Effects of Defatted Safflower Seed Extract and Phenolic Compounds in Diet on Plasma and Liver Lipid in Ovariectomized Rats Fed High-Cholesterol Diets

Abstract

Six polyphenolic compounds were isolated from ethylacetate extract secondary to 80% ethanol extraction of defatted safflower seeds. They were categorized into three types: lignans, flavones and serotonin derivatives. Female Sprague-Dawley rats weighing 163.4±6.3 g were ovariectomized (Ovx) and fed either ethylacetate extract at a level of 1% (w/w) or three types of safflower polyphenolic compounds at a level of 200 mg/kg in a diet containing 0.5% (w/w) cholesterol for four wk. The sham and Ovx control groups were fed the same diet without safflower components. Plasma GOT and GPT levels did not differ among the six experimental groups. The plasma levels of total cholesterol were reduced in the four safflower groups by 20-30% as compared to the Ovx control. The plasma level of HDL-cholesterol was higher in the Ovx+ethylacetate extract group or appeared to be in the three Ovx+safflower polyphenolic groups than in the Ovx control. The level of plasma triglyceride was also significantly lower in the Ovx+lignan group than in the Ovx control. The liver level of cholesterol was significantly reduced in the Ovx+ethylacetate extract group. Fecal excretion of cholesterol increased by the safflower lignans and flavones, whereas that of bile acid was not significantly changed by the safflower polyphenols. Matairesinol and acacetin isolated from safflower seeds reduced the cholesterol content in cultured HepG2 cells at a concentration of 0.01-0.1 μM and all three safflower polyphenolics decreased triglyceride content at the concentration of 0.1 μM. These results suggest that safflower polyphenols have the effect of improving blood lipid status via increasing HDL-cholesterol formation and cholesterol excretion without significant uterotropic action in estrogen-deficient animals.