The biofortification of medicinal plants has been proposed as a novel approach to introduce essential mineral nutrients into the human diet. Yet, its increased levels may affect the synthesis of secondary metabolites and the health-promoting properties of these plants. California poppy (Eschscholzia californica Cham.) has been widely used in traditional medicine for analgesic and sedative purposes due to the presence of alkaloids such as californidine, protopine, allocryptopine, and sanguinarine. The study evaluated the effects of inorganic and organic iodine compounds on the growth and accumulation of iodine and selected alkaloids in California poppy grown in a hydroponic system. ICP-MS was used to analyse the total iodine content in plants after TMAH extraction. The levels of selected alkaloids in leaves were determined by the LC-MS/MS technique after ultrasound-assisted sample extraction in 50 mM HCl in MeOH. Iodine content in plants increased in all tested combinations, with the highest levels noted for 5-iodosalicylic acid (5-ISA). An increase in whole-plant biomass after the application of potassium iodide (KI) and 5-ISA suggests a possible growth-promoting effect on Eschscholzia plants. Leaf-level sanguinarine increased across all iodine combinations, with the highest level observed with 5-ISA. Berberine content increased only after 5-ISA application, while protopine content increased after KI treatment. The leaf levels of allocryptopine, californidine, chelerythrine, coptisine, corydaline, dehydrocorydaline, and reticuline tended to be higher in the KI combination, but the observed changes were not statistically significant. The observed modifications in the alkaloid profile suggest that iodine is involved in regulating its biosynthesis. Further studies are required to monitor changes in root alkaloid levels to fully evaluate the effect of iodine on the production and distribution of these metabolites in Eschscholzia plants.
This research was funded in whole by the National Science Centre, Poland (grant no. UMO-2024/53/B/NZ9/00614.
