Antihyperglycaemic activity of aqueous leaf extract of Combretum micranthum (Combretaceae) in normal and alloxan-induced diabetic rats

Aim of the study

To investigate antidiabetic effect of the leaves of Combretum micranthum G. Don, a medicinal plant used for treating diabetes in Northwestern Nigeria.

Materials and methods

Three doses (100 mg/kg, 200 mg/kg and 400 mg/kg) of the aqueous leaf extract of Combretum micranthum were administered to normal glucose loaded, subdiabetic and diabetic rats.

Results

Of the doses tested, 100 mg/kg of the extract was the most effective. It produces a significant hypoglycaemic and antidiabetic activity comparable to the effect of standard drug (0.6 mg/kg glibenclemide).

Conclusion

This study demonstrated the potential antidiabetic property of aqueous leaf extract of Combretum micranthum thus justifying its traditional usage.     

Antidiabetic activity of Paspalum scrobiculatum Linn. in alloxan induced diabetic rats

Ethnopharmacological relevance

Paspalum scrobiculatum Linn. (Poaceae) is traditionally used to treat diabetes mellitus. The grains of Paspalum scrobiculatum are having potential in the development of drug for diabetes due to their antidiabetic activity.

Aim of the study

To evaluate the antidiabetic activity of aqueous and ethanolic extracts of grains of Paspalum scrobiculatum Linn. (Poaceae) in alloxan induced diabetic rats.

Materials and methods

Aqueous and ethanolic extracts (250 and 500 mg/kg body weight), were administered orally to male Wistar albino rats. Alloxan monohydrate was used to induce diabetes mellitus. Total phenolic content was estimated in the extracts. The parameters studied included oral glucose tolerance test, fasting blood glucose, serum insulin and glycated haemoglobin levels, liver glycogen content, serum lipid profile, and changes in body weights.

Results

In oral glucose tolerance test, reduction of fasting blood glucose levels took place from 60 min of extract administration. The extracts produced a dose-dependent fall in fasting blood glucose (FBG). After 15 days of treatment with extracts the maximum reduction in FBG (35.14%) was observed in diabetic rats treated with ethanolic extract 500 mg/kg dose. A significant increase in serum insulin level was observed in the treated rats. Serum lipid levels were reversed towards near normal and a control in the loss of body weight was observed in treated rats as compared to diabetic control. The extract treatment also showed a significant increase in the liver glycogen and a significant decrease in glycated haemoglobin levels. The results demonstrate that Paspalum scrobiculatum possesses significant antidiabetic activity in diabetic rats.

Conclusion

The results suggest that Paspalum scrobiculatum has antidiabetic activity, thereby justifying its traditional claim and augmenting it into the present day systems of medicine.     

Antidiabetic effect of Ficus religiosa extract in streptozotocin-induced diabetic rats

Aims of study

In Indian traditional system of medicine, Ficus religiosa (Family Moraceae) is prescribed for the treatment of diabetes mellitus. In the present study, the antidiabetic effect of aqueous extract of Ficus religiosa bark (FRAE) was investigated in normal, glucose-loaded hyperglycemic and streptozotocin (STZ)-induced diabetic rats.

Materials and methods

Oral administration of FRAE at the doses of 25, 50 and 100 mg/kg was studied in normal, glucose-loaded and STZ-diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 and 100 mg/kg than 25 mg/kg. FRAE also showed significant increase in serum insulin, body weight and glycogen content in liver and skeletal muscle of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FRAE also showed significant antilipidperoxidative effect in the pancreas of STZ-induced diabetic rats. The antidiabetic effect of Ficus religiosa was compared with glibenclamide, a well-known hypoglycemic drug.

Conclusion

The results indicate that aqueous extract of Ficus religiosa bark possesses significant antidiabetic activity.     

