Artemisinin and flavonoids yield from aqueous extracts and tinctures of Artemisia annua L

Malaria morbidity and mortality continue to increase across the entire world [1]. This is largely as a result of the continued use of chloroquine and sulfadoxine-pyrimethamine, despite widespread resistance. Artemisinin is an interesting molecule to treat multidrug-resistant Plasmodium falciparum malaria. It is extracted from the plant qinghao (Artemisia annua L. or sweet wormwood) [2]. After the discovery of the active principle artemisinin almost all the clinical evaluations have focused on pure, isolated artemisinin and its derivatives. Clinical trials with patients using teas or decoctions have appeared in the most recent literature [3–5], after development of high artemisinin-yielding plants (>0.5% per dried weight). The principal aim of such investigations is related to the possibility for populations in endemic areas to cultivate selected breedings of A. annua and prepare teas or decoctions with a positive effect in the treatment of malaria. In this study the qualitative profile and content of artemisinin and polymethoxyflavones is investigated on infusions and decoctions prepared with different methods and on 40% w/v and 60% w/v tinctures using a hybrid form of A. annua successfully cultivated in Brasil. The aerial parts of the plant contained 0.52% artemisinin per dry weight, and approximately 27–40% of this artemisinin could be extracted by simple tea preparation methods or decoctions and the best extraction is obtained with a short decoction (5min) followed by an infusion of 9g herbal drug in 1 L water. Tinctures 40% w/v extracted about 26% artemisinin while tincture 60% w/v about 40%. The content of total polymethoxylated flavonoids in the plant was about 2.6% mainly represented by chrisoplenetin plus casticin (1.4%), eupatin (0.8%) and artemetin (0.4%). The total flavonoid content extracted in the infusions ranged 30–60% and that of tinctures was less than 40%. Tinctures showed also the presence of chrisoplenol.

Acknowledgements: The financial support of MIUR (PRIN 2004) and Ente Cassa di Risparmio di Firenze is gratefully acknowledged for financial support.

References: 1. World Health Organization, (2000), Trans. R. Soc. Trop. Med. Hyg. 94: 1–90. 2. O'Neill, P. et al. (2004), J. Med. Chem. 47: 2945–2964. 3 Mueller, M.S. et al. (2000), J. Ethnopharmacol. 73: 487–493. 4 Mueller, M.S. et al. (2004), Trans. Royal Soc. Trop. Med. Hyg. 98: 318–321. 5 Räth, K. et al. (2004), Am. J. Tropical Med. Hyg. 70: 128–132.