Effects of Orthosiphon stamineus aqueous extract on plasma glucose concentration and lipid profile in normal and streptozotocin-induced diabetic rats

Fabrication and characterization of responsible approach for targeted intestinal releasing and enhancing the effectivity of kidney tea saponin upon porous starch /xanthan gum /sodium alginate-based hydrogel bead

To enhance the intestinal targeted release of kidney tea saponins, a simple delivery system was designed through the use of porous starch (PS), sodium alginate (ALG) and xanthan gum (XG). Porous starch was prepared by hydrolysis with a combination of α-amylase and amyloglucosidase and it was characterized by scanning electron microscopy, which revealed the formation of porous structures in the starch granules. The results of one-way optimisation illustrated that this unique delivery system achieved 79.00 ± 1.22 % of the optimal encapsulation rate. The carrier structure was subjected to analysis using Fourier transform infrared spectroscopy and X-ray diffraction. The α-glucosidase inhibition assay showed better inhibition of kidney tea saponin compared to the positive control acarbose. In addition, the effectiveness of this delivery design was confirmed via an in vitro simulated digestion method. It was showed that only a 15.57 ± 1.27 % release rate of kidney tea saponin was observed in the upper gastrointestinal tract, whereas release rates of 17.51 ± 1.29 % and 41.07 ± 0.76 % were observed for xanthan gum/sodium alginate/kidney tea saponin and sodium alginate/kidney tea saponin beads, respectively. It was concluded that the utilization of PS and a xanthan gum/sodium alginate coating represents an efficacious methodology for the development of an intestinal targeted delivery system.

Arbuscular Mycorrhizal Fungi Ameliorate Selenium Stress and Increase Antioxidant Potential of Zea mays in Seleniferous Soil

The indigenous arbuscular mycorrhizal fungi (AMF) spores were isolated from rhizosphere soil associated with maize plants grown in natural selenium-impacted agricultural soils present in north-eastern region of Punjab, India (32°46' N, 74°46' N), with selenium concentration ranging from 2.1 to 6.1 mg kg-1 dry weight, and their role in plant growth promotion, mitigation of selenium stress and phytochemical and antioxidant potential of host maize plants in natural seleniferous soil were examined. Soils with selenium content between 2 and 200 mg kg-1 and producing plants with 45 mg selenium kg-1 dry weight are considered seleniferous soils. AMF inoculum consisting of indigenous AMF spores multiplied in pot cultures were inoculated to maize seeds at the time of sowing alongside control maize seeds in a total of 12 plots (6 replicates) made in seleniferous agricultural fields and sampled at maturity, i.e. 3 months. A significant difference was observed in plant growth parameters between control and AMF-inoculated maize plants. AMF-inoculated plants had 24.0 cm and 101.1 cm higher root and shoot length along with 27.2 g, 119.4 g and 28.1 g higher root, shoot and maize cob biomass in comparison to control plants. Se uptake studies through measurement of the emission spectrum of piazselenol complex by fluorescence spectrometry revealed that AMF inoculation led to 6.3 µg g-1 more selenium accumulation in mycorrhizal maize roots in comparison to control roots but lesser translocation to shoots and seeds, i.e. 17.17 µg g-1 and 19.58 µg g-1 lesser. AMF increased total phenolic content by 13 µg GAE mg-1 and total flavonoid content by 13.4 µg QE mg-1 in inoculated maize plants when compared to control plants. Antioxidant studies revealed that AMF inoculation also led to significant rise in enzyme activities by a difference of 115 and 193 EU g-1 in catalase, 140 and 93 EU g-1 in superoxide dismutase, 15 and 37 EU g-1 in ascorbate peroxidase and 19.8 and 23.6% higher DPPH radical scavenging activities, respectively, in shoots and roots of plants with AMF inoculation. The findings of this study imply that AMF inoculated to maize plants in seleniferous field boost their plant growth and phytochemical and antioxidant properties, as well as minimize Se bioaccumulation in shoots and seeds of plants inoculated with AMF in comparison to control plants.

In Vivo and In Vitro Antidiabetic Efficacy of Aqueous and Methanolic Extracts of Orthosiphon Stamineus Benth

Orthosiphon stamineus is a popular folk herb used to treat diabetes and some other disorders. Previous studies have shown that O. stamineus extracts were able to balance blood glucose levels in diabetic rat animal models. However, the antidiabetic mechanism of O. stamineus is not fully known. This study was carried out to test the chemical composition, cytotoxicity, and antidiabetic activity of O. stamineus (aerial) methanol and water extracts. GC/MS phytochemical analysis of O. stamineus methanol and water extracts revealed 52 and 41 compounds, respectively. Ten active compounds are strong antidiabetic candidates. Oral treatment of diabetic mice with O. stamineus extracts for 3 weeks resulted significant reductions in blood glucose levels from 359 ± 7 mg/dL in diabetic non-treated mice to 164 ± 2 mg/dL and 174 ± 3 mg/dL in water- and methanol-based-extract-treated mice, respectively. The efficacy of O. stamineus extracts in augmenting glucose transporter-4 (GLUT4) translocation to the plasma membrane (PM) was tested in a rat muscle cell line stably expressing myc-tagged GLUT4 (L6-GLUT4myc) using enzyme-linked immunosorbent assay. The methanol extract was more efficient in enhancing GLUT4 translocation to the PM. It increased GLUT4 translocation at 250 µg/mL to 279 ± 15% and 351 ± 20% in the absence and presence of insulin, respectively. The same concentration of water extract enhanced GLUT4 translocation to 142 ± 2.5% and 165 ± 5% in the absence and presence of insulin, respectively. The methanol and water extracts were safe up to 250 µg/mL as measured with a Methylthiazol Tetrazolium (MTT) cytotoxic assay. The extracts exhibited antioxidant activity as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. O. stamineus methanol extract reached the maximal inhibition of 77 ± 10% at 500 µg/mL, and O. stamineus water extract led to 59 ± 3% inhibition at the same concentration. These findings indicate that O. stamineus possesses antidiabetic activity in part by scavenging the oxidants and enhancing GLUT4 translocation to the PM in skeletal muscle.

A Systematic Review of Orthosiphon stamineus Benth. in the Treatment of Diabetes and Its Complications

(1) Background: Orthosiphon stamineus Benth. is a traditional medicine used in the treatment of diabetes and chronic renal failure in southern China, Malaysia, and Thailand. Diabetes is a chronic metabolic disease and the number of diabetic patients in the world is increasing. This review aimed to systematically review the effects of O. stamineus in the treatment of diabetes and its complications and the pharmacodynamic material basis. (2) Methods: This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the databases ScienceDirect, PubMed, and Web of Science. (3) Results: Thirty-one articles related to O. stamineus and diabetes were included. The mechanisms of O. stamineus in the treatment of diabetes and its complications mainly included inhibiting α-amylase and α-glucosidase activities, antioxidant and anti-inflammatory activities, regulating lipid metabolism, promoting insulin secretion, ameliorating insulin resistance, increasing glucose uptake, promoting glycolysis, inhibiting gluconeogenesis, promoting glucagon-likepeptide-1 (GLP-1) secretion and antiglycation activity. Phenolic acids, flavonoids and triterpenoids might be the main components for hypoglycemia effects in O. stamineus. (4) Conclusion: O. stamineus could be an antidiabetic agent to treat diabetes and its complications. However, it needs further study on a pharmacodynamic substance basis and the mechanisms of effective constituents.

