Antihyperglycemic,antihyperlipidemic and antioxidant effects of ethanol and aqueous extracts of Cyclocarya paliurus leaves in type 2 diabetic rats

Ethnopharmacological relevance

Cyclocarya paliurus (CP) Batal., the sole species in its genus and native to China, is a herbal tea, which has been traditionally used in the folk medicine for the treatment of diabetes and hyperlipidemia in China. To evaluate the antihyperglycemic, antihyperlipidemic and antioxidant effects of ethanol and aqueous extracts from CP in high fat diet (HFD) and streptozotocin (STZ) induced diabetic rats.

Materials and methods

Type 2 diabetes was induced in 140 rats by feeding with HFD and high sugar water for 6 weeks and single injection of STZ (30 mg/kg, intraperitoneally). CP ethanol extract (CPEE) and aqueous extract (CPAE) at three doses at 2, 4 and 8 g/kg/day were orally administered once daily for four weeks. Blood glucose, serum insulin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), free fatty acid (FFA), total cholesterol (TC), triglyceride (TG), low density lipoprotein–cholesterol (LDL–C), high density lipoprotein–cholesterol (HDL–C), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), blood urea nitrogen (BUN), creatinine (CREA) and glycated serum protein (GSP) were examined. The content of total flavonoids and polysaccharides in CPEE and CPAE were assayed by ultraviolet spectrophotometry.

Results

Both CPEE and CPAE increased OGTT, ITT, HDL–C, SOD and GSH-Px, while they decreased FFA, TC, TG, LDL–C, MDA, BUN, CREA and GSP. The amount of total flavonoids was found in CPEE (30.41 mg/g extract), followed by CPAE (6.75 mg/g extract). Similarly, the polysaccharides content (4.13 mg/g extract) was observed in CPAE, while absent in CPEE.

Conclusions

The results suggested that CPEE and CPAE exhibited the similar antihyperglycemic, antihyperlipidemic and antioxidant effects in type 2 diabetic rats, and there were no significant differences between these two extracts.     

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.     

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.     

Antihyperglycemic and insulin secretory activity of Costus pictus leaf extract in streptozotocin induced diabetic rats and in in vitro pancreatic islet culture

Aim of the study

The leaves of Costus pictus D. Don were used extensively for its antihyperglycemic activity by the people in Kerala, India. In the present study, the antihyperglycemic and insulin secretory activity of an aqueous extract of Costus pictus leaf extract was investigated in streptozotocin induced diabetic rats.

Materials and methods

Oral Glucose Tolerance Test was done to determine the effective dose of Costus pictus extract. Aqueous extract of Costus pictus leaves was given orally to the diabetic rats for 14 days. The insulin secretory action of the leaf extract was investigated using isolated pancreatic islets from rat. Liver glucose uptake activity was measured using d-[¹⁴C] glucose.

Results

The oral administration of an aqueous extract of Costus pictus at a dose of 250 mg/kg body weight significantly decreased the blood glucose with significant increase in plasma insulin level in diabetic rats at the end of 14 days treatment. The Costus pictus leaf extract significantly increased glucose induced insulin secretion at both 4 mM and 20 mM glucose concentrations which represents normal physiological and diabetic condition respectively. The decreased glucose uptake activity of the liver of diabetic rats was reverted to near normal levels after the treatment with Costus pictus leaf extract.

Conclusion

Our results suggest the glucose lowering effect of Costus pictus to be associated with the potentiation of insulin release from pancreatic islets and enhancement of peripheral utilization of glucose.     

Withanolides from Whitania aristata and their diuretic activity

Aim of the study

Withania aristata is an endemic plant used traditionally in Canary Islands as a diuretic. In this paper, we report on this pharmacological activity in several extracts of the dry vegetal material collected and the identification and diuretic activity of two withanolides, one of them previously not reported, isolated from the most active fraction.

Material and methods

Four Whitania aristata extracts at 100 mg/kg were orally administered to laboratory animals to evaluate their diuretic activity. From the most active fraction, two withanolides were isolated. Both and a mixture of them at 5 and 10 mg/kg were analyzed too as diuretics. Water excretion rate and content of Na⁺ and K⁺ electrolytes were measured in the urine of saline-loaded animals.

