Sweet wormwood was used in ancient Chinese therapy to treat various illnesses, including fevers typical of malaria.

Nearly five decades ago, Chinese scientists identified its active ingredient, artemisinin.

In 2005, the World Health Organisation recommended Artemisinin-based Combination Therapies (ACTs) as the most effective malaria treatment available.

Global demand for artemisinin then increased but the quality and supply had not been stable.

According to researchers from the Institute of Process Engineering (IPE), Chinese Academy of Sciences due to its complex structure, artemisinin is currently difficult and not economically feasible to chemically synthesize.

The traditional industrial method to produce artemisinin is to treat sweet wormwood leaves with organic solvents like petroleum ether.

The extraction process is long, energy consumption is high and productivity is low.

In the study, the IPE researchers proposed to enhance the contact between the solvent and the leaves by reflux to speed up the artemisinin extraction.

The extraction time was reduced from seven hours to four and a half hours.

After treating sweet wormwood leaves with solvents, they optimised the evaporation process with a thin film evaporator, an apparatus that provides a continuous evaporation process, especially for heat-sensitive products to retrieve the solvents.

Compared to the traditional process, the time it takes to produce the artemisinin concentrate is reduced by 87.5 per cent.

Meanwhile, the purity of the final product is increased to more than 99 per cent, and energy consumption is also reduced.

The new technology makes the recovery of the solvents reach 99.9 per cent, energy consumption per tonne of artemisinin drop by 43 per cent and the product purity is higher than 99 per cent, said Wang Hui from the IPE.

“This technology solves the main shortcomings in the traditional artemisinin production process and could also provide ideas for other natural products production,” said Zhang Suojiang, the Director of IPE.