Recent findings have suggested that oxidative damage might contribute to the cytotoxicity and carcinogenicity of
aflatoxin B1 (AFB1). Induction of oxidative stress also plays an important role in the toxicity of another
mycotoxin,
ochratoxin A (OTA). In the present study, the protective effect of
cyanidin-3-O-beta-glucopyranoside (C-3-G; an
anthocyanin contained in oranges, blackberries, strawberries and cranberries) against AFB1- and OTA-induced cytotoxicity was investigated in a human
hepatoma-derived cell line (Hep G2) and a human colonic
adenocarcinoma cell line (CaCo-2). The ability of C-3-G to reduce the production of
reactive oxygen species (ROS), the inhibition of
protein and
DNA synthesis and the apoptosis caused by the two
mycotoxins was also investigated in both cell lines. Our experiments proved the significant cytoprotective effect of C-3-G in vitro against OTA- and AFB1-induced cell damage. In particular, 24 h of pretreatment with 50 microm-C-3-G inhibited the cytotoxicity of 10 microm-AFB1 (by 35 %) and of 10 microm-OTA (by 25 %) in Hep G2 cells (P < 0.001) and of 10 microm-AFB1 (by 10 %, P < 0.01) and of 10 microm-OTA (by 14 %, P < 0.05) in CaCo-2 cells. Moreover, 50 microm-C-3-G attenuated ROS production induced by the two toxins in both cell lines (P < 0.05). Inhibition of
DNA and
protein synthesis induced by the
mycotoxins was counteracted by pretreatment with the
antioxidant at 50 microm. Similarly, apoptotic cell death was prevented as demonstrated by a reduction of DNA fragmentation and inhibition of
caspase-3 activation. The in vitro
free-radical scavenging capacity of the
anthocyanin was tested with the Briggs-Rauscher oscillating reaction. This system works at pH approximately 2. The results showed good scavenging power, in accordance with the observed inhibition of ROS production.