Comparative effects of rose hip and corn oils on biliary and plasma lipids in rats

The comparative effects of dietary level and time of feeding corn (CO) and rose hip (RHO) oils on bile and plasma lipid composition were studied. 48 males Sprague Dawley rats were divided in two groups fed semipurified diets containing CO or RHO as the only lipid source. Groups of 6 rats were fed ad libitum diets containing 5 per cent or 15 per cent vegetable oil during 15 or 60 days. Food intake was not dependent on the type of oil, and was higher in 15 per cent oil diets (p < 0.01), increasing with time of feeding (p < 0.001). Bile flow was similar in all groups. Biliary concentrations of cholesterol, phospholipids and bile acids were affected by the time of feeding (p < 0.001). Plasma total and high density lipoprotein (HDL) cholesterol levels were higher in 15 per cent oil fed rats (p < 0.05). Triglycerides concentrations were similar in all groups. The results indicate that oil concentration and time of feeding were the most important variables affecting the lipid composition of rats, independently of the fatty acid composition of the ingested fats

Absence of genotoxic activity of beta-myrcene in the in vivo cytogenetic bone marrow assay

beta-Myrcene (MYR, 7-methyl-3-methylene-1,6 octadiene) is a peripheral analgesic substance and one of the major constituents of lemongrass oil (Cymbopogon citratus, Stapf), a plant widely used in Brazilian folk medicine. In the present study the genotoxicity of MYR was evaluated in vivo using the rat bone marrow cytogenetic assay. Male and female Wistar rats weighing 250 g (223 to 286 g) and 178 g (168 to 186 g), respectively, were used. Two or four rats of either sex were treated orally with MYR (0.1, 0.5 and 1.0 g/kg po), corn oil (negative control) and cyclophosphamide 30 mg/kg ip (positive control). Animals were sacrificed and bone marrow cells were harvested 24 and 48 h after MYR administration. The mitotic index and the frequency of chromosome aberrations were evaluated. Fifty metaphase cells were examined per animal. A dose related increase in mitotic index was observed 24-h after MYR administration. No evidence of MYR-induced clastogenicity was observed under the experimental conditions of this in vivo assay. The present results and previous negative findings of in vitro mutagenicity tests strongly indicate that MYR is not a genotoxic substance

Modulation of postprandial glycaemia and insulinaemia by pectin in mixed nutrient combinations.

The present study was designed to examine the effect of pectin (P) on postprandial glycaemia and insulinaemia when ingested with glucose (G), casein (Cs) and corn oil (Co) in various combinations. The study was conducted on five healthy male volunteers, on each of whom five meal tolerance tests were performed. The meals were isocaloric and consisted of G; G and P; G, Cs and P; G, Co and P; and G, Cs, Co and P. The meals were administered after an overnight fast. In addition to a fasting blood sample, blood was collected 0.5, 1.0, 1.5 and 2.0 h after ingestion for measurement of serum glucose and insulin levels. The glycaemic and insulinaemic response to GP did not differ significantly from that to G. All the other meals, viz. GCsP, GCoP and GCsCoP, gave a significant reduction in postprandial glycaemia as compared to G. The corn oil containing meals, viz. GCoP and GCsCoP, in addition, gave a significant reduction in postprandial insulinaemia as compared to G. Pectin alone is not a dependable dietary constituent for reducing postprandial glycaemia. Its combination with protein and fat significantly lowers the postprandial glycaemic as well as insulinaemic response to orally administered glucose.