Elicitation of Pharmacologically Active Substances in an Intact Medical Plant

Abstract

The quality of medical plants used for the production of galenics or pharmacologically useful compounds is usually assessed by the content of biologically active compounds. Because most of these plants are grown in fields, this study focused on stimulation of active compounds by in vivo elicitation. Foliar application of elicitors on the immunostimulating medical plant purple coneflower ( Echinacea purpurea L. Moench.) grown on soil was used to increase the content of biologically active phenolics. Natural plant stress mediators and their derivatives (acetylsalicylic acid, salicylic acid, and methyl salicylate) as well as newly introduced biocompatible metal elicitor [titanium(IV) ascorbate] were chosen as active components of foliar sprays. A tremendous increase of phenolics (up to 10 times compared to control) and stimulation of the biomass yield were achieved. Tuning of organ specificity by modulation of the concentration of elicitor was also observed. This methodology represents a convenient alternative to cell suspension or hydroponic cultures being applicable in wide agricultural practice.

New insights explain that drought stress enhances the quality of spice and medicinal plants: potential applications

“…Based on such promising approaches, the usage of methyl jasmonate for quality improvement of medicinal and spice plants seems to be an encouraging alternative for a direct drought treatment. In the same manner, salicylic acid, an endogenous key signal substance, responsible for systemic resistance (for review, see Durrant and Dong 2004), was also used for influencing the synthesis and accumulation of secondary metabolites: the content of phenolics could strongly be increased by the application of salicylic acid to Echinacea purpurea plants (Kuzel et al 2009), as well as the accumulation of glucosinolates in oilseed rape (Kiddle et al 1994). Unfortunately, apart from their effects on secondary metabolism, salicylic acid and methyl jasmonate also impact on primary metabolism and developmental processes.…”

Xenohormesis: health benefits from an eon of plant stress response evolution

“…Indeed, commonly consumed food products like lettuce and fruits can be nutritionally enhanced by cold stress, light stress, water deficit, or nutrient deficit stress (Atkinson et al 2005;Oh et al 2009). Heavy metals, salicylic acid, and other compounds can function as hormetic elicitors without compromising crop yield (Kuzel et al 2009;Zhang et al 2006). Finally, viral, fungal, and bacterial infection can, in some cases, paradoxically improve the plant's nutritional content via hormesis (Banchio et al 2010;De Vos et al 2005;Métraux et al 1990).…”

Chitosan Oligosaccharides Promote the Content of Polyphenols in Greek Oregano (Origanum vulgare ssp. hirtum)

“…15 Currently, elicitors are extensively used to enhance the yield of secondary metabolites in medicinal plants. 16 The most widely used elicitors are fungal carbohydrates, yeast extracts, and chitosan. 17 Chitosan is frequently used in cell cultures of medicinal plants as well as plant organs for inducing the accumulation of bioactive secondary metabolites.…”