(709f) Development from Batch to Continuous Solid Liquid Extraction- Artemisinin Extraction from Artemisia Annua Leaves

Artemisinin (ARTE) is recommended as the first-line treatment of malaria. It can be produced by chemically synthesis, semi-synthetically or by extraction from plants. Due to the complexity and expenses related to the synthetic processes, the isolation of artemisinin from sweet wormwood (Artemisia annua) is recommended to provide the larger quantities required on the international market [1].

Batch-wise extraction of valuable target components from plants is the state of the art. Less systematic activities have been devoted to continuous extraction techniques, in particular for simultaneous co-extraction of equally valuable precursors also present in the plants.

Our research is focused on studying continuous countercurrent ARTE extraction from Artemisia annua with joint isolation of dihydroartemisinic acid (DHAA), which is known to be an important precursor for the biosynthesis of ARTE. Significant amounts of DHAA were reported to be present in different extracts of Artemisia annua. In [2] it was shown that DHAA could be oxidized photocatalytically to ARTE, which allows increasing the overall ARTE yield of the extraction process. For the mentioned photoreaction the co-extraction of chlorophyll is also of large interest since it acts as an efficient green photosensitizer [3].

We will present results regarding the distribution equilibria of the components mentioned. This information is incorporated into a multi-stage equilibrium stage model describing a countercurrent extraction process. The model allows identifying suitable operating conditions, which maximize the sum of the amounts of ARTE and DHAA extracted. Finally, results of continuous extraction carried out in pilot plant will be presented to demonstrate the efficiency of the process.

[1] E.A.Brisibe; African Journal of Biotechnology, 7(25), 2008; 4884-4896

[2] F.Levesque, P.H.Seeberger, Continuous-flow synthesis of the anti-malaria drug Artemisinin, 51(7), 2014, 1706-1709

[3] S.Triemer, K.Gilmore, G.T.Vu, P.H.Seeberger, A.Seidel-Morgenstern, Angewandte, 57(19), 2018, 5525-5528