Modulatory effects of α- linolenic acid on generation of reactive oxygen species in elaidic acid enriched peritoneal macrophages in rats.

Fatty acids are known to influence the ability of macrophages to generate reactive oxygen species (ROS). However the effect of elaidic acid (EA, 18:1 trans fatty acid) on ROS generation is not well studied. Rat peritoneal macrophages were enriched with elaidic acid by incubating the cells with 80 µM EA. The macrophages containing EA generated higher amounts of superoxide anion (O2·-), hydrogen peroxide (H2O2) and nitric oxide (NO˙) by 54, 123 and 237%, respectively as compared to control cells which did not contain EA. To study the competition of other C18 fatty acids with EA macrophages were incubated with EA along with stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and α- linolenic acid (ALA, 18:3). ALA significantly reduced the incorporation of EA into macrophage lipids. This also significantly reduced the generation of O2· -, H2O2, NO˙ by macrophages. Studies were also conducted by feeding rats with diet containing partially hydrogenated vegetable fat (PHVF) as a source for EA and linseed oil (LSO) as a source for ALA. The rats were fed AIN-93 diet containing PHVF with 17% EA and incremental amounts of linseed oil for 10 weeks. The peritoneal macrophages from rats fed partially hydrogenated vegetable fat generated higher levels of O2·-, H2O2, NO˙ by 46, 161 and 76% respectively, when compared to rats fed control diets containing ground nut oil. Macrophages from rats fed PHVF with incremental amounts of LSO produced significantly lower levels ROS in a dose dependent manner. Thus ALA reduces the higher levels of ROS generated by macrophages containing EA.

Sub chronic toxicity studies of lactulose in rats.

Lactulose has profound health benefits by way of increasing bifidobacterial flora in the intestine of infants thereby protecting them against enteric infection, constipation and systemic encephalopathy. In the present study to assess the sub chronic toxicity of lactulose syrup, the rats were fed on a basal feed supplemented with lactulose syrup at 0.5, 1.0, 2.0 and 5.0% for a period of 21 weeks. Monitoring of food consumption, gain in body weight and physical observations did not reveal any treatment-related toxicity in any of the group of rats. Terminal autopsy also did not reveal any signs of toxicity. Further, no significant alterations in relative organ weight, serum biochemistry and urinalysis were observed up to 1% lactulose supplementation level. The results suggest that supplementation of lactulose in the diet does not produce any toxicity at the doses tested.

Assessment of protein quality of infant milk food formula supplemented with lactulose.

To examine the protein quality of infant food formula supplemented with lactulose (bifidogenic factor), groups of 21 day male weanling rats were fed diet containing lactulose at 0.5% for 4 weeks. The gain in body weight of rats fed lactulose supplemented diet were similar to that of rats fed lactulose free and skim milk powder fed diet as controls. No difference in overall acceptability pattern was also observed in studies conducted with human subjects for organoleptic evaluation. The results suggest that supplementation of lactulose in infant food formula does not affect either the protein quality as indicated by protein efficiency ratio in rats as compared to control formulae or overall acceptability by human subjects.

Nutritional properties of trans fatty acids.

The role of trans fatty acids (TFA) present in partially hydrogenated fats widely consumed in food and their link with coronary heart disease has been examined in this review. Most of the studies carried out have been on the effects of TFA on blood-lipid profile. The perceived effects of TFA intake depend on the fat or oil with which they are compared and appears to be in between that of dietary saturated fats and monounsaturated fatty acids. When compared to saturated fat, TFA intake shows lower levels of total and LDL-cholesterol in blood. But when both TFA and saturated fatty acids are compared with cis fatty acids or native unhydrogenated oil, increase in total and LDL-cholesterol are noted. The effects of TFA on HDL-cholesterol and Lp(a) are not clearly established. The undesirable effects of TFA can be overcome by inclusion of essential fatty acids at a minimum of 2 energy per cent level in the diet. The link between trans fatty acid intake and coronary heart disease (CHD) are not unequivocally established.

Inhibitory effect of Garcinia kola on lipid peroxidation in rat liver homogenate.

Garcinia kola, (a herb grown in Nigeria; calorific value 358.54 k.cal/100 g) inhibited in vitro lipid peroxidation of rat liver homogenate in a dose dependent manner. The inhibitory activity of G.kola was not affected by heating (100 degrees C/10 min). The antioxidant component of G.kola was soluble in aqueous and ethanolic media. The active component(s) in G. kola responsible for its inhibitory activity on lipid peroxidation is tentatively identified as isoflavones.

Scavenging of superoxide anions by spice principles.

Effect of spice principles on scavenging of superoxide anion has been investigated. The superoxide anions, as measured by nitrobluetetrazolium (NBT) reduction in xanthine-xanthine oxidase system, were inhibited by superoxide dismutase, spice principles eugenol (cloves) and cuminaldehyde (cumin), antioxidants, butylated hydroxy toluene and butylated hydroxyanisole in a dose-dependent manner. The K(i) values for the inhibition of NBT reduction by eugenol and cuminaldehyde were 64 microM and 120 microM respectively. Zingerone (ginger) and linalool (coriander) inhibited NBT reduction to a maximum of 23 and 28% respectively. However, piperine (black pepper) and turmeric extracts (aqueous and acid) failed to scavenge superoxide anions.