Rapid and efficient isolation of polymethoxylated flavonoids and artemisinin from Artemisia annua L. acetone extract

Artemisia annua L., sweet or annual wormwood (in Chinese qïnghao: green herb) (Asteraceae) is an annual herb that is native to temperate Asia. It has been used in China for more than 2000 years for treating many disorders including malaria [1]. Polymethoxyflavonoids and artemisinin, one of the main compounds presents in Artemisia annua L., are among the most promising natural products for antimalarial and anticancer purposes [2].

In this work, three different chromatographic methods, including a rapid and selective isolation method of the main polymethoxyflavonoids (PMFs) – namely eupatin, the isomers casticin and chrysosplenetin, artemetin and 5-OH-3,4',6,7-tetramethoxyflavone – and artemisinin from A. annua acetone dried extract, have been compared. Briefly, the method consists of a pretreatment of the original extract between organic and aqueous layers and further purification of the richest extract in PMFs and artemisinin with Sephadex LH-20, silica gel normal phase column chromatografies and flash chromatography equipped with a prepacked normal phase silica column were performed. Quali-quantitative analyses of the main PMFs found in the extract were also reported. The best results in terms of efficiency of isolation were obtained by flash chromatography and to the best of our knowledge this is the first report on the separation of the pair of isomers casticin and chrysosplenetin from A. annua by flash chromatography.

Acknowledgement: Acnowledgments: Hanze University Groningen, Institute for Life Sciences and Technology, Groningen (NE) in combination with Erasmus European Comission Education and Training for the fellowship to C. Wessels.

References: 1. Bilia et al. (2006) Phytomedicine13: 487–493

2. Ferreira et al. (2010) Molecules 15: 3135–3170