title: Oral Rg1 supplementation strengthens antioxidant defense system against exercise-induced oxidative stress in rat skeletal muscles.
abstract: BACKGROUND
  Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1) on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress.
  
  
  METHODS
  Forty weight-matched rats were evenly divided into control (N = 20) and Rg1 (N = 20) groups. Rg1 was orally administered at the dose of 0.1 mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA) muscles were surgically collected immediately after exercise along with non-exercise rats.
  
  
  RESULTS
  Exhaustive exercise significantly (p<0.05) increased the lipid peroxidation of control group, as evidenced by elevated malondialdehyde (MDA) levels. The increased oxidative stress after exercise was also confirmed by decreased reduced glutathione to oxidized glutathione ratio (GSH/GSSG ratio) in control rats. However, these changes were completely eliminated in Rg1 group. Catalase (CAT) and glutathione peroxidase (GPx) activities were significantly (p<0.05) increased by Rg1 in non-exercise rats, while no significant change after exercise. Nevertheless, glutathione reductase (GR) and glutathione S-transferase (GST) activities were significantly increased after exercise in Rg1 group.
  
  
  CONCLUSIONS
  This study provide compelling evidences that Rg1 supplementation can strengthen antioxidant defense system in skeletal muscle and completely attenuate the membrane lipid peroxidation induced by exhaustive exercise. Our findings suggest that Rg1 can use as a nutraceutical supplement to buffer the exhaustive exercise-induced oxidative stress.
authors.affiliation: Laboratory of Exercise Biochemistry, Taipei Physical Education College, Taipei City, Taiwan.
authors.forename: Szu-Hsien
authors.initials: SH
authors.lastname: Yu
authors.affiliation: Department of Food Science, Nutrition, and Nutraceutical Biotechnology, Shih-Chien University, Taipei City, 10462, Taiwan.
authors.forename: Hui-Yu
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Laboratory of Exercise Biochemistry, Taipei Physical Education College, Taipei City, Taiwan.
authors.forename: Mallikarjuna
authors.initials: M
authors.lastname: Korivi
authors.affiliation: Laboratory of Exercise Biochemistry, Taipei Physical Education College, Taipei City, Taiwan.
authors.forename: Ming-Fen
authors.initials: MF
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan.|Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan.
authors.forename: Chih-Yang
authors.initials: CY
authors.lastname: Huang
authors.affiliation: Laboratory of Exercise Biochemistry, Taipei Physical Education College, Taipei City, Taiwan.
authors.forename: Chien-Wen
authors.initials: CW
authors.lastname: Hou
authors.affiliation: Laboratory of Exercise Biochemistry, Taipei Physical Education College, Taipei City, Taiwan.
authors.forename: Chung-Yu
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chung-Lan
authors.initials: CL
authors.lastname: Kao
authors.affiliation: Department of Nursing, Tzu Chi University, Hualien, Taiwan.
authors.forename: Ru-Ping
authors.initials: RP
authors.lastname: Lee
authors.affiliation: Department of Physical Therapy and Graduate Institute of Rehabilitation Science, China Medical University, Taichung, Taiwan.|Department of Healthcare Administration, Asia University, Taichung, Taiwan.
authors.forename: Shin-Da
authors.initials: SD
authors.lastname: Lee
authors.affiliation: Laboratory of Exercise Biochemistry, Taipei Physical Education College, Taipei City, Taiwan.|Department of Physical Therapy and Graduate Institute of Rehabilitation Science, China Medical University, Taichung, Taiwan.
authors.forename: Chia-Hua
authors.initials: CH
authors.lastname: Kuo