title: Genotoxicity-suppressing effect of aqueous extract of Connarus ruber cortex on cigarette smoke-induced micronuclei in mouse peripheral erythrocytes.
abstract: BACKGROUND
  According to published information, it has not been determined whether the inhalation of cigarette smoke can induce chromosome aberrations and/or point mutations in mice, though cigarette smoke is clearly carcinogenic to mice. We tested clastogenicity of inhaled cigarette smoke in mouse by a micronucleus test using peripheral erythrocytes. Since it is important to determine the in vivo anti-genotoxic effect against inhaled cigarette smoke to reduce the risk of tobacco carcinogenesis, we also tested in vivo anti-gnotoxic effect against inhaled cigarette smoke of a Connarus extract whose in vitro anti-genotoxic effect was shown.
  
  
  RESULTS
  Male ICR mice were exposed for 1 min to a 6-fold dilution of the smoke once a day for up to 14 consecutive days. Although the frequencies of reticulocytes with micronucleus (MNRETs) and erythrocytes with micronuclei (MN erythrocytes) did not increase within 72 h after a single inhalation of cigarette smoke, the frequency of MN erythrocytes increased significantly upon inhalation for 7 and 14 days. When the Connarus extract was fed to mice at >23.7 ppm during the inhalation period of 14 days, frequency of MN erythrocytes was significantly lower than that at 0 ppm. In vitro antioxidant activity of Connarus extract was almost same to that of vitamin C. The antioxidant activity of the Connarus extract might play an important role in its anti-genotoxic effect against cigarette smoke in vivo, like vitamins C.
  
  
  CONCLUSIONS
  Consecutive inhalation of cigarette smoke is clastogenic to mouse bone marrow as shown by the increased frequency of MN erythrocytes. Also, it was shown the possibility that the Connarus extract reduces the risk of tobacco carcinogenesis.
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Faculty of Chemical and Biological Engineering, Hachinohe National College of Technology, Aomori, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ishida
authors.affiliation: Faculty of Chemical and Biological Engineering, Hachinohe National College of Technology, Aomori, Japan.
authors.forename: Kasumi
authors.initials: K
authors.lastname: Ainai
authors.affiliation: Faculty of Chemical and Biological Engineering, Hachinohe National College of Technology, Aomori, Japan.
authors.forename: Shigeto
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Mechanical Engineering, Hachinohe National College of Technology, Aomori, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Shirata
authors.affiliation: Department of Mechanical Engineering, Hachinohe National College of Technology, Aomori, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Murayama
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Kurimoto
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
authors.forename: Katsuyasu
authors.initials: K
authors.lastname: Saigo
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Murashige
authors.affiliation: Iwate Institute of Environmental Health Sciences, Iwate, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Tsuda
authors.affiliation: Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo, Japan ; Faculty of Chemical and Biological Engineering, Hachinohe National College of Technology, Aomori, Japan ; Laboratory of Genotoxicity, Faculty of Chemical and Biological Engineering, Hachinohe National College of Technology, Tamonoki Uwanotai 16-1, Hachinohe, Aomori, 039-1192 Japan.
authors.forename: Yu F
authors.identifier: 0000-0002-2999-9327
authors.initials: YF
authors.lastname: Sasaki
keywords: Anti-genotoxic effect; Antioxidant; Cigarette smoke; Connarus ruber; Micronuclei