Antidiabetic and antioxidant effects of Annona muricata (Annonaceae), aqueous extract on streptozotocin-induced diabetic rats

Ethnopharmacological relevance

The leaves of Annona muricata are used in Cameroon to manage diabetes and its complications. The aim of this study was to evaluate the antidiabetic, antioxidant activities and the potential toxicity of aqueous extract of Annona muricata in streptozotocin-induced diabetic rats.

Material and methods

Oral administration of Annona muricata aqueous extract (100 mg/kg or 200 mg/kg) was studied in normal and streptozotocin-induced diabetic rats. In long term treatment, 2 weeks after streptozotocin-induced diabetic rats, animals received plant extract during 28 consecutive days. For a protective effect, extract was administered 3 days prior to streptozotocin exposure and animals were observed 2 weeks without treatment.

Results

The plant extract was not effective in normal rats. In diabetic rats, single administration of the extract significantly reduced blood glucose levels by 75% and 58.22% respectively at the dose of 100 mg/kg and 200 mg/kg as compared to the initial value. Treatment of normal rats 3 days prior to diabetes induction showed that, Annona muricata extract has no effect within 72 h following STZ injection. However, after 14 days post-treatment, the extract at the dose of 100 mg/kg significantly reduced blood glucose levels as compared with initial value and diabetic control rats. Immunohistochemical staining of pancreatic β-cells of diabetic rats treated with the dose of 100 mg/kg expressed strong staining for β-cell compared to diabetic control. In a long-term study daily administration of Annona muricata aqueous extract for 28 days to diabetic rats, reduced blood glucose levels, serum creatinine, MDA, AST, ALT activity, and nitrite levels LDL-cholesterol. Total cholesterol, triglycerides, SOD, and CAT activity contents were restored.

Conclusion

These different results show that the antidiabetic activity of Annona muricata aqueous extract can be explained by its hypolipidaemic effect, its antioxidant and protective action on pancreatic β-cells, which in turn improve glucose metabolism.     

In vitro anti-breast cancer activity of ethanolic extract of Wrightia tomentosa: role of pro-apoptotic effects of oleanolic acid and urosolic acid

Ethnopharmacological relevance

Pterocarpus marsupium Roxb. (PM) is an Ayurvedic traditional medicine well known for its antidiabetic potential.

Aim

To fractionate the antidiabetic constituent(s) of the aqueous of extract of PM hardwood (PME).

Materials and methods

Bio-assay methods including, insulin secretion from mouse pancreas and glucose uptake by mouse skeletal muscle, were used to determine and fractionate the antidiabetic activity of PME. Results obtained from the in vitro experiments were then verified by examining the effect of PME on glucose clearance in normoglycemic, non-diabetic sheep in vivo.

Results

Exposure of mouse pancreatic and muscle tissues to PME stimulated the insulin secretion and glucose uptake, respectively, in a concentration-dependent manner. PME-mediated muscle glucose uptake was not potentiated in the presence of insulin indicating that PME acts via pathways which are utilized by insulin. Bio-assay-guided fractionation of PME yielded a high molecular weight fraction which had potent antidiabetic properties in vitro, and in in vivo.

Conclusions

Our findings, we believe for the first time, provide novel insights for the antidiabetic constituents of PM and demonstrate that a high molecular weight constituent(s) of PM has potent insulinotrophic and insulin-like properties.     

Antidiabetic effects of Justicia spicigera Schltdl (Acanthaceae)

Ethnopharmacological importance

Justicia spicigera is a plant species used for the Teenak (Huesteca Potosina) and Mayan (Yucatan peninsula) indigenous for the empirical treatment of diabetes, infections and as stimulant.

Aim of the study

To evaluate the cytotoxicity, antioxidant and antidiabetic properties of J. spicigera.

Materials and methods

The effects of ethanolic extracts of J. spicigera (JSE) on the glucose uptake in insulin-sensitive and insulin-resistant murine 3T3-F442A and human subcutaneous adipocytes was evaluated. The antioxidant activities of the extract of JSE was determined by ABTS and DPPH methods. Additionally, it was evaluated the antidiabetic properties of JSE on T2DM model.

