In vivo evaluation of anti-oxidant and anti-lipidimic potential of Annona squamosa aqueous extract in Type 2 diabetic models.

AIM OF THE STUDY: Diabetes is known to involve oxidative stress and changes in lipid metabolism. Many secondary plant metabolites have been shown to possess antioxidant activities, improving the effects of oxidative stress due to diabetes. The present study was aimed to evaluate the effect of water extract of Annona squamosa leaves on antioxidant enzymes and lipid profile of animal models of type 2, non-insulin dependent diabetes mellitus (NIDDM). MATERIAL AND METHODS: The plant material was extracted with boiling water for 2 h. Albino Wistar rats (n=24) were divided into four groups. Diabetes was induced by streptozotocin injection (ip) at a dose of 50 mg/kg. Animals of treated groups were given the dose of 350 mg/kg of the extract. The excised rat tissues were rinsed in ice-cold saline, blotted dry and weighed. RESULTS AND CONCLUSIONS: The results clearly suggest that the water extract of Annona squamosa leaves possessed antioxidant activity as shown by increased activities of scavenging enzymes, catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione reductase (GR) and glutathione-s-transferase (GST) and decrease in malondialdehyde levels present in various tissues. Administration of the extract also improved the lipid profile of the treated groups indicating thereby that the high levels of triglyceride and total cholesterol associated with diabetes can also be significantly managed with the extract.

Assessment of antidiabetic potential of Cynodon dactylon extract in streptozotocin diabetic rats.

This study was undertaken to investigate the hypoglycemic and antidiabetic effect of single and repeated oral administration of the aqueous extract of Cynodon dactylon (Family: Poaceae) in normal and streptozotocin induced diabetic rats, respectively. The effect of repeated oral administration of aqueous extract on serum lipid profile in diabetic rats was also examined. A range of doses, viz. 250, 500 and 1000mg/kg bw of aqueous extract of Cynodon dactylon were evaluated and the dose of 500mg/kg was identified as the most effective dose. It lowers blood glucose level around 31% after 4h of administration in normal rats. The same dose of 500mg/kg produced a fall of 23% in blood glucose level within 1h during glucose tolerance test (GTT) of mild diabetic rats. This dose has almost similar effect as that of standard drug tolbutamide (250mg/kg bw). Severely diabetic rats were also treated daily with 500mg/kg bw for 14 days and a significant reduction of 59% was observed in fasting blood glucose level. A reduction in the urine sugar level and increase in body weight of severe diabetic rats were additional corroborating factors for its antidiabetic potential. Total cholesterol (TC), low density lipoprotein (LDL) and triglyceride (TG) levels were decreased by 35, 77 and 29%, respectively, in severely diabetic rats whereas, cardioprotective, high density lipoprotein (HDL) was increased by 18%. These results clearly indicate that aqueous extract of Cynodon dactylon has high antidiabetic potential along with significant hypoglycemic and hypolipidemic effects.

Studies on the glycemic and lipidemic effect of Murraya koenigii in experimental animals.

Diabetes is often accompanied by lipid abnormalities, which contribute significantly to cardiovascular morbidity and mortality in diabetic patients. Previously, we have demonstrated potent hypoglycemic activity of lyophilized aqueous extract of Murraya koenigii leaves in normal and alloxan induced diabetic rabbits for short duration of 6 h. In this study, we examined the effect of 1 month oral administration of Murraya koenigii aqueous leaves extract in normal and STZ induced severe diabetic rats, at the dose of 300 mg/kg bw, on various biochemical parameters, viz., fasting blood glucose (FBG), total cholesterol (TC), HDL-cholesterol (HDL), triglyceride (TG), alkaline phosphatase (ALKP), serum glutamate oxaloacetate and pyruvate transaminases (SGOT and SGPT) and serum creatinine. In case of diabetic animals fasting blood glucose (FBG) levels of treated animals reduced by 48.2% after 30 days treatment with the aqueous leaves extract. A fall of 19.2 and 30.8% in TC and 22.97 and 37.1% in TG levels were also observed in the case of treated normal as well as diabetic rats, respectively. Feeding the extract increased the HDL-cholesterol level by 16 and 29.4% in normal and diabetic rats, respectively, as compared with their initial values. In the normal rats after 1 month of oral administration of the extract SGOT and SGPT levels were decreased by 21.7 and 25.0%. Serum alkaline phosphatase values of the treated normal animals were also reduced by 33% while negligible change was observed in the normal control animals. In the case of diabetic rats, SGOT and SGPT levels were reduced by 36.7 and 32.2%, respectively, whereas ALKP levels decreased by 39.7% after 1 month oral administration of the extract. The serum creatinine levels decrease in normal as well as in the diabetic animals by 17.75 and 18.2%, respectively, as compared to initial values. In the diabetic control animals the urinary sugar remains at +4 level but there was a decrease of 75% in urine sugar in the case of treated diabetic rats. This indicates that the aqueous extract of Murraya koenigii has favorable effect in bringing down the severity of diabetes.

