Summary Folate is a vital vitamin for the human being and its defi ciency can lead to a variety of clinical abnormalities ranging from neural tube defects to cancers. Benzo(a)pyrene (BaP), a strong mutagen and carcinogen, is considered one of the common contaminants in food. The aim of this study was to investigate the positive effect of folate on cancer prevention at a fundamental level. In the present study, we investigated the impact of folic acid on BaP-induced mutagenicity and genotoxicity by means of in vitro and in vivo experiments. The reformed Ames test was applied to study the antimutagenicity of folic acid against BaP. The protective effect of folic acid on cytotoxicity caused by BaP in human liver cell line L02 was evaluated by MTT assay. In addition, the effect of folic acid on the BaP-induced genotoxicity in vivo was assessed by mouse bone marrow micronucleus assay. The results indicated that folic acid signifi cantly inhibited the reverse mutation of Salmonella typhimurium strains TA98 and TA100, and protected the viability of human liver cells against BaP (pϽ0.01). The micronucleus test showed that all doses of folic acid had a remarkable protective effect for the female mice (pϽ0.01). In conclusion, folic acid was found to reduce the mutagenicity and genotoxicity induced by BaP.

This study is designed to evaluate antioxidant and antigenotoxic activities of corn tassel extracts (CTTs). The major bioactive components of CTTs include flavonoid, saponin and polysaccharide. The antioxidant properties of the three bioactive components of CTTs were investigated by Ferric Reducing Antioxidant Property (FRAP) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assays. The activities of the extracts were determined by assessing the inhibition of mutagenicity of the direct-acting mutagen fenaminosulf, sodium azide, and indirect-acting mutagen 2-aminofluorene using the Ames test (strains TA98 and TA100). The results showed that the extraction rates of flavonoid, saponin, and polysaccharide from the dried corn tassels were 1.67%, 2.41% and 4.76% respectively. DPPH and FRAP assay strongly demonstrated that CTTs had antioxidant properties. CTTs at doses of 625, 1250 and 2500 μg per plate reduced 2-aminofluorene mutagenicity by 12.52%, 28.76% and 36.49% in Salmonella typhimurium TA98 strain assay respectively and by 10.98%, 25.27% and 37.83%, at the same doses in Salmonella typhimurium TA100 assay system, respectively. 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay showed that the different concentrations of CTTs inhibited the proliferation of MGC80-3 cells in a dose-dependent manner (P<0.01). It is concluded that these integrated approaches to antioxidant and antigenotoxicity assessment may be useful to study corn tassel as a natural herbal material.

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