Recently clinical trials indicate that an increasing relative

2. Bioavailibility and Effect on Lipid Metabolism of Crude β- Carotene Extract from Sweet Potato Leaves and Synthetic β- Carotene in Rats Fed Different High Fat Diets • Recently clinical trials indicate that an increasing relative • risk of death from cardiovascular disease following • synthesized beta-carotene supplement. We are • interested in the problem whether synthetic beta-carotene is • suitable for use as a dietary supplement. The purpose of • this study was to investigate the effects of different • sources of beta-carotene and lipids on lipid metabolism and • beta-carotene availability in rats. Forty adult male Wistar • rats were randomly divided into five groups with the • variables including the sources the sources of beta-carotene • (synthetic and natural beta-carotene crude extract from sweet • potato leaves ) and lipids (soybean oil and lard ). Diets and • water were given ad libitum, and was 10g/kg cholesterol • added in diets for forty days. The results showed that for • (-carotene concentration in the serum and liver, the • synthetic (-carotene groups were significantly higher • than the beta-carotene extract groups (P<0.05). Comparison of • the effect of different lipids under the same beta-carotene • source indicated that, the lard groups were • significantly higher in beta-carotene concentration than the • soybean oil groups. Different sources of beta-carotene • and lipid fed did not affect the serum and liver retinol • concentration in both the soybean oil-fed groups and the lard- • fed groups (P>0.05). The effects on lipid metabolism • were as follows: The synthetic beta-carotene groups had • significantly higher ratio between high density lipoprotein • cholesterol (HDL-C) and low density lipoprotein • cholesterol (LDL-C) than the beta-carotene extract • groups (P<0.05), the beta-carotene extract groups is the most • significant. Besides, the synthetic beta-carotene groups • and the beta-carotene extract groups could both cause liver

3. Bioavailibility and Effect on Lipid Metabolism of Crude β- Carotene Extract from Sweet Potato Leaves and Synthetic β- Carotene in Rats Fed Different High Fat Diets • total cholesterol content decreasing, and the beta-carotene • extract groups is the most significant. The synthetic beta- • carotene groups serum and liver acyltriglyceride • concentration are significant higher than the beta-carotene • extract groups. The rat serum, liver and adrenal gland beta- • carotene concentration in the synthetic beta-carotene • groups are all the lard group significant higher than the • soybean oil group. Under the injection of soybean oil, the beta- • carotene extract group serum and liver acyltriglyceride • concentration are significant lower than the synthetic • beta-carotene group, but the groups under the lard injection are • not statistically different. The effects on fatty acid • were as follows: Among the soybean oil groups, the • serum and liver linoleic acid (18:2,n-6) ratios were • significantly higher in the synthetic beta-carotene groups than • in the beta-carotene extract groups (P<0.05); and Among the • lard groups the serum and liver oleic acid (18:1,n-9) • ratios were significantly higher in the synthetic beta-carotene • groups than in the beta-carotene extract groups (P<0.05). • These results suggest that ingestion of beta-carotene • crude extract from sweet potato leaves, as compared to • injestion of the synthetic beta-carotene, has the benefit of • decreasing serum lipids. Except this, the lard diet could • cause more beta-carotene deposit in the liver and increase • beta-carotene bioavailability.