Results

JSE stimulated 2-NBDG uptake by insulin-sensitive and insulin-resistant human and murine adipocytes in a concentration-dependent manner with higher potency than rosiglitazone 1 mM. JSE showed antioxidant effects in vitro and induced glucose lowering effects in normoglycemic and STZ-induced diabetic rats.

Conclusion

The antidiabetic effects of administration of J. spicigera are related to the stimulation of glucose uptake in both insulin-sensitive and insulin-resistant murine and human adipocytes and this evidence justify its empirical use in Traditional Medicine. In addition, J. spicigera exerts glucose lowering effects in normoglycemic and STZ-induced diabetic rats.     

Antidiabetic effects of Swertia macrosperma extracts in diabetic rats

Ethnopharmacological relevance

Swertia macrosperma is a traditional folk medicine used for its anti-hepatitis, antipyretic and antidotal effects as “Dida” or “Zangyinchen” in Tibet, Yunnan and Guizhou province for a long time, and it has been reported for its anti-diabetic effects in a Chinese patent. Swertia macrosperma was reported rich in xanthones, iridoids, seco-iridoids and their glycosides, several of which had been documented as potential antidiabetic agents. The objective of this study was to investigate the antidiabetic effect of Swertia macrosperma in diabetic rats.

Materials and methods

This study was designed firstly to evaluate the effect of Swertia macrosperma on glucose consumption in HepG2 cells. Based on the result in HepG2 cells, the antidiabetic effect of ethanol extract (EE) and n-butanol extract (BE) were investigated in diabetic rats induced by high fat fed and streptozotocin. The effects of EE and BE on fasting blood glucose, oral glucose tolerance test, serum insulin, glycosylated hemoglobin, serum lipid level, serum antioxidant parameters, glucokinase, glucose-6-phosphatase activities and glycogen content in liver tissue were measured, histology examination of pancreatic tissue was also carried out.

Results

After 4 weeks treatment with EE and BE, apparently decreased fasting blood glucose concentrations were observed in these treated groups, compared with the diabetic control groups. Additionally, improvement in serum antioxidant parameters and lipid profile were evidenced clearly. Moreover, EE and BE had effects of protecting the pancreatic β-cells and stimulating insulin secretion from the remaining pancreatic β-cells, evidenced by pancreatic histology examination. Increased glucokinase activity and decreased glucose-6-phosphatase activity were observed in liver.

Conclusion

The results of in vivo and in vitro experiment suggested that EE and BE of Swertia macrosperma had excellent effects on controlling the hyperglycemia and hyperlipidemia in diabetic rats.     

Ibervillea sonorae (Cucurbitaceae) induces the glucose uptake in human adipocytes by activating a PI3K-independent pathway

Ethnopharmacological relevance

Ibervillea sonorae (S. Watson) Greene (Cucurbitaceae), a plant used for the empirical treatment of type 2 diabetes in México, exerts antidiabetic effects on animal models but its mechanism of action remains unknown. The aim of this study is to investigate the antidiabetic mechanism of an Ibervillea sonorae aqueous extract (ISE).

Materials and methods

Non-toxic ISE concentrations were assayed on the glucose uptake by insulin-sensitive and insulin-resistant murine and human cultured adipocytes, both in the absence or the presence of insulin signaling pathway inhibitors, and on murine and human adipogenesis. Chemical composition of ISE was examined by spectrophotometric and HPLC techniques.

