Effect of Vaccinium bracteatum Thunb. leaves extract on blood glucose and plasma lipid levels in streptozotocin-induced diabetic mice

Aim of the study

To investigate the hypoglycemic effects of Vaccinium bracteatum Thunb. leaves (VBTL) extract in streptozotocin-induced diabetic mice.

Materials and methods

After administration of VBTL extract for 4 weeks, the body weight, organ weight, blood glucose (BG), insulin and plasma lipid levels of streptozotocin-induced diabetic mice were measured.

Results

Body weights of diabetic mice treated with VBTL extract were partly recovered. The BG levels of AEG (diabetic mice treated with VBTL aqueous extract) were reduced to 91.52 and 85.82% at week 2 and week 4, respectively (P < 0.05), while those of EEG (diabetic mice treated with VBTL ethanolic extract) were reduced slightly (P > 0.05). The insulin levels of AEG and EEG were obviously higher (P < 0.05) than those of MC (diabetic mice in model control group). Comparing with MC, AEG and EEG had significantly lower (P < 0.05) TC or TG levels and similar HDL-cholesterol or LDL-cholesterol levels. In comparison with non-diabetic control mice, AEG had similar plasma lipid levels except higher LDL-cholesterol level, while EEG had higher TC, TG and LDL-cholesterol levels and lower HDL-cholesterol levels.

Conclusions

Both aqueous and ethanolic extract of VBTL possess a potential hypoglycemic effect in streptozotocin-induced diabetic mice.     

Momordica charantia extract on insulin resistance and the skeletal muscle GLUT4 protein in fructose-fed rats

Aim of the study

We investigated the preventive effect of Momordica charantia Linn. (Cucurbitaceae) fruit, commonly known as bitter melon, on hyperglycemia and insulin resistance in rats fed with a fructose-enriched diet.

Materials and methods

First, rats were divided randomly into two groups: the control group was fed with control diet, whereas the experimental group was fed with a 60% high-fructose diet for 8 weeks. After the first 6 weeks, the fructose-treated rats were further subdivided into six groups and were orally fed with or without Momordica charantia L. or rosiglitazone (ROS) for 2 weeks while rats were still on fructose diet.

Results

We demonstrated that bitter melon was effective in ameliorating the fructose diet-induced hyperglycemia, hyperleptinemia, hyperinsulinemia, and hypertriglyceridemia as well as in decreasing the levels of free fatty acid (FFA) (P < 0.001, P < 0.05, P < 0.05, P < 0.05, P < 0.05, respectively). Bitter melon reversed fructose diet-induced hypoadiponectinemia (P < 0.05), which provides a therapeutic advantage to insulin resistance in improving insulin sensitivity. Additionally, bitter melon decreased the weights of epididymal (P < 0.05) and retroperitoneal white adipose tissue (WAT) (P < 0.05). Bitter melon increased the expression of peroxisome proliferator-activated receptor γ (PPARγ) in white adipose tissue (WAT). Conversely, bitter melon decreased the expression of leptin in WAT. Furthermore, we demonstrate that bitter melon significantly increases the mRNA expression and protein of glucose transporter 4 (GLUT4) in skeletal muscle.

Conclusions

This study demonstrates, for the first time, the beneficial effects of two different extracts of bitter melon on insulin resistance in rats fed a high-fructose diet thereby producing evidence of the role of changes in expression of PPARγ and GLUT4.     

Cardiovascular effects of Tulbaghia violacea Harv. (Alliaceae) root methanolic extract in Dahl salt-sensitive (DSS) rats

Ethnopharmacological relevance

In African folk medicine, Tulbaghia violacea Harv.(Alliaceae), a herbaceous plant also known by other common local names such as ‘wild garlic’, ‘society garlic’ and ‘sweet garlic’, has been used for the management, control and/or treatment of several human ailments; including hypertension.The aim of the present study was to investigate the cardiovascular effects of methanolic extract of Tulbaghia violacea Harv. in Dahl salt-sensitive (DSS) rats.

