A Comprehensive Analysis to Elucidate the Effects of Spraying Mineral Elements on the Accumulation of Flavonoids in Epimedium sagittatum during the Harvesting Period

The harvesting period is a critical period for the accumulation of flavonoids in the leaves of the important medicinal plantEpimedium sagittatum. In this study, we conducted an experiment onE. sagittatumleaves sprayed with mineral elements with the aim of improving the quality of the herbal leafage during the harvesting period. We elucidated the changes in flavonoids (icariin, epimedin A, epimedin B, and epimedin C) inE. sagittatumleaves. The sum of main flavonoids content reached a maximum (11.74%) at 20 days after the high-concentration Fe2+(2500 mg·L−1) treatment. We analyzed the FT-IR spectra characteristics ofE. sagittatumleaf samples using the FT-IR technique, and constructed an OPLS-DA model and identified characteristic peaks to achieve differentiated identification ofE. sagittatum. Further, widely untargeted metabolomic analysis identified different classes of metabolites. As the most important characteristic flavonoids, the relative contents of icariin, icaritin, icariside I, and icariside II were found to be up-regulated by high-Fe2+treatment. Our experimental results demonstrate that high-concentration Fe2+treatment is an effective measure to increase the flavonoids content inE. sagittatumleaves during the harvesting period, which can provide a scientific basis for the improvement ofE. sagittatumleaf cultivation agronomic measures.Keywords:Epimedium sagittatum;flavonoids;icariin;FT-IR;metabolomic