Enzymatic Degradation of Echinacoside and Cynarine in Echinacea angustifolia Root Preparations

Abstract

Echinacea preparations are among the bestselling herbal medicinal products in North America and Europe. Echinacoside and cynarine are the major polar constituents in the roots of Echinacea angustifolia DC and therefore are often used as marker compounds for the standardization of corresponding Echinacea preparations. This study demonstrates that echinacoside and cynarine are highly susceptible to enzymatic degradation and oxidation in hydroalcoholic solutions during the extraction process. This makes their use as analytical marker compounds still possible, although care must be taken to avoid error due to this enzymatic degradation. Batch-to-batch consistency and standardization of preparations from E. angustifolia roots require in particular a control of this enzymatic activity. The polyphenol oxidase (PPO), which is responsible for the oxidative degradation of echinacoside and cynarine, was isolated from the roots of E. angustifolia. An Electrospray Ionization-Liquid Chromotography-Mass Spectometry (ESI-LC-MS) method was used to monitor this effect and to determine the kinetics of the degradation.

Keywords: :

• Cynarine
• echinacea
• echinacoside
• enzymatic degradation
• LC-MS analysis
• polyphenol oxidase