Materials and methods

DSS rats were treated intraperitoneally (i.p) as follows: distilled water, control (CON) (3 ml/kg/b.w.); captopril (CAP) (25 mg/kg/b.w.); or methanolic extract of Tulbaghia violacea (TVL) (50 mg/kg/b.w.) for 7 weeks. Systolic blood pressure (SBP) was measured bi-weekly whilst 24-hour urine volumes and sodium concentrations were assessed weekly. Animals were sacrificed on day 49 by halothane overdose. Blood was removed for the determination of aldosterone concentration and angiotensin converting enzyme (ACE) activity. Left kidney was harvested for angiotensin Ia (AT1a) receptor gene expression.

Results

CON showed a significant percentage increase in SBP (mmHg) on day 49 compared to day 0 (baseline values) (9.75±1.7% vs. 2.33±0.77%; p<0.05). CAP and TVL showed significant percentage decreases in SBP at week 7 when compared to baseline (8.13±1.23% and12.88±3.12% p<0.01). Urine volumes (ml) increased significantly in CAP from week 1 to week 4 (9.63±2.22 vs.10.97±1.75 p<0.05) and in TVL from week 2 to 7 (9.23±0.91 vs. 11.90±1.17 p<0.05). Urinary sodium concentration (mmol/L/24 h urine samples) was significantly higher in CAP (0.72±0.07 vs.1.31±0.03 p<0.05) and in TVL (0.71±0.09 vs. 1.68±0.16; p<0.05) at week 7 compared to baseline levels. There was no significant difference in the plasma aldosterone levels (pmol/L) of all the three groups. Serum ACE (U/L) activity was significantly higher in CAP compared to CON and TVL (277.0±11.6 vs. 121.5±3.93; and 147.0±6.63; p<0.05 respectively). CAP showed a significant 6.4 fold increase in AT1a mRNA expression vs. CON (p<0.05) and a 4.5 fold increase vs. TVL (p<0.05). There was no significant difference between CON and TVL treated rats. CAP and TVL showed no significant change in the expression of AT2.

Conclusion

This study showed that TVL possesses antihypertensive effect in Dahl salt-sensitive rats when administered over a long-term.     

Prospective randomized controlled study of a Chinese herbal medicine compound Tangzu Yuyang Ointment for chronic diabetic foot ulcers: a preliminary report

Aim of the study

The purpose of this study was to evaluate the efficacy and safety of a topical Chinese herbal medicine (CHM) compound Tangzu Yuyang Ointment (TYO) for treatment of chronic diabetic foot ulcers.

Materials and methods

This multi-center, prospective, randomized, controlled and add-on clinical trial was conducted at seven centers in the China mainland. Fifty-seven patients with chronic diabetic foot ulcers of Wagner's ulcer grade 1-3 were enrolled in this study. Patients who were randomly assigned to the control group (n = 28) received standard wound therapy (SWT), whereas those randomized to the treatment group (n = 28) received SWT plus topical TYO. Only 48 patients who finished 24 weeks of observations were entered for data analysis.

Results

The TYO and SWT groups were comparable for baseline characteristics. Ulcer improvement was 79.2% in the TYO group and 41.7% in the SWT group (P = 0.017) at 12 weeks, and 91.7% vs. 62.5% (P = 0.036) at 24 weeks. The number of ulcers that were completely healed at 4, 12 and 24 weeks was similar in both groups, as were the numbers of adverse events. Healing time was 96 ± 56 days (n = 19) in the TYO group and 75 ± 53 days (n = 14) in the SWT group (P = 0.271).

Conclusion

TYO plus SWT is more effective than SWT in the management of chronic diabetic foot ulcers and has few side-effects.     

Treatment of high fat diet induced type 2 diabetes in C57BL/6J mice by two medicinal plants used in traditional treatment of diabetes in the east of Algeria

Aim of the study

Hydro-alcoholic extracts of Centaurium erythraea Rafn (CE), Gentianaceae and Artemisia herba-alba Asso (AHA), Asteraceae, medicinal plants used in traditional treatment of diabetes in north-eastern Algeria, were tested in established type 2 diabetes induced with a standardized high fat diet (HFD) in mice.

Materials and methods

After confirmation of diabetes (17th week), plant extracts were administered orally by gavage at a dose of 2 g/kg daily for 18 weeks to male C57BL/6J mice fed HFD. Animals were weighed, food intake and plasma glucose measured weekly, insulin and lipid profile at study end.