Results

ISE stimulated the 2-NBDGlucose uptake by mature adipocytes in a concentration-dependent manner. ISE 50 µg/ml induced the 2-NBDG uptake in insulin-sensitive 3T3-F442A, 3T3-L1 and human adipocytes by 100%, 63% and 33%, compared to insulin control. Inhibitors for the insulin receptor, PI3K, AKT and GLUT4 blocked the 2-NBDG uptake in murine cells, but human adipocytes were insensitive to the PI3K inhibitor Wortmannin. ISE 50 µg/ml also stimulated the 2-NBDG uptake in insulin-resistant adipocytes by 117% (3T3-F442A), 83% (3T3-L1) and 48% (human). ISE induced 3T3-F442A adipogenesis but lacked proadipogenic effects on 3T3-L1 and human preadipocytes. Chemical analyses showed the presence of phenolics in ISE, mainly an appreciable concentration of gallic acid.

Conclusion

Ibervillea sonorae exerts its antidiabetic properties by means of hydrosoluble compounds stimulating the glucose uptake in human preadipocytes by a PI3K-independant pathway and without proadipogenic effects.     

Isolation and characterization of a novel antihyperglycemic protein from the fruits of Momordica cymbalaria

Aim of the study

A new antihyperglycemic protein was identified in the aqueous extract of fruits of Momordica cymbalaria by bioassay-guided fractionation. The study was aimed at isolation and characterization of this protein.

Materials and methods

The active principle was purified to homogeneity by ammonium sulphate precipitation, gel filtration column chromatography on Sephadex G-50 followed by reverse phase HPLC. Its N-terminal amino acid sequence was identified and compared in the protein data bank. Optimum dose and route of administration of the active principle was determined in STZ induced diabetic rats.

Results

A 17 kDa protein with an isoelectric point of 5.0 was identified as the active principle of antidiabetic action present in the aqueous extract of fruits of MC. It is named as M.Cy protein and found to be a novel protein by comparing its N-terminal amino acid sequence with those in the protein data bank. It did not produce any hypoglycemia in either normal or diabetic rats.

Conclusions

The results suggest that ‘M.Cy protein’, present in the fruits of Momordica cymbalaria is an effective antihyperglycemic active principle in STZ induced diabetic rats at a dose of 2.5 mg/kg b.w.     

Antidiabetic and antioxidant activities of Toddalia asiatica (L.) Lam. leaves in Streptozotocin induced diabetic rats

Ethnopharmacological relevance

The leaves of Toddalia asiatica (L.) Lam. have been utilized traditionally for the cure of diabetes.

Aim of the study

The present study was aimed to assess the antidiabetic and antioxidant effects of T. asiatica leaves in Streptozotocin (STZ) induced diabetic rats.

Materials and methods

The phytochemical screening, total phenolic content, HPLC analysis, acute toxicity study and oral glucose tolerance test were carried out. Glucose lowering effect of the hexane, ethyl acetate and methanol extracts of T. asiatica leaves was studied in STZ-induced diabetic rats. The antidiabetic and antioxidant activities were studied for the ethyl acetate extract. The effects of extracts on blood glucose, body weight, plasma insulin, total protein, liver glycogen, plasma enzymes (SGOT, SGPT and ALP) and activities of SOD, CAT and GPx were analyzed.

Results

T. asiatica leaves ethyl acetate extract (TALEe) showed highly significant blood glucose lowering effect. Phytochemical evaluation of TALEe showed the presence of alkaloids, terpenoids, cumarins, flavonoids and phenolic compounds. The total phenolic content of TALEe was 126 mg of gallic acid equivalents/g extract. HPLC analysis revealed the presence of flindersine and ulopterol. Acute toxicity study of TALEe revealed no death or toxicity. The oral glucose tolerance test showed lowered area under curve (AUC_glucose) values in TALEe treated rats. After treatment with TALEe (250 and 500 mg/kg) for 28 days there was a significant decrease in blood glucose, plasma enzymes (SGOT, SGPT and ALP) and significant increase in body weight, total protein, serum insulin and liver glycogen levels in treated diabetic rats. The activities of antioxidant enzymes SOD, CAT and GPx were reversed to near normal in treated diabetic rats. Histopathology of pancreas in TALEe treated groups showed regeneration of β-cells.

