SEMI-AUTOMATED SAMPLING DURING TEA INFUSION: DETERMINATION OF THE TRANSFER OF SESQUITERPENE LACTONES FROM BOTANICAL PREPARATIONS (ARNICA MONTANA) INTO HOT TEA INFUSIONS

A botanical preparation is any preparation obtained from plants by various processes. The extraction process of secondary plant constituents with an aqueous hot infusion is frequently practiced worldwide and is used for the preparation of different popular tea beverages. The infusion process itself can lead to a selective enrichment, depletion or formation of new substances not contained in the original plant material. Consequently, kinetic studies need to be conducted to answer the question of such different behavior of secondary plant substances originating from herbal preparations into ready-to-drink tea infusions. Such hot infusions are complex mixtures of secondary plant constituents that consist either of different plant parts or mixtures of different plant species. Besides the well-known beneficial effects of hot tea beverages, it is also important to consider some safety aspects related to the presence of contaminants, addictive, psychotropic or other substances of concern [1]. The EFSA database "Compendium of Botanicals" lists plant parts or preparations from plants, including their respective secondary plant constituents, which may be of concern for human
health when ingested through foods [2]. This list also includes substances from the group of sesquiterpene lactones (SL), that are naturally occurring substances in plants with about 5000 structures showing a 15-carbon core structure which is derived from the assembling of three isoprene units and a gamma-lactone ring. Listed are the pseudoguajanolide-type SLs (PSL) helenalin, dihydrohelenalin, arnifolin, chamissonolide and their esters present in arnica, helenium and ambrosia species or the eudesmanolide-type SL santonin produced by artemisia species for example [2]. Such plant species would therefore be considered a botanical source of contamination
of tea. Hence, we targeted to develop and validate an HPLC-MS/MS method for the determination of these structurally very similar PSL in botanicals at the German Federal Institute for Risk Assessment (BfR). So far, this method comprises 44 SL including 19 PSL in addition to numerous flavonoids and caffeic acid ester. In order to improve the data basis for health risk assessment, we established a semi-automatic peristaltic pump sampling system to investigate the time-dependent transfer of SLs
from the dry plant material into the hot infusion. Subsequently, Arnica montana was used as a model plant to establish kinetics of the transfer of SLs. The SL profiles in the hot infusion, in the infused plant material and in the dry starting material were compared. The results on the transfer into the hot tea infusion and the fate in the plant material of selected SLs are presented.