Context: Blackcurrant (Ribes nigrum L.) is a classical fruit that has long been used to make juice, liqueur and sometimes medicines in Europe. The beneficial effects of blackcurrant, which are inhibition of lipopolysaccharide-stimulated inflammatory, anticarcinogenesis and other health effects, have been reported. Objective: Previously, we reported the antimutagenic activities of blackcurrant using a yeast gene mutation assay. In this study, we investigated whether this antimutagenicity of blackcurrant was confirmed in human cells. Materials and methods:We prepared four types of aqueous blackcurrant extracts (BCE) from mature and premature with or without heat treatment by microwave. Antioxidant activities of BCE were measured by the DPPH radical scavenger assay. In the DPPH radical scavenger assay, the maximum concentration of BCE was 1.6 mg/reaction. We investigated the antigenotoxic activities of BCE by the comet assay and micronucleus test using the human lymphoblastoid cell line TK6. In the comet assay, TK6 was treated with 300 mM H 2 O 2 without or with BCE at concentrations of 0.5, 1.0, 2.0 and 3.0 mg/mL. In the micronucleus test, TK6 was treated with 1 mg/mL BCE without or with H 2 O 2 . Results: All BCEs exhibited more than 90% of inhibition rates of DPPH radicals at the maximum concentration of BCE. DNA damage and micronuclei induced by H 2 O 2 significantly decreased in the each BCE-treated condition. Conclusion:The results suggest that BCE treatment can reduce the genomic instability induced by H 2 O 2 in human cells. We consider that these antigenotoxic effects are related to polyphenols, L-ascorbic acid and other antioxidant compounds.

IntroductionBlackcurrant (Ribs nigrum L.) is a classical fruit that has long been used to prepare juice, jam, liqueur, and sometimes medicines in Europe. Previously, we reported a genome defense effect by the antioxidative activity of several types of blackcurrant extracts (BCEs) in yeast and human cell gene mutation assays. In this study, we determined if BCE exerted radioprotective activity against DNA damage, chromosomal aberration, and gene mutations in the TK6 human lymphoblastoid cell line. We prepared aqueous BCE extracted from mature fruits cultivated in the Aomori Prefecture, Japan.FindingsIn the micronucleus test and TK gene mutation assay, TK6 cells were irradiated with 0, 0.125, 0.250, 0.500, and 1.000 Gy with or without 1.0 mg/mL BCE. Intracellular hydrogen peroxide (H2O2) was measured using the fluorescent probe BES-H2O2-Ac. Induction of micronuclei and gene mutations by γ-irradiation exposure was suppressed in combination with BCE. In addition, BCE reduced intracellular H2O2 levels caused by γ-irradiation.ConclusionsOur findings clearly support the genome defense potential of blackcurrant against γ-induced DNA damage. We postulate that these genome defense activities are related to the antioxidant compounds in blackcurrant.