Conclusion

The results of the experiments showed that TALEe exerted significant antidiabetic and antioxidant effects in STZ-induced diabetic rats justifying its traditional use.     

A bioactivity guided study on the antidiabetic activity of Juniperus oxycedrus subsp. oxycedrus L. leaves

Ethnopharmacological relevance

Juniperus (Cupressaceae) species are widely used as folk medicine in spreading countries. Decoction of Juniperus oxycedrus subsp. oxycedrus L. leaves is used internally to lower blood glucose levels in Turkey.

Aim of the study

To determine hypoglycaemic and antidiabetic activities of Juniperus oxycedrus subsp. oxycedrus leaves and to identify active compounds through bioactivity guided isolation technique.

Materials and methods

Ethanol and water extracts of Juniperus oxycedrus subsp. oxycedrus (Joso), leaves on oral administration were studied using in vivo models in normal, glucose-hyperglycemic and streptozotocin-induced diabetic rats. Through in vivo bioactivity-guided fractionation processes, a nonpolar fraction was separated from the n-hexane subextract by silica gel column chromatography as the main active fraction. Subfractions of this fraction was found to possess antidiabetic activity and their chemical composition was investigated by GC-FID and GC–MS, simultaneously.

Results

This is the first report on the antidiabetic constituents of Joso leaves. Fatty acids, such as palmitic, linoleic and linolenic acid were found as the major compounds in subfractions.

Conclusion

Results indicated that Joso leaf extract and its active constituents might be beneficial for diabetes mellitus.     

Hypoglycemic and antihyperglycemic effect of Witheringia solanacea in normal and alloxan-induced hyperglycemic rats

Aim of the study

Witheringia solanacea is a small shrub that belongs to the Solanaceae family. The plant is used as an antidiabetic in Costa Rican herbal medicine. The aim of this study was to evaluate the hypoglycemic and antihyperglycemic activity of the aqueous extract of W. solanacea leaves in rodent models.

Materials and methods

A crude extract of W. solanacea leaves was prepared in boiling water and the aqueous filtrate was lyophilized. A single oral dose of 250, 500 and 1000 mg/kg of the extract was evaluated for hypoglycemic activity in a glucose tolerance test in normal rats and for antihyperglycemic activity in alloxan-induced (140 mg/kg) diabetic rats. The blood glucose level was determined at different times by the glucose oxidase method.

Results

Dosage of 500 and 1000 mg/kg of the extract significantly decreased (p < 0.05) blood glucose levels in the glucose tolerance test in normal rats after 1 h, there was no significant difference observed at 250 mg/kg. Dose of 500 mg/kg of the extract significantly reduced (p < 0.05) blood glucose levels in alloxan induced hyperglycemic rats at 4 and 5 h.

Conclusions

In the present study, the hypoglycemic and antihyperglycemic potential of the W. solanacea was demonstrated in rats. These results give support to the traditional use of W. solanacea as antidiabetic herbal medicine.     

Fertility inducing effect of aerial parts of Coccinia cordifolia L. in female rats

Ethnopharmacological relevance

The aerial parts of Coccinia cordifolia L. are used to treat female infertility in West Bengal state of India.

Aim of the study

The present study was undertaken to evaluate the fertility inducing effect of aerial parts of Coccinia cordifolia L. in female rats.

Materials and methods

The effect of aqueous extract of Coccinia cordifolia L. on hyperprolactinemia induced infertility, endometriosis induced infertility and androgen-induced infertility was studied. The effect on serum estrogen level, serum progesterone level and reproductive tract was also evaluated in normal healthy female rats. The extract was administered orally at two different doses of 500 mg/kg and 1000 mg/kg.

