Water extract of Aralia elata prevents cataractogenesis in vitro and in vivo

The water extract of Aralia elata (Aralia extract) has been used in Korean traditional medicine to treat diabetes mellitus. Here, we investigated the aldose reductase inhibitory activity, antioxidant activity and anticataract capacity of Aralia extract using various experimental systems. To determine its aldose reductase inhibitory activity and its antioxidant effect, we used rat lens homogenates. Rat lens cultures and a rat model were used to observe anticataract activity. The resulting IC50 value of Aralia extract in vitro as an aldose reductase inhibitor was 11.3 microg/ml and as an antioxidant was 25.1 microg/ml. Rat lenses in media containing 20 mM xylose developed a distinctly opaque ring in 9h, and treatment with Aralia extract at a concentration of 1mg/ml lowered lens opacity by 36.4 and 31.3% after 24 and 48 h, respectively. In vivo experiments were performed with streptozotocin (STZ) induced diabetic rats. The diabetic control animals developed cataracts at 11 weeks after STZ injection, while oral Aralia extract administered at 300 and 600 mg/kg body weight for 11 weeks reduced cataract formation by 15 and 12%, respectively. The present study shows that Aralia extract inhibits aldose reductase and acts in vitro as an antioxidant, and suggests that these activities have a preventive effect on cataractogenesis in xylose containing lens organ cultures and in in vivo in STZ induced diabetic rats.     

Effect of Sclerocarya birrea (Anacardiaceae) stem bark methylene chloride/methanol extract on streptozotocin-diabetic rats

Sclerocarya birrea (Anacardiaceae) is used as a traditional treatment of diabetes in Cameroon. In this study, we investigated the possible antidiabetic effect of the stem bark extract in diabetic rats. Diabetes was induced by intravenous injection of streptozotocin (STZ, 55 mg/kg) to male Wistar rats. Experimental animals (six per group), were treated by oral administration of plant extract (150 and 300 mg/kg body weight) and metformin (500 mg/kg; reference drug) for comparison, during 21 days. The stem bark methanol/methylene chloride extract of Sclerocarya birrea exhibited at termination, a significant reduction in blood glucose and increased plasma insulin levels in diabetic rats. The extract also prevented body weight loss in diabetic rats. The effective dose of the plant extract (300 mg/kg) tended to reduce plasma cholesterol, triglyceride and urea levels toward the normal levels. Four days after diabetes induction, an oral glucose tolerance test (OGTT) was also performed in experimental diabetic rats. The results showed a significant improvement in glucose tolerance in rats treated with Sclerocarya birrea extract. Metformin, a known antidiabetic drug (500 mg/kg), significantly decreased the integrated area under the glucose curve. These data indicate that Sclerocarya birrea treatment may improve glucose homeostasis in STZ-induced diabetes which could be associated with stimulation of insulin secretion.     

Hypoglycaemic activity of Nelumbo nucifera gaertn. (Fam. Nymphaeaceae) rhizome (methanolic extract) in streptozotocin-induced diabetic rats

The hypoglycaemic effect of the rhizome extract of Nelumbo nucifera was studied in streptozotocin-induced diabetic rats. A methanol extract of the plant obtained by soxhlet extraction from finely pulverized rhizomes was used. The LD₅₀ of the extract was found to be 2 g/kg. The extract (300 mg/kg and 600 mg/kg, orally) caused a reduction of blood glucose levels in streptozotocin-induced diabetic rats by 53% (p<0.001) and 55% (p<0.001) respectively at the end of 12 h. The results of this study indicate that the methanol extract of the rhizome possesses favourable hypoglycaemic activity in hyperglycaemic animals taking chlorpropamide as a standard.     

Effect of an antidiabetic extract of Catharanthus roseus on enzymic activities in streptozotocin induced diabetic rats.