Results

Whitania aristata water fraction, the two withanolides and the mixture of these compounds displayed high diuretic activity, with a significant excretion of sodium and potassium ions in laboratory animals.

Conclusions

This research supports the ethno-medicinal use of Whitania aristata as diuretic. This activity seems to be associated to the presence of a new type of natural diuretic agents, such as withaferin A and witharistatin.     

Antidiabetic and antioxidant effect of various fractions of Phyllanthus simplex in alloxan diabetic rats

Aim of the study

To evaluate the antidiabetic and antioxidant effects of various fractions of Phyllanthus simplex on alloxan induced diabetes in rats.

Materials and methods

Hypoglycemic effect of Phyllanthus simplex fractions was evaluated in normal and diabetic rats. Diabetes was induced by intraperitoneal injection of alloxan monohydrate (120 mg/kg). Normal and diabetic rats were divided into different groups (six rats each group) and orally administered with petroleum ether (P.E.) (200 and 400 mg/kg), ethyl acetate (EtOAc) (100 and 200 mg/kg), methanol (125 and 250 mg/kg), water fraction (150 and 300 mg/kg) and glibenclamide (10 mg/kg) for 21 days. Blood samples were collected from overnight fasted normal rats on day 21, from overnight fasted diabetic rats at 7, 14 and 21 days of treatment and analyzed for blood glucose level. On day 22 blood samples were collected from diabetic rats to estimate biochemical parameters, rats were sacrificed by single stunning and tissues were excised to measure their antioxidant and glycogen status.

Results

In the normoglycemic rats, MeOH (125 and 250 mg/kg) and aqueous fractions (150 and 300 mg/kg) showed a significant (P < 0.05) hypoglycemic effect on day 21. In diabetic control rats, MeOH (125 and 250 mg/kg) and aqueous fractions (150 and 300 mg/kg) showed significant antihyperglycemic effect (P < 0.001). The active fractions (MeOH and aqueous) of Phyllanthus simplex also increased the body weight of diabetic rats significantly compared to the control group. The active fractions were able to normalize the marked alterations in antioxidant enzymes and antioxidant parameters levels in liver and kidney. Treatment with the active fractions also normalized the diabetic induced hyperlipidemia and liver glycogen.

Conclusions

These results demonstrate the antidiabetic and antioxidant potential of fractions of Phyllanthus simplex and suggests that the plant may have therapeutic value in diabetes and related complications.     

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.     

Antihyperglycemic activity of kinsenoside, a high yielding constituent from Anoectochilus roxburghii in streptozotocin diabetic rats

Different doses of kinsenoside, a high yielding constituent from Anoectochilus roxburghii, was orally administered to further investigate its biological activity and pharmacological mechanisms that involve in the hypoglycemic effect on streptozotocin (STZ) diabetic rats. Our study showed that this compound exhibited significantly antihyperglycemic activity at the dose of 15mg/kg body weight, which is speculated to be partially attributed to modulating the activity of enzymatic antioxidants, scavenging free radicals, and reducing the content of factor NO. Much more intact beta cells in the islets of Langerhans with denser insulin in kinsenoside-treated groups than the negative control were observed, which greatly supported the morphological and functional elucidation. These results displayed that kinsenoside could be useful for repairing beta cells in pancreatic islet injury as well as improving its function. The OGTT evidenced that this compound could promote the glucose tolerance of acute glucose increase in both diabetic and normal healthy rats.     

Hypoglycemic effects of Cecropia pachystachya in normal and alloxan-induced diabetic rats

Ethnopharmacological relevance

Leaves of Cecropia pachystachya are described in the folk medicine as possessing antitusive, expectorant, antiasthmatic and hypoglycemic effects.

Aim of the study

To investigate the hypoglycemic and antioxidant effects of methanolic extract from the leaves of Cecropia pachystachya. The total amount of phenolic and flavonoids compounds was determined and the qualitative composition of the extract was analyzed.