Results

In hyperprolactinemia induced infertility model, the numbers of uterine implants were almost 10 times more in the extract treated groups as compared to control. The high dose of extract also produced a significant increase in serum estrogen levels (p < 0.01) and number of corpus luteum (p < 0.05) in healthy female rats. The extract at both doses was effective in reducing the weight of endometrial implants by 70–80%, but failed to induce fertility in rats with endometriosis. The extract was ineffective in inducing fertility in androgen-induced infertility model.

Conclusions

The aqueous extract of Coccinia cordifolia L. induces fertility in hyperprolactinemia induced infertility model in female rats.     

Leucas cephalotes regulates carbohydrate and lipid metabolism and improves antioxidant status in IDDM and NIDDM rats

Ethnopharmacological relevance

Leucas cephalotes (Roth.) Spreng. (Laminaceae) is an ayurvedic traditional medicinal plant used in India, Nepal and Pakistan to treat several ailments including diabetes.

Aim of the study

The aim of the present study is to investigate the antidiabetic, antihyperlipaemic and antioxidant activities of Leucas cephalotes for its purported use in diabetes.

Materials and methods

The ethanol extract of leaves of Leucas cephalotes was administered (150, 300 and 450 mg kg⁻¹ bw) to diabetes induced (IDDM and NIDDM) rats and carbohydrate, lipid, antioxidant, urea and creatinine profiles were assessed.

Results

All the three doses of extract decreased plasma glucose and lipid profiles and, improved the antioxidant status of both types of diabetic rats. The extract administration improved hepatic glycogen content and hexokinase activity, decreased glucose-6-phosphatase activity, blood urea, creatinine contents and decreased lipid peroxidation in diabetic rats. Of the three doses used, 450 mg kg⁻¹ bw dose was found to be more potent in its effects comparable to those of glibenclamide and metformin.

Conclusion

Leucas cephalotes regulates both carbohydrate and lipid metabolism and, improves body antioxidant defense systems in both types of diabetes.     

Phenological and geographical influence in the concentration of selected bioactive 4-phenylcoumarins and chlorogenic acid in Hintonia latiflora leaves

Ethnopharmacological relevance

Hintonia latiflora is a Mexican medicinal plant with well-documented ethnomedical record comprising more than 400 years; in modern Mexico is used for treating several maladies such as diabetes and gastric ulcers. Although the pharmacological actions of the stem-bark and leaves have been demonstrated, the phenological and geographical effect on the concentration of active principles remains unexplored.

Aim of the study

The main goals of this study were to analyze the amount of selected 4-phenylcoumarins and chlorogenic acid in the leaves in order to assess the best harvesting period, and consequently their pharmacological efficacy. In addition, the preclinical antidiabetic efficacy of the infusion of the leaves was corroborated using standard pharmacological tests.

Materials and methods

The aqueous extracts from the leaves of Hintonia latiflora were prepared by infusion. For phenological and geographical comparison, leaves of Hintonia latiflora were collected in two different regions in Chihuahua and Michoacán. The material was analyzed by UPLC applying an analytical method that developed and validated for this purpose following the ICH guidelines. Investigation of the antidiabetic action was accomplished using an acute hypoglycemic test and oral glucose and sucrose tolerance tests.

Results

The validated analytical method was successfully applied for quantifying chlorogenic acid (1) and 4-phenylcoumarins (2–5) in the leaves of 12 different batches (1–12) during one-year period, and seven different batches for each geographical region; the concentration of the metabolites at the phenological cycle was significantly different, their concentration increased during the pre-senescence phase whereas in the leaf renovation stage the highest concentration of 2–5 was reached. The overall analysis of the active compounds concentration between the two populations investigated seems to be less important than the phenological variations. The aqueous extract of the leaves of Hintonia latiflora exerted its antidiabetic effect by different mechanisms showing comparable effect to the organic extract.

Conclusions

The findings of the present investigation reveal that the best harvest season for the leaves of Hintonia latiflora is between the leaves renovation and senescence stages avoiding the flowering period. In addition, no significant differences were found among the two different geographical populations analyzed. The infusions of the leaves, rich in 4-phenylcoumarins and chlorogenic acid, showed comparable antidiabetic action than the organic extract.     