Hypoglycemic activity was detected in dichloromethane:methanol extract (1:1) of leaves and twigs of Catharanthus roseus (family Apocynaceae), a traditionally used medicinal plant, using streptozotocin (STZ) induced diabetic rat model. Extract at dose 500 mg/kg given orally for 7 and 15 days showed 48.6 and 57.6% hypoglycemic activity, respectively. Prior treatment at the same dose for 30 days provided complete protection against STZ challenge (75 mg/kg/i.p.x1). Enzymic activities of glycogen synthase, glucose 6-phosphate-dehydrogenase, succinate dehydrogenase and malate dehydrogenase were decreased in liver of diabetic animals in comparison to normal and were significantly improved after treatment with extract at dose 500 mg/kg p.o. for 7 days. Results indicate increased metabolization of glucose in treated rats. Increased levels of lipid peroxidation measured as 2-thiobarbituric acid reactive substances (TBARS) indicative of oxidative stress in diabetic rats were also normalized by treatment with the extract.     

Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare growing wild in Tafilalet region

The effect of an aqueous extract of Origanum vulgare (OV) leaves on blood glucose levels was investigated in normal and streptozotocin (STZ) diabetic rats. In normal rats, the blood glucose levels were slightly decreased 6 h after a single oral administration (P<0.05) as well as 15 days after once daily repeated oral administration of aqueous OV extract (P<0.05) (20 mg/kg). After a single dose or 15 daily doses, oral administration of the aqueous extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (P<0.001). In STZ rats, the blood glucose levels were normalised from the fourth day after daily repeated oral administration of aqueous OV extract (20 mg/kg) (P<0.001). However, this effect was less pronounced 2 weeks after daily repeated oral administration of OV extract. In addition, no changes were observed in basal plasma insulin concentrations after treatment in either normal or STZ diabetic rats indicating that the aqueous OV extract acted without changing insulin secretion. We conclude that an aqueous extract of OV exhibits an anti-hyperglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.     

Anti-diabetic activity of methanol/methylene chloride stem bark extracts of Terminalia superba and Canarium schweinfurthii on streptozotocin-induced diabetic rats

Stem bark extracts of Terminalia superba Engl. and Diels and Canarium schweinfurthii Engl. are used in Africa for the treatment of various ailments, including diabetes mellitus. The anti-diabetic effects of the methanol/methylene chloride extracts of the stem barks on streptozotocin (STZ)-induced diabetes were evaluated on male rats. Through the subcutaneous route, diabetes was induced using 60 mg/mL of streptozotocin. After 2 days, the rats received, by gavage, 150 mg/kg and 300 mg/kg of extract daily for 14 days. At 300 mg/kg, the two extracts (Terminalia superba and Canarium schweinfurthii), significantly showed at least 67.1% and 69.9% reduction in blood glucose level, respectively, while insulin (three units) given subcutaneously and once daily, had 76.8% reduction compared to diabetic untreated control rats. Similarly, the weight gains were 6.6% and 4.9%, respectively, and were comparable to the normal rats, whereas, diabetic untreated rats lost 14.1% body weight. Still with the same dose, there was 68.5% and 58.5% (p < 0.001) significant decrease in food consumption and 79.7% and 64.0% (p < 0.001) in fluid intake by diabetic rats treated with the respective plant extracts. The insulin-treated rats showed 56.4% and 75.8% decrease in food and fluid intake compared to an augmentation for diabetic control rats, 43.0% and 383.8%, respectively, at the end of the second week of experimentation. These results showed that the plant extracts can reverse hyperglycemia, polyphagia and polydipsia provoked by streptozotocin, and thus, they have anti-diabetic properties.     

Cholesterol and triglycerides lowering activities of caraway fruits in normal and streptozotocin diabetic rats

The purpose of this study was to examine the effect of single and repeated oral administration of the aqueous extract of Carum carvi L. fruits at a dose of (20mg/kg) on lipid metabolism in normal and streptozotocin-induced diabetic rats (STZ). After a single oral administration, Carum carvi extract produced a significant decrease on triglycerides levels in normal rats (p<0.05). In STZ diabetic rats, cholesterol levels were decreased significantly 6h after Carum carvi treatment (p<0.05). On the other hand, repeated oral administration of Carum carvi extract exhibited a significant hypotriglyceridemic and hypocholesterolemic activities in both normal (p<0.01 and <0.001 respectively) and STZ diabetic rats (p<0.001) 15 days after Carum carvi treatment. We conclude that the aqueous extract of Carum carvi (20mg/kg) exhibits a potent lipid lowering activity in both normal and severe hyperglycemic rats after repeated oral administration of Carum carvi aqueous extract.     

