Comparative Chromatographic Analysis of Polyphenolic Compounds in Comfrey Leaf and Root with Determination of Their...

Symphytum officinale L. (Boraginaceae) is a plant with proven anti-inflammatory and analgesic activity on the musculoskeletal system. The traditional use of comfrey primarily refers to its roots, although some literature also mentions the leaves as an alternative plant material. Comparing the therapeutic potential of both plant materials requires additional data on the chemical composition of S. officinale leaves and their biological properties. The aim of the study was to analyze polyphenols in comfrey leaves of different origins and to assess their antioxidant and anti-inflammatory potential against comfrey roots, also collected from different sources. Polyphenol profiles were recognized by 2D TLC and HPLC-DAD-ESI-MS methods, and quantitative analysis was performed by the HPLC-UV/Vis (high performance liquid chromatograph with-ultraviolet/visible detection) method. The antioxidant activity was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl), FRAP (ferric reducing antioxidant power), and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid) diammonium salt) assays, and for leaves also using the TLC-DB (thin layer chromatography-direct bioautography) technique with the DPPH radical. Chemometric analysis to assess the relationship between the antioxidant activity and the origin of comfrey plant raw materials was performed. Factor analysis (FA) confirmed that geographic origin and cultivation conditions influenced the antioxidant content of both plant raw materials. The study results indicate that comfrey leaves can substitute for comfrey roots containing not only caffeic acid derivatives but also flavonoids, and exhibiting stronger antioxidant activity.