Variations in key artemisinic and other metabolites throughout plant development in Artemisia annua L. for potential therapeutic use

Abstract

Dried leaves of Artemisia annua show promise as an inexpensive and sustainable antimalarial therapeutic, especially for use in developing countries. Along with the potent terpene, artemisinin, many other small molecules produced by the plant seem to aid in the therapeutic response. However, little is known about the ontogenic and phenological production of artemisinin in the plant, and its plethora of other important secondary metabolites. From a consistently high artemisinin-producing A. annua clone (SAM) we extracted and analyzed by GC/MS 22 different metabolites including terpenes, flavonoids, a coumarin, and two phenolic acids as they varied during leaf development and growth of the plant from the vegetative stage through the reproductive, full flower stage. As leaves developed, the maximum amount of most metabolites was in the shoot apical meristem. Artemisinin, on the other hand, maximized once leaves matured. Leaf and apical tissues (e.g. buds, flowers) varied in their metabolite content with growth stage with maximum artemisinin and other important secondary metabolites determined to be at floral bud emergence. These results indicated that plants at the floral bud stage have the highest level of artemisinin and other therapeutic compounds for the treatment of malaria.

Effect of leaf digestion and artemisinin solubility for use in oral consumption of dried Artemisia annua leaves to treat malaria

“…Two Artemisia annua L. clonal cultivars propagated by rooted cuttings (Towler and Weathers, 2015; Weathers and Towler, 2012) were used in this study: SAM (DLAS) (voucher MASS 00317314), a high AN-producing cultivar (~1.4% w/w), and GLS (DLAG) (vouchers OR State Univ 171772 and 170353), a glandless AN-null mutant cultivar with no glandular trichomes that produces no AN (Duke et al, 1994) and 25% of the flavonoids found in SAM. SAM plant material used in protein and dietary constituent experiments was field grown in Stow, MA, harvested at floral budding stage, dried and processed as previously described (Weathers et al, 2014b).…”

“…AN in extracts was quantified using GCMS according to the method detailed in Towler and Weathers (2015). Flavonoids in extracts were quantified using the spectrophotometric AlCl 3 method (Arvouet-Grand et al, 1994) with quercetin as a standard.…”

Root regulation of artemisinin production in Artemisia annua: trichome and metabolite evidence

“…Artemisinic and flavonoid analyses are detailed elsewhere (Towler and Weathers 2015). Briefly, the five artemisinic compounds were analyzed from methylene chloride extracts of weighed fresh tissues using GCMS via their retention time, ion signatures, comparison to authentic external standards, and some published mass spectra .…”

Variation in Phenolics, Flavonoids at Different Stages of Fruit Development of Pouteria Campechiana (Kunth) Baehni. And Its Antioxidant Activity

“…For example, variations in metabolites throughout plant development in Artemisia annua was reported [16]. Chemical changes and antioxidant activity in pomegranate arils during fruit development was also noticed [17].…”