Hypoglycaemic activity of Leucas lavandulaefolia Rees. in streptozotocin-induced diabetic rats

The antidiabetic activity of Leucas lavandulaefolia Rees (Family - Labiatae) extract on streptozotocin (STZ) induced diabetic rats has been investigated. A methanol extract of the herb at doses of 200 and 400 mg/kg, and glybenclamide (1 mg/kg) were administered concurrently to STZ-diabetic rats. The extract caused a significant reduction of blood glucose levels in streptozotocin-induced diabetic rats by 29.8% (p <0.001) compared with control groups. © 1997 John Wiley & Sons, Ltd.     

Hypoglycaemic effect of Triticum repens P. Beauv. in normal and diabetic rats

The hypoglycaemic effect of an aqueous extract of Triticum repens (TR) rhizomes was investigated in normal and streptozotocin (STZ) diabetic rats. After a single oral administration of the aqueous extract (20mg/kg) a significant decrease on blood glucose levels in STZ diabetic rats (p<0.001) was observed; the blood glucose levels were normalized after 2 weeks of daily oral administration of TR aqueous extract (20mg/kg) (p<0.001). Significant reduction on blood glucose levels were noticed in normal rats after both acute (p<0.001) and chronic treatment (p<0.001). In addition, no changes were observed in basal plasma insulin concentrations after treatment in either normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of TR exhibits a potent hypoglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.     

Antihyperglycemic and antihyperlipidemic activities of wild musk melon (Cucumis melo var. agrestis) in streptozotocin-nicotinamide induced diabetic rats

Objective: Wild musk melon (Cucumis melo var. agrestis, CMA) is one of the edible plants form Tamil Nadu. Traditionally, this plant was used as diabetic diet (leaves of CMA with Momordica charantia leaves), but there is no scientific report on antidiabetic action of this plant material. Hence, the current research work was designed to evaluate its evaluate the anti-hyperglycemic and antihyperlipidemic effect of hydroalcoholic extract of CMA leaves (HALEC) in streptozotocin (STZ)-nicotinamide (NIC)-induced diabetic rats. Methods: Diabetes was induced by administration of STZ (60 mg/kg, i.p.) after 15 min of NIC (120 mg/kg i.p.) administration. The diabetic rats were treated with HALEC (300 and 600 mg/kg, p.o., respectively) for 21 d. Results: After the management with HALEC, blood glucose, HbA1c levels, total cholesterol, LDL cholesterol, triglycerides levels, glycogen phosphorylase and glucose-6-phosphatase levels were significantly diminished in diabetic rats. However, haemoglobin level, HDL cholesterol, liver glycogen, total protein, hexokinase, glucose-6-phosphate dehydrogenase levels were significantly increased in HALEC treated diabetic rats. The histopathological studies of the pancreas in HALEC-treated diabetic rats showed almost normal appearance. L6 cell line study revealed the increased glucose uptake activity of HALEC. High performance thin layer chromatography (HPTLC) analysis confirms the presence of active principles such as rutin, gallic acid and quercetin in HALEC. Conclusion: The results indicated that HALEC possess significant antihyperglycemic and antihyperlipidemic activity in STZ-NIC-induced type II diabetic rats with protective effect. This research work will be useful for the isolation of active principles and development of herbal formulation in phytopharmaceuticals.     

Acute and chronic hypoglycemic effect of Ibervillea sonorae root extracts-II

Ibervillea sonorae's root, or "wareque" (Cucurbitaceae), is widely used in Mexican traditional medicine for the control of diabetes mellitus. In the present study, the hypoglycemic effects produced by the acute and chronic administration of various extracts of Ibervillea sonorae were investigated. Both the traditional preparation (aqueous decoction) and the raw extract (juice) from the root resulted in significant reductions of glycemia in healthy mice after intraperitoneal administration at a dose of 600 mg/kg. Additionally, ground dried root was used to obtain a dichloromethane (DCM) extract and a methanol (MeOH) extract. The DCM extract induced a clear reduction of glycemia in healthy (P < 0.05) and in alloxan-diabetic mice. The intraperitoneally administered DCM extract caused a severe hypoglycemia that produced lethality in all the treated animals when doses of 300 and 600 mg/kg body weight were used. Since the DCM extract showed a marked hypoglycemic activity, it was administered daily per os to alloxan diabetic rats, employing corn oil and tolbutamide as controls. After 41 days of DCM extract administration at a dose of 300 mg/kg/day, diabetic rats showed improvement in glycemia, body weight, triglycerides, and GPT in comparison with the diabetic control group. Total cholesterol, GOT, and uric acid blood levels were not affected.     