Results

At 35 weeks, groups treated with AHA or CE vs. HFD control had a significant reduction in mean (±SD) fasting blood glucose concentrations (143.8 ± 23.9 and 139.5 ± 14.2 vs. 229.0 ± 20.8 mg/dL, p < 0.05, respectively), triglyceride (18.9 ± 11.1 and 16.0 ± 6.5 vs. 62.8 ± 18.3 mg/dL, p < 0.05), total cholesterol (1.2 ± 0.1 and 1.2 ± 0.3 vs. 1.8 ± 1.1 g/L, p < 0.05) and serum insulin concentrations (1.7 ± 0.7 and 0.9 ± 0.7 vs. 3.3 ± 14.3 ng/mL, p < 0.05). Plant extracts also markedly reduced insulin resistance as compared to HFD controls (AHA: 15.6 ± 9.1, CE: 9.0 ± 7.7 vs. HFD control 38.5 ± 30.3, p < 0.05). The plant extracts decreased calorie intake and had little effect on body weight or HDL-cholesterol.

Conclusion

AHA has already been shown to have a antihyperglycaemic and antihyperlipidemic effect but this is the first demonstration of an effect of AHA and CE on established HFD-induced diabetes.     

Antiemetic effect of Xiao-Ban-Xia-Tang,a Chinese medicinal herb recipe,on cisplatin-induced acute and delayed emesis in minks

Ethnopharmacological relevance

Xiao-Ban-Xia-Tang (XBXT), a traditional Chinese herbal medicine, has been used in China for more than 2000 years, and proved to be effective on various cases of vomiting in the clinic.

Objective

To investigate the antiemetic effect of XBXT on cisplatin-induced acute and delayed emesis and its effective mechanism on Neurokinin-1 receptor (NK₁-R) in the new vomiting model of minks.

Materials and methods

Minks were randomly divided into the normal group, cisplatin group, cisplatin + ondansetron group, cisplatin + low-dose XBXT group and cisplatin + high-dose XBXT group. The antiemetic effect of drugs was investigated in the vomiting model of minks induced by cisplatin (6 mg kg⁻¹, i.p.) in 72 h observation, and the expression of NK₁-R in the area postrema and ileum was measured by Western blot.

Results

The frequency cisplatin induces retching and vomiting was significantly reduced by pretreatment with XBXT in a dose-dependent manner during the 0–24-h and 24–72-h periods (P < 0.05), and XBXT exhibited effective dose-dependent (P < 0.05) inhibition on the increase of expression levels of NK1 receptor in both the ileum and area postrema.

Conclusions

XBXT has good activity against cisplatin-induced acute and delayed emesis in minks possibly by inhibiting central or peripheral increase of NK₁-R.     

Acute toxicity studies of Croton membranaceus root extract

Aim of the study

Croton membranaceus root and leaf extracts are used in the Bahamas to aromatize tobacco, in Nigeria to improve digestion, and in Ghana, for benign prostate hyperplasia. Despite claims of success there is paucity of information on its toxicity. The aim of this study was to determine if Croton membranaceus has acute toxicity properties.

Materials and methods

Roots were air-dried in a solar dryer for one week before milling. The powder was extracted with 96% ethanol, freeze-dried and re-extracted with distilled water and freeze-dried. 15 male Sprague-Dawley rats (180-200 g) were divided equally into 2 treatment groups [low dose (LD) and high dose (HD)], plus a control group (C). LD and HD received 1500 and 3000 mg/kg b.wt. Croton membranaceus aqueous extract, respectively, one time and observed for 14 days. Haematological [Full Blood Count and haemoglobin (Hb)], biochemical [bilirubin, alanine aminotransferase (ALA), aspartate aminotransferase (AST), total protein, albumin, globulin, alkaline phosphatise (ALP), γ-glutamyltranspetidase (GGT), urea, creatinine, creatinine kinase - Muscle and Brain (CK-MB), creatinine kinase - Total (CK-R)] examinations were performed.

Results

Control group's CK-MB (5444 ± 534 U/L) and LD group CK-MB (4014 ± 1016 U/L) were significantly different (p < 0.05). Control and the HD group CK-MB (3955 ± 1135 U/L) were significantly different (p < 0.05). Both LD and HD CK-R levels (697 ± 197 U/L and 732 ± 203 U/L, respectively), were lower than the control (1139 ± 220 U/L) at 48 h and 14 days (p < 0.05, p < 0.05, respectively). γ-GT levels of the HD group was 4.8 ± 0.4 U/L compared to the Control group value of 0.9 ± 0.2 U/L (p < 0.05).

