Effect of Dried Powders or Ethanol Extracts of Onion Flesh and Peel on Lipid Metabolism, Antioxidative and Antithrombogenic Capacities in 16-Month-Old Rats

This study was performed to investigate effect of dried powder or ethanol extracts of onion flesh and peel intakes on lipid metabolism, antioxidative and antithrombogenic capacities in 16-month -old rats. Total of 40 Sprague-Dawley male rats of 16-month-old and weighing 816 +/- 6 g were blocked into 5 groups according to body weight and raised for three months with control and experimental diets containing 5% (w/w) of dried powders of onion flesh or peel or ethanol extracts from equal amount of each dried powder. Contents of total flavonoids and total dietary fibers in peel powder were highest among onion preparations. Body weight gain and epididymal pad fat weight were lower in peel powder group than other groups. Plasma total lipid, triglyceride and total cholesterol concentrations of onion-containing groups were lower than control group. Above all, peel ethanol extract intake decreased them most remarkably. Plasma HDLcholesterol concentrations in onion-containing groups were higher than control group, especially that of flesh powder group was the highest among groups. Liver total lipid, triglyceride and total cholesterol concentrations were not significantly different among all experimental groups. However, liver total lipid and triglyceride concentrations were tended to be lower in onion-containing groups than control group. Thiobarbituric acid reactive substances (TBARS) concentrations in LDL + VLDL fraction was not significantly affected by onion intakes, However peel powder group showed the lowest concentration, Plasma TXB2 concentrations in onion flesh powder, peel powder and peel ethanol extract groups were lower than control group, while plasma 6-keto-PGF1alpha concentrations in these same groups were higher than control group. Clotting time was tended to be increased in peel ethanol extract group. In conclusion onion diets seemed to improve lipid metabolism and antithrombogenic capacity while effect on antioxidative was not significant.

Effect of Dietary Iron Levels on Lipid Metabolism, Antioxidative and Antithrombogenic Capacities in 16-month-old Rats

This study was conducted to examine the effect of dietary iron levels on lipid metabolism, antioxidative and antithrombogenic capacities in 16-month-old rats. Thirty-two Sprague-Dawley male 16-month-old rats weighing 618 +/- 6 g were raised for 10 days with medium-iron diet (35 ppm in diet) and blocked into 4 groups according to their body weights. One of groups was sacrificed to obtain initial data and the rest 3 groups were raised for 3 months with experimental diets containing different levels of iron (5 ppm, 35 ppm, and 350 ppm). Total lipid, triglyceride and total cholesterol concentrations in plasma and liver, HDL-cholesterol concentration in plasma, fecal total lipid triglyceride and total cholesterol excretions, thiobarbituric acid reactive substances (TBARS) level in plasma LDL + VLDL (low density lipoprotein + very low density lipoprotein) fractions, blood-clotting time and eicosanoids levels in plasma were measured. The results are as follows: Plasma total lipid, triglyceride and total cholesterol concentrations, TBARS level in plasma LDL + VLDL fractions were increased and blood-clotting time tended to be shortened during 3 months of experimental period. Low (5 ppm) iron diet improved lipid metabolism via increasing HDL-cholesterol and fecal cholesterol excretion. High (350 ppm) iron diet decreased plasma total lipid, triglyceride and total cholesterol concentrations as compared to medium (35 ppm) iron diet and lowered body weight and epididymal fat pad weight. On the other hand, TBARS level in plasma LDL + VLDL fractions and blood-clotting time were increased with high iron diet. It is plausible that low iron diet improves lipid metabolism, antioxidative and antithrombogenic capacities in 16-month-old rats.