Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 4/15/2008
Publication Date: 4/22/2008
Citation: Ferreira, J.F. 2008. Seasonal variation of artemisinin, artemisinic acid, and dihydroartemisinic acid in Brazilian, Chinese, and Swiss cultivars of Artemisia annua in WV, and effect of drying procedures on artemisinin and its precursors. Plant Medica. 74:310-311. Interpretive Summary:
Technical Abstract: The increased demand for artemisinin worldwide has led to the increased worldwide cultivation of Artemisia annua for the production of artemisinin. Artemisinin is a safe and effective sesquiterpene lactone effective against a range of diseases caused by protozoa (e.g., malaria, coccidiosis, leishmaniosis, babesiosis), blood parasitic worms (Schistosoma spp.), cancer, and with potential to treat gastrointestinal parasites in animals and humans. Although there are several publications on the production of artemisinin in vivo and in vitro, there are few publications addressing artemisinin production in specific environments, and even fewer on its post-harvest stability. Cultivars of Artemisia annua from Brazil (seeded), China (seeded), and Switzerland (cloned) were cultivated in Beckley, WV, in a silty-loamy Mesic Hapludult soil for one growing season (June to October) in 2005, 2006, and 2007. Plants were sampled every one/two weeks from 30 days after being transplanted to the field until flowering, and analyzed for artemisinin and its precursors by HPLC. In a separate experiment in, the cloned plants were harvested in early September and submitted to freeze-drying, oven drying (45 deg C), sun, and shade drying (the latter two for three weeks before a 24-hour finishing in a oven set at 45 deg C). All cultivars reached the peak in artemisinin production between August 28 and September 1st. The artemisinin peak coincided with day lengths and temperatures ranging from 13h, 09 min, with temperature max = 25 deg C/min = 19 deg C (August 28) to 12h, 52 min, with temperature max = 30 deg C/min = 12 deg C (September 4). According to previous reports, a photoperiod below 13 h, 20 min, associated with mild temperatures, are factors known to induce flowering in A. annua. Thus, regardless of being early flowering (Chinese) or late flowering (Brazilian and Swiss), seeded or cloned, the cultivars peaked in artemisinin within the same week. Regarding artemisinin precursors, artemisinic acid (AA) was mostly unchanged throughout the season, and dihydroartemisinic acid (DHAA) followed the same trend as artemisinin, except for the Brazilian clone in which DHAA decrease as Art increased. The data also points to a post-harvest conversion of DHAA into Art. Artemisinin increased from freeze-dried<oven dried<sun-dried ~ shade-dried plants. Comparing freeze dried plant material with other treatments, DHAA was significantly higher that other treatments, while artemisinin was 50% lower. The seasonal accumulation of artemisinin differs from previous work with a Chinese cultivar that peaked at full flowering in West Lafayette, IN. The post-harvest data for artemisinin accumulation during drying procedures is consistent with two previous reports from West Lafayette, IN, and Tasmania, Australia. Data on the both concentration and seasonal variation of artemisinin precursors have not been previously reported. Overall, artemisinin seems to accumulate at the end of the vegetative stage/pre-flowering stage, independent of the cultivar, and is not degraded by Oven, Sun or Shade drying. Artemisinin actually tend to increase with the latter two methods, which have practical application for its commercial production.