Antihyperglycemic and hypolipidemic effects of Costus speciosus in alloxan induced diabetic rats

Hyperglycemia, abnormal lipid and antioxidant profiles are the most usual complications in diabetes mellitus. In the present study, the antihyperglycemic, antihyperlipemic and antioxidant potency of an ethanol extract of Costus speciosus root was investigated in alloxan-induced diabetic male (Charles Foster) rats. Four groups of alloxan diabetic rats (n = 6) were administered orally with different doses of Costus speciosus root extract (150, 300 and 450 mg/kg BW) and a standard drug, glibenclamide (600 microg/kg BW), for 4 weeks. Two groups of rats (n = 6) served as normal and diabetic controls. While the diabetic controls showed significant abnormal carbohydrate, lipid and antioxidant profiles, administration of 150 mg/kg BW dose neither improved glucose nor lipid metabolism and antioxidant levels. Administration of 300 and 450 mg/kg BW doses, however, resulted in a reversal of diabetes and its complications. Both doses significantly brought down blood glucose concentration (26.76%, 34.68%), increased glycogenesis and decreased glyconeogenesis bringing the glucose metabolism toward normalcy. These doses also reversed the hyperlipidemia by reducing plasma total lipid (12.87%, 178.24%), cholesterol (21.92%, 30.77%) and triglyceride (25.32%, 33.99%) and improved hepatic antioxidant enzyme activities. The high dose (450 mg/kg BW) was found to have more potential antioxidant activities compared with glibenclamide. It is concluded that Costus speciosus root extract possesses anti-hyperglycemic, antihyperlipemic and antioxidative effects, which may prove to be of clinical importance in the management of diabetes and its complications.     

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.     

Study of the hypoglycaemic activity of Lepidium sativum L. aqueous extract in normal and diabetic rats

The hypoglycaemic effect of an aqueous extract of Lepidium sativum L. (LS) seeds was investigated in normal and streptozotocin (STZ)-induced diabetic rats. After a acute (single dose) or chronic (15 daily repeated administration) oral treatments, the aqueous LS extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (p < 0.001); the blood glucose levels were normalised 2 weeks after daily repeated oral administration of aqueous LS extract (20 mg/kg) (p < 0.001). Significant reduction on blood glucose levels were noticed in normal rats after both acute (p < 0.01) and chronic treatment (p < 0.001). In addition, no changes were observed in basal plasma insulin concentrations after treatment either in normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of LS exhibits a potent hypoglycaemic activity in rats without affecting basal plasma insulin concentrations.     

Effect of the desert plant Retama raetam on glycaemia in normal and streptozotocin-induced diabetic rats

The effect of the aqueous extract of Retama raetam (RR) on blood glucose levels was investigated in fasting normal and streptozotocin-induced diabetic rats after single and repeated oral administration. The aqueous extract of RR at a dose of 20mg/kg significantly reduced the blood glucose in normal rats 6h after a single oral administration (P<0.005) and two weeks after repeated oral administration (P<0.05). This hypoglycaemic effect is more pronounced in streptozotocin (STZ) diabetic rats (P<0.001). The aqueous extract of RR had no effect on basal plasma insulin levels indicating that the underlying mechanism of RR activity is extra-pancreatic. These findings suggest that the aqueous extract of RR possess significant hypoglycaemic effect in both normal and STZ diabetic rats.     

