EFFECT OF DRYING METHODS ON THE RECOVERY AND YIELD OF ARTEMISININ FROM ARTEMISIA ANNUA L

Abstract

Postharvest methods of handling Artemisia annua L. were evaluated to determine the recovery of artemisinin, a sesquiterpene used in the treatment of malaria, because low yields have been a limitation to commercialization. Immediately following field harvest in October, plants were subjected to: freeze drying, oven drying (40C), and open air drying. Leaf samples (50 gfw) were dried for 7 days in each treatment, and stable weights were achieved after day 2 for oven or open air drying and day 1 for freeze drying. One gram of dry weight was sampled from each treatment for artemisinin analysis using reverse phase chromatography by HPLC with EC detection. Open air drying of samples gave significantly higher artemisinin yield (0.13g/100g) than oven drying (0.10g/100g) and freeze drying (0.02g/100g). In a second experiment, open air drying for 2,4,6, and 8 days was compared to microwave drying for 2 minutes, of foliage samples with 10 gfw, of a plant low in artemisinin. Time of drying did not affect artemisinin content but microwave drying greatly reduced artemisinin (0.02g/100g air drying vs 0.002g/100g microwave drying). In our protocol artemisinin was detected in a greenhouse plant (0.3g/100g artemisinin) in samples as low as 50 mgdw.