Impact of elicitors and light on biosynthesis of sesquiterpene lactones in tissue culture of Arnica montana and their its variety Arbo

Agata Parafiniuk^1,2*Krystyna Danuta Kromer²Mariusz Grzegorz Fleszar¹Katarzyna Wróblewska³Jerzy Wisniewski⁴Andrzej Wincenty Gamian⁵

• ¹Wroclaw Medical University, Wrocław, Poland
• ²University of Wrocław, Wrocław, Silesian, Poland
• ³Wroclaw University of Environmental and Life Sciences, Wrocław, Silesian, Poland
• ⁴Wrocław University of Technology, Wrocław, Silesian, Poland
• ⁵Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Silesian, Poland

Arnica montana is a popular medicinal plant known for the sesquiterpene lactones (SLs) found in its flowers, which are valuable ingredients in pharmacology and cosmetology. We present an alternative method for acquiring these metabolites by the application of the plant in vitro culture method of the species A. montana, representing the dihydrohelenalin type and the Arbo variety, richer in helenalin. Employing high-resolution liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) to determine SL content facilitated the identification of optimal culture conditions. On the basic Murashige and Skoog (MS) medium without growth regulators, an increase in light intensity had a positive effect, stimulating SLs biosynthesis. The highest content of SLs was confirmed in in vitro cultured leaves of both taxa, particularly at the highest tested light intensity of 150 µmol m-2 s-1 (A. montana: 32.57 mg/g DW; A. montana ‘Arbo’: 73.90 mg/g DW). Chitosan, jasmonic acid (JA), and red light alter the spectrum of the present SLs, supporting helenalin derivatives formation. By expanding the culture's scale, the bioreactor efficiency was obtained at 4025.02 mg SL per 100 g dry leaf weight, which means that the in vitro procedure can be adapted to receive these compounds.