diabetes mellitus occurs when the body ca nt use glucose normally , and is associated with increased serum triglycerides , decreased serum hdl and sometimes increased serum ldl . according to ancient medical texts , urtica dioica may be used for the treatment of high blood sugar . hypoglycemic activity of urtica dioica was detected in a large pharmacological screen of european species with known potential anti - diabetic effects . it has also been reported that the extract of the leaves or other parts of the plan were of benefits in conditions such as prostatic hyperplasia , inflammation , arthritis rheumatoid , hypertension and allergic rhinitis . urtica dioica has been reported to have histamine , formic acid , acetylcholine , acetic acid , butyric acid , leukotrienes , 5-hydroxytryptamine , and other irritants . this study aimed to evaluate the effect of urtica dioica leaf extract on blood glucose , lipid profile , insulin and leptin in rat model of fructose - induced insulin resistance . forty male wistar rats , weighting 200 - 250 g were obtained from the animal breeding center , jundishapur university of medical sciences , and were kept under standard conditions ( 12/12 light - dark cycle , 20 - 24c , 55% humidity ) with free access to water and food . all procedures were performed in accordance with the university guidelines for care and use of laboratory animals . urtica dioica was collected around the city of ahwaz and identified by a faculty of the department of pharmacognosy , jundishapur university of medical sciences . the leaves were dried under the shade and ground to powder by an electrical grinder . the powder was macerated for 72 hours at room temperature using 70% ethanol and 30% water . the mixture was filtered with whatman filter paper ( no 1 ) , and the filtrate was centrifuged at 3000 rpm for 20 min . the supernatant was evaporated at ambient temperature and the extract powder ( 15.1% of leaf powder ) was kept at 4c until used . experimental studies 
  one group of rats was assigned as sham group ( n=8 ) and given tap water . thirty two rats , given daily fresh fructose 10% in drinking water , for eight weeks . starting from the 6 week , they were randomly divided into four groups ( n=8 each ) including a control receiving intraperitoneal ( ip ) vehicle for urtica dioica , and three other groups receiving single administrations of ip hydro - alcoholic extract of urtica dioica at 50 , 100 or 200 mg / kg . twenty four hours after the last ip injection , the animals were lightly anesthetized and blood samples were obtained by cardiac puncture . the serum of blood samples were separated and were used to determine levels of blood glucose , insulin , fasting insulin resistance index ( firi ) , leptin , triglycerides ( tg ) , total cholesterol , low - density lipoprotein ( ldl ) cholesterol , high - density lipoprotein ( hdl ) cholesterol , very low - density lipoprotein ( vldl ) cholesterol and hepatic enzymes . fifty l of serum was used for the measurement of insulin by immunoradiometric assay ( biosource ins - irma kit ) . lipid profile , firi , alanin transaminase ( alt ) , and alkaline phosphatase ( alp ) were determined by commercial kits and enzymic ways . the data were analyzed by one - way anova and post hoc least significant different ( lsd ) tests . effect of fructose administration 
  compared to control group , daily administration of fructose for eight weeks was associated with significant increase in blood glucose ( p<0.05 ) , insulin ( p<0.001 ) , and firi ( p<0.001 ) ( figures 1 - 3 ) . serum glucose concentration ( meansem n=8 each ) of control , fructose - treated and urtica dioica extract - treated rats at 50 , 100 or 200 mg / kg / day . * indicates significant difference from the control group ; indicates significant difference from fructose group serum insulin concentration ( meansem , n=8 each ) of control , fructose - treated and urtica dioica extract - treated rats at 50 , 100 or 200 mg / kg / day ) . * indicates significant difference from the control group ; indicates significant difference from the fructose group the values ( meansem , n=8 each ) of fasting insulin resistance index ( firi ) of control , fructose - treated and urtica dioica extract - treated ( 50 , 100 , 200 mg / kg / day ) rats . * indicates significant difference from the control group ; indicates significant difference from fructose group 
 effect of urtica dioica extract 
  compared to vehicle , urtica dioica extract at 100 mg / kg ( p<0.01 ) and 200 mg / kg ( p<0.001 ) significantly decreased serum glucose ( figure 1 ) . moreover , compared to the vehicle , urtica dioica at 50 , 100 and 200 mg / kg significantly ( p<0.001 ) decreased serum insulin and firi ( figures 2 and 3 ) . effect of urtica dioica extract on lipid profile 
  daily administration of fructose for eight weeks did not change serum tg , total cholesterol , vldl , ldl - cholesterol , hdl - cholesterol , ldl / hdl ratio compared to those of the control group ( table 1 ) . the values ( mean sem , n=8 each ) of serum lipid profile , hepatic enzymes , and leptin of control , fructose - treated and urtica dioica extract - treated ( 50 , 100 , 200 mg / kg / day ) rats tg : triglyceride ; hdl : high density lipoprotein ; ldl : low - density lipoprotein ; vldl : very low - density lipoprotein ; alt : alanine transaminase ; alp : alkaline phosphatase ; * indicate significant difference ( p0.05 ) from the control group ; indicates significant difference from the fructose group compared to the fructose group , urtica dioica extract at 50 mg / kg significantly ( p<0.05 ) increased serum tg and vldl - cholesterol , and significantly ( p<0.05 ) decreased serum ldl and ldl / hdl ratio ( table 1 ) . moreover , compared to fructose group , the extract at 100 and 200 mg / kg / day significantly ( p<0.05 ) increased tg , and significantly ( p<0.05 ) decreased ldl and ldl / hdl ratio . effect of extract on hepatic enzymes 
