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Browsing ENIDH - EMM - Artigo Científico by Subject "Antioxidant capacity"
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- Antioxidant Capacity and Identification of Bioactive Compounds of Myrtus communis L. Extract Obtained by Ultrasound-Assisted ExtractionPublication . Pereira, P.; Cebola, M.J.; Oliveira, M.C.; Bernardo-Gil, M. G.Ultrasound-assisted extraction was used to investigate the polyphenolic compounds, particularly anthocyanins, present in myrtle alcoholic extracts. This type of extract is typical in the making of liqueurs obtained from herbs or plants, especially medicinal plants. The leaf extracts were found to contain flavonoids from the quercetin and myricetin families. Besides these, the berry extracts also showed the presence of anthocyanins, hydrolysable tannins and quinic acid. The antioxidant capacity was studied using the ORAC and TEAC methods and the polyphenol content was measured using the Folin–Ciocalteu method. The results showed that the values produced by the ORAC and TEAC methods were in agreement and that the antioxidant capacity correlated with the polyphenol content. The results showed that the leaf extracts exhibited higher antioxidant capacity than the berry extracts. The extraction method was easily implementable, and proved to be a swift method for obtaining bioactive compounds from vegetable matrices.
- Supercritical Fluid Extraction vs Conventional Extraction of Myrtle Leaves and Berries: Comparison of Antioxidant Activity and Identification of Bioactive CompoundsPublication . Pereira, P.; Cebola, M. J.; Oliveira, M. C.; Bernardo-Gil, M. G.In this work, the antioxidant capacity of extracts of Portuguese myrtle (Myrtus communis L.) is being studied over a period of three years. The samples were leaves of myrtle collected at the flowering stage and berries sampled at an early ripened stage. Supercritical fluid extraction (SFE) extracts were obtained at 23 MPa, 45 °C and a CO2 flow of 0.3 kg h−1 using ethanol as co-solvent with a flow rate of 0.09 kg h−1. Hydrodistillation was carried out in a Clevenger type apparatus and the aqueous phase was extracted with diisopropylether having obtained what is hereby designated as liquid phase extract (LPE). The antioxidant capacity of all the extracts was determined by using three different methods: the Folin–Ciocalteu, the Trolox Equivalent Antioxidant Capacity (TEAC) and the Oxygen Radical Absorbance Capacity (ORAC). The results show that the SFE extracts present a significantly higher antioxidant capacity. The extracts were characterized and quantified by HPLC-DAD-MS/MS methods. The bioactive compounds identified in all the extracts were phenolic acids (only in the LPE extracts), flavonoids and anthocyanins (only in the SFE extracts). The results indicate that the higher antioxidant capacity of the SFE myrtle extracts is mainly correlated with the concentration of flavonol glycosides, the myricetin-O-glycosides.