In vitro and in vivo production of artemisinin by artemisia species

Abstract

Artemisinin is produced in the leaves of Artemisia annua and is currently one of the most valuable antimalarial treatments. A. annua is of Asian origin but many other family members have been identified worldwide. A. annua however, is the only one that produces artemisinin. Synthetic production of artemisinin is not yet feasible, not to mention very expensive and the product yields are relatively low. The aims of this study were threefold: 1) To regenerate callus, cell cultures and plants from genetically modified root cultures of A. afra into which an artemisinin biosynthetic gene was inserted from A. annua 2) To investigate the probability that fungal endophytes are responsible for the production of artemisinin and 3) To establish two fields of high yielding varieties of A. annua plants and evaluate whether artemisinin production of these two locations will remain high. Callus and cell cultures of the genetically modified A. afra root cultures were established, but no shoots have been produced as of yet and this is an on-going investigation. Fungal endophytes were sampled and none of the endophytes produced artemisinin. Five different lines of A. annua were cultivated, successfully grown and harvested. Measurements were taken at different stages of processing, these were compared and analysed using various methods such as height and mass comparisons. Comparisons revealed that the production of artemisinin is correlated to local sets of conditions rather than the variety of individual lines. The genetic potential to produce high quantities of artemisinin appears to have been lost, instead of being maintained. We confirmed that secondary compound production and specifically, artemisinin, is enhanced by certain stress factors on the plants.