Protective effects of raw and cooked blackcurrant extract on DNA damage induced by hydrogen peroxide in human lymphoblastoid cells

Abstract

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 μM H₂O₂ 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 H₂O₂.

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 H₂O₂ significantly decreased in the each BCE-treated condition.

Conclusion: The results suggest that BCE treatment can reduce the genomic instability induced by H₂O₂ in human cells. We consider that these antigenotoxic effects are related to polyphenols, l-ascorbic acid and other antioxidant compounds.

• Antigenotoxicity
• antioxidative activity
• oxidative stress

Acknowledgements

The authors are grateful to Dr. Kazuo Yamamoto, emeritus professor at Tohoku University, for his advice about DNA damage and repair mechanisms. The authors are also grateful to Dr. Yu F. Sasaki, professor at Hachinohe National College of Technology, for his advice about the comet assay.