Sweet wormwood

How do traditional remedies fare in such trials Some perform quite well and prove to be highly effective, but others are no better than placebos. One striking success is an extract of sweet wormwood (Artemisia annua), which Chinese physicians have prescribed for the chills and fevers of malaria for more than two thousand years. About twenty-five years ago, Chinese chemists obtained from sweet wormwood its principal active component, a compound now called artemisinin. Clinical trials on malaria patients in Southeast Asia agreed with Chinese tradition on the value of artemisinin and also identified a few even more useful drugs prepared from it in the laboratory. These compounds are effective against the deadliest form of malaria and are now frequently the therapies of choice for treating it. 

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. ... 

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. 

Artemisinin is used here as an example of a plant sesquiterpenoid with both traditional value as well as with medicinal and social value in the twenty-first century. Research on artemisinin has also established new benchmarks for biochemical engineering and functional genomics of plant terpenoids. Artemisinin is a functionalized sesquiterpene with a unique peroxide linkage from the sweet wormwood Artemisia annua). Chinese herbalists have used it since ancient times, and it is now used for its unique efficacy to treat multidrug-resistant strains of the malaria parasite Plasmodium falciparum. Its medicinal importance has prompted studies into its biosynthesis and its biochemical engineering so that cost-effective methods for producing it in large scale and in consistent quality may be realized. 

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. 

Figure 6.13 Principle of an evaporative light-scattering detector and its application for plant constituents. (Chromatograms after J. L Veuthey, Analytical Pharmaceutical Chemistry, University of Geneva.) Conditions sample, extract of Artemisia annua (sweet wormwood) column, 12.5cm x 4mm i.d. stationary phase, Nucleosil 100 Cqg/ 5pm mobile phase, 1 ml min water with trifluoroacetic acid (pH 3)/acetonitrile (39 61). Peaks 1 = artemisinin 2 = artemisinic acid.

Two major breakthroughs of the past few decades have renewed the assault of scientists to this infective disease. The first is the complete sequencing of the genome of Plasmodium falciparum [4] that is expected to provide useful information for the identification of new drug targets. The second is the discovery by Chinese researchers of artemisinin (qinghaosu), an endoperoxide sesquiterpene lactone, as the active principle of the sweet wormwood, Artemisia annua, an herbal remedy used in folk Chinese medicine for 2000 years [5]. This molecule and its... 

History. For thousands of years Chinese herbalists treated fever with a decoction of the plant called "qinghao", Artemisia annua, "sweet wormwood" or "annual wormwood" belonging to the family of Asteraccae. In the 1960s a program of the People Republic of China re-examined traditional herbal remedies on a rational scientific basis including the qinghao plant. Early efforts to isolate the active principle... 

The marked and pronoimced antimalarial activity of Quinghausu as the constituent of a traditional Chinese medicinal vQrh Artemisia annunaL., (sweet wormwood) has been known in China for over 200 years. However, the active principle was first isolated in 1972 and found to be a sesquiterpene lactone with a peroxy moiety. 

Sweet wormwood contains the compound artemisinin. Artemisinin and compounds derived from sweet wormwood are widely used as antimalarial drugs (Meshnick 2002). 

No adverse effects from sweet wormwood are reported in texts on traditional Chinese medicine for normal doses prepared as a decoction (Bensky et al. 2004 Chen and Chen 2004), though use of an extract tablet (dosage not provided) is reported to have caused gastrointestinal side effects in 3.4% of patients (Bensky et al. 2004). 

No information on the safety of sweet wormwood during lactation was identified. While this review did not identify any concerns for use while nursing, safety has not been conclusively established. 

Flavonol compounds isolated from sweet wormwood were found to potentiate the activity of berberine and norfloxacin against a multidrug-resistant strain of Staphylococcus aureus (Stermitz et al. 2002). 

No information on the safety of sweet wormwood during lactation was identified. 

However, the most modern drugs in our armoury to fight malaria infections are derivatives of artemisinin. This natural product originates from the sweet wormwood, Artemisia annua), a traditional Chinese herbal medicine, which had already been in use for malaria treatment some 1,300 years prior to quinine, albeit its active principle was only discovered in the 1970s. 

Sweet wormwood (Artemisia annua) was first described in 1753 by the Swedish botanist and physician Carl von Linni (1707-1778) in Species Plantarum. [460]... 

Experiments with and -labelled precursors provided unambiguous evidence, that there are several branch points in the biosynthesis of artemisinin. The most prominent sesquiterpene metabolites in sweet wormwood are, aside from artemisinin, artemisinic acid and arteannuin B, which branch off at the artemisinic aldehyde stage. [465]... 

Notable is as well the impact of methyl jasmonate on the biosynthesis of artemisinin, which regulates as a phytohormone the response of a plant to abiotic or biotic stress (e.g. drought, wind, or attacks from herbivores). In case of sweet wormwood, methyl jasmonate stimulates the expression of amorpha-4,11-diene synthase (ADS) and the cytochrome P450 monooxygenase (CYP71AV1), leading ultimately to an enhanced formation of artemisinin. [464]... 

While the mode of action of artemisinin is not yet completely understood, the drug was isolated in the 1970s from sweet wormwood Artemisia annua). The plant known in Traditional Chinese Medicine to treat malaria for at least 1,600 years. 

On an industrial scale, artemisinin is obtained from plant extracts of sweet wormwood, and by fermentation combined with partial synthesis. 

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