Materials and methods

The hypoglycemic effect of the extract was tested in normal, glucose loading and alloxan-induced diabetic rats. The antioxidant activity was assessed by DPPH free radical scavenging and reduction power assays. The total amount of phenolic and flavonoids compounds was determined by Folin-Denis and AlCl₃ reagent method, respectively. The qualitative composition of the extract was analyzed using a HPLC-DAD system.

Results

The glucose tolerance test showed that in diabetic rats, the extract caused a significant hypoglycemic effect with a blood glucose reduction of 68% after 12 h. The administration of the extract in alloxan-induced diabetic rats also produced a significant reduction in the blood glucose levels at all points being more pronounced at 90 min (reduction of 60%). After 120 min, no significant difference was observed between the blood levels of the rats treated with the extract and those treated with the standard drugs (metformin and glibenclamide). The extract also presented relevant antioxidant activity with IC₅₀ = 3.1 μg/ml (DPPH assay) and EC₅₀ = 10.8 μg/ml (reduction power). Results were compared with the reference antioxidants quercetin, rutin, and ascorbic acid. The content of flavonoids was 83 mg/g plant and that of phenolics was 326 mg/g plant. Chlorogenic acid and the C-glycosylated flavones, orientin and isoorientin, were identified in the extract.

Conclusions

In conclusion, the findings showed that the folk medicinal plant Cecropia pachystachya possesses hypoglycemic and antioxidant effects which confirmed the traditional use of the plant in the treatment of diabetes. Chlorogenic acid and the C-glycosylated flavonoids may explain these activities.     

In vitro and in vivo hepatoprotective and antioxidant activity of ethanolic extract from Meconopsis integrifolia (Maxim.) Franch

Ethnopharmacological relevance

Meconopsis integrifolia (Maxim.) Franch is a high mountain endemic species used as a traditional Tibetan and Mongolian herb to treat hepatitis, pneumonia, and edema. This study aims to investigate the hepatoprotective and antioxidant effects of Meconopsis integrifolia ethanolic extract (MIE) in vitro and in vivo.

Materials and methods

The in vitro antioxidant property of MIE was investigated by employing various established systems. Rats with carbon tetrachloride (CCl₄)-induced liver injury were used to assess the hepatoprotective and antioxidant effect of MIE in vivo. The level or activity of alkaline phosphatase (ALP), glutamate pyruvate transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TB) in the blood serum and thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) in the liver and kidney of the rats were assayed using standard procedures.

Results

MIE exhibited strong antioxidant ability in vitro. In the rats with CCl₄-induced liver injury, the groups treated with MIE and silymarin showed significantly lower levels of ALT, AST, ALP, and TB. MIE demonstrated good antioxidant activities in both the liver and kidney of the rats in vivo.

Conclusions

MIE exhibits excellent hepatoprotective effects and antioxidant activities in vitro and in vivo, supporting the traditional use of Meconopsis integrifolia in the treatment of hepatitis.     

Hepatoprotective and antioxidant effects of the methanolic extract from Halenia elliptica

Aims of study

Halenia elliptica, a medicinal herb of Tibetan origin, was commonly used in folk medicine to treat hepatitis. The aim of the present study is to evaluate the hepatoprotective and antioxidant activity of Halenia elliptica against experimentally induced liver injury.

Materials and methods

The antioxidant property of methanolic extract (ME) of Halenia elliptica was investigated by employing various established in vitro systems. The ME of Halenia elliptica was studied here for its hepatoprotective effects against CCl₄-induced liver toxicity in rats. Activity was measured by monitoring the levels of alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin.

Results

The ME possessed strong antioxidant activity in vitro. The results of CCl₄-induced liver toxicity experiment showed that rats treated with the ME of Halenia elliptica (100 mg/kg and 200 mg/kg), and also the standard treatment, silymarin (50 mg/kg), showed a significant decrease in ALT, AST, ALP, and total bilirubin levels, which were all elevated in the CCl₄ group (p < 0.01). The results observed after administration of 100 mg/kg ME were comparable to those of silymarin at 50 mg/kg (p > 0.05). The ME did not show any mortality at doses up to 2000 g/kg body weight.

