Genotoxicity-Suppressing Effect of Sophora japonica L. Aqueous Extract
Yuki Tahara
Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
Satomi Hayashi-Shita
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Takanori Nakamura
Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
Ryo Murashige
Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
Kayoko Yamasaki
Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
Katsutoshi Matsumoto
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Akira Hasegawa
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Takayuki Saito
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Kumiko Sato
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Tetsuo Honma
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Ayumi Yamamoto
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Hirotada Arai
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Yoshihiro Kadoma
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Satomi Kawaguchi
Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Yasuaki Kikuchi
Department of General Science and Education, National Institute of Technology, Hachinohe College, Aomori, Japan.
Kazuyuki Furuya
Mechanical and Medical Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
Yu F. Sasaki *
Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan and Material and Biological Engineering Course, Department of Industrial Systems Engineering, National Institute of Technology, Hachinohe College, Aomori, Japan.
*Author to whom correspondence should be addressed.
Abstract
The dry flower buds of Sophora japonica L. are used as a hemostatic agent in traditional Chinese medicine. In the comet assay, aqueous extracts of S. japonica decreased and increased the tail length significantly in cultured human lymphoblastoid WTK1 cells exposed to UV in the absence and presence of DNA repair inhibitors, respectively. The extract did not affect the tail length in methyl methanesulfonate-exposed cells. In the present study, the aqueous extract of the flower buds of S. japonica was separated by repeated column chromatography, yielding four types of flavonoid glycosides. Among them, only rutin, similar to the extract, decreased and increased the tail length significantly in WTK1 cells exposed to UV in the absence and presence of DNA repair inhibitors hydroxyurea (10 mM) and cytosine-1-β-D-arabinofuranoside (1.8 mM), respectively. The genotoxicity-suppressing effect of rutin was further studied using the micronucleus test. Rutin significantly decreased the frequency of micronucleated binucleate cells in UV-exposed WTK1 cells but did not affect this frequency in UV-exposed XPL3KA (Xeroderma pigmentosum group C) cells. These results suggest that the anti-genotoxic potential of rutin is due to an enhanced incision step of global genome repair (GGR) sub-pathways in nucleotide excision repair (NER). Herein, we show that S. japonica exhibits heretofore unknown anti-genotoxic potential against UV by enhancing the incision of GGR sub-pathways in NER, and that its anti-genotoxic component is rutin.
Keywords: Anti-genotoxic potential, incision step, nucleotide excision repair, rutin, Sophora japonica L. extract