Effects of two abiotic elicitors on secondary metabolites accumulation and bioactivity in tree wormwood in vitro shoot cultures

Artemisia arborescens L., well known as tree wormwood, is a medicinal species of the Asteraceae family that makes a part of the folk medicine system in the Mediterranean regions. Several scientific studies have validated the traditional medicinal use of tree wormwood and confirmed its antimicrobial, anti-tumor, antioxidant, anti-inflammatory and hepatoprotective properties. In this study, the incidence of two abiotic elicitors (NaCl and KCl) on the concentration and bioactivity of secondary metabolites in tree wormwood microshoots regenerated in vitro was evaluated. The obtained results showed that the application of 100 mM NaCl or KCl to one-month old in vitro developed microshoots resulted in the enhancement of the accumulation of total polyphenols, flavonoids, condensed tannins and volatile compounds. The highest improvement rates of total polyphenols (80%) and flavonoids (53%) over the control were obtained with NaCl elicitor. However, KCl elicitor has been shown more efficient in the enhancement of condensed tannins (430%) and volatile metabolites (39%) contents. The application of the two salt elicitors led also to a significant increase of the antioxidant activities of ethanolic and volatile metabolites extracts in the treated microshoots. The obtained results are promising and further detailed investigations are needed for the optimization of this strategy to improve the in vitro production of Artemisia arborescens L. phytochemicals with high potentialities in alternative medicine and pharmaceutical industry.