Conclusion

These results seem to support the traditional use of Halenia elliptica in pathologies involving hepatotoxicity, and the possible mechanism of this activity may be due to strong free radical-scavenging and antioxidant activities of ME.     

Orofacial antinociceptive effect and antioxidant properties of the hydroethanol extract of Hyptis fruticosa salmz ex Benth

Ethnopharmacological relevance

Hyptis fruticosa is a plant native to Brazil with antinociceptive and antiinflamatory properties. This study evaluated the antinociceptive activity of the hydroethanol extract of the plant leaves (CHEE) against orofacial pain as well as its in vitro effect against lipid peroxidation.

Materials and methods

The antinociceptive activity was investigated in mice orally treated with different doses of the CHEE (50, 100, and 200 mg/kg) and morphine (5 mg/kg) using formalin, glutamate, and capsaicin orofacial pain models using. Lipoperoxidation was induced in egg yolk by AAPH and FeSO₄ in the absence and presence of the CHEE (5, 50, 100, and 150 μg/mL).

Results

CHEE (200 mg/kg) significantly reduced (ρ<0.001) the pain response in the first (69.6%) and second (81.8%) phases of the formalin test, while the nociception caused by capsaicin was significantly (ρ<0.001) reduced by up to 62% at 200 mg/kg of extract. When glutamate was used as algogen, a significant (ρ<0.001) nociception reduction of up to 85% at 200 mg/kg extract was observed. CHEE showed a higher protection against lipoperoxidation caused by FeSO₄ (82.3% TBARS inhibition) than AAPH (35.7% TBARS inhibition) at 150 μg/mL.

Conclusion

Hyptis fruticosa leaf CHEE is of pharmacological interest because it was able to inhibit the peripheral and central transmission of orofacial pain, while reducing the spreading of the inflammatory processes by neutralizing reactive oxygen species, which are by-products in the biosynthesis of pain mediators.     

Anti-osteoporotic activity of aqueous-methanol extract of Berberis aristata in ovariectomized rats

Ethnopharmacological relevance

Traditionally Berberis aristata is employed for its supposed properties in treatment of joint pain and also used in alleviating symptoms of menopause.

Aim of the study

The aim of the present study is to evaluate the antiosteoporotic effect of Berberis aristata in ovariectomized (OVX) rats.

Materials and methods

Sprague-Dawley rats were divided into sham and OVX groups. The OVX rats were further divided into four groups, which received standard estrogen (0.0563 mg/kg) and 100, 300, and 500 mg/kg aqueous-methanol extract of Berberis aristata, daily for 42 days. The uterine weight, bone loss, ash content, biomechanical, biochemical and histopathological observation were carried out for antiosteoporotic activity.

Results

The experimental animals treated with Berberis aristata aqueous-methanol extract showed dose dependent activity. The significant increase in uterine weight, femur BMD, ash content and lumbar hardness were observed. In addition, increased levels of calcium and phosphorus in serum and significant decreased in urine were observed as compared to control OVX group. The histopathological results also confirm the protective effect of extract.

Conclusion

The present findings strongly suggest that Berberis aristata possess the potent antiosteoporosis activity in ovariectomized rats and substantiates the ethnic use in treatment of postmenopausal osteoporosis.     

Antidiabetic activity of Ficus amplissima Smith. bark extract in streptozotocin induced diabetic rats

Ethnopharmacological relevance

Ficus amplissima commonly known as kal-itchchi have a long history of use in Ayurveda, Siddha and Unani herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim

The aim of the present study was to evaluate the effect of methanolic extract of the bark of Ficus amplissima (FAB) in streptozotocin-induced diabetic rats.

Materials and methods

Oral administration of FAB bark at the doses of 50 mg/kg, 100 mg/kg and 150 mg/kg was studied in normal, glucose-loaded and STZ—induced diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 mg/kg and 100 mg/kg than 150 mg/kg. FAB also showed significant increase in serum insulin and body weight. The glycogen content in liver, skeletal muscle, total protein contents were markedly increased and marker enzymes of hepatic function of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FAB also showed significant anti-lipid peroxidative effect in the pancreas of STZ-induced diabetic rats. The anti-diabetic effect of FAB was compared with glibenclamide, a well known hypoglycemic drug. Histological analysis showed the regenerative effect of FAB on the β-cells of diabetic rats.