Conclusions

Taking all factors into consideration, Croton membranaceus ingestion does not produce general acute toxicity. However, its creatinine kinase lowering ability could be explored.     

Effects of Ningdong granule on the dopamine system of Tourette's syndrome rat models

Ethnopharmacological relevance

Ningdong Granula (NDG) is a traditional Chinese medicine (TCM) preparation for the treatment of Tourette's syndrome (TS).

Aim of the study

To explore the effects of NDG on stereotyped behavior, homovanillic acid (HVA) in sera, dopamin (DA) and dopamin D2 receptor (DRD2) in striatum in TS rats.

Materials and methods

Sixty-four rats were randomly divided into control group and three experimental groups. TS rat models were induced by intraperitoneal injection (i.p.) of Apomorphine (Apo, 2 mg/kg) in the experimental groups. After Apo i.p., rats were intragastrically injected (i.g.) with NDG at 370 mg/kg (NDG + Apo group), haloperidol (Hal) at 1.0 mg/kg (Hal + Apo group), and normal saline (0.9%) at 10 ml/kg (control group and Apo group), respectively, once a day for 12 weeks. The behaviors of the rats were observed and recorded each day. After 12 weeks, all rats were sacrificed and sera and striatum were collected. The levels of HVA in sera, DA in striatum were examined by ELISA, and the expression of DRD2 mRNA in striatum was measured by RT-PCR.

Results

NDG could increase the HVA content in sera (P < 0.05), meanwhile downregulate the expression of DRD2 mRNA in striatum (P < 0.05), and inhibit the stereotyped behaviors induced by Apo (P < 0.01) in TS rats, the same effects with Hal. NDG could also reduce the DA content in striatum (P < 0.01), while Hal could not.

Conclusions

NDG could effectively inhibit the stereotyped behaviors in TS rats, and the mechanisms may be related to the suppression of DA system by increasing the content of HVA in sera, decrease the content of DA and repressing the expression of DRD2 mRNA in striatum.     

Aqueous extract of Astragali Radix ameliorates proteinuria in adriamycin nephropathy rats through inhibition of oxidative stress and endothelial nitric oxide synthase

Aim of the study

To investigate the effects of aqueous extract of Astragali Radix (ARE) on the oxidative stress status and endothelial nitric oxide synthase level in adriamycin (ADR) nephropathy rats.

Materials and methods

ADR nephropathy rats were randomly treated with ARE (2.5 g/kg/d, n = 6, ARE group), or benazepril (10 mg/kg/d, n = 6, angiotensin-converting enzyme inhibitor (ACEI) group) for ten weeks. Serum urea nitrogen, creatinine, albumin, total protein, cholesterol and 24-h urinary protein concentration were determined. Renal cortex catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), malondialdehyde (MDA) activities, and 24-h urinary NO₃⁻/NO₂⁻ excretion were determined by chromatometry. Renal cortex cyclic guanosine monophosphate (cGMP) level was measured by enzyme immunoassay and eNOS expression was determined by immunohistochemistry.

Results

ARE and ACEI treatments could remarkably reduce more 24 h urinary protein excretion than that in ADR group (88.32 ± 9.96 mg, 81.78 ± 16.28 mg vs. 153.91 ± 28.63 mg, P < 0.01), and there was no difference between ARE and ACEI group. Renal cortex CAT, GSH-Px activities in ARE and ACEI group were significantly higher than ADR group, and renal cortex SOD activity in ARE group was higher than ADR group. Renal cortex MDA activity, cGMP level, and glomerular and tubular eNOS expression in ARE and ACEI group were lower than that in ADR group, and 24-h urinary NO₃⁻/NO₂⁻ excretion in ARE group was lower than ADR group. Renal cortex MDA content (r = 0.895, P < 0.01), cGMP content (r = 0.666, P < 0.01) and eNOS expression in glomerulus (r = 0.910, P < 0.01) were strongly positively associated with 24 h urinary protein excretion. And renal cortex SOD content was negatively associated with 24 h urinary protein excretion (r = −0.861, P < 0.01).

Conclusions

ARE may ameliorate the proteinuria by suppressing the over expression of eNOS, and inhibiting the oxidative injury in ADR nephropathy rats.