Urtica dioica extract and its impact on blood lipids, glycemia & inflammation in the rat model. (c2005)

Abstract

The present study evaluates the effects of a one month period of chronic consumption of water and petroleum ether extracts of Urtica dioica on fasted blood lipoprotein profile, sugar level, liver toxicity, stool lipid excretion and water content in the rat model. In order to cover different lifestyles, animals during the study period were receiving either a regular or a high-fat diet. The present investigation also included the anti-inflammatory effect of the plant aqueous extract on acute and chronic induced inflammation. Both, water and petroleum ether extracts contributed to an improvement il~ the blood lipid profile. Serum TAG concentrations were relatively reduced with both extracts intake but a significant effect was only reached when the diet was high in fat. Both extracts reduced significantly serum total cholesterol concentrations irrespective of the fat content in the diet. No effect on HDL cholesterol levels has been observed among the different groups. LDL cholesterol and LDLlHDL cholesterol ratios were reduced with the chronic intake of the extracts, but significance was reached with the water extract group only. Compared with the control group, a significant decrease in plasma total ApoB concentration was observed with both extract groups and dietary life-styles. Assessment of stool TAG and cholesterol excretion did not show any noticeable changes. This suggests that observed changes in lipid profile were not the result of a direct effect of the drug on lipid absorption through the gastrointestinal tract. However, the plant water extract resulted in significant water retention in the stools and exhibited a slight laxative effect but not diarrhea. Determination of sGOT, sGPT and LDH activities did not show any increase in their levels in both extract groups, but on the contrary the activities were relatively reduced, thus implying no liver damage has occurred during the study period. A general hypoglycemic effect was observed with chronic intake of both extracts in the fasted state. Significant reduction in serum glucose concentration was only reached with the water extract group. The hypoglycemic effects observed were accompanied with relative increases in serum insulin concentrations. In the acute inflammation induced by carrageenan, Udioica water extract was highly efficient in reducing inflammation in a dose dependent manner reaching a 41 % inhibition with the 250mg/Kg BW dose which was even greater than diclofenac (38%). Increasing the concentration to 500mg/kg BW did not substantially increase the inhibition (42%). In the chronic study, Udioica water extract showed a dose dependent anti-inflammatory effect upon inflammation induced by formalin. The 500mg/kg BW dose had similar anti-inflammatory effect compared with diclofenac (80%). In conclusion, a positive impact on atherosclerosis, hyperglycemia and inflammation can be detected as a general overview of this study, especially with water extract. Toxicity assessment showed no signs of liver damage except for a mild laxative effect on the gastrointestinal tract.