Assessment of glycemic potential ofMusa paradisiaca stem juice.

The present study reveals the effect of Musa paradisiaca stem juice on blood glucose level (BGL) of normal & diabetic rats. The dose of 500 mg/kg bodyweight produces a significant rise of 28.3% in blood glucose level after 6h of oral administration in normal rats. Whereas, in sub diabetic rats the same dose produces a rise of 16.4% in blood glucose levels within 1h during glucose tolerance test (GTT) and a rise of 16% after 4 h in fasting blood glucose levels of severe diabetic cases. These results were unexpected and important to report as other species of Musa like Musa sapientum has been reported for its hypoglycemic effect.

Hypoglycemic and antihyperglycemic activity of Aegle marmelos seed extract in normal and diabetic rats.

Aegle marmelos Corr. (Rutaceae) is widely used in Indian Ayurvedic medicine for the treatment of diabetes mellitus. The aqueous extract of Aegle marmelos seeds was administered orally at different doses (100, 250 and 500 mg/kg) to normal as well as sub (fasting blood glucose (FBG) normal; glucose tolerance abnormal) and mild (FBG 120-250 mg/dl) diabetic rats. The dose of 250 mg/kg was found to be most effective dose and it decreases blood glucose level (BGL) by 35.1% in normal healthy rats after 6h of administration. The same dose also showed a marked reduction in BGL of 41.2% in sub and 33.2% in mild diabetic rats in glucose tolerance test (GTT) after 2 h. Treatment of severely (FBG >250 mg/dl) diabetic rats for 14 days with a dose of 250 mg/kg reduces the fasting blood glucose by 60.84% and urine sugar by 75% than their pretreatment levels. It brought about fall in level of total cholesterol (TC) by 25.49% with increase of 33.43% in high density lipoprotein (HDL) and decrease of 53.97 and 45.77% in low density lipoprotein (LDL) and triglyceride (TG), respectively. These results clearly indicate that aqueous seed extract of Aegle marmelos possess antidiabetic and hypolipidemic effects in diabetic rats.

Nutritional and hypoglycemic effect of fruit pulp of Annona squamosa in normal healthy and alloxan-induced diabetic rabbits.

The nutritive value of the pulp of the edible fruit of Annona squamosa and its effect on various biochemical parameters has been assessed in normal and alloxan-induced diabetic rats. Different doses (2.5, 5.0, 10.0 g/kg b.w.) of fresh fruit pulp of A. squamosa were given to the three groups each of normal healthy and diabetic rabbits orally daily for 1 month. There was a control group of normal as well as diabetic animals which did not receive fruit pulp. Protein efficiency ratio (PER), digestibility coefficient (DC), biological value (BV) and net protein utilization (NPU) were calculated and improvement in the nutritional level was studied by comparing with the control group. Effect of the fruit pulp was also studied on various biochemical parameters, namely fasting blood glucose (FBG), total cholesterol (TCH), HDL-cholesterol, triglyceride (TG), total protein (TPR), alkaline phosphatase (ALKP), serum glutamate oxaloacetate and pyruvate transaminases (SGOT and SGPT), serum creatinine (CRTN) and serum bilirubin (BIL). Protein and glucose in urine were also estimated. Total hemoglobin and glycohemoglobin (HbAc) were estimated in blood before and after 1 month of feeding fruit pulp. Fruit pulp increased the net protein utilization by 29.3 in normal healthy rabbits with 10 g/kg b.w. and 34.1 in induced diabetic (induced by alloxan) animals with 5 g/kg b.w. of the fruit pulp feeding when compared with the control group of rabbits (p < 0.001). Feeding fruit pulp with the same amount increased the total hemoglobin content by 21.0% in normal rabbits and 10.8% in diabetic rabbits. Fruit pulp also reduced the total cholesterol level by 45-46% in normal and 32.4% in diabetic animals with increased HDL-cholesterol. Feeding pulp improved the liver function in normal as well as diabetic rabbit as shown by reduction in the serum SGOT, SGPT, ALKP and bilirubin levels. The optimal improvement in nutritive value of normal animals was found with 5.0-10.0 g/kg b.w. of the fruit pulp feeding, while in diabetic animals it was 2.5-5.0 g/kg b.w. In the diabetic animals pulp feeding between 2.5 and 5.0 g/kg b.w. showed improvement in the glucose tolerance. Further, 5 g/kg b.w. of fruit pulp brought down urine sugar, urine protein and glycohemoglobin in diabetic rabbits. Feeding pulp had increased utilization of dietary protein, body weight as well as the ratio of gain in body weight per gram of protein consumed. It had a protective effect on liver and heart as indicated by reduction in the SGOT, SGPT, ALKP and serum bilirubin levels.