Standardized Aqueous Tribulus terristris (Nerunjil) Extract Attenuates Hyperalgesia in Experimentally Induced Diabetic Neuropathic Pain Model: Role of Oxidative Stress and Inflammatory Mediators

The present study aimed to evaluate standardized aqueous Tribulus terristris (nerunjil) extract on the pain threshold response in streptozotocin (STZ)‐induced diabetic neuropathic pain model in rats. After a single injection of STZ (40 mg/kg; i.p.), Wistar male rats were tested by the thermal and chemical‐induced pain models. Diabetic rats exhibited significant hyperalgesia, and these rats were left untreated for the first four weeks. Thereafter, treatment was initiated and continued up to week‐8. All the rats except the vehicle‐treated group received insulin 5 IU/kg/day to maintain plasma glucose levels. Treatment with nerunjil (100 and 300 mg/kg; p.o.) for 4 weeks significantly attenuated the nociception in behavioural models. Nerunjil also inhibited the tumour necrosis factor‐α and interleukin‐1 beta levels. The effect of nerunjil (300 mg/kg) is comparable to the standard drug Pregabalin (100 mg/kg). Nerunjil increased the superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, and decreased the lipid peroxide levels in dose‐dependent manner. Insulin alone‐treated rats failed to attenuate hyperalgesic response. In comparison to insulin alone‐treated rats, nerunjil exhibited significant increase in the pain threshold response. It could be concluded that in controlled diabetic states, nerunjil attenuated the neuropathic pain through modulation of oxidative stress and inflammatory cytokine release. Copyright © 2012 John Wiley & Sons, Ltd.     

The effect of Momordica charantia and Mucuna pruriens in experimental diabetes and their effect on key metabolic enzymes involved in carbohydrate metabolism

The Indian traditional system of medicine prescribed traditional plant therapies. Two such plants, i.e. Momordica charantia (MC) and Mucuna pruriens (MP), earlier shown to reduce hyperglycaemia, were assessed for their anti hyperglycaemic effect on varying degrees of hyperglycaemia and diabetic complications. Alcohol and aqueous extracts of MC (50, 100 and 200 mg/kg/day) and only an alcohol extract of MP (100, 200 and 400 mg/kg/day) were evaluated in a pilot study (plasma glucose >180 mg/dL, 21 days), a chronic study in alloxanized rats (plasma glucose >280mg/dL, 120 days) and streptozotocin (STZ) mice (plasma glucose >400 mg/dL, 60 days). In the pilot study, the maximum antihyperglycaemic effect occurred with an aqueous extract of MC at week 3 and an alcohol extract of MP at week 6 at a dose of 200 mg/kg/day. In chronic alloxanized rats, the selected dose of MC led to a significant fall of 64.33%, 66.96%, 69.7% and 70.53% in plasma glucose levels at 1, 2, 3 and 4 months, respectively. MP showed a decrease of 40.71%, 45.63%, 50.33% and 51.01% at the same time period. In chronic STZ diabetic mice, MC led to a mean reduction of 15.37%, 18.68% and 22.86% in plasma glucose levels on days 40, 50 and 60 of sampling while MP had no significant effect. The alteration in hepatic and skeletal muscle glycogen content and hepatic glucokinase, hexokinase, glucose-6-phosphate and phosphofructokinase levels in diabetic mice were partially restored by MC but not by MP. The mechanism of action of MC and MP is discussed.     

Hypoglycaemic effect of Clausena anisata (Willd) Hook methanolic root extract in rats