  treatment with fructose did not change serum alp or ast significantly relative to the control group . at none of the doses used urtica dioica extract changed serum alp relative to that of the fructose group . however , at 100 and 200 mg / kg / day , the extract increased serum ast relative to that of the fructose group ( table 1 ) . effect of extract on leptin 
  the fructose - treated group had a significantly ( p<0.05 ) higher serum leptin compared to that of the control group . urtica dioica extract at 50 and 100 mg / kg / day , but not 200 mg / kg / day , reduced serum leptin compared to that of the fructose group ( table 1 ) . type 2 diabetes is a multi - factorial disease , frequently associated with a cluster of pathologies including obesity , hypertriglyceridemia , impaired glucose tolerance , and insulin resistance . fructose intake may be associated with increased risk of type 2 diabetes through several biological mechanisms . a higher fructose intake may play a role in an increase in body weight due to the positive energy balance . positive energy balance leads to obesity that is associated with a higher concentration of nonesterified fatty acids , which may reduce insulin sensitivity , increase hepatic glucose production , and have a deleterious effect on the beta cell function . golalipour et al showed that the protective administration of hydroalcholic extract of urtica dioica had hypoglycemic effect as well as protective activity on pancreatic beta cells in hyperglycemic rats . our findings are agreement with those of ahangarpour , and jalal s , studies that higher intake of fructose increased glucose , insulin , and firi . the increase of serum glucose by fructose in our study is similar to that of magno et al . who showed that glucose concentrations increased to 145 - 150 mg / dl in animals drinking 10% fructose solutions . urtica dioica is known in iran s folk medicine to have hypotensive and antidiabetic activities . moreover , it was shown that a preparation containing various plants with urtica dioica extract had antidiabetic activity . however , other studies reported no hypoglycemic action of this plant . the results of this study showed that hydroalcoholic extract of urtica dioica leaves could decrease the blood glucose and insulin in hyperglycemic rats , which may be caused in part by the reduction of insulin resistance . cholesterol is one of the body fats and is an important building block in the structure of biological membranes , and used in the biosynthesis of steroid hormones , bile acids and vitamin d. moreover , the high cholesterol concentration in the blood increases the risk of developing atherosclerosis and related cardiovascular diseases . low - density lipoprotein takes the cholesterol from liver to tissues , whereas high - density lipoprotein facilitates the translocation of cholesterol from the peripheral tissues to liver for catabolism . therefore , hdl has a useful effect in reducing serum cholesterol and the increase of its level in serum is suggested . low dose of urtica dioica decreased ldl / hdl cholesterol ratio in comparisons with fructose group . this finding is similar to that of a previous finding by daher et al . in this study urtica dioica extract leptin secretion by adipocytes is stimulated by insulin , and plasma leptin significantly correlates with plasma insulin . thus the decreasing effect of urtica dioica on plasma insulin level may play a role in leptin reduction . leptin stimulates vascular inflammation , oxidative stress , and vascular smooth muscle hypertrophy that may contribute to the pathogenesis of type 2 diabetes mellitus , hypertension , atherosclerosis , and coronary heart disease . by decreasing serum leptin urtica dioica extract they leak into the blood , when parenchymal liver cells are damaged , resulting in elevated levels of these enzymes in the bloodstream , however , some patients with liver damage have normal or near normal alt . serum levels of alt and alp show that no liver damage had occurred during in the present study , which show that that low dose of the extract decreased alt significantly and showed a tendency to decrease alp . this study demonstrated that urtica dioica extract had hypoglycemic and antidiabetic activities with no deleterious effect on hepatic enzymes .
background : 
 urtica dioica has been used as antihypertensive , antihyperlipidemic and antidiabetic herbal medicine . 
 the purpose of this study was to study the effect of hydroalcoholic extract of urtica dioica on fructose - induced insulin resistance rats . 
 methods : forty male wistar rats were randomly divided into five groups including control , fructose , extract 50 , extract 100 and extract 200 . 
 the control rat received vehicle , the fructose and extract groups received fructose 10% for eight weeks . the extract groups received single daily injection of vehicle , 50 , 100 or 200 mg / kg / day for the two weeks . 
 blood glucose , insulin , last fasting insulin resistance index ( firi ) , serum triglyceride ( tg ) , low - density lipoprotein ( ldl ) , very low - density lipoprotein ( vldl ) , high - density lipoprotein ( hdl ) , alanin trasaminase ( ast ) and alkaline phosphatase ( alp ) , leptin and ldl / hdl ratio were determined . 
 results : compared to control group , daily administration of fructose was associated with significant increase in firi , blood glucose and insulin , significant decrease in lepin , and no significant change in tg , hdl , ldl , ldl / hdl ratio , vldl , alt , and alp . 
 the extract significantly decreased serum glucose , insulin , ldl and leptin , and ldl / hdl ratio and firi . 
 it also significantly increased serum tg , vldl , and ast , but did not change serum alp . 
 conclusion : we suggest that urtica dioica extract , by decreasing serum glucose , and firi , may be useful to improve type 2 diabetes mellitus . also , by positive effect on lipid profile and by decreasing effect on leptin , it may improve metabolic syndrome .