Hypoglycemic and antidiabetic effect of ethanolic extract of leaves of Annona squamosa L. in experimental animals.

The ethanolic extract of Annona squamosa L. (Annonaceae) leaves was administered orally at different doses to normal as well as streptozotocin (STZ)-induced diabetic rats and alloxan-induced diabetic rabbits. The dose of 350 mg/kg body weight (bw) reduced the fasting blood glucose (FBG) level by 6.0% within 1 h, whereas, the peak blood glucose at 1 h during glucose tolerance test (GTT) was reduced by 17.1% in normal rats. The same dose of ethanolic extract reduced FBG by 26.8% and improved glucose tolerance by 38.5 and 40.6% at 1 and 2 h, respectively, during GTT in alloxan-induced diabetic rabbits. In STZ-diabetic rats, a fall of 13.0% in FBG and an improvement in glucose tolerance by 37.2 and 60.6% at 1 and 2 h, respectively, was observed during GTT. The dose of 350 mg/kg bw of ethanolic extract in 10-day treatment of a group of STZ-diabetic rats produced 73.3% fall in FBG level and no sugar was observed in fasting urine. Treatment of severely-diabetic rabbits for 15 days with a dose of 350 mg/kg of extract reduce FBG by 52.7% and urine sugar by 75%. It brought about fall in the level of total cholesterol (TC) by 49.3% with increase of 30.3% in high-density lipoprotein (HDL) and decrease of 71.9 and 28.7% in low-density lipoprotein (LDL) and triglycerides (TG) levels, respectively.

Hypoglycemic effects of Murraya koenigii on normal and alloxan-diabetic rabbits.

In past there have been many medicinal plants, which have been used in traditional medicines for their antidiabetic properties without any scientific support and pharmacological evidence. The aqueous extract of Murraya koenigii leaves has been taken to evaluate the hypoglycemic activity in normal and alloxan induced diabetic rabbits. This plant is promising as it is widely and regularly used as a spice for food flavoring and as such it appears to be without any side effects and toxicity. Adequate characterization of hypoglycemic activity of aqueous extract has not been yet done, as no such reports are available in the literature though the activity is reported. The scientific evaluation of its hypoglycemic activity was, therefore, explored and also compared with the effect of a standard hypoglycemic drug, tolbutamide. A single oral administration of variable dose levels (200, 300 and 400 mg/kg) of aqueous extract led to lowering of blood glucose level in normal as well as in diabetic rabbits. The maximum fall of 14.68% in normal and 27.96% in mild diabetic was observed after 4 h of oral administration of 300 mg/kg. The same dose also showed a marked improvement in glucose tolerance of 46.25% in sub-diabetic (AR) and 38.5% in mild diabetic rabbits in glucose tolerance test after 2 h. The findings from this study suggest that the aqueous extract of these leaves may be prescribed as adjunct to dietary therapy and drug treatment for controlling diabetes mellitus.

Two aurone glycosides from heartwood of Pterocarpus santalinus.

Two new aurone glycosides, 6 hydroxy 5 methyl 3',4',5' trimethoxy aurone 4-O-alpha-L-rhamnopyranoside and 6,4' dihydroxy aurone 4-O-rutinoside have been isolated from the ethanolic extract of the wood of Pterocarpus santalinus. Their structures were determined on the basis of chemical and spectroscopic analysis (UV, IR, EIMS, (1)H and (13)C NMR).