Resumo

MENDOZA MEZA, Dary Luz; PARRA FLOREZ, Loreinys  e  LOZA ROSAS, Sergio. FREE RADICAL SCAVENGING CAPACITY OF ESSENTIAL OIL AND ETHANOLIC EXTRACTS OF YACÓN (Smallanthus sonchifolius Poepp. & Endl) H. Robinson, CULTIVATED IN COLOMBIA. Biosalud [online]. 2014, vol.13, n.2, pp.9-23. ISSN 1657-9550.

Introduction: Smallanthus sonchifolius is an Andean crop with important medicinal and nutritional properties, used mainly as a hypoglycemic. The aim of this study was to determine free radical scavenging activity of essential oil and phenolic fractions of an ethanolic extract of yacón leaves grown in Colombia. Materials and Methods: The essential leaf oil was extracted through hydrodistillation assisted by microwave radiation and was analyzed using gas chromatography coupled with mass spectrometry (GC-MS). Phenolic fractions of different polarity were also separated from an ethanolic leaf extract using Amberlite XAD-2 resin. The total phenolic compounds were determined with the Folin-Ciocalteu reagent and analyzed using liquid chromatography coupled with mass spectrometry (HPLC-MS). The antioxidant activity was evaluated using DPPH radicals (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonate]. Results and Discussion: The essential oil showed the ABTS radical scavenging activity (EC50 = 2.11 mg / ml). The major compounds identified in the essential oil were: Sabinene (40.75%), D-germacrene (15.36%), Caryophyllene (9.93%) and 1-Terpinen-4-ol (5.51%). The total phenolic content in the fractions separated on Amberlite XAD-2 was F1 (H₂O) > F2 (H₂O/MeOH, 1:1 v/v) > F3 (MeOH). All fractions showed scavenging activity with DPPH^• and ABTS^•+. Phenolic acids identified using HPLC-SM were quinic, hidroxiferulic, caffeoylquinic, dicaffeoylquinic, dicaffeoilglucaric and caffeoiltartaric derivatives. In conclusion, yacón leaves grown in Duitama (Boyacá) contain secondary metabolites able to protect cells against oxidative stress induced by free radicals.

Palavras-chave : Smallanthus sonchifolius; essential oil; ethanolic extract; antioxidants; ABTS; DPPH.

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