Effect of Dried Powders or Ethanol Extracts of Garlic Flesh and Peel on Antioxidative Capacity in 16-month-old Rats

Shin, Seong Hee; Kim, Mi Kyong

Abstract

This study was performed to investigate effect of dried powders and ethanol extracts of garlic flesh and peel on antioxidative capacity in 16-month- old rats. Forty Sprague-Dawley male rats weighing 618.1 +/- 6.5 g were blocked into five groups according to body weight and raised for 3 months with experimental diets containing 5% (w/w) of dried powders of garlic flesh or peel, or ethanol extracts from equal amount of each dried powder. Total polyphenols, flavonoids, beta-carotene, vitamin C, vitamin E, and total antioxidant status (TAS) levels were determined in garlic preparations. Thiobarbituric acid reactive substances (TBARS) levels in plasma, liver and VLDL + LDL fraction, oxidative DNA damage (8-hydroxy-2'-deoxyguanosine, 8OHdG) in kidney, xanthine oxidase (XO) activities in plasma and liver, superoxide dismutase (SOD) activities in erythrocyte and liver, and carotenoid concentration, and total antioxidant status (TAS) in plasma were measured. Total polyphenols and flavonoids contents in garlic preparations were highest in peel ethanol extract. Vitamin C content was not different significantly among preparations, but peel powder contains slightly more vitamin C. The content of beta-carotene was highest in peel ethanol extract and vitmain E content was highest in flesh ethanol extract. The highest level of TAS was observed in peel ethanol extract. Plasma TBARS levels in all the experimental groups were found to be significantly lower than control group, and TBARS concentration in VLDL + LDL fraction was decreased in all the experimental groups in comparison to control group. Also levels of 8OHdG in kidney in experimental groups were lower than that of control group. Plasma and liver XO activities were decreased in all experimental groups, and erythrocyte and liver SOD activities were higher in experimental groups compared to control group. All experimental groups also showed higher plasma TAS levels than control group. Especially, garlic flesh powder group was significantly lower in plasma and liver XO activities, and significantly higher in erythrocyte and liver SOD activities than control group. Moreover, plasma TBARS level and kidney 8OHdG level were decreased in flesh powder group. In conclusion, garlic diets showed effect of improving antioxidative capacity in 16-month old rats, especially, garlic flesh powder was prominent in inhibiting XO activitiy, promoting SOD activity and decreasing kidney 8OHdG level among experimental groups.