Artemisia annua antimalarial activity

In 1972, Chinese researchers isolated, by extraction at low temperature from a plant, a crystalline compound that they named qinghaosu [the name artemisinin (la) is preferred by Chemical Abstracts, RN 63968-64-9]. The plant source of artemisinin is a herb, Artemisia annua (Sweet wormwood), and the fact that artemisinin is a stable, easily crystallizable compound renders the extraction and purification processes reasonably straightforward. The key pharmacophore of this natural product is the 1,2,4-trioxane unit (2) and, in particular, the endoperoxide bridge. Reduction of the peroxide bridge to an ether provides an analogue, deoxyartemisinin 3, that is devoid of antimalarial activity. ... 

Artemisinin 1, a naturally occurring sesquiterpene peroxy-lactone, has been isolated in up to 0.25% yield from the dry leaves of Artemisia annua L.1 Interest in artemisinin is based on its phytomedicinal properties. In 168 b.c. China, as described in a Treatment of 52 Sicknesses, the leaves of A. annua (Qinghao) were used for the treatment of chills and fever.2 It was not until 1972 that the active antimalarial agent qinghaosu was isolated in pure form. This allowed for the unequivocal elucidation of its structure through the use of x-ray crystallography. This complex tetracyclic peroxide is now referred to as artemisinin in various sources such as Chemical Abstracts or the Merck Index. 

Artemisinin (23), isolated from a Chinese medicinal plant, annual wormwood Artemisia annua L.), is a unique sesquiterpene lactone bearing an endoperoxide moiety. This compound displays a strong antimalarial activity and inhibits seed germination and plant growth.11... 

Qinghao (Sweet Wormwood) is the dried aerial parts of the herb Artemisia annua L. (Asteraceae family), which has been used in China for centuries to treat fever and malaria. Artemisinin (Nl) (Qing Hao Su) (128), the active principle, directly kills Plasmodium falciparum (malaria parasites) with little toxicity to animals and humans. Thus, it is a clinically effective, safe, and rapid antimalarial agent (129, 130). The novel endo-peroxide link is essential for the antimalarial activity. 

Artemisia annua (sweet wormwood, qing hao) has been used in Chinese medicine for well over 1000 years. The earliest recommendation is for the treatment of hemorrhoids, but there is a written record of use in fevers dated 340 A.D. Modem development dates from the isolation of a highly active antimalarial, artemisinin (qing-haosu), in 1972, and has been carried out almost entirely in China. Much of the original 1 iterature is therefore in Chinese, but there is an excellent review on qinghaosu by Trigg (196) and an account of the uses of A annua (197). This section is largely a summary of these two articles. 

Whole plant extracts often show promising activity that may not be traceable to single components. This is obviously not true of Artemisia annua extracts, but it is interesting to note that other constituents, notably me-thoxylated flavones, have potentiating effects on the antimalarial activity of artemisinin (206). 

Artemisia annua, known in China as Qinghaosu, contains artemisinin, which has antimalarial activity. Several derivatives of the original compound have proved effective in the treatment of Plasmodium falciparum malaria and are currently available in a variety of formulations artesunate (intravenous, rectal, oral), artelinate (oral), artemisinin (intravenous, rectal, oral), dihydroartemisinin (oral), arte-mether (intravenous, oral, rectal), and artemotil (intravenous). Artemisinic acid (qinghao acid), the precursor of artemisin, is present in the plant in a concentration up to 10 times that of artemisinin. Several semisynthetic derivatives have been developed from dihydroartemisinin (11). The artemisinin derivatives are the subject of a separate monograph. 

Artemisinin (Fig. 1), isolated in 1972 from Chinese medicinal plant Artemisia annua L, is a novel antimalarial drug with a sesquiterpene lactone structure containing an internal endoperoxide linkage which is essential for the drug s activity. Artemisinin and its derivatitives form a series of antimalarial compounds with activity against chloroquine-resistant malaria parasites. In contrast to chloroquine, artemisinin penetrates the blood brain barrier, which makes it especially valuable for the treatment of cerebral malaria. ... 

Artemisinin (qinghaosu) provides a more recent example of a plant-derived antimalarial agent. Based on the reputed antimalarial use of Artemisia annua in the Chinese system of traditional medicine, artemisinin was isolated from the plant as the active compound, developed as a drug, and released for clinical use as a blood schizonticide (66-68). Artemisinin is a... 

Malaria remains a parasitic scourge that is still extending in incidenoe. In 1972, the aotive principle from Artemisia annua, a plant used for centuries in Chinese traditional medioine to treat fevers and malaria, was established as a novel antimalarial ohemotype. This oompound, artemisinin ( qinghaosu in Chinese), is a sesquiterpene lactone with an endoperoxide group that is essential for activity, and it reacts with the iron in heme in the malarial parasite, Plasmodium falciparum (Fig. 1.3). Beoause this compound is poorly soluble in water, a number... 

Antimalarial Activity of Artemisia annua Flavionoids from Whole Plants and Cell Cultures. [Coll. Med., Natl. Taiwan Univ., Taipei, Taiwan] Plant Cell Rep 11(12) 637640. 

The most important peroxide belonging to the 1,2,4-trioxane family is a natural product, obtained from Artemisia annua, which is a very potent antimalarial drug having low human toxicity. The compound, artemisinin, originates from research on traditional Chinese medicinal practice. Its antimalarial activity is associated with the presence of the... 

Artemisia annua is one of the most important Asteraceae species as antimalarial plant. There are many reports of microbial biotransformation of artemisinin (283), which is active antimalarial rearranged cadinane sesquiterpene endoperoxide, and its derivatives to give novel antimalarials with increased activities or differing pharmacological characteristics. 

Artemisinin, another sesquiterpene lactone, contains a rare endoper-oxide bridge that is necessary for its antimalarial activity. Artemisinin is derived fi om an antique Chinese herbal remedy and has been isolated fi om Artemisia annua, also known as qing hao or sweet wormwood, a species of the Asteraceae family. This plant has been used in Chinese herbal medicine for over 200 years. Artemisinin and its de-... 

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