eng Science and Education Publishing Journal of Food and Nutrition Research 2333-1240 2014-09-09 2 9 621 626 10.12691/jfnr-2-9-15 JFNR20142915 article Jiong Yang 1 Chaoyin Chen chaoyinchen@163.com 1 Shenglan Zhao 2 Feng Ge 2 Diqiu Liu 2 Faculty of life science, Kunming University of Science and Technology, Kunming, People's Republic of China Yunnan University of Traditional Chinese Medicine, Kunming, People's Republic of China Walnut shell is a waste generated in the walnut (Juglans regia L.) harvest, containing natural compounds with antioxidant properties. In this connection, the effect of the solvent (water, chloroform, methanol, ethanol, ethyl acetate and N-butanol) on the extraction yields, total flavonoids content and antioxidant properties was analyzed. Total flavonoids content of extracts was determined by NaNO2-Al(NO3)3 method. Extract antioxidant activity was measured by hydroxyl, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide anion radical scavenging capacity and the total antioxidant capacity and reducing power assay. The highest extraction yield was achieved with N-butanol (4.54%) and the greatest total flavonoids content shown by the samples extracted with ethyl acetate. The highest ability to scavenging DPPH, hydroxyl and superoxide radicals was ethyl acetate extract (EC50=81.03μg/mL), methanol extract (EC50=131.35μg/mL) and chloroform extract (EC50=176.35̦g/mL) respectively under the concentration of 500 ̦g/mL. The methanol extract showed the greatest total antioxidant activity and reducing power. The results showed that different solvent had significant effect on total flavonoids content and antioxidant activity. The result obtained demonstrated the potential of walnut shell as a source of antioxidant. http://pubs.sciepub.com/jfnr/2/9/15/jfnr-2-9-15.pdf walnut shell solvent extraction total flavonoids content antioxidant activity