Accumulation of Total Content of Polyphenol Compounds and Antioxidant Activity of Echinacea Moench Species

Abstract

Echinacea Moench species (Asteraceae Bercht. & J. Presl) are one of the most known medicinal and ornamental plants with numerous pharmacological activities. The objects of this study were plant raw materials of Echinacea angustifolia DC. (Kherson Oblast, Ukraine) and E. purpurea (L.) Moench (Kherson and Poltava Oblast, Ukraine) was collected at the start of the vegetation, budding, flowering, and seed ripening period in 2021–2022. It was determined The total polyphenol content (TPC) by the Folin-Ciocalteu method, the total flavonoid content (TFC) by the aluminum chloride method, and the total phenolic acid content (TPAC) with Arnova reagent. The antioxidant activity of investigated plant extracts was conducted by the phosphomolybdenum method (molybdenum-reducing power, MRP) and DPPH method (free radical scavenging activity with 2,2-diphenyl-1-picrylhydrazyl radical). The TPC was determined in the amount of 21.15–78.34 mg GAE.g^-1, TFC in the amount of 8.23–47.98 mg QE.g^-1, and TPAC in the amount of 7.34–29.21 mg CAE.g^-1 depending on species, stage, and region of growth. The MRP of investigated extracts was in the range of 54.32–161.34 mg TE.g^-1 and FRSA in the range of 6.12–9.69 mg TE.g^-1 depending on species, stage, and region of growth. The lowest content of TPC, TFC, and TPAC was determined in the extracts of E. angustifolia in all investigated periods. The highest content of the TPC, TFC, and TPAC was detected in the extracts of E. purpurea from the Kherson region of Ukraine. A positive strong correlation was found between investigated parameters in spring growth, budding, and flowering (r = 0.675–0.998). The negative weak correlation was found in the seed ripening period between TFC and MRP (r = -0.079). The obtained results showed that the accumulation of the total polyphenol content and antioxidant activity of ethanol extracts of Echinacea plants depended on species, period, and region of growth. It can be useful for further pharmacological and biochemical investigations.