Antidiabetic, anti-oxidant and antimicrobial activities of Fadogia ancylantha extracts from Malawi

Ethnopharmacological relevance

Communities in Chilumba, Malawi use herbal tea prepared from Fadogia ancylantha Schweinf (Rubiaceae) leaves for the management of diabetes, hypertension and alleviation of symptoms of gastrointestinal disorders and pneumonia. The objective of the study was to evaluate the in vitro antidiabetic, anti-oxidant and antimicrobial activities of the crude extracts of the leaves prepared by using three different extraction methods.

Materials and methods

Each of the organic, cold and hot aqueous extracts of the herbal tea was evaluated for its effect on glucose uptake in C2C12 muscle and Chang cell lines. Metformin and insulin were used as positive controls. The anti-oxidant activity, based on neutralisation of DPPH free radicals, was determined spectrophotometrically. The Agar serial dilution method was utilised to determine the minimum inhibitory concentration (MIC) of the extracts for the selected fungal and bacterial strains.

Results and discussion

The organic extract (12.5 μg/ml) exhibited the highest in vitro glucose uptake increases in Chang cells (181.24±0.29%) and C2C12 muscle cells (172.29±0.32%) while the hot and cold aqueous extracts gave lower uptakes, 145.94±0.37% and 138.70±0.52% in Chang cells respectively. At 100 μg/ml, aqueous extracts gave significantly higher (p<0.01) anti-oxidant activity (range 85.78–86.29%) than their organic counterpart (68.16%). The minimum inhibitory concentration (156 μg/ml) was obtained in the organic extract against the fungus Aspergillus fumigatus and moderate growth inhibition was observed with other test micro-organisms. The hot aqueous extract inhibited the growth of all test organisms except Pseudomonas aeruginosa. The cold aqueous extract was inactive against Pseudomonas aeruginosa and Candida albicans. The differences in the MIC values between the aqueous extracts seem to suggest that raised temperatures, as traditionally practised, facilitate the extraction of secondary bioactive metabolites.

Conclusion

These results show that Fadogia ancylantha extracts have high antidiabetic and anti-oxidant properties.     

Sarcopoterium spinosum extract as an antidiabetic agent: In vitro and in vivo study

Ethnopharmacological relevance

Sarcopoterium spinosum (L.) sp., a common plant in the Mediterranean region, is widely used as an antidiabetic drug by Bedouin healers. However, the antidiabetic properties of Sarcopoterium spinosum had not been fully validated using scientific tools.

Aim of the study

To determine the effectiveness of Sarcopoterium spinosum extract as an antidiabetic agent in vitro and in vivo.

Materials and methods

RINm pancreatic β-cells, L6 myotubes, 3T3-L1 adipocytes and AML-12 hepatocytes were treated with an aqueous Sarcopoterium spinosum extract (0.001–10 mg/ml). The effect of the extract on specific physiological functions, including insulin secretion, pancreatic β-cell viability, GSK3β phosphorylation, lipolysis and glucose uptake was measured. In vivo studies were performed using KK-A^y mice, given the extract for several weeks. IPGTT was performed, and plasma insulin, FFA, food consumption and body weight were measured. In addition, diabetic KK-A^y mice were given a single dose of the extract, and IPGTT was performed.

Results

Sarcopoterium spinosum extract increased basal and glucose/forskolin-induced insulin secretion in RINm cells, and increased cell viability. The extract inhibited lipolysis in 3T3-L1 adipocytes, and induced glucose uptake in these cells as well as in AML-12 hepatocytes and L6 myotubes. GSK3β phosphorylation was also induced in L6 myotubes, suggesting increased glycogen synthesis. Sarcopoterium spinosum extract had a preventive effect on the progression of diabetes in KK-A^y mice. Catechin and epicatechin were detected in Sarcopoterium spinosum extract using hyphenated LC–MS/MS.

