Effect of onion (Allium cepa) ultra-high pressure processing and hot water extracts on the serum cholesterol level in high cholesterol-fed rats

Abstract

Effects of high pressure-processed onion extracts (OHP) on high cholesterol diet (HCD)-fed rats were investigated using 5 groups of normal diet, HCD, HCD with OHP (medium-dose (OHP-1) or high-dose (OHP-2)), and HCD with onion hot water extract (OHW) as a control for 6 weeks. OHP increased serum AST, total cholesterol, and HDL and LDL cholesterol levels. The LDL cholesterol level was 7.76 mg/dL in the normal diet group and 155.06 mg/dL in the HCD-fed group. Treatment with 8.1 g/kg/day OHP reduced LDL levels to 82.38 mg/ dL. Total hepatic lipid and cholesterol levels were reduced in HCD-fed and OHP treated rats, compared with HCD- fed rats. Fecal lipid and cholesterol levels were significantly (tonal lipid, p<0.05; cholesterol, p<0.05) increased in HCD-fed rats, compared with controls, and OHP treatment increased lipid and cholesterol excretion. OHP prevented hyperlipidemia by improving lipid metabolism via decreased liver lipid contents and increased fecal lipid excretion.