title: Variability in the composition of anti-oxidant compounds in Echinacea species by HPLC.
abstract: A fast and reliable HPLC method for the determination of caffeic acid derivatives (caftaric acid, chlorogenic acid, caffeic acid, cynarin, echinacoside and cichoric acid) in various species of the genus Echinacea has been developed. Extraction of root samples by magnetic stirring with 80% methanol aqueous solution at room temperature allowed the complete recovery of all compounds of interest. Root extracts were analysed on a reversed-phase column with gradient elution and photodiode array detection. Caffeic acid derivatives showed differential qualitative and quantitative distributions in Echinacea species. The total amount of phenolic compounds ranged from 33.95 to 0.32 mg/g. The highest contents of caffeic acid derivatives were found in E. paradoxa var. paradoxa, E. paradoxa var. neglecta and E. purpurea, followed by E. angustifolia var. angustifolia, E. simulata, E. pallida and E. laevigata, whilst E. tennesseensis, E. sanguinea and E. atrorubens had low amounts of phenolic compounds. The radical scavenging activities of methanolic extracts of roots of Echinacea species was evaluated in vitro using the DPPH* radical scavenging method. The EC50 values of the samples ranged from 122 to 1223 microg/mL. The radical scavenging activities of the root extracts were correlated with the content of phenolic compounds, with a correlation coefficient (r2) of 0.923.
authors.affiliation: Department of Pharmaceutical Sciences, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy. pellati.federica@unimo.it
authors.forename: Federica
authors.initials: F
authors.lastname: Pellati
authors.forename: Stefania
authors.initials: S
authors.lastname: Benvenuti
authors.forename: Michele
authors.initials: M
authors.lastname: Melegari
authors.forename: Todd
authors.initials: T
authors.lastname: Lasseigne
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002109:Caffeic Acids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D020900:Echinacea / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000032:analysis; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D016166:Free Radical Scavengers