The Catharanthus (or Vinca) alkaloids comprise a group of about 130 terpenoid indole alkaloids. Vinblastine is now marketed for more than 40 years as an anticancer drug and became a true lead compound for drug development. Due to the pharmaceutical importance and the low content in the plant of vinblastine and the related alkaloid vincristine, Catharanthus roseus became one of the best-studied medicinal plants. Consequently it developed as a model system for biotechnological studies on plant secondary metabolism. The aim of this review is to acquaint a broader audience with the recent progress in this research and with its exciting perspectives. The pharmacognostical aspects of the Catharanthus alkaloids cover botanical (including some historical), phytochemical and analytical data. An up-to-date view on the biosynthesis of the alkaloids is given. The pharmacological aspects of these alkaloids and their semi-synthetic derivatives are only discussed briefly. The biotechnological part focuses on alternative production systems for these alkaloids, for example by in vitro culture of C. roseus cells. Subsequently it will be discussed to what extent the alkaloid biosynthetic pathway can be manipulated genetically ("metabolic engineering"), aiming at higher production levels of the alkaloids. Another approach is to produce the alkaloids (or their precursors) in other organisms such as yeast. Despite the availability of only a limited number of biosynthetic genes, the research on C. roseus has already led to a broad scientific spin-off. It is clear that many interesting results can be expected when more genes become available.

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The secoiridoid glucoside secologanin is the terpenoid building block in the biosynthesis of terpenoid indole alkaloids. A method for its determination in plant tissues and in cell suspension cultures has been developed. This assay is based on the condensation of secologanin with tryptamine, yielding strictosidine, in a reaction catalysed by the enzyme strictosidine synthase (STR; E.C. 4.3.3.2). Subsequently, the formation of strictosidine is quantified by high performance liquid chromatography (HPLC). STR was isolated from transgenic Nicotiana tabacum cells expressing a cDNA-derived gene coding for STR from Catharanthus roseus. The high specificity of STR for secologanin, in combination with a sensitive and selective HPLC system, allows a simple extraction of secologanin from plant tissue. The detection limit of this method is 15 ng secologanin. Using this assay, secologanin contents were determined in tissues of various plant species; Lonicera xylosteum hairy roots were found to contain 1% of secologanin on a dry weight basis.

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