This study was designed to examine the hypoglycaemic effect of Clausena anisata (Willd) Hook [family: Rutaceae] root methanolic extract in normal (normoglycaemic) and in streptozotocin-treated diabetic rats. Young adult, male Wistar rats (Rattus norvegicus) weighing 250-300 g were used. Diabetes mellitus was induced in the group of diabetic 'test' rats by intraperitoneal injections of streptozotocin (STZ, 90 mg/kg). In one set of experiments, graded doses of the methanolic root extract of C. anisata (CAME, 100-800 mg/kg p.o.) were administered to both fasted normal and fasted diabetic rats. In another set of experiments, 800 mg/kg of CAME, a dose of the plant extract which produced maximal hypoglycaemic effect in both fasted normal and diabetic rats in the previous set of experiments, was used. The hypoglycaemic effect of this single dose of C. anisata root methanolic extract (i.e. CAME, 800 mg/kg p.o.) was compared with those of insulin (5 micro U/kg s.c.) and glibenclamide (0.2 mg/kg p.o.) in both fasted normal and fasted diabetic rats. Following acute treatment, relatively moderate to high doses of CAME (100-800 mg/kg p.o.) produced dose-dependent, significant reductions (P<0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. On their own, both insulin (5 micro U/kg s.c.) and glibenclamide (0.2 mg/kg p.o.) produced significant reductions (P<0.01-0.001) in the blood glucose concentrations of the fasted normal and diabetic rats. At a dose of 800 mg/kg p.o., CAME reduced the mean basal blood glucose concentrations of fasted normal and fasted diabetic rats by 57.52 and 51.30%, respectively. C. anisata contains a diverse group of chemical compounds (see Table 1). Since methanol extractives of plants are usually known to contain many chemical compounds, each of which is capable of producing definite biological activities via different mechanisms, it is difficult to draw any logical conclusion on the mechanism of the hypoglycaemic effect of such a diverse mixture of chemical compounds contained in the plant extract used in this study. While it is possible that the hypoglycaemic effect of the plant extract may be due, at least in part, to its terpenoid and coumarin contents, the mechanism of its hypoglycaemic action remains largely speculative, and is unlikely to be due to the stimulation of pancreatic beta-cells and subsequent secretion of insulin. Although C. anisata root methanolic extract is less potent than insulin as an antidiabetic agent, the results of this experimental animal study indicate that the herb possesses hypoglycaemic activity; and thus lend credence to the suggested folkloric use of C. anisata root in the management and/or control of adult-onset, Type-2 diabetes mellitus in some communities of South Africa.     

Antidiabetic effect of Symplocos cochinchinensis (Lour.) S. Moore. in type 2 diabetic rats

Aim

Symplocos cochinchinensis (Lour.) S. Moore. is used in Indian system of traditional medicine to treat diabetes mellitus. The present study aims to investigate the antidiabetic efficacy of the hexane extract of Symplocos cochinchinensis leaves in high fat diet-low streptozotocin (STZ) induced type 2 diabetic rats.

Materials and methods

The doses for the study were fixed based on Irwin test. The hypoglycemic effect of the hexane extract of Symplocos cochinchinensis leaves were studied in normal rats. Oral glucose and insulin tolerance tests were carried out. The antihyperglycemic effect of the hexane extract at 250 and 500 mg/kg was studied in high fat diet-low STZ induced type 2 diabetic rats for 28 days.

Results

The extracts showed no adverse effects up to 5 g/kg concentration. In hypoglycemic study, after treatment with hexane extract at 250 and 500 mg/kg the blood glucose was mildly reduced. In oral glucose tolerance test, the treatment with the hexane extract at 250 and 500 mg/kg showed a highly significant reduction of 12.07% and 23.58% in plasma glucose levels, respectively 30 min after glucose load. The insulin tolerance test also showed improved insulin sensitivity after 60 min of insulin treatment. In high fat diet-low STZ induced type 2 diabetic rats, after 28 days treatment with the hexane extract at 250 and 500 mg/kg reduced the plasma glucose level by 17.04% and 42.10%, respectively. A significant reduction in plasma insulin, plasma and hepatic total cholesterol (TC), triglycerides (TG) and free fatty acids (FFA) and a significant increase in liver glycogen were observed in treated diabetic rats.

Conclusion

This study demonstrated the potential antidiabetic property of hexane extract of Symplocos cochinchinensis leaves on type 2 diabetes mellitus, thus justifying its traditional usage.     

Hypolipidaemic activity of Helicteres isora L. bark extracts in streptozotocin induced diabetic rats

In this study, the hypolipidaemic effect of an aqueous extract of the bark of Helicteres isora was investigated in streptozotocin (STZ)-induced diabetic rats. Administration of the bark extract of Helicteres isora (100 and 200 mg/kgb.w.) for 21 days resulted in significant reduction in serum and tissue cholesterol, phospholipids, free fatty acids and triglycerides in STZ diabetic rats. In addition to that, significant (p<0.05) decrease in high-density lipoprotein (HDL) whereas significant increase (p<0.05) low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) were observed in STZ diabetic rats, which were normalized after 21 days of bark extract treatment. The bark extract at a dose of 200 mg/kgb.w. showed much significant hypolipidaemic effect than at the dose of 100 mg/kgb.w.