Codonopsis javanica root extracts attenuates hyperinsulinemia and lipid peroxidation in fructose-fed insulin resistant rats
Kun-Ning Chen a,b, Wen-Huang Peng c, Chien-Wen Hou a, Chung-Yu Chen a, Hwei-Hsien Chen d, Chia-Hua Kuo a, Mallikarjuna Korivi a,d,e,*
a Laboratory of Exercise Biochemistry, Department of Sports Sciences, University of Taipei, Taipei, Taiwan, ROC
b Department of Physical Education, National Ping-Tung University of Education, Ping-Tung, Taiwan, ROC
c Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, College of Pharmacy, China
Medical University, Taichung, Taiwan, ROC
d Center for Neuropsychiatric Research, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan, ROC
e Department of Occupational Therapy, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC
From ancient times, Dǎngshen (Codonopsis javanica) has been used in Chinese traditional medicine. In this study we investigated the anti-hyperinsulinemia and antioxidant properties of C. javanica root extracts in a rat model of insulin resistance (IR), induced by chronic fructose feeding. Twenty-four SpragueeDawley rats were randomized into control, fructose-treated (10%, w/v), and fructose then C. javanica (Fru þ Cod)-treated groups. After 8 weeks fructose feeding, increased fasting serum insulin levels (2.6 0.45 mg/L) and insulin area under the curve confirmed the IR (p < 0.001). However, C. javanica treatment to fructose-fed rats significantly attenuated the hyperinsulinemia with correspondingly improved glucose tolerance. Weight gain in Fru þ Cod group was comparably (p < 0.01) lower than in the fructose-fed group. Furthermore, IR-induced increased hepatic lipid peroxidation, as demonstrated by elevated malondialdehyde levels, were significantly (p < 0.001) alleviated by C. javanica treatment. These findings reveal that chronic fructose intake may facilitate IR and oxidative damage, which could be eradicated by improved antioxidant status. Accordingly, we found that C. javanica treatment significantly improved the antioxidant enzyme activities, including superoxide dismutase, glutathione peroxidase and glutathione reductase in the liver. These findings that fructose-induced hyperinsulinemia and associated oxidative stress could be attenuated by C. javanica root extracts.
Keywords:Antioxidants, Herbal medicine, Insulin, Lipid peroxidation, Oxidative stress