Hypolipidemic Activity of Peony Seed Oil Rich in α-Linolenic, is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid ß-Oxidation.

Peony seed oil (PSO) is a new resource food rich in α-Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein-cholesterol (LDL-C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n-6 to n-3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element-binding proteins 1C (SREBP-1c), acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS)-reduced lipid synthesis; Activation of peroxisome proliferator-activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl-CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.

Hypocholesterolaemic mechanism of bitter melon aqueous extracts via inhibition of pancreatic cholesterol esterase and reduction of cholesterol micellar solubility.

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of ß-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.

Anti-diabetic activity of peony seed oil, a new resource food in STZ-induced diabetic mice.

This study was conducted to investigate the components of a new resource food in China, peony seed oil (PSO) by GC-MS (gas chromatography-mass spectrometry), its inhibitory effects on carbohydrate hydrolyzing enzymes in vitro and its anti-diabetic effects on mice induced by streptozotocin (STZ). The results showed that peony seed oil showed weak anti-α-amylase activity; however, strong anti-α-glucosidase activity was noted. The GC-MS analysis of the oil showed 9 constituents of which α-linolenic acid was found to be the major component (38.66%), followed by linoleic acid (26.34%) and oleic acid (23.65%). The anti-diabetic potential of peony seed oil was tested in STZ induced diabetic mice. Administration of peony seed oil and glibenclamide reduced the blood glucose level and the area under curve (AUC) in STZ induced diabetic mice. There were significant increases in body weight, liver glycogen content, serum insulin level, high-density lipoprotein cholesterol (HDL-C) and decreases in glycosylated hemoglobin (HbA1C), total serum cholesterol (TC), and triglyceride (TG) in test groups as compared to the untreated diabetic groups. In vivo antioxidant studies on STZ induced diabetic mice revealed the reduction of malondialdehyde (MDA) and increase of glutathione peroxides (GSH-px), superoxide dismutase (SOD), and glutathione (GSH). The results provided a sound rationale for future clinical trials of oral administration of peony seed oil to alleviate postprandial hyperglycemia in streptozotocin-induced diabetic mice.