Indian herbs and herbal drugs used for the treatment of diabetes

A Fraxinus excelsior L. seeds/fruits extract benefits glucose homeostasis and adiposity related markers in elderly overweight/obese subjects: a longitudinal, randomized, crossover, double-blind, placebo-controlled nutritional intervention study

PURPOSE

The aim of this study was to investigate the potential benefits of an extract obtained from seeds/fruits of an Oleaceae (Fraxinus excelsior L.) on glucose homeostasis and associated metabolic markers in non-diabetic overweight/obese subjects.

MATERIALS AND METHODS

This study was performed in 22 participants (50-80 years-old; BMI 31.0 kg/m(2)). The design was a longitudinal, randomized, crossover, double-blind, placebo-controlled 7-week nutritional intervention. The participants received daily 3 capsules each containing either 333 mg of an extract from Fraxinus excelsior L. seeds (Glucevia(®)) or placebo capsules (control) in a random order for 3 weeks with 1 week of washout between treatments. Moreover, they followed a balanced covert energy-restricted diet (-15% energy). All variables were measured at the beginning and at the end of each period.

RESULTS

Compared to baseline, the administration of 1 g of Glucevia(®) for 3 weeks resulted in significantly lower incremental glucose area under the curve (-28.2%; p<0.01), and significantly lower 2 h blood glucose values (-14%; p<0.01) following an oral glucose tolerance test. No significant changes were found in the control group (-7.9% AUC, -1.6% 2h blood glucose). Furthermore, significant differences were found between responses in the control and Glucevia(®) groups with respect to serum fructosamine and plasma glucagon levels (p<0.01 and p<0.05, respectively). Interestingly, administration of Glucevia(®) significantly increased the adiponectin:leptin ratio (p<0.05) and decreased fat mass (p<0.01) compared to control (p<0.05).

CONCLUSION

The administration of an extract from Fraxinus excelsior L. seeds/fruits in combination with a moderate hypocaloric diet may be beneficial in metabolic disturbances linked to impaired glucose tolerance, obesity, insulin resistance and inflammatory status, specifically in older adults.

Blood glucose-lowering effect of Tectona grandis flowers in type 2 diabetic rats: a study on identification of active constituents and mechanisms for antidiabetic action

BACKGROUND

Ayurveda documents antidiabetic activity of Tectona grandis flowers. However, until now, the effects of T. grandis flowers in preclinical models of type 2 diabetes (T2D) have been unknown. Hence, the aim of the present study was to evaluate the blood glucose-lowering effect of methanol extract of T. grandis flowers (METGF) in T2D rats and to identify possible active constituents as well as the mechanisms for the antidiabetic action.

METHODS

Rats were rendered diabetic by administration of streptozotocin-nicotinamide (65 mg/kg-110 mg/kg, i.p.). After the induction of diabetes, Groups 3 and 4 received METGF (100 and 200 mg/kg respectively) while Group 5 received glibenclamide (5 mg/kg) orally for 4 weeks. Blood glucose and body weight were determined at the end of Weeks 2 and 4. Hemoglobin, HbA1c, total protein, urea, creatinine, insulin, and lipid levels were determined in Week 4. Active constituents in METGF were identified using HPLC analysis. Antidiabetic mechanisms of METGF were evaluated by investigating the insulin sensitizing action and inhibition of α-amylase and α-glucosidase activity.

RESULTS

Both METGF and glibenclamide significantly improved body weight, reduced blood glucose, and normalized altered biochemical parameters (P < 0.001) in T2D rats. The presence of polyphenolic active constituents, such as gallic acid, quercetin, rutin, ellagic acid, ferulic acid, and kaempferol, in METGF was confirmed by HPLC. In vitro, METGF, gallic acid, quercetin, and rutin exhibited significant (P < 0.001) insulin sensitizing action and inhibition of α-amylase and α-glucosidase activity.

CONCLUSIONS

Polyphenolic active constituents present in METGF are possibly responsible for the blood glucose-lowering effect in T2D rats via an insulin-sensitizing action, as well as inhibition of α-amylase and α-glucosidase activity.

Virtual Screening of Natural and Synthetic Ligands Against Diabetic Retinopathy by Molecular Interaction With Angiopoietin-2

PURPOSE

Diabetic retinopathy (DR) is the most common diabetic eye disease and a leading cause of blindness. The role of angiopoietin-2 a tyrosine kinase receptor is well-reported in angiogenesis during the onset of the disease. The purpose of this study is to screen out more potential herbal molecules which can evidently be used as a better, natural and safe herbal drug against this disease.

DESIGN

In silico virtual screening and molecular interaction studies were performed.

METHODS

The current course of work focused on molecular interactions on angiopoietin-2 protein with selected natural ligands, namely allicin, ajoene, D-pinitol and salacinol, along with synthetic ones like nateglinide, biguanide, tolbutamide and tolazamide. There was an attempt to carry out the virtual comparative study between natural and synthetic ligands. Proceeding toward this approach, docking of all molecules was performed using the Autodock 4.2 program.