Conclusions

Sarcopoterium spinosum extract has effects that mimic those of insulin and provide the basis for antidiabetic activity of the extract.     

Anti-diabetic activity of extract from Persea americana Mill. leaf via the activation of protein kinase B (PKB/Akt) in streptozotocin-induced diabetic rats

Ethnopharmacological relevance

The leaves of Persea americana Mill. (Lauraceae) have been popularly used in the treatment of diabetes in countries in Latin America and Africa.

Aim of the study

To investigate the hypoglycaemic properties and to determine the molecular mechanism by which the hydroalcoholic extract of the leaves of Persea americana reduce blood glucose levels in streptozotocin (STZ)-induced diabetes in rats via the enzymatic pathway of protein kinase B (PKB/Akt).

Methods

The hydroalcoholic extract of the leaves of Persea americana (0.15 and 0.3 g/kg/day), vehicle and metformin (0.5 g/kg/day) were administered orally to STZ-diabetic rats (n = 7/group) for 4 weeks. Changes in body weight, food and water intake, fasting glucose levels and oral glucose tolerance were evaluated. Phosphorylation and the expression of PKB in the liver and soleus muscle were determined by Western blot.

Results

The hydroalcoholic extract of the leaves of Persea americana reduced blood glucose levels and improved the metabolic state of the animals. Additionally, PKB activation was observed in the liver and skeletal muscle of treated rats when compared with untreated rats.

Conclusion

The results indicate that the hydroalcoholic extract of the leaves of Persea americana has anti-diabetic properties and possibly acts to regulate glucose uptake in liver and muscles by way of PKB/Akt activation, restoring the intracellular energy balance.     

Antidiabetic and antioxidant potential of Emblica officinalis Gaertn. leaves extract in streptozotocin-induced type-2 diabetes mellitus (T2DM) rats

Ethnopharmacological relevance

In traditional Indian medicine, all parts of Emblica officinalis Gaertn plant including the fruit, seed, leaves, root, bark and flowers are used in various herbal preparations for the treatment of diabetes mellitus, chronic diarrhea, anti-inflammatory and antipyretic.

Aim of the study

To evaluate the hypoglycemic and antioxidants effects of the hydro-methanolic (20:80) extract of leaves of Emblica officinalis Gaertn. (HMELEO) in streptozotocin induced diabetic rats.

Material and methods

The hypoglycemic effect was measured by blood glucose and plasma insulin level. The oxidative stress was measured in liver and kidney by level of antioxidant markers i.e. lipid peroxidation (LPO), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT), and the biochemical parameters, i.e. blood serum levels of creatinine, urea, serum glutamic pyruvic transaminases (SGPT), serum glutamic oxaloacetic transaminases (SGOT), alkaline phosphatase (ALP), total cholesterol and triglyceride levels were the salient features observed in diabetic control and treated rats.

Results

Oral administration of the HMELEO at a concentration of 100, 200, 300 and 400 mg/kg b.w. daily for 45 days showed a significant (P<0.05) decrease in fasting blood glucose and increase insulin level as compared with the diabetic rats. Also it significantly (P<0.05) reduced all biochemical parameters (serum creatinine, serum urea, SGOT, SGPT and lipid profile). The treatment also resulted in a significant (P<0.05) increase in reduced glutathione, glutathione peroxidase, superoxide dismutase, catalase, and decrease LPO level in the liver and kidney of diabetic rats.

Conclusion

The results clearly suggest that the hydro methanolic extract of leaves of Emblica officials Gaertn. treated group may effectively normalize the impaired antioxidant status in streptozotocin induced diabetes at dose dependent manner than the glibenclamide-treated groups. The extract exerted rapid protective effects against lipid peroxidation by scavenging of free radicals and reducing the risk of diabetic complications.