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Aqueous extract from Taiwanese Agrocybe cylindracea strain B protects DNA against • OH- mediated strand breaks


Water extract from Agrocybe cylindracea strain B (ACE), an edible mushroom produced in Taiwan, has previously been studied for its antioxidative activities. ACE is an efficient antioxidant in vitro. Since oxidative alterations of DNA can be linked to the development of cancer, we decided to study whether ACE protects DNA against oxidative stress. We report here that pUC18 plasmid DNA and HepG2 cells' DNA are damaged by • OH radicals generated from Cu (II) plus H2O2. The DNA damage was quantified by determining the diminution of supercoiled DNA forms and the DNA migration after oxidative attack using agarose gel electrophoresis. The IC50 values of ACE were 69.7 μg/mL and 91.6 μg/mL for cupric-mediated • OH formation by determining the diminution of supercoiled DNA forms and Comet assay, respectively. The antioxidant capacity of ACE was significantly higher than that of Lentinus edodes extract (LEE) and the two known scavengers of hydroxyl radical, mannitol and thiourea. ACE and LEE could also inhibit the oxidative degradation of 2′-deoxyribose caused by • OH radicals generated from metal ions plus H2O2. The malondialdehyde (MDA) inhibition effect of active fractional protein from ACE was better than that of LEE. The major protein components of ACE were different from LEE.

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