Production of triterpenoids with cell and tissue cultures.

Triterpenes are group of biologically active compounds which can be found in higher plants. Their main source are plants bark, leaves, twigs, fruits, resins or oils. The biological activity of triterpens is very diversified and many studies have already confirmed the following therapeutic effects: anti-inflammatory, antimicrobial, antiviral, antifungial, immunomodulatory, and hepatoprotective. Synthesis of triterpenes derivates can be performed by chemical or enzymatic reactions, however biotransformation is more specific and eliminates the side products and the molecule alterations. These processes use isolated enzymes or microorganisms. Cell culture in vitro eliminates problems like extract variability as well as instability of the compounds being obtained during the extraction process. What is more, it ensures high reproducibility and optimal regio- and enantioselectivity. The most widely used technique is a classical screening of a series of microbial strains. Studies on triterpene biotransformation give a lot of information about new biologically active compounds and let predict the metabolism of biological compounds. This review presents most important advancements in the metabolic engineering of microorganisms for the production of triterpenoids. Moreover, the review highlights general strategies to obtain rich biochemical diversity of plants by employing the biocatalysts produced by microorganisms or tissue cultures.