Monoterpenes Catharanthus

Within the natural products field, the investigation of complete biosynthetic pathways at the enzyme level has been especially successful for plant alkaloids of the monoterpenoid indole alkaloid family generated from the monoterpene gluco-side secologanin and decarboxylation product of tryptophan, tryptamine [3-5]. The most comprehensive enzymatic data are now available for the alkaloids ajmalicine (raubasine) from Catharanthus roseus, and for ajmaline from Indian Rauvolfia serpentina [6] the latter alkaloid with a six-membered ring system bearing nine chiral carbon atoms. Entymatic data exsist also for vindoline, the vincaleucoblastin (VLB) precursor for which some studies on enzymatic coupling of vindoline and catharanthine exist in order to get the so-called dimeric Catharanthus indole-alkaloids VLB or vincristine [7-9] with pronounced anti-cancer activity [10, 11]. 

Figure 2.13 Putative localization and intercellular trafficking of monoterpene indole alkaloids in Catharanthus roseus. (After Facchini and De Luca, 2008 Murata et a ., 2008.)...

Buriat, V., Oudin, A., Courtois, M., Rideau, M. and St. Pierre, B. (2004) Co-expression of three MEP pathway genes and geraniol-lO-hydroxylase in internal phloem parenchyma of Catharanthus roseus implicates multicellular location of intermediates during the biosynthesis of monoterpene indole alkaloids and isoprenoid-derived primary metabolites. Plant., 38,131 1. 

Schiel, O., Witte, L. and Berlin, J. (1987) Geraniol-lO-hydroxylase activity and its relation to monoterpene indole alkaloid accumulation in cell suspension cultures of Catharanthus roseus. Z. Naturforsch., 42c, 1075-81. 

Salim V, De Luca V. Towards complete elucidation of monoterpene indole alkaloid biosynthesis pathway Catharanthus roseus as a pioneer system. In Advances in Botanical Research - New Light on Alkaloid Biosynthesis and Future Prospect. 2013. p. 1-37. 

This is a very large group of alkaloids whose basic structure contains a pyrrole ring fused to a benzene ring. Biosynthesis of pure indoles involves the amino acid tryptophan as precursor, while that of a major subgroup of the indoles, including the Catharanthus and Rauwolfia alkaloids, involves a second precursor— the monoterpene iridoid loganin. 

FIGURE 19.13 Biotransformation of geraniol (271), citronellol (258), and linalool (206) by plant suspension cells of Catharanthus roseus. (Modi ed from Hamada, H. et al Biotransformation of acyclic monoterpenes by biocatalysts of plant cultured cells and Cyanobacterium, Proceedings of 48th TEAC, 2004, pp. 393-395.)... 

The Madagascar periwinkle Catharanthus roseus, Apocynaceae, formerly known as Vmca rosea) is a small subshrub or herbaceous plant native to Madagascar. It contains about 130 monoterpene indole alkaloids of different subclasses (vanderHeijden et ah, 2004). Nowadays, C. roseus occurs worldwide in subtropical and tropical regions. It is cultivated as an ornamental plant, but it has also found application in the folk medicine of various countries. Because the plant was used as an antidiabetic in Jamaica, it was screened for hypoglycaemic activity by Eli-Lilly, USA, and the Cancer Research Center,... 

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