Rape Pollen Supercritical Carbon Dioxide Extract On Lipid Metabolism In Hyperlipidemic Rats

Objective: The study aimed to evaluate the effects on lipid profiles in hyperlipidemic rats of rape pollen extract enriched with ALA using supercritical carbon dioxide extraction (SCE). Research Methods & Procedures: The experimental hyperlipidemic rats were established by providing with high fat diets, randomized into six groups, assigned to three doses of pollen extract, lovastatin, basic diet or fat diet. After four weeks of intragastric administration, the rats were executed, lipid levels and fatty acids component of serum and hepatic tissue were determined, also metabolic enzyme of lipid such as LCAT and HMG-CoA reducase were measured. Results: Total cholesterol and triacylglycerol levels in serum were significantly lower in pollen extract groups and medicinal control (MC) group than in high fatty control (HFC) group. Hepatic total cholesterol levels were decreased in rats fed pollen extract and lovastatin. A higher concentration of HDL-Cholesterol and apoAI in hepatic tissue were observed after intake of pollen extract compared to the HFC group (P<0.05). LCAT activity in serum of pollen extract groups was significantly higher than HFC group and HMG-CoA reductase showed decreasing tendency in groups of pollen extract. The contents of DHA in hepatic tissue in pollen extract groups were found higher than HFC group. Figures of H.E. waxed stain and Sudan Ⅲiced stain showed that hepatic cell of HFC group exhibited higher degree of fatty degeneration than other experimental groups. No significant changes of MDA were observed between HFC and other experimental pollen groups in this experiment,suggesting edible security of pollen extract. These results suggest that extract from rape pollen enriched in alpha-linolenic acid are effectively in decreasing the levels of lipid in plasma and hepatic tissue to various extent compared to high fats diet. This is possibly due to increasing level of HDL-C and activity of LCAT, decreasing activity of HMG-CoA reductase and the ratio of clearance of free cholesterol so as to promote transportation, excretion and metabolism of cholesterol in hepatic tissue and serum, also indirectly increasing in DHA concentration of hepatic tissue. Conclusion: Rape pollen extract enriched with alpha-linolenic acid is likely to be a novel agent capable of promoting a favorable lipid profile in hepatic tissue and serum. AlA is dietary essential fatty acid which is considered to be substitute for fish oil with regard to cardioprotectic benefit. Pollen extract contain not only the mainly component of ALA also other kind of complex substrates, therefore the lipid-lowing effects on serum and liver are carried out by ALA interacting with other natural product. The results are in accordance with many researches that consuming ALA from dietary show preventive effects against cardiovascular disease. Nevertheless some studies reported that intake of ALA is not associated with beneficial effect on cardiovascular heart diseases perhaps owing to various experimental animal and diets souse, diversified technology of processing as well as different trial designs. Further research should be conducted in the interest of steady safety usage when ALA is recommended in nutrition and clinical field.