Conclusion

Results of this experimental study indicated that FAB possessed anti-diabetic and antioxidant activities. Hence it could be used as a natural source of antidiabetic (Type-I) and antioxidant drug.     

Anti-diabetic activity of Swertia corymbosa (Griseb.) Wight ex C.B. Clarke aerial parts extract in streptozotocin induced diabetic rats

Ethnopharmacologicals relevance

Swertia corymbosa locally called as Shirattakuchi have a long history of use in Ayurveda herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim of the study

The present study aimed to investigate the effect of the methanolic extract of Swertia corymbosa (SC) in diabetic and to analyze its chemical composition by HPLC–ESI/MS that may correlate with their pharmacological activities.

Materials and methods

The in vitro anti-diabetic activity of the extracts was measured by using α-glucosidase and α-amylase enzyme inhibitory activity. The methanolic extract of Swertia corymbosa were administered orally (125, 250 and 500 mg/kg, for 28 days) to streptozotocin-induced diabetic rats. Hypoglycemic effects, oral glucose tolerance test, change in body weight and lipid profile, biochemical analysis and histopathological examination were assessed. High-performance liquid chromatography–electrospray ionization/mass spectrometry (HPLC–ESI/MS) method was also developed to analyze the chemical composition.

Results

In vitro anti-dabetic study, the methanol extract of SC is found to be a potent inhibitor of α-glucosidase and α-amylase activity. Oral administration of SC and standard drug for 28 days caused a significant decrease in the concentrations of blood glucose level, total cholesterol (TC), serum triglycerides (TGs), low-density lipoprotein-cholesterol (LDL-C), malondialdehyde (MDA) and significant increase in the concentrations of high density lipoprotein-cholesterol (HDL-C), serum insulin and body weight. Furthermore, activities of antioxidative enzymes, including SOD, GPx, GSH and CAT were enhanced dosed dependently with SC. Histopathological studies of the pancreas showed the regeneration of the β-cells by extract which were earlier necrosed by streptozotocin. Ten major compounds such as loganic acid (1), swertiamarin (2), sweroside (3), gentiopicroside (4), isovitexin (5), amoroswertin (6), amarogentin (7), gentiacaulein (8), decussatin (9) and swertianin (10) were analyzed by HPLC–ESI/MS system.

Conclusions

These results demonstrate that SC aerial parts of methanolic extract is an effective anti-diabetic and antioxidant activities which provides the scientific proof for the folklore medicine.     

Trapa natans L. root extract suppresses hyperglycemic and hepatotoxic effects in STZ-induced diabetic rat model

Ethnopharmacological relevance

Trapa natans L. has a folkloric reputation as nutrient, appetizer and astringent. Its utility as antidiabetic, anticancer, diuretic, aphrodisiac, antidiarrhoeal and in many other maladies is well reported in the literature. Therefore, the present study has been carried out to study the antihyperglycemic effect of root extract of Trapa natans L. and its various fractions. Furthermore, hepatotoxic effects and lipid peroxidation risks have also been evaluated.

Methods

The ethanol extract and its successive fractions obtained from roots of Trapa natans have been administered in sucrose loaded and STZ- induced diabetic Wistar rats at doses of 50, 100 and 200 mg/kg b.w. Glibenclamide was used as positive control. The evaluation of protective effects of extract as well as fractions against hepatotoxicity and lipid peroxidation at 600 mg/kg b.w. has also been carried out.

Results

The methanol fraction emerged as the most potent antihyperglycemic fraction. It has also been found that the ethanolic extract as well as its fractions did not cause any lipid peroxidation and hepatotoxicity risks.

Conclusion

It can be concluded that the intense investigations of the methanol fraction obtained from Trapa natans root extract can be done to provide an alternative natural therapy for hyperglycemia.     