Comprehensive chemical and metabolic profiling of anti-hyperglycemic active fraction from Clerodendranthi Spicati Herba

Extensive pharmacological research has demonstrated that Clerodendranthi Spicati Herba has an obvious anti-hyperglycemic effect via α-glucosidase inhibitory activity. However, the anti-hyperglycemic active fraction and its metabolic behavior in vivo have not been elaborated clearly. In this study, ultra-high-performance liquid chromatography coupled to quadrupole time of flight tandem mass spectrometry with data filtering strategy, including mass defect screening, diagnostic product ions and neutral loss identification, was established for chemical and metabolic profiling of anti-hyperglycemic active fraction from Clerodendranthi Spicati Herba. A total of 28 methoxylated flavonoids and 61 diterpenoids were rapidly identified. Four main known methoxylated flavonoids were purified and unambiguously identified by nuclear magnetic resonance analysis. Thirty-one absorbed diterpenoids, 12 absorbed methoxylated flavonoids, and 56 methoxylated flavonoids metabolites were identified in rat plasma, urine, bile, and feces after oral administration of anti-hyperglycemic active fraction. The methoxylated flavonoids were predominantly metabolized by demethylation, sulfation, and glucuronidation. Glucuronidation metabolites found in bile and urine after demethylation were dominant metabolites. Diterpenoids were absorbed into the blood mainly in the form of prototypes and excreted through bile and urine. These results indicated that methoxylated flavonoids and diterpenoids were responsible for α-glucosidase inhibitory activity, which might provide novel drug candidates for the management of diabetes mellitus.

Medicinal plants utilized in Thai Traditional Medicine for diabetes treatment: Ethnobotanical surveys, scientific evidence and phytochemicals

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus remains the most lethal metabolic disease of contemporaneous times and despite the therapeutic arsenal currently available, research on new antidiabetic agents remains a priority. In recent years, the revitalization of Thai Traditional Medicine (TTM) became a clear priority for the Thai government, and many efforts have been undertaken to accelerate research on herbal medicines and their use in medical services in various hospitals. Additionally, and particularly in rural areas, treatment of diabetes and associated symptomatology frequently relies on herbal preparations recommended by practitioners of TTM. In the current work, medicinal plants used in Thailand for treating diabetes, as well as their hypoglycaemic pharmacological evidences and potential therapeutic use for diabetes-related complications were reviewed.

MATERIALS AND METHODS

Ethnopharmacological information on the plant materials used in TTM for diabetes treatment was collected through literature search in a range of scientific databases using the search terms: diabetes, folk medicine, Thailand medicinal plants, traditional medicine. Information regarding scientific evidence on the antidiabetic effects of surveyed species was obtained considering not only the most common taxonomic designation, but also taxonomic synonyms, and including the keywords 'diabetes' and 'hypoglycaemic effect'.

RESULTS

A total of 183 species known to be used for diabetes management in TTM were reviewed, with 30% of them still lacking experimental evidences to support claims regarding the mechanisms and phytochemicals underlying their antidiabetic properties. Moreover, a total of 46 bioactives displaying effective antidiabetic effects have been isolated from 24 species, their underlying mechanism(s) of action being fully or partially disclosed.

CONCLUSIONS

We deliver the most extensive survey dealing with the ethnomedicinal knowledge of Thai medicinal plants utilized on diabetes management. We are certain that the current review will spark further research on Thai plants for the development of new standardized phytomedicines through drug discovery programmes.

Molecular docking analysis and anti-hyperglycaemic activity of Synacinn™ in streptozotocin-induced rats

Synacinn™ is a standardized polyherbal supplement formulated from Cinnamomum zeylanicum Blume, Curcuma zanthorrhiza Roxb., Syzygium polyanthum (Wight) Walp., Orthosiphon stamineus Benth. and Andrographis paniculata (Burm.f.) Nees. It is designed for the synergistic treatment of diabetes mellitus and its complications. Although the beneficial effects are yet to be verified scientifically, it is traditionally used to improve general health in patients with diabetes. This study aimed to evaluate the anti-hyperglycemic effects of Synacinn™ in a streptozotocin-induced type 1 diabetes rat model. Initially, Synacinn™ was used for in vivo acute oral toxicity tests and 14 day repeated dose toxicity tests to determine the toxicity levels. An efficacy study of Synacinn™ was carried out via the oral administration of 10, 50, 100, 250, and 250 (b.i.d.) mg kg-1 doses to streptozotocin-induced diabetic rats. After 28 days, blood serum was collected to measure the fasting blood glucose, triglyceride, cholesterol, alanine aminotransferase, alkaline phosphatase, creatinine, and uric acid levels. The liver, kidney, and pancreas structures were histopathologically analyzed. In silico binding interaction studies of five phytochemicals in Synacinn™ identified via HPLC with glucokinase were performed using molecular docking analysis. The results showed that although no mortality was observed during the acute oral toxicity tests, notable damage to the liver and kidney occurred during the 14 day repeated dose testing at Synacinn™ levels of 600 mg kg-1 and 2000 mg kg-1. Treatment with 250 mg kg-1 (b.i.d.) Synacinn™ of the streptozotocin-induced type 1 diabetic rats significantly (p < 0.05) improved the fasting blood glucose (59%), triglyceride (58%), cholesterol (47%), alanine aminotransferase (60%), alkaline phosphatase (90%), and creatinine (32%) levels. Synacinn™ also improved the relative weights of liver (35%), kidney (36%), and pancreatic (36%) tissue. Histological analysis showed improvements in the conditions of the central vein of the liver, the kidney Bowman's capsule and glomerulus, and the pancreatic islets of Langerhans. HPLC analysis of a standardized extract identified five active phytochemicals: andrographolide (17.36 mg g-1), gallic acid (11.5 mg g-1), curcumin (2.75 mg g-1), catechin (3.9 mg g-1), and rosmarinic acid (5.54 mg g-1). Molecular docking studies with glucokinase showed that andrographolide yields the highest binding energy (-12.1 kcal mol-1), followed by catechin (-10.2 kcal mol-1), rosmarinic acid (-8.6 kcal mol-1), curcumin (-7.8 kcal mol-1), and gallic acid (-5.6 kcal mol-1). These current findings suggest that Synacinn™ at a dose of 250 mg kg-1 was non-toxic to rats. A twice-daily 250 mg kg-1 dose of Synacinn™ is an effective anti-hyperglycemic agent, lowering blood glucose, triglyceride, and cholesterol levels, and assisting the recovery of organ impairment caused by streptozotocin in type 1 diabetic rats.

Rationale of Orthosiphon aristatus for Healing Diabetic Foot Ulcer

Orthosiphon aristatus (Blume) Miq. is traditionally used for wound healing in South East Asia and scientifically proven for its antidiabetic potential. Wounds due to diabetes, especially diabetic foot ulcer (DFU), always involve a complicated healing process. The present work aims to review the information on the rationale of the phytochemicals from O. aristatus in promoting DFU healing. The findings showed that the DFU healing potential of O. aristatus was characterized by a reduction in the blood glucose level, mainly attributed to the significant concentration of constituents such as caffeic acid, rosmarinic acid, and sinensetin in the plant extract. These phytochemicals possibly induce insulin secretion and sensitivity, improve the lipid profile, and stimulate glucose uptake. Furthermore, the healing effect may also be contributed to the antioxidant, anti-inflammatory, and antihyperglycemic properties of the plant. The roles of phytochemicals have been systematically postulated in the 4 phases of the healing process. Moreover, no adverse toxic sign or abnormality has been reported upon oral administration of the plant extract. This suggests that O. aristatus extract could be a potential diabetic wound healing phytomedicine for further preclinical and clinical studies.

PTP1B Inhibitory Flavonoids From Orthosiphon stamineus Benth. and Their Growth Inhibition on Human Breast Cancer Cells

In our preliminary screening study on the protein tyrosine phosphatase 1B (PTP1B) inhibitory and cytotoxic activities, an ethyl acetate soluble fraction of the aerial part of Orthosiphon stamineus Benth. was found to inhibit PTP1B activity. Thus, based on assay-guided isolation of this active fraction, ten compounds (1-10) were purified and evaluated for their inhibitory effects on PTP1B and their growth inhibition on MCF7, tamoxifen-resistant MCF7 (MCF7/TAMR), and MDA-MB-231 human breast cancer cell lines. Among the isolates, compounds 5, 6, 9, and 10 showed potencies against PTP1B with IC50 values of 9.76, 10.12, 6.88, and 8.92 μM, respectively, followed by compounds 1 and 4 with IC50 values of 16.92 and 22.25 μM. Kinetic study showed that the active compounds (1, 5, 9, and 10) possessed mixed-competitive inhibition, which was similar to the positive control (ursolic acid, IC50 value of 3.42 μM, mixed-competitive). The others showed noncompetitive inhibition (4 and 6). In addition, all these active compounds (1, 4-6, and 9-10) displayed growth inhibition on three cancer cell lines, especially the most PTP1B inhibitory flavanones (9 and 10) exhibited comparable inhibitory effects on MCF7, MCF7/TAMR, and MDA-MB-231 cancer cells (IC50 values of 11.5 and 15.4, 8.9 and 10.5, and 17.6 and 21.3 μM, respectively) with tamoxifen, the positive control used in this assay (IC50 values of 11.9, 12.1, and 12.7 μM, respectively). The results suggest that these active constituents from O. stamineus might be considered as new natural compounds for the development of anticancer agents via PTP1B inhibition.

Glucose Uptake Stimulatory and PTP1B Inhibitory Activities of Pimarane Diterpenes from Orthosiphon stamineus Benth

Seven pimarane diterpenes (1–7) were isolated from Orthosiphon stamineus Benth. by assay-guided isolation. All of the isolates possessed a 2-deoxy-2-((7-nitro-2,1,3-benzoxadiazol-4-yl)amino)-d-glucose uptake effect in 3T3-L1 adipocytes at concentrations of 5 and 10 μM. Most of them showed potent inhibition against protein tyrosine phosphatase 1B with IC₅₀ values ranging from 0.33 to 9.84 μM. In the kinetic study, all inhibition types were exposed for the examined potencies, including mixed-competitive (1), non-competitives (3 and 5), competitive (6), and uncompetitive (7). The results suggested that O. stamineus and its pimarane diterpenes might exert the hypoglycemic effect via the insulin signaling pathway targeting inhibition of protein tyrosine phosphatase 1B (PTP1B) activity.

Understanding glycaemic control and current approaches for screening antidiabetic natural products from evidence-based medicinal plants

Type 2 Diabetes Mellitus has reached epidemic proportions as a result of over-nutrition and increasingly sedentary lifestyles. Current therapies, although effective, are not without limitations. These limitations, the alarming increase in the prevalence of diabetes, and the soaring cost of managing diabetes and its complications underscores an urgent need for safer, more efficient and affordable alternative treatments. Over 1200 plant species are reported in ethnomedicine for treating diabetes and these represents an important and promising source for the identification of novel antidiabetic compounds. Evaluating medicinal plants for desirable bioactivity goes hand-in-hand with methods in analytical biochemistry for separating and identifying lead compounds. This review aims to provide a comprehensive summary of current methods used in antidiabetic plant research to form a useful resource for researchers beginning in the field. The review summarises the current understanding of blood glucose regulation and the general mechanisms of action of current antidiabetic medications, and combines knowledge on common experimental approaches for screening plant extracts for antidiabetic activity and currently available analytical methods and technologies for the separation and identification of bioactive natural products. Common in vivo animal models, in vitro models, in silico methods and biochemical assays used for testing the antidiabetic effects of plants are discussed with a particular emphasis on in vitro methods such as cell-based bioassays for screening insulin secretagogues and insulinomimetics. Enzyme inhibition assays and molecular docking are also highlighted. The role of metabolomics, metabolite profiling, and dereplication of data for the high-throughput discovery of novel antidiabetic agents is reviewed. Finally, this review also summarises sample preparation techniques such as liquid-liquid extraction, solid phase extraction, and supercritical fluid extraction, and the critical function of nuclear magnetic resonance and high resolution liquid chromatography-mass spectrometry for the dereplication, putative identification and structure elucidation of natural compounds from evidence-based medicinal plants.

Orthosiphon stamineus as a potential antidiabetic drug in maternal hyperglycemia in streptozotocin-induced diabetic rats

Background

Maternal hyperglycemia is associated with increased risk of adverse outcomes for both mother and offspring. Insulin is the standard treatment of hyperglycemia with the aim to reduce risks of complications, however, due to several restrictions, the search for more effective drugs from traditional medicinal plants continues.

Methods

The antidiabetic effects of Orthosiphon stamineus (O . stamineus ) in non-pregnant and pregnant streptozotocin-induced Sprague Dawley rats were identified. The effect of different concentrations of O. stamineouson insulin level using isolated pancreatic islets in response to low and high concentrations of glucose was identified. Oral glucose tolerance test was performed in both pregnant and non-pregnant rats prior to and after treatment with O. stamineus (0.1 g/100 g of body weight). O. stamineus was given orally daily for 2 weeks in non-pregnant and 10 days in pregnant rats.

Results

Oral glucose tolerance test indicated that treatment with O. stamineus in non-pregnant and pregnant rats significantly reduced blood glucose level and stimulated glucose-induced insulin secretion. No mortality was recorded throughout the study and no signs of toxicity during the experimental period including in both mother and foetus. For plasma analysis, the interactions of peptides such as GLP-1 and ghrelin level might contribute to the glucose lowering effect by O. stamineus via stimulation of insulin. The incubation of islets showed that O . stamineussignificantly stimulated insulin release in response to high glucose.

Conclusion

O. stamineus could be a potential source of a specific oral hypoglycaemic agent to treat glucose intolerance in pregnancy.

In Vitro Antiatherothrombotic Effects of Extracts from Berberis Vulgaris L., Teucrium Polium L., and Orthosiphon Stamineus Benth

Coronary artery disease is the leading cause of mortality and morbidity worldwide. The pathogenesis is mainly due to atherosclerosis, plaque rupture, and platelet thrombus formation. The main risk factors for coronary artery disease include obesity, hypercholesterolemia, smoking, diabetes, and high blood pressure. As a part of disease management, treatment options using anticoagulant and antiplatelet drugs can be applied with addition to lipid-lowering medication. However, medicinal plants comprising antiatherothrombotic effects can be used as options to combat the disease rather than drug therapies with lesser adverse effects. Therefore, the haematological effect of Berberis vulgaris L., Teucrium polium L., and Orthosiphon stamineus Benth extracts was studied using in vitro model to prevent and to treat coronary atherothrombotic disease. The aqueous, methanol, and polysaccharide extracts of B. vulgaris, T. polium, and O. stamineus, respectively, were studied for their anticoagulant and antiplatelet effect on human whole blood. Extracts were subjected to the prothrombin time (PT) and activated partial thromboplastin time (APTT) test for anticoagulant activity. The antiplatelet activity was investigated using an electrical impedance method. B. vulgaris aqueous extract (BVAE), B. vulgaris polysaccharide extract (BVPE), T. polium aqueous extract (TPAE), and T. polium polysaccharide extract (TPPE) significantly prolonged the coagulation time in a concentration-dependent manner (p<0.05). The administration of BVAE demonstrated the most effective antiplatelet activity against platelet aggregation caused by arachidonic acid (AA) and collagen. These antiplatelet activities may correspond to the presence of higher total phenolic compound, which thus inhibit the platelet aggregation activity. In conclusion, these findings provide strong evidence on the antiatherothrombotic effect of BVAE and TPAE.

Evaluating Traditional Chinese Medicine and Herbal Products for the Treatment of Gestational Diabetes Mellitus

Gestational diabetes mellitus is the most common metabolic disorder during pregnancy with health consequences for both lives during and after pregnancy. Studies found that many pregnant women turn to complementary and alternative medicine for health maintenance or symptom relief, such as herbal medicine and acupuncture from traditional Chinese medicine. With the growing popularity of traditional Chinese medicine, we conducted a systemic search in PubMed, Web of Science, and Embase databases on research studies that investigated traditional Chinese medicine during pregnancy. The resultant hits were further searched in relation to all diabetes mellitus. In total, we found three major herbal medicine/herbal products that were associated with glycemic control in gestational diabetes, including Zuo Gui Wan, red raspberry leaves, and Orthosiphon stamineus. We further reviewed them and their relatives in relation to type 2 diabetes mellitus and found more evidence of metabolic benefits. None of the herbal medicine and products examined reported toxicity in the experimental models. Overall, treatments of gestational diabetes by western or alternative interventions are grossly understudied. It is critical to have a standardized protocol when evaluating efficacy of herbal medicine and produce quality results for women and their health-care providers to make informed treatment decisions.

Hypoglycaemic activity of Mathurameha, a Thai traditional herbal formula aqueous extract, and its effect on biochemical profiles of streptozotocin-nicotinamide-induced diabetic rats

BACKGROUND

The Thai traditional herbal formula-Mathurameha, consisting of 26 medicinal plants, has been used as an alternative and complementary medicine for diabetes treatment in Wangnamyen Hospital, Thailand. To provide scientific evidences on the efficacy and safety of this herbal formula, in vivo hypoglycaemic activity, effect on serum biochemical profiles and acute toxicity were investigated.

METHODS

Experimental type 2 diabetes was induced in male Sprague-Dawley rats by intraperitoneal injection of nicotinamide 15 min prior to intravenous injection of streptozotocin. The most effective extract from the oral glucose tolerant test (OGTT) was administered daily via the oral route to diabetic rats for 2 weeks. Two-hour postprandial plasma glucose (2h-PPG) levels were measured on days 0, 7, and 14. Biochemical data were measured at the end of daily oral administration experiment.

RESULTS

Aqueous extract of the herbal formula was the most potent extract for improving glucose tolerance of streptozotocin-nicotinamide-induced diabetic rats after single oral administration. After 2 weeks of daily oral administration, the aqueous extract showed a dose-dependent glucose lowering effect. At doses of 12.5, 25, and 50 mg/kg, the 2h-PPG level of diabetic rats decreased by 3.32%, 15.78%, and 17.94%, respectively. Most of the biochemical profiles of diabetic rats were improved, including the total cholesterol (TC), alkaline phosphatase (ALP), total protein, albumin, globulin, creatinine, and uric acid levels. The significantly increased triglyceride (TG) level observed in treated diabetic rats indicated a lack of a beneficial effect of the extract on lipid homeostasis. Nevertheless, there were no signs or symptoms of acute toxicity observed after oral administration of aqueous extract (5 g/kg) to both male and female rats.

CONCLUSIONS

The results revealed that the herbal formula aqueous extract has hypoglycaemic activity, beneficial effects on biochemical profiles and a lack of acute toxicity. This study confirms the efficacy and safety of the Mathurameha herbal formula used for treating type 2 diabetes mellitus.

Urinary metabolomics study on the protective role of Orthosiphon stamineus in Streptozotocin induced diabetes mellitus in rats via 1H NMR spectroscopy

Background

Orthosiphon stamineus (OS) is a herb known in ethnomedicine for treating diabetes mellitus (DM). In this study, a ¹H NMR based urine metabolomics tool has been used for the first time to identify the metabolic protective mechanism of OS in DM using Streptozotocin (STZ) induced experimental model in rats.

Methods

Four different solvent extracts of OS, namely aqueous, ethanolic, 50% aqueous ethanolic and methanolic, at a dose of 500 mg/kg body weight (bw) were orally administered for 14 days to diabetic rats induced via intraperitoneal injection of 60 mg/kg bw STZ. NMR metabolomics approach using pattern recognition combined with multivariate statistical analysis was applied in the rat urine to study the resulted metabolic perturbations.

Results

OS aqueous extract (OSAE) caused a reversal of DM comparable to that of 10 mg/kg bw glibenclamide. A total of 15 urinary metabolites, which levels changed significantly upon treatment were identified as the biomarkers of OSAE in diabetes. A systematic metabolic pathways analysis identified that OSAE contributed to the antidiabetic activity mainly through regulating the tricarboxylic acid cycle, glycolysis/gluconeogenesis, lipid and amino acid metabolism.

Conclusions

The results of this study validated the ethnopharmacological use of OS in diabetes and unveiled the biochemical and metabolic mechanisms involved.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1777-1) contains supplementary material, which is available to authorized users.

Evaluation of α-Glucosidase Inhibitory Effect of 50% Ethanolic Standardized Extract of Orthosiphon stamineus Benth in Normal and Streptozotocin-Induced Diabetic Rats

In the present study, a 50% ethanolic extract of Orthosiphon stamineus was tested for its α-glucosidase inhibitory activity. In vivo assays of the extract (containing 1.02%, 3.76%, and 3.03% of 3′hydroxy-5,6,7,4′-tetramethoxyflavone, sinensetin, and eupatorin, resp.) showed that it possessed an inhibitory activity against α-glucosidase in normal rats loaded with starch and sucrose. The results showed that 1000 mg/kg of the 50% ethanolic extract of O. stamineus significantly (P < 0.05) decreased the plasma glucose levels of the experimental animals in a manner resembling the effect of acarbose. In streptozotocin-induced diabetic rats, only the group treated with 1000 mg/kg of the extract showed significantly (P < 0.05) lower plasma glucose levels after starch loading. Hence, α-glucosidase inhibition might be one of the mechanisms by which O. stamineus extract exerts its antidiabetic effect. Furthermore, our findings indicated that the 50% ethanolic extract of O. stamineus can be considered as a potential agent for the management of diabetes mellitus.

Effects of a Proprietary Standardized Orthosiphon stamineus Ethanolic Leaf Extract on Enhancing Memory in Sprague Dawley Rats Possibly via Blockade of Adenosine A 2A Receptors

The aim of the study was to explore a propriety standardized ethanolic extract from leaves of Orthosiphon stamineus Benth in improving impairments in short-term social memory in vivo, possibly via blockade of adenosine A_2A receptors (A2AR). The ethanolic extract of O. stamineus leaves showed significant in vitro binding activity of A2AR with 74% inhibition at 150 μg/ml and significant A2AR antagonist activity with 98% inhibition at 300 μg/mL. A significant adenosine A₁ receptor (A1R) antagonist activity with 100% inhibition was observed at 300 μg/mL. Its effect on learning and memory was assessed via social recognition task using Sprague Dawley rats whereby the ethanolic extract of O. stamineus showed significant (p < 0.001) change in recognition index (RI) at 300 mg/kg and 600 mg/kg p.o and 120 mg/kg i.p., respectively, compared to the vehicle control. In comparison, the ethanolic extract of Polygonum minus aerial parts showed small change in inflexion; however, it remained insignificant in RI at 200 mg/kg p.o. Our findings suggest that the ethanolic extract of O. stamineus leaves improves memory by reversing age-related deficits in short-term social memory and the possible involvement of adenosine A₁ and adenosine A_2A as a target bioactivity site in the restoration of memory.

Antioxidant plants and diabetes mellitus

The incidence of diabetes mellitus (DM) is increasing rapidly and it is expected to increase by 2030. Other than currently available therapeutic options, there are a lot of herbal medicines, which have been recommended for its treatment. Herbal medicines have long been used for the treatment of DM because of the advantage usually having no or less side-effects. Most of these plants have antioxidant activities and hence, prevent or treat hard curable diseases, other than having the property of combating the toxicity of toxic or other drugs. In this review other than presenting new findings of DM, the plants, which are used and have been evaluated scientifically for the treatment of DM are introduced.

Hexane Extract of Orthosiphon stamineus Induces Insulin Expression and Prevents Glucotoxicity in INS-1 Cells

BACKGROUND

Hyperglycemia, a characteristic feature of diabetes, induces glucotoxicity in pancreatic β-cells, resulting in further impairment of insulin secretion and worsening glycemic control. Thus, preservation of insulin secretory capacity is essential for the management of type 2 diabetes. In this study, we evaluated the ability of an Orthosiphon stamineus (OS) extract to prevent glucotoxicity in insulin-producing cells.

METHODS

We measured insulin mRNA expression and glucose-stimulated insulin secretion (GSIS) in OS-treated INS-1 cells after exposure to a high glucose (HG; 30 mM) concentration.

RESULTS

The hexane extract of OS elevated mRNA expression of insulin as well as pancreatic and duodenal homeobox-1 of INS-1 cells in a dose-dependent manner. The hexane OS extract also increased the levels of phosphorylated phosphatidylinositol 3-kinase (PI3K) in a concentration-dependent manner. Additionally, Akt phosphorylation was elevated by treatment with 100 and 200 µmol of the hexane OS extract. Three days of HG exposure suppressed insulin mRNA expression and GSIS; these expressions were restored by treatment with the hexane OS extract. HG elevated peroxide levels in the INS-1 cells. These levels were unaffected by OS treatment under both normal and hyperglycemic conditions.

CONCLUSION

Our results suggested that the hexane extract of OS elevates insulin mRNA expression and prevents glucotoxicity induced by a 3-day treatment with HG. This was associated with the activation of PI-3K and Akt.

Protein glycation inhibitory activity and antioxidant capacity of clove extract

Syzygium aromaticum (L.) (clove) is one of the most widely cultivated spices in many tropical countries. The aim of this study was to determine the phytochemical content, the antioxidant properties and the antiglycation properties of aqueous extract of clove against fructose-mediated protein glycation and oxidation. The result showed that the content of total phenolics and flavonoids in clove extract was 239.58 ± 0.70 mg gallic acid equivalents/g dried extract and 65.67 ± 0.01 mg catechin equivalents/g dried extract, respectively. In addition, clove exhibited antioxidant properties including DPPH radical scavenging activity (IC50 = 0.29 ± 0.01 mg/ml), Trolox equivalent antioxidant capacity (4.69 ± 0.03 μmol Trolox equivalents/mg dried extract), ferric reducing antioxidant power (20.55 ± 0.11 μmol ascorbic acid equivalents/mg dried extract), Oxygen radical absorbance capacity (31.12 ± 0.21 μmol Trolox equivalents/mg dried extract), hydroxyl radical scavenging activity (0.15 ± 0.04 mg Trolox equivalents/mg dried extract), and superoxide radical scavenging activity (18.82 ± 0.50 mg Trolox equivalents/mg dried extract). The aqueous extract of clove (0.25-1.00 mg/ml) significantly inhibited the formation of fluorescent advanced glycation end products (AGEs) and non-fluorescent AGEs (N(ɛ)-(carboxymethyl) lysine (CML)) in glycated BSA during 4 weeks of incubation. The extract also markedly prevented oxidation-induced protein damage by decreasing protein carbonyl formation and protecting against the loss of protein thiol group. These results clearly demonstrated that a polyphenol enriched clove extract, owing to its antioxidant, was capable to inhibit the formation of AGEs and protein glycation. The findings might lead to the possibility of using the clove extract for targeting diabetic complications.

Morphological re-description of Cochlochila bullita (Stål) (Heteroptera: Tingidae), a potential pest of Orthosiphon aristatus Blume Miq. (Lamiales: Lamiaceae) in Malaysia

One species of lace bug Cochlochila bullita Stål (Heteroptera: Tingidae) was found heavily infested Orthosiphon aristatus Blume Miq., an important medicinal plant in Malaysia. A morphological re-description of C. bullita was done in order to facilitate the identification of this oligophagous insect pest. Five variables, body length and width, antenna length, tibia length and head width were measured from 15 samples from each stage. Among these variables, body length and width were used to construct the ratio for species identification; while body lengths with the other three variables were used to distinguish the nymphs from each developmental stage. The measurements of four traits except the antenna length showed significant differences between the development stages. And thus suggest the body width, tibia length and head width were suitable parameters used to distinguish the nymphal stages. However, the result on the growth factor showed only the sizes of the head followed a more constant growth rate with growth ratios (1.21-1.39) lie between the Dyar's ratio. Body length and width ratio for the adult female and male was 1.51 +/- 0.00 and 1.59 +/- 0.01, respectively. These data are pertinent for identifying developmental stages and to distinguish the species of the lace bug.

Effect of active fraction isolated from the leaf extract of Dregea volubilis [Linn.] Benth. on plasma glucose concentration and lipid profile in streptozotocin-induced diabetic rats

OBJECTIVE

The objective of the present study was to evaluate the effect of active fraction from Dregea volubilis [Linn.] Benth leaves on serum glucose and lipid profile in normal and diabetic rats.

MATERIALS AND METHODS

Diabetes was induced by streptozotocin in wistar rats. Petroleum ether, ethyl acetate, and ethanol extracts of Dregea volubilis [Linn.] Benth leaves were administered orally at a dose of 200 mg/kg, p.o. Metformin was used as standard Anti-diabetic drug (50 mg/kg, p.o). The extract showing for higher Anti-diabetic activity was subjected to column chromatography that led to isolation of an active fraction, which was given trivial name Dv-1. Dv-1 (100 mg/kg, p.o.) was studied for its hypoglycemic and hypolipidemic potential.

RESULTS

Ethanol extract was found to lower the Fasting blood glucose (FBG) level significantly (p < 0.05) in diabetic rats. Dv-1 caused a significant (p < 0.05) reduction in FBG level. Additionally it also caused reduction in cholesterol, triglyceride levels and improvement in the HDL level in diabetic rats.

CONCLUSION

Reduction in the FBG, cholesterol, triglyceride levels and improvement in the HDL by Dv-1 indicates that Dv-1 has Anti-diabetic activity along with anti hyperlipidemic efficacy and provides a scientific rationale for the use as an Anti-diabetic agent.

Vascular Reactivity Concerning Orthosiphon stamineus Benth-Mediated Antihypertensive in Aortic Rings of Spontaneously Hypertensive Rats

Orthosiphon stamineus Benth has been traditionally used to treat hypertension. The study aimed to investigate the vascular reactivity of water extract (WOS) and water : methanolic (1 : 1) extract (WMOS) of Orthosiphon stamineus Benth and AT₁ receptors blocker in the mechanisms of antihypertensive mediated by α₁-adrenergic receptor and EDNO and PGI₂ releases in the SHR aortic rings. SHR (230–280 g) were divided into four groups: control, WOS, WMOS, and losartan. After being fed orally for 14 days, the aorta was harvested and subjected to PE (10⁻⁹ to 10⁻⁵ M) and ACh (10⁻⁹ to 10⁻⁵ M) with and without L-NAME (100 µM) and indomethacin (10 µM), respectively. WOS, WMOS, and losartan significantly reduced the contractile responses to PE intact suggesting the importance of endothelium in vasorelaxation. Losartan significantly enhanced the ACh-induced vasorelaxation. L-NAME significantly inhibited the ACh-induced relaxation in all groups. Indomethacin enhanced ACh-induced vasorelaxation in WMOS. Collectively, Orthosiphon stamineus leaves extract reduced vasoconstriction responses by the alteration of α₁-adrenergic and AT₁ receptors activities. The involvement of EDNO releases was clearly observed in this plant. In WOS, PGI₂ releases might not participate in the ACh-induced vasorelaxation. However, in WMOS, enhancement of vasorelaxation possibly due to continuous release of PGI₂.

Combined treatment of betulinic acid, a PTP1B inhibitor, with Orthosiphon stamineus extract decreases body weight in high-fat-fed mice

Leptin resistance is a common feature of obesity and is accompanied by hyperleptinemia. Although leptin sensitizers improve leptin resistance, they also decrease plasma leptin levels that attenuate the leptin-associated antiobesity effect. We hypothesized that the combinational treatment of leptin sensitizer and endogenous leptin expression stimulant would synergistically induce an antiobesity effect in high-fat-fed obese animals. Betulinic acid (BA) isolated from Saussurea lappa suppressed the hypothalamic protein tyrosine phosphatase 1B in mice and enhanced the antiobesity effect of leptin in obese rats. Ethanol extract of Orthosiphon stamineus (OS) induced leptin expressions in both 3T3-L1 adipocytes and mice in a dose-dependent manner. To evaluate our hypothesis, we treated obese mice induced by 6 weeks of high-fat-diet feeding with BA and OS for 2 weeks. Although BA or OS alone did not decrease body weight in obese mice, the combinational treatment of BA and OS decreased body weight significantly compared to either BA- or OS-treated obese mice. These results suggest that combinational treatment of BA and OS would be effective for the treatment of obesity.

Prophylactic effects of Orthosiphon stamineus Benth. extracts on experimental induction of calcium oxalate nephrolithiasis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Orthosiphon stamineus (OS) popularly known as "diuretic agent" are traditionally used in folk medicine in the treatment of hyperuricemia, rheumatism, gout, nephritis, nephrolithiasis, urethritis and cystitis.

AIM OF THE STUDY

To evaluate prophylactic potentials of total flavonoids, total phenolics and polysaccharides from OS on experimental induction of calcium oxalate (CaOx) nephrolithiasis in rats.

MATERIALS AND METHODS

Nephrolithic rats were induced by treating with 1.0% ethylene glycol and 1.0% ammonium chloride for 7 days. Rats in the treated groups were also given OS extracts at the doses of 80 mg/kg and 160 mg/kg. Urine samples (4h) and serum samples were collected at 7th day for biochemical analysis. Kidney tissues were stained with H.E. and analyzed by light microscopy. Expressions of OPN protein were detected by immunohistochemistry. Rates of nucleation and aggregation of calcium oxalate crystals were derived from 20-min time-course measurements of optic density at 620 nm after mixing solutions containing calcium chloride, sodium oxalate and OS extracts at 37°C, pH 5.7.

RESULTS

Polysaccharides exhibited the most significant prophylactic effects by reversing BUN and S(cr) levels, ameliorating histopathological changes, increasing urine C(2)O(4)(2-) and Ca(2+) excretion and down-regulating OPN protein expression of kidney in the model rats in comparison with those effects of total flavonoids and total phenolics. Polysaccharides could also significantly inhibit both nucleation and aggregation of CaOx crystals.

CONCLUSIONS

Polysaccharides were the main therapeutic materials in OS. It had impressive prophylactic effects on CaOx stones in nephrolithic rats, playing a role as a regulator of OPN protein expression to increase urine C(2)O(4)(2-) and Ca(2+) excretion and also as an inhibitor of CaOx crystallization.

Potent α-glucosidase and α-amylase inhibitory activities of standardized 50% ethanolic extracts and sinensetin from Orthosiphon stamineus Benth as anti-diabetic mechanism

Background

In the present study, we tested a 50% ethanolic extract of Orthosiphon stamineus plants and its isolated bioactive compound with respect to their α-glucosidase and α-amylase inhibitory activities.

Methods

Bioactive flavonoid sinensetin was isolated from 50% ethanolic extract of Orthosiphon stamineus. The structure of this pure compound was determined on the NMR data and the α-glucosidase and α-amylase inhibitory activities of isolated sinensetin and 50% ethanolic extract of Orthosiphon stamineus were evaluated.

Results

In vitro studies of a 50% ethanolic extract of O. stamineus and the isolated sinensetin compound showed inhibitory activity on α-glucosidase (IC₅₀: 4.63 and 0.66 mg/ml, respectively) and α-amylase (IC₅₀: 36.70 mg/ml and 1.13 mg/ml, respectively). Inhibition of these enzymes provides a strong biochemical basis for the management of type 2 diabetes via the control of glucose absorption.

Conclusion

Alpha-glucosidase and α-amylase inhibition could the mechanisms through which the 50% ethanolic extract of O. stamineus and sinensetin exert their antidiabetic activity, indicating that it could have potential use in the management of non-insulin-dependent diabetes.

Hepatoprotective Effects of Orthosiphon stamineus Extract on Thioacetamide-Induced Liver Cirrhosis in Rats

Orthosiphon stamineus as medicinal plant is commonly used in Malaysia for treatment of hepatitis and jaundice; in this study, the ethanol extracts were applied to evaluate the hepatoprotective effects in a thioacetamide-induced hepatotoxic model in Sprague Dawley rats. Five groups of adult rats were arranged as follows: Group 1 (normal control group), Group 2 Thioacetamide (TAA) as positive control (hepatotoxic group), Group 3 Silymarin as a well-known standard drug (hepatoprotective group), and Groups 4 and 5 as high and low dose (treatment groups). After 60-day treatment, all rats were sacrificed. The hepatotoxic group showed a coarse granulation on the liver surface when compared to the smooth aspect observed on the liver surface of the other groups. Histopathological study confirmed the result; moreover, there was a significant increase in serum liver biochemical parameters (ALT, AST, ALP, and Bilirubin) and the level of liver Malondialdehyde (MDA), accompanied by a significant decrease in the level of total protein and Albumin in the TAA control group when compared with that of the normal group. The high-dose treatment group (200 mg/kg) significantly restored the elevated liver function enzymes near to normal. This study revealed that 200 mg/kg extracts of O. stamineus exerted a hepatoprotective effect.

Evaluation of alpha-glucosidase, alpha-amylase and protein glycation inhibitory activities of edible plants

The present study was to investigate in vitro alpha-glucosidase, pancreatic alpha-amylase and protein glycation inhibitory activities of nine edible plants. The results indicated that total phenolics, flavonoids, and condensed tannins of nine edible plants showed marked variations, ranging from 12.2 to 80.1 mg gallic acid equivalent/g extract, 2.34 to 13.65 mg quercetin equivalent/g extract, and 97.2 to 460.1 mg catechin equivalent/g extract, respectively. Our findings showed that grape seed, Cat's whiskers and Sweetleaf extract were the most effective pancreatic alpha-amylase, intestinal maltase, and sucrase inhibitor with IC(50) values of 0.29 +/- 0.01 mg/ml, 0.97 +/- 0.10 mg/ml and 0.86 +/- 0.01 mg/ml, respectively. All extracts (1 mg/ml) markedly inhibited the glycation of bovine serum albumin in fructose-mediated non-enzyme glycation by 50-30% at week 1. It was found that Pennywort maintained the high percentage inhibition among those of the extracts during the 4 weeks of experiment. These edible plants may be used for controlling blood glucose level and prevention of the development of type 2 diabetes.

HPLC and anti-inflammatory studies of the flavonoid rich chloroform extract fraction of Orthosiphon stamineus leaves

The aim of the present study was to verify the anti-inflammatory activity of Orthosiphon stamineus leaf extracts and to identify the active compound(s) contributing to its anti-inflammatory activity using a developed HPLC method. Active chloroform extract of O. stamineus was fractionated into three fractions using a dry flash column chromatography method. These three fractions were investigated for anti-peritoneal capillary permeability, in vitro nitric oxide scavenging activity, anti-inflammatory and nitric oxide (NO) inhibition using carrageenan-induced hind paw edema method. The flavonoid rich chloroform extract fraction (CF2) [containing sinensetin (2.86% w/w), eupatorin (5.05% w/w) and 3’-hydroxy-5,6,7,4’-tetramethoxyflavone (1.101% w/w)], significantly reduced rat hind paw edema, NO and decreased dye leakage to peritoneal cavity at p < 0.05. IC₅₀ of in vitro NO scavenging of CF2 was 0.3 mg/mL. These results suggest that the anti-inflammatory properties of these CF2 may possibly be due to the presence of flavonoid compounds capable of affecting the NO pathway.

The antihyperglycemic effect of aerial parts of Salvia splendens (scarlet sage) in streptozotocin-induced diabetic-rats

Salvia splendens (Labiatae) is widely used in Indian traditional medicine for the control of diabetes mellitus. In this study, the hypoglycemic effects produced by the acute and subacute administration of various extracts of S. splendens were investigated. Both the aqueous extract (SSAE) and the methanolic extract (SSME) from the aerial parts resulted in significant reductions of glycemia in streptozotocin (STZ)-induced diabetic rats after oral administration at a dose of 100 and 200 mg/kg, respectively. On oral administration, aqueous and methanolic extracts showed statistically significant (P < 0.001) effect by reducing the effect of glycemia in STZ-induced diabetic rats. These findings suggest the significant antihyperglycemic potential of the S. splendens extracts in ameliorating the diabetic conditions in diabetic rats. No significant effects were found in the normal rats.

Insulin-releasing properties of a series of cinnamic acid derivatives in vitro and in vivo

Cinnamic acid derivatives are naturally occurring substances found in fruits, vegetables, and flowers and are consumed as dietary phenolic compounds. In the present study, cinnamic acid and its derivatives were evaluated for insulin secreting activity in perfused rat pancreas and pancreatic beta-cells (INS-1) as well as an increase in [Ca(2+)]i in vitro. The presence of m-hydroxy or p-methoxy residues on cinnamic acid was a significantly important substituent as an effective insulin releasing agent. The introduction of p-hydroxy and m-methoxy-substituted groups in cinnamic acid structure (ferulic acid) displayed the most potent insulin secreting agent among those of cinnamic acid derivatives. In particular, the stimulatory insulin secreting activities of test compounds were associated with a rise of [Ca(2+)]i in INS-1. In perfused rat pancreas, m-hydroxycinnamic acid, p-methoxycinnamic acid, and ferulic acid (100 microM) significantly stimulated insulin secretion during 10 min of administration. The onset time of insulin secretion of those compounds was less than 1 min and reached its peak at 4 min that was about 2.8-, 3.3-, and 3.4-fold of the baseline level, respectively. Intravenous administration of p-methoxycinnamic acid and ferulic acid (5 mg/kg) significantly decreased plasma glucose and increased insulin concentration in normal rats and maintained its level for 15 min until the end of experiment. Meanwhile, m-hydroxycinnamic acid induced a significant lowering of plasma glucose after 6 min, but the effects were transient with plasma glucose concentration, rapidly returning to basal levels. Our findings suggested that p-methoxycinnamic acid and ferulic acid may be beneficial for the treatment of diabetes mellitus because they regulated blood glucose level by stimulating insulin secretion from pancreatic beta-cells.

Studies on diuretic and hypouricemic effects of Orthosiphon stamineus methanol extracts in rats

AIM OF THE STUDY

Orthosiphon stamineus (Labiatae) is a traditional folk medicine widely used in Southeast Asia for the treatment of several kidney disorders, gout and as a diuretic. This study was conducted to examine the diuretic and hypouricemic effects of Orthosiphon stamineus leaf extracts.

MATERIALS AND METHODS

The diuretic effect of different methanol extracts was examined by treating different groups of Sprague-Dawley rats with single (2g/kg) oral doses of methanol and methanol:water (1:1) extracts. Hydrochlorothiazide (10mg/kg) was used as positive control in acute study. Methanol and methanol water (1:1) extracts at 0.5 g/kg were administered for a period of 7 consecutive days. Cumulative urine volume and electrolytes (Na+ and K+) concentrations at different time intervals were measured. On the other hand, hypouricemic activity of methanol:water extract (1:1) was experimented using different oral single doses (0.25, 0.5, 1 and 2g/kg). Allopurinol was used as positive control. Uric acid concentration in serum was analyzed by using RP-HPLC at 280 nm.

RESULTS

Sodium and potassium excretion increased significantly (p<0.05 and <0.01) in the first 8h of treatment with a single dose (2g/kg) of the extracts in a pattern comparable to that of the known diuretic hydrochlorothiazide. Meanwhile, repeated administration of 0.5 g/kg methanol:water (1:1) extract showed a significant increase in urine volume (from day 3 to day 7) (p<0.01) and electrolytes excretion (Na+ and K+) from day 2 to day 7 (p<0.05 and <0.01). On the other hand, 0.5, 1 and 2g/kg of methanol:water (1:1) extract and the standard allopurinol reduced the serum urate level in hyperuricemic rats at hour 6.

CONCLUSION

These results provided an evidence of the high tendency of methanol:water (1:1) extract of Orthosiphon stamineus towards diuretic and hypouricemic effects in rats.

Effects of seaweed supplementation on blood glucose concentration, lipid profile, and antioxidant enzyme activities in patients with type 2 diabetes mellitus

The present study was carried out to evaluate the physiological effects of seaweed supplementation on blood glucose levels, lipid profile, and antioxidant enzyme activities in subjects with type 2 diabetes mellitus. Subjects were randomized into either a control group or a seaweed supplementation group. Pills with equal parts of dry powdered sea tangle and sea mustard were provided to the seaweed supplementation group three times a day for 4 weeks. Total daily consumption of seaweed was 48 g. We found that total dietary fiber intake was 2.5 times higher in subjects receiving seaweed supplementation than in the control group. Accordingly, fasting blood glucose levels (p<0.01) and 2-hour postprandial blood glucose measurements (p<0.05) were decreased significantly in those ingesting seaweed. Furthermore, the serum concentrations of triglycerides were decreased and high-density lipoprotein cholesterol was increased significantly in seaweed supplement group (p<0.05). However, the concentrations of total cholesterol and low-density lipoprotein cholesterol were not affected by seaweed supplementation. The level of thiobarbituric acid reactive substances in erythrocytes was significantly lower with seaweed supplementation compared to controls (p<0.05). Catalase and glutathione peroxidase activities with seaweed supplementation were higher than the controls (p<0.05), but superoxide dismutase activity was not affected. We, therefore, conclude that ingestion of seaweed influences glycemic control, lowers blood lipids, and increases antioxidant enzyme activities.

Fructus Corni suppresses hepatic gluconeogenesis related gene transcription, enhances glucose responsiveness of pancreatic beta-cells, and prevents toxin induced beta-cell death

ETHNOPHARMACOLOGICAL RELEVANCE

Fructus Corni, the fruits of Cornus officinalis Sieb. et Zucc., is one important ingredient in Quei Fu Di Huang Wan, a Chinese herbal mixture.

AIM OF THE STUDY

In the present study, additional anti-diabetic actions of Fructus Corni on transcriptional regulation of hepatic gluconeogenesis or beta-cell functions were investigated.

MATERIALS AND METHODS

Insulin mimetic action of Fructus Corni on dexamethasone and 8-bromo-cAMP induced phosphoenolpyruvate carboxykinase (PEPCK) expression in H4IIE cells was investigated. Besides, BRIN-BD11 cells were used to evaluate both insulinotropic and beta-cell protective effect of Fructus Corni.

RESULTS

Firstly, both methanol extract (CO-W-M) and fraction (CO-W-M2) had potent insulin mimic activity on PEPCK expression. Secondly, possibility of both loganin and ursolic acid as the responsible compounds was excluded. Moreover, indication of the existence of phenolic compounds in CO-W-M2 was noticed. In the presence of CO-W-M2, not only was the viability of BRIN-BD11 cells treated with alloxan, streptozotcin, or cytokine mix all significantly increased but also glucose-stimulated insulin secretion was potentiated.

CONCLUSIONS

The ability of CO-W-M2 to reduce gene expression for hepatic gluconeogenesis, to protect beta-cell against toxic challenge, and to enhance insulin secretion strengthen the role of Fructus Corni in diabetes therapy.

Proposal open for discussion: defining agreed diagnostic procedures in experimental diabetes research

BACKGROUND

Animal experimentation has a long tradition in diabetes research and has provided invaluable benefits with regard to insulin discovery and treatment assessment.

METHODS

The review focuses on chemical-induced diabetes in rats and surveys the protocols of diabetes induction, diabetes diagnosis, and glucose tolerance evaluation in a selection of recent research.

RESULTS

This brief review of techniques in experimental diabetes highlights that there is no uniformity, whereas standardisation of procedures is desirable so that comparability will exist among experiments carried out in different settings.

CONCLUSIONS

On this basis, questions are put and standards are proposed. It would be a platform to promote the exchange of ideas through expert consultation about practical issues related to animal research and a basis on which standards can be set according to user requirements and animal respect.

Herbal medicines as diuretics: a review of the scientific evidence

There is increasing interest in the health and wellness benefits of herbs and botanicals. This is with good reason as they might offer a natural safeguard against the development of certain conditions and be a putative treatment for some diseases. One such area may be the lowering of blood pressure in those where it is elevated (i.e., hypertension). One class of clinical medicines used to lower blood pressure are known as diuretics and work by increasing the excretion of urine from the body as well as the amount of sodium in urine. There are a growing number of studies purporting diuretic effects with traditional medicines. The aim of this article was to review these studies and identify which extracts promote diuresis (which we assessed on terms of urine excreted and urinary sodium excretion) and also to identify the research needs in this area. We identified a number of species and genuses reporting diuretic effects. Of these, the most promising, at the present time, are the species Foeniculum vulgare, Fraxinus excelsior, Hibiscus sabdariffa, Petroselinum sativum and Spergularia purpurea, and species from the genuses Cucumis (Cucumis melo and Cucumis trigonus), Equisetum (Equisetum bogotense, Equisetum fluviatile, Equisetum giganteum, Equisetum hiemale var. affine and Equisetum myriochaetum), Lepidium (Lepidium latifolium and Lepidium sativum), Phyllanthus (Phyllanthus amarus, Phyllanthus corcovadensis and Phyllanthus sellowianus) and Sambucus (Sambucus mexicana and Sambucus nigra). However, there the number of studies is limited and we recommend that further studies be conducted to confirm reported effects. Such evidence is needed to provide scientific credence to the folklore use of traditional medicines and even be helpful in the development of future medicines, treatments and treatment guidelines.

Contribution of tomato phenolics to antioxidation and down-regulation of blood lipids

This study was performed to understand the characteristics and biological activities of phenolics in tomatoes and to examine the effect of tomato on the regulation of blood lipids. Tomatoes of both big and small sizes were used fresh, after blanching, or after blanching and heating. Moreover, a human clinical trial was conducted to examine plasma antioxidation, status of blood lipids, and phenolic responses after ingestion of fresh tomato, tomato juice, and a lycopene drink. The contents of tomato phenolics were increased by 34% for small tomato and by 23% for big tomato after treatment by blanching and heating at 100 degrees C for 30 min. Tomato phenolics showed fair antioxidant activity (57-71%) and also synergistically promoted the antioxidation (81-100%) of tomato carotenoids. In the human clinical study, total antioxidant capacity and phenolic contents in plasma were increased after administration of fresh tomato and tomato juice, but no significant difference was found for lycopene drink consumption. Triglyceride levels and low-density lipoprotein cholesterol were decreased after administration of fresh tomato and tomato juice, and high-density lipoprotein cholesterol was increased.