids from tryptophan has long been known.1,2 In new experiments with DL-[2-14C,2, 3 - 3C2]tryptophan [as (94)], this has been confirmed for vindoline (106).35 Incorporation measured by assay for radioactivity and by n.m.r. spectroscopy was the same, thus indicating an intact incorporation (with loss, of course, of the carboxy-group) (for discussion of the particular application of 13C labelling used here, see pp. 1-2). 

Synthesis of the anti-arrhythmic drug ajmaline from Rauvolfia plants, an efficient source of several alkaloid types used in therapy, represents an even more advanced study of the total enzymatic synthesis of terpenoid indole alkaloids. Ajmaline is a class I anti-arrhythmic alkaloid because of its activity as heart muscle sodium channels antagonist [35],... 

Keywords. Anthocyanins, AP2-domain, Jasmonate, Terpenoid indole alkaloids, Transcription factor... 

Regulation of the Terpenoid Indole Alkaloid Biosynthetic Pathway 111... 

Research on the terpenoid indole alkaloids (TIAs) is mainly primed by the pharmaceutical applications of several of the compounds. The monomeric alkaloids serpentine and ajmalicine are used as a tranquilizer and to reduce hy-... 

Terpenoid Indole Alkaloids.—Experiments in intact plants have in the past given results from which a fairly clear picture of the biosynthesis of terpenoid indole alkaloids has emerged.114 An important stage in the biosynthesis of these alkaloids is reached when tryptamine (128) condenses with secologanin (129) to give... 

Terpenoid Indole Alkaloids.—Current knowledge on the biosynthesis of terpenoid indole alkaloids, with particular emphasis on the very important results obtained with enzyme preparations from tissue cultures of Catharanthus roseus, has been authoritatively reviewed.53 Further work on cell lines of C. roseus that are able to produce Aspidosperma-type alkaloids has been published54 (cf. Vol. 11, p. 19). 

Following earlier work on the use of radioimmunoassay for the analysis of terpenoid indole alkaloids cf. Vol. 9, p. 22), this technique has been successfully developed for the analysis of vindoline.57... 

Figure 7.3 Biosynthetic pathway for terpenoid indole alkaloids showing the location of enzymes for which the corresponding cDNAs have been isolated.

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