Anti-hyperglycemic effect,inhibition of inflammatory cytokines expression,and histopathology profile in streptozotocin-induced diabetic rats treated with Arracacia tolucensis aerial-parts extracts

Ethopharmacological relevance

Arracacia tolucensis is a medicinal plant used in northeast of Mexico as a remedy to treat people with Diabetes mellitus (DM); however, there are no scientific studies that support this information. Thus, we evaluated the anti-hyperglycemic effect of the hexane, ethyl acetate and ethanol extracts from aerial parts in streptozotocin-induced diabetic rats.

Materials and methods

DM was induced in Wistar male rats by single intraperitoneal injection of streptozotocin (STZ 50 mg/kg). After STZ-induction, hyperglycemic rats were treated with all three extracts orally at a single dose (250 mg/kg) each 48 h for 21 days. Glibenclamide (1 mg/kg) was used as a reference drug. The fasting blood glucose levels, the hematic biometry and biochemical profiles, and the inhibition of inflammatory cytokines expression were estimated. Histopathology analysis of pancreas, liver, spleen, and kidney tissue was carried out.

Results

Ours results showed that ethyl acetate extract decreased blood glucose levels significantly (75%, p< 0.05) when compared to diabetic rats and controlled the body weight loss; the lipids level did not change, but the enzyme levels of aspartate aminotransferase and alanine aminotransferase decreased significantly (60.83% and 66.16%, respectively, p< 0.05) and inhibited the expression of inflammatory cytokines,with respect to diabetic rats. Histopathology injury was not observed; by contrast repair of islet of Langerhans was exhibited.

Conclusion

These results validate the use of Arracacia tolucensis as a treatment against DM and suggests it is suitable to continue studies for its safe therapeutic use.     

Antihyperglycemic effects of total flavonoids from Polygonatum odoratum in STZ and alloxan-induced diabetic rats

Aim of the study

Total flavonids of Polygonatum(P) odoratum (TFP) were tested for anti-diabetic activity in streptozotocin (STZ)-induced diabetic mice and alloxan-induced diabetic rats.

Materials and methods

Rhizoma Polygonati Odorati, well-known Chinese traditional medicine, is widely used for treatment of diverse diseases for example diabetes. In our study, TFP was extracted by 70% ethanol and purified by macroreticular resin. The experiments were designed to detect the anti-diabetic activity of TFP by determination of blood glucose (BG) using one touch gluco-meter and insulin levels by using a radioimmunoassay kit in streptozotocin (STZ)-induced diabetic mice and alloxan-induced diabetic rats and alpha-amylase inhibitory activity by alpha-amylase inhibition assay in vitro.

Results

TFP had beneficial effects on regulation of blood glucose. Daily administration with 50–200 mg/kg body weight of TFP for 9 days can reduce significantly hyperglycemia in STZ-induced diabetic mice. Thirtieth day administration with TFP (50–200 mg/kg body weight) also decreased significantly fasting blood glucose in alloxan-induced diabetic rats. The hypoglycemic effect of TFP at 50 and 100 mg/kg is less than that of acarbose 20 mg/kg and gliclazide 15 mg/kg. The hypoglycemic effects of TFP at 200 mg/kg is similar to that of acarbose 20 mg/kg and gliclazide 15 mg/kg. TFP also could increase significantly the insulin level in alloxan-induced type 2 diabetic rats (P < 0.05) compared with control. Alpha-amylase inhibition assay in vitro showed that TFP inhibited significantly alpha-amylase activity in a dose-dependent manner.

Conclusions

TFP possess significant dose-dependent anti-diabetic activity. TFP is one of the primary hypoglycemic active compounds of Polygonatum odoratum which would worth further study and development.     

Antioxidant and anti-inflammatory activities of aqueous extract of Centipeda minima

Ethnopharmacological relevance

Centipeda minima (L.) is traditionally used in Chinese folk medicine for the treatments of rhinitis, sinusitis, relieving pain, reducing swelling, and treating cancer for a long history in Taiwan. However, there is no scientific evidence which supports the use in the literature.

Aim of the study

The aim of this study was to evaluate the antioxidant and anti-inflammatory activities of the aqueous extract of Centipeda minima (ACM).

