Artemisia annua L. (A. annua)
At maturity A. annua ranges in height from 0.3 – 2.5 metres and takes around five months from seed to harvest
Artemisia annua L. (A.annua) is an annual aromatic herb originating from Asia . The 184 species of the Artemisia a genus are members of the family Asteraceae, (formerly known as Compositae), and include a range of plants that have been used in medicine, perfumes and flavourings such as French tarragon, absinthe, southernwood and mugwort.
A. annua forms part of the natural steppe vegetation in China and extends as a native species from Southern Siberia through to Vietnam and Northern India . It now grows wild in Europe , North and South America .
Artemisinin is synthesised and stored in specialised groups of cells, known as glandular trichomes which protrude from the epidermis of leaves, stems and flowers of the plant.
Until recently most artemisinin is thought to have been harvested from wild-crafted natural stands of A. annua. Now it is grown as a crop in China , Vietnam and a number of countries in Africa including Tanzania and Kenya . The crop is harvested near to flowering when artemisinin concentration is highest and leaf biomass is greatest. It is dried and the leaf and flower tissue are separated from the stems. Artemisinin is usually extracted using solvents such as hexane or petroleum ether.
The yield of dry leaf per hectare varies from one ton
to forty five tons per hectare. It contains 0.01 – 1.5% artemisinin, 40 – 75% of which can be extracted. Estimates of typical yield per hectare therefore vary significantly, but reports indicate a yield of 10 – 15 kg
of artemisinin per hectare can be expected from well managed plantations in Africa .
Yield of artemisinin is highly heritable. Development of cultivars of A.annua with high yield of artemisinin will both reduce the costs of cultivation and the costs of extraction associated with artemisinin production. It will also produce better returns to farmers who grow the crop.
A. annua has a long history of use in Traditional Chinese Medicine. The first mention of the name Qing Hao is in a silk book excavated from a tomb from 168 BC. In 340 AD the first record of its application for treatment of fevers appeared in a medical book, “Handbook of Prescriptions for Emergency Treatment”. In 1596 the famous Chinese material medica “Ben Cao Gang Mu” described its use for treatment of chills and fevers caused by malaria.
In 1967, the Chinese government began a systematic screen of plants used in Traditional Chinese Medicine with a specific focus on malaria treatments. Chinese scientists isolated and chemically characterised the active principle, artemisinin, in 1972.
“Artemisia” in Book Series “ Medicinal and Aromatic Plants - Industrial Profiles” edited by Colin W. Wright, published London , Taylor and Francis 2002, ISBN 0-415-27212-12
As Summarized by Centre for Novel Agricultural Products – Artemisia Projects