Investigation of the protective effect of Cinnamomum cassia bark extract against H2O2-induced oxidative DNA damage in human peripheral blood lymphocytes and antioxidant activity

Cinnamon, one of the most widely used spices in the world, has been shown to have various biological functions including antidiabetic and antitumor activities. Its antidiabetic and antitumor effects were linked with its strong antioxidant activity. In the present study we aimed to investigate the antioxidant activity and possible protective effect of Cinnamomum cassia bark water extract against H2O2-induced oxidative DNA damage. Viability of lymphocytes was determined by Trypan Blue test. For the evaluation of the antioxidant activity, total phenol and flavonoid contents and 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibitory activity of the extract were determined. DNA damage was determined by alkaline comet assay in human peripheral blood lymphocytes. Lymphocytes exhibited >86 % survival up till the concentration of 800 μg/ml of the extract. Total phenol and flavonoid contents were calculated as 10.6 g ± 0.001 gallic acid equivalents/ 100 g dry weight and 2.25±0.004 g quercetin equivalents/100 g dry weight of the extract, respectively. The extract concentration providing 50 % inhibition of DPPH was found as 76.68 μg/ml. Cinnamomum cassia bark water extract at ≥100 μg/ml concentrations caused significant protection against H2O2-induced oxidative DNA damage in lymphocytes. Our results support the suggestions that Cinnamomum cassia bark water extract could be beneficial as a prophylactic agent in prevention of oxidative stress-related diseases.