Materials and methods

The following activities were investigated: antioxidant activities [2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), DPPH (1,1-diphenyl-2-picrylhydrazyl)], and anti-inflammatory [lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 macrophages and paw-edema induced by λ-carrageenan (Carr)]. We also investigated the anti-inflammatory mechanism of ACM via studies of the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) and the levels of malondialdehyde (MDA) in the edema paw. Serum NO, tumor necrosis factor α (TNF-α), and interleukin-1β (IL-1β) were also measured in vivo. In HPLC analysis, the fingerprint chromatogram of ACM was established.

Results

ACM showed the highest TEAC and DPPH radical scavenging activities, respectively. ACM also had highest contents of polyphenol and flavonoid contents. We evaluated that ACM and the reference compound of protocatechualdehyde and caffeic acid decreased the LPS-induced NO production in RAW264.7 cells. Administration of ACM showed a concentration dependent inhibition on paw edema development after Carr treatment in mice. The anti-inflammatory effects of ACM could be via NO, TNF-α, and IL-1β suppressions and associated with the increase in the activities of antioxidant enzymes. Western blotting revealed that ACM decreased Carr-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions.

Conclusions

Anti-inflammatory mechanisms of ACM might be correlated to the decrease in the level of Malondialdehyde (MDA), iNOS, and COX-2 via increasing the activities of CAT, SOD, and GPx in the edema paw. Overall, the results showed that ACM demonstrated antioxidant and anti-inflammatory activity, which supports previous claims of the traditional use for inflammation and pain.     

Chemical characterization of Centaurium erythrea L. and its effects on carbohydrate and lipid metabolism in experimental diabetes

Ethnopharmacological relevance

Centaurium erythrea L. fam. Gentianaceae (CE) has been traditionally used for centuries in folk medicine of Balkans as a bitter medicinal herb for digestive complications and for treating febrile conditions and diabetes. The aim of this study was to gain insight into the chemical composition and underlying biochemical mechanism of action of the antihyperglycemic and antilipidemic activities of the dry extract of Centaurium erythrea L., wildly growing and traditionally used medicinal plant in the Republic of Macedonia.

Materials and methods

An ultrasonic methanol maceration of the aerial parts of the dried plant was performed and the extract was freeze-dried. HPLC–DAD–ESI–MSⁿ was carried out on 150 mm×4.6 mm, 5 μm RP-18 Eclipse XDB column, at 40 °C. Mobile phase: water with 1% formic acid (A) and methanol (B) with linear gradient starting with 10% B was used to reach 15% at 5 min, 40% B at 25 min, 55% of B at 50 min and 100% at 60 min, with flow rate of 0.4 mL min⁻¹. Normal and streptozotocin (STZ) hyperglycemic Wistar rats were used for assessment of the antihyperglycemic and antilipidemic activity by measurement of the key carbohydrate-related enzymes and substrates, as well as lipid state of the organism.

Results

HPLC–DAD–ESI–MSⁿ analyses revealed presence of four different secoiridoids, seven flavonoid glycosides and seven xanthones in the freeze-dried extract of CE representing 53%, 25% and 22% of all compounds, respectively. The short-term (12 days) treatment of the STZ-diabetic rats with CE-extracts resulted in a 74% reduction of the produced hyperglycemia, which is only 6% less than the reduction caused by glibeclamide (GLB, positive control). The CE-extract had a significant impact on the hepatic carbohydrate metabolism enhancing the direct synthesis of glycogen, normalizing phosphorylase a activity and reducing the activity of glucose-6-phosphatase, which further causes reduction in production of blood glucose level. The long-term (45 days) treatment showed that the HbA1c in CE-treated group of animals was even lower than in the GLB-treated groups. The antilipidemic assessment of the CE-extract revealed decrease of total cholesterol, triglycerides, HDL and LDL level in the blood of the normal and STZ-hyperglycemic rats.

Conclusion

The obtained results indicate that treatment with CE extract in STZ-diabetic rats regulates the elevated level of blood glucose and carbohydrate-related disturbances slightly better than the effect of glibenclamide. There was also regulation of the serum lipid status in diabetic rats. Identified groups of bitter compounds in the extract (flavonoides, iridoids and xanthones) probably have influence on the expressed antihyperglycaemic effect.