Potential Implications of Medicinal Plant Production in Controlled Environments: The case of Feverfew (Tanacetum parthenium)

Abstract

<jats:p>The purpose of this review is to promote a discussion about the potential implications of herb production in controlled environments, focusing on our recent works conducted with feverfew. Research suggests that the content of secondary metabolites in medicinal plants fluctuates with changing environmental conditions. Our studies with feverfew (<jats:italic>Tanacetum parthenium</jats:italic> [L.] Schultz-Bip., Asteraceae) lend support to this hypothesis. Feverfew plants exposed to different water and light conditions immediately before harvest exhibited changes in content of some secondary metabolites. The highest yield of parthenolide (PRT) was in plants that received reduced-water regimes. Phenolics concentration however, was higher in plants receiving daily watering. Light immediately before harvest enhanced accumulation of PRT, but reduced the phenolic content. Notably, PRT decreased at night whereas total phenolics decreased during the photoperiod and increased at night. PRT also increased with increased plant spacing. UV light supplementation increased PRT only in plants that had undergone water stress, whereas phenolics increased when UV was applied to continuosly watered plants. Clearly, production of medicinal plants under greenhouse conditions is a promising method for controlling levels of phytochemicals through manipulation of light and water as discussed here, and possibly other environmental factors such as temperature and daylength. However, better understanding of how the environment alter secondary metabolite levels is needed as it was revealed that manipulating the environment to favor increased accumulation of one group of phytochemicals could result in a decline of other key metabolites.</jats:p>

Effect of Different Light Intensities on Total Phenolics and Flavonoids Synthesis and Anti-oxidant Activities in Young Ginger Varieties (Zingiber officinale Roscoe)

“…The results show that leaves in both of varieties have a higher content of TF (5.95 mg/g dry weight in Halia Bentong and 8.45 mg/g dry weight in Halia Bara) under 310 μmol m −2 s −1 of light intensity. A similar trend of increasing TF content with decreasing light intensity were seen in Tanacetum parthenium and strawberry [32,33] and in some medicinal plants illustrating a considerable influence of low irradiance on enhancement of plant TF [19]. Michel et al [34] reported TF production related to plant pigments (chlorophyll and carotenoids), and in contrast to flavonoids, the xanthophyll cycle seems to be mainly relevant to the protection of photosynthesis against sudden increases in light intensity.…”

Water deficit‐induced oxidative stress affects artemisinin content and expression of proline metabolic genes in Artemisia annua L.

“…Excess photoassimilates would be incorporated into secondary metabolites [3], such as artemisinin. Munn e-Bosch et al [63] found similar results in a drought-resistant shrub, Cistus creticus L. Plants under drought stress usually accumulate abscisic acid, which activates changes in the content of secondary metabolites [64]. However, different studies have shown inconsistent artemisinin contents under water stress conditions.…”

Potential of cultivar and crop management to affect phytochemical content in winter-grown sprouting broccoli (Brassica oleraceaL. var.italica)

“…In green broccoli very high density planting (97 000 plants ha −1 ) has been shown to increase levels of some glucosinolates and manipulation of plant density has been explored as a method of increasing levels of bioactive phenolic compounds in some crops . In this study we measured levels of phenolics and flavonoids in the purple sprouting variety ‘TZ 6002’ in two growing seasons (2008 and 2010).…”