The present study examined the hypolipidemic activity of hawthorn fruit. New Zealand white rabbits were fed one of three diets, a reference diet with no cholesterol added (NC), a high cholesterol diet (1g/100g, HC) and a HC diet supplemented with 2g/100g hawthorn fruit powder (HC-H). After 12 wk, serum total cholesterol (TC) and triacylglycerols (TG) were 23.4 and 22.2% lower, respectively, in the hawthorn fruit group compared with the HC rabbits (P﹤0.05). Hawthorn supplementation led to 50.6% less cholesterol accumulation in aorta (P﹤0.05) and 23-95% greater excretion of neutral and acidic sterols (P﹤0.05). Supplementation of hawthorn fruit did not affect the activities of hepatic 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA-R) or cholesterol 7 -hydroxylase (CH) but it suppressed the activity of intestinal acyl CoA:cholesterol acyltransferase (ACAT, P ﹤0.05). The results suggest that the mechanism by which hawthorn fruit decreases serum cholesterol involves, at least in part, the inhibition of cholesterol absorption mediated by down-regulation of intestinal ACAT activity. J. Nutr. 132: 5-10, 2002.

The present study was to investigate the mechanisms by which hawthorn fruit lowers serum cholesterol in hamsters. The control group was fed a semisynthetic diet containing 0.1% cholesterol while the tested group was maintained on the same diet but supplemented with 0.5% hawthorn fruit aqueous ethanolic extract for 4 weeks. Serum total cholesterol (TC) and triacylglycerols (TG) were decreased by 10 and 13%, respectively, in hawthorn fruit group as compared with the control (P<0.05). Supplementation of hawthorn fruit aqueous ethanolic extract led to greater excretion of both neutral and acidic sterols. Further enzymatic assays suggest the mechanisms by which hawthorn fruit decreases serum cholesterol involve a greater excretion of bile acids mediated by up-regulation of hepatic cholesterol 7α-hydroxylase (CH) activity, and an inhibition of cholesterol absorption mediated by down-regulation of intestinal acyl CoA:cholesterol acyltransferase (ACAT) activity.

The extract prepared from hawthorn (Crataegus fruit) was examined for its relaxant effect in rat isolated mesenteric arteries. Hawthorn extract induced concentrationdependent relaxation of the U46619-precontracted artery with an IC50 of 0.22

Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3*-gallate (TF2B) and theaflavin-3,3*-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu12-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3>ECG>EGCG≥TF2B≥TF2A>TF1≥ EC>EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu+2-mediated LDL oxidation at concentrations of 5-40mmol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their freeradical-scavenging activity. J. Nutr. 131: 2248-2251, 2001.

This study compared the antioxidative activity of green tea catechin (GTC) extract with that of rosemary extract in canola oil, pork lard, and chicken fat. The GTC extract was obtained from jasmine and longjing green teas and mainly consisted of four epicatechin isomers including (−)epigallocatechin gallate (EGCG), (−)epigallocatechin (EGC), (−)epicatechin (EC), and (−)epicatechin gallate (ECG). The oxidation was conducted at 100±2℃ by monitoring oxygen uptake. The oxygen consumption test demonstrated that GTC extract was much more effective than the rosemary extract against lipid oxidation in canola oil, pork lard, and chicken fat under the conditions of the present study. Together with our previous study which showed that GTC extract was more protective than butylated hydroxytoluene as an antioxidant, these results suggest that GTC as a mixture of EGCG, EGC, EC, and ECG may serve as an antioxidant in processed foods.