title: Characterisation of polyphenols by HPLC-PAD-ESI/MS and antioxidant activity in Equisetum telmateia.
abstract: The antioxidant activity of an aqueous extract (infusion) and respective ethyl acetate fraction of Equisetum telmateia Ehrh. (Equisetaceae), a plant used in traditional medicine for its anti-inflammatory and diuretic properties, has been evaluated by DPPH, TEAC and TBARS assays. A high and significant antioxidant activity was detected in the ethyl acetate fraction. Analysis of the aqueous extract and the ethyl acetate fraction by HPLC-PAD-ESI/MS allowed the identification of the major phenolic compounds as flavan-3-ol, kaempferol and phenolic acid derivatives. Among the flavan-3-ols, A-type proanthocyanidins and afzelechin derivatives were detected as well as the more common B-type procyanidins, B2 and C1, whose identification was further confirmed by HPLC using detection involving chemical reaction with p-dimethylamino-cinnamaldehyde. The results suggest that the anti-inflammatory activity of E. telmateia could be due, at least in part, to the presence of compounds with antioxidant activity.
authors.affiliation: Centro de Estudos Farmacêuticos and Laboratório de Farmacognosia, Faculdade de Farmácia Universidade de Coimbra, Portugal.
authors.forename: Helena
authors.initials: H
authors.lastname: Correia
authors.forename: Ana
authors.initials: A
authors.lastname: González-Paramás
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Amaral
authors.forename: Celestino
authors.initials: C
authors.lastname: Santos-Buelga
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Batista
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D020829:Equisetum / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry*; D010636:Phenols / Q000032:analysis* / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D059808:Polyphenols; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols