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Oxidative Medicine and Cellular Longevity
Volume 2016, Article ID 8915729, 12 pages
Research Article

Bioactive Flavonoids, Antioxidant Behaviour, and Cytoprotective Effects of Dried Grapefruit Peels (Citrus paradisi Macf.)

1Analytical Chemistry and Food Technology Area, Faculty of Pharmacy, University of Castilla-La Mancha, 02071 Albacete, Spain
2Food Technology Area, Faculty of Chemistry, University of Castilla-La Mancha, 02071 Ciudad Real, Spain
3Medical Sciences Department, Faculty of Medicine, University of Castilla-La Mancha, 02071 Albacete, Spain

Received 11 October 2015; Revised 30 November 2015; Accepted 1 December 2015

Academic Editor: Denis Delic

Copyright © 2016 Lucia Castro-Vazquez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Grapefruit (Citrus paradisi Macf.) is an important cultivar of the Citrus genus which contains a number of nutrients beneficial to human health. The objective of the present study was to evaluate changes in bioactive flavonoids, antioxidant behaviour, and in vitro cytoprotective effect of processed white and pink peels after oven-drying (45°C–60°C) and freeze-drying treatments. Comparison with fresh grapefruit peels was also assessed. Significant increases in DPPH, FRAPS, and ABTS values were observed in dried grapefruit peel samples in comparison with fresh peels, indicating the suitability of the treatments for use as tools to greatly enhance the antioxidant potential of these natural byproducts. A total of thirteen flavonoids were quantified in grapefruit peel extracts by HPLC-MS/MS. It was found that naringin, followed by isonaringin, was the main flavonoid occurring in fresh, oven-dried, and freeze-dried grapefruit peels. In vivo assay revealed that fresh and oven-dried grapefruit peel extracts (45°C) exerted a strong cytoprotective effect on SH-SY5Y neuroblastoma cell lines at concentrations ranging within 0.1–0.25 mg/mL. Our data suggest that grapefruit (Citrus paradisi Macf.) peel has considerable potential as a source of natural bioactive flavonoids with outstanding antioxidant activity which can be used as agents in several therapeutic strategies.