RESULTS

Inference of this interaction study is that D-pinitol, which is the herbal extract of Glycine max, shows a very reliable docking pattern as compared with the synthetic ligand tolazamide. Although the binding energy of a synthetic ligand is lower compared to that of the natural ones, the binding energy of synthetic and natural ligands are at an approximate level. The lower the binding energy, the better the ligand molecular interaction.

CONCLUSIONS

Our findings suggest that D-pinitol, the natural, safe ligand, can be used in the treatment of diabetic retinopathy with few or no side effects after estimating and calculating proper doses using in vitro approaches.

Differential anti-diabetic effects and mechanism of action of charantin-rich extract of Taiwanese Momordica charantia between type 1 and type 2 diabetic mice

Momordica charantia Linn. (Cucurbitaceae), also called bitter melon, has traditionally been used as a natural anti-diabetic agent for anti-hyperglycemic activity in several animal models and clinical trials. We investigated the differences in the anti-diabetic properties and mechanism of action of Taiwanese M. charantia (MC) between type 1 diabetic (T1D) and type 2 diabetic (T2D) mice. To clarify the beneficial effects of MC, we measured non-fasting glucose, oral glucose tolerance, and plasma insulin levels in KK/HIJ mice with high-fat diet-induced diabetes (200 mg/kg/day of charantin-rich extract of MC [CEMC]) and in ICR mice with STZ-induced diabetes. After 8 weeks, all the mice were exsanguinated, and the expression of the insulin-signaling-associated proteins in their tissue was evaluated, in coordination with the protective effects of CEMC against pancreatic β-cell toxicity (in vitro). Eight weeks of data indicated that CEMC caused a significant decline in non-fasting blood glucose, plasma glucose intolerance, and insulin resistance in the KK/HIJ mice, but not in the ICR mice. Furthermore, CEMC decreased plasma insulin and promoted the sensitivity of insulin by increasing the expression of GLUT4 in the skeletal muscle and of IRS-1 in the liver of KK/HIJ mice; however, CEMC extract had no effect on the insulin sensitivity of ICR mice. In vitro study showed that CEMC prevented pancreatic β cells from high-glucose-induced cytotoxicity after 24 h of incubation, but the protective effect was not detectable after 72 h. Collectively, the hypoglycemic effects of CEMC suggest that it has potential for increasing insulin sensitivity in patients with T2D rather than for protecting patients with T1D against β-cell dysfunction.

Phytotherapy in diabetes: Review on potential mechanistic perspectives

Diabetes mellitus (DM) is a widely spread epidemic disease that results from the absence of insulin, decreased secretion and/or impaired function. Since DM is a multi-factorial disease, the available pharmaceuticals, despite their sensible treatment, target mostly one pathway to control hyperglycemia and encounter several side effects. Therefore, new therapeutic paradigms aim to hit several pathways using only one agent. Traditionally, antidiabetic plants and/or their active constituents may fulfill this need. More than 200 species of plants possess antidiabetic properties which were evaluated mostly by screening tests without digging far for the exact mode of action. Searching among the different literature resources and various database and in view of the above aspects, the present article provides a comprehensive review on the available antidiabetic plants that have been approved by pharmacological and clinical evaluations, and which their mechanism(s) of action is assured. These plants are categorized according to their proved mode of action and are classified into those that act by inhibiting glucose absorption from intestine, increasing insulin secretion from the pancreas, inhibiting glucose production from hepatocytes, or enhancing glucose uptake by adipose and muscle tissues. The current review also highlights those that mimic in their action the new peptide analogs, such as exenatide, liraglutide and dipeptidylpeptidase-4 inhibitors that increase glucagon-like peptide-1 serum concentration and slow down the gastric emptying.

Diabetes and related remedies in medieval Persian medicine

Diabetes Mellitus is a common metabolic disorder presenting increased amounts of serum glucose and will cover 5.4% of population by year 2025. Accordingly, this review was performed to gather and discuss the stand points on diagnosis, pathophysiology, non-pharmacological therapy and drug management of diabetes this disorder as described in medieval Persian medicine. To this, reports on diabetes were collected and analyzed from selected medical and pharmaceutical textbooks of Traditional Persian Medicine. A search on databases as Pubmed, Sciencedirect, Scopus and Google scholar was also performed to reconfirm the Anti diabetic activities of reported herbs. The term, Ziabites, was used to describe what is now spoken as diabetes. It was reported that Ziabites, is highly associated with kidney function. Etiologically, Ziabites was characterized as kidney hot or cold dystemperament as well as diffusion of fluid from other organs such as liver and intestines into the kidneys. This disorder was categorized into main types as hot (Ziabites-e-har) and cold (Ziabites-e-barid) as well as sweet urine (Bole-e-shirin). Most medieval cite signs of Ziabites were remarked as unusual and excessive thirst, frequent urination and polydipsia. On the management, life style modification and observing the essential rules of prevention in Persian medicine as well as herbal therapy and special simple manipulations were recommended. Current investigation was done to clarify the knowledge of medieval scientists on diabetes and related interventions. Reported remedies which are based on centuries of experience might be of beneficial for- further studies to the management of diabetes.

Iranian medicinal plants for diabetes mellitus: a systematic review

In the Iranian traditional medicine a significant usage of herbs is promoted for their anti-diabetic activity. The aim of this review to assess the efficacy of glucose lowering effects of medicinal plants cultivated in Iran. An electronic literature search of MEDLINE, Science Direct, EMBASE, Scopus, Web of Science, Cochrane Library Database, Ebsco and Google Scholar from database inception conducted up to May 2012. A total of 85 studies (18 humans and 67 animals) examining 62 plants were reviewed. The quality of Randomized Controlled Trials (RCTs) assessed by using the Jadad scale. Among the RCTs studies, the best results in glycemic control was found in Aloe vera, Citrullus colocynthus, Plantago ovata, Silybum marianum, Rheum ribes and Urtica dioica. The majority of plants that have been studied for antidiabetic activity showed promising results. However, efficacy and safety of the most plants used in the treatment of diabetes are not sufficient.

Paederia foetida Linn. leaf extract: an antihyperlipidemic, antihyperglycaemic and antioxidant activity

Background

The primary objective of the present investigation is to evaluate the antidiabetic, antihyperlidemic and antioxidant activity of the methanolic extract of the Paederia foetida Linn. (PF) leaf extract in the streptozotocin induced diabetic rats.

Methods

Single intraperitoneal injection (IP) of streptozotocin (60 mg/kg body weight) was used for induction of diabetes is swiss albino (wistar strain) rats. The induction of diabetes was confirmed after 3 days as noticing the increase in blood sugar level of tested rats. PF at a once a daily dose of 100 mg/kg, 250 mg/kg, 500 mg/kg, p.o. along with glibenclamide 10 mg/kg, p.o. was also given for 28 days. On the 28^th day rats from all the groups fasted overnight fasted and the blood was collected from the puncturing the retro orbit of the eye under mild anesthetic condition. There collected blood sample was used to determine the antihyperlipidemic, hypoglycemic and antioxidant parameters.

Results

The oral acute toxicity studies did not show any toxic effect till the dose at 2000 mg/kg. While oral glucose tolerance test showed better glucose tolerance in tested rats. The statistical data indicated that the different dose of the PF significantly increased the body weight, hexokinase, plasma insulin, high density lipoprotein cholesterol, superoxide dismutase, catalase and glutathione peroxides. It also decreases the level of fasting blood glucose, total cholesterol, triglycerides, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, malonaldehyde, glucose-6-phosphate, fructose-1-6-biphosphate and glycated hemoglobin in STZ induced diabetic rats. The histopathology of STZ induce diabetic rats, as expected the test dose of PF extract considerably modulates the pathological condition of various vital organ viz. heart, kidney, liver, pancreas as shown in the histopathology examinations.

Conclusions

Our investigation has clearly indicated that the leaf extract of Paederia foetida Linn. showed remarkable antihyperglycemic activity due to its possible systematic effect involving in the pancreatic and extra pancreatic mechanism. Forever, the antihyperlipidemic activity was exerted possible by lowering the higher level of lipid profile and decreasing the intercalated disc space in the heart. The antioxidant activity of extract was due to inhibition of lipid peroxidation and increasing the SOD, GPx and CAT. It was corroborate that the extract shown the Paederia foetida Linn leaves potential to be act as antidiabetic, antihyperlipidemic and antioxidant properties.

Ethnomedicinal plants used by the villagers of district Udhampur, J&K, India

Plants are an integral part of life in many indigenous communities. Besides, being the source of food, fodder, fuel, etc., the use of plants as herbal medicines in curing several ailments goes parallel to the human civilization. Ethnopharmacology involves the investigation of the plants used by the traditional communities and further understand the pharmacological basis of these culturally important medicinal plants. Present study was conducted to enlist the medicinal plants used by the local inhabitants of Udhampur district of Jammu and Kashmir, India.

MATERIAL AND METHODS

Direct interviews of the 182 informants were conducted. The data generated through interviews was analysed using quantitative tools like use-value, factor informant consensus and fidelity level.

RESULTS

A total of 166 species of flowering plants belonging to 63 families and 145 genera were observed to be medicinal and used to cure 78 ailments. Medicinal plants were mainly from Asteraceae, Solanaceae, Lamiaceae, Poaceae, Fabaceae and Amaranthaceae families. Leaves were the most used plant part in the medicinal preparations. The most important medicinal species of the present study site as per the use-value (UV) were: Achyranthes aspera, Zanthoxylum armatum, Acorus calamus, Syzygium cumini, Phyllanthus emblica, Plumbago zeylanica etc. The important ailment categories classified on the basis of factor informant consensus (Fic) were diabetes, external parasite, liver complaints and gastrointestinal disorders. The maximum number of species was utilized to cure gastrointestinal and dermatological ailments. Important species for each ailment category were also assessed using fidelity level. It was found that the older informants provided more information about the ethnomedicinal plants, but this valuable treasure of traditional knowledge