Orange juice vs vitamin C: effect on hydrogen peroxide-induced DNA damage in mononuclear blood cells

Serena Guarnieria1 , Patrizia Risoa1 and Marisa Porrinia1

a1 Department of Food Science and Microbiology, Division of Human Nutrition, University of Milan, 20133 Milan, Italy

Abstract

The intake of fruits rich in vitamin C seems to increase the antioxidant defence of the organism. However, it is still not clear whether vitamin C alone is responsible for this effect. The aim of the present investigation was to study the effect of the intake of a single portion of blood orange juice (BOJ, 300 ml, providing 150 mg vitamin C) on mononuclear blood cell (MNBC) DNA damage, compared with a drink supplemented with the same amount of vitamin C (C-drink) or sugars (S-drink). Seven young healthy subjects were randomised in a repeated-measures design in which they received each drink on different occasions, 2 weeks apart. Blood samples were collected at baseline, every hour for 8 h, and at 24 h after the intake of each drink. Vitamin C was analysed at each time point by HPLC, whereas H2O2-induced MNBC DNA damage was evaluated at 0, 3 and 24 h by means of the comet assay. Plasma vitamin C concentration increased similarly following BOJ or C-drink intake and was not affected by the S-drink. DNA damage significantly decreased 3 h after BOJ intake (about 18 %; P < 0·01) and remained constant at 24 h (about 16 %; P < 0·01). No effect of the C-drink and S-drink was observed. In conclusion, the intake of a single portion of BOJ provided an early protection of MNBC against oxidative DNA damage; however, the protective effect of BOJ was not explained by vitamin C alone, thus other phytochemicals could be involved.

(Received June 29 2006)

(Revised October 27 2006)

(Accepted October 30 2006)

Key Words:

  • Orange juice;
  • Vitamin C;
  • DNA damage;
  • Plasma;
  • Mononuclear blood cells

Correspondence

c1 Corresponding author: Dr Serena Guarnieri, fax +39 02 503 16071, email serena.guarnieri@unimi.it

Footnotes

  Abbreviations: BOJ, blood orange juice; C-drink, water with added vitamin C; MNBC, mononuclear blood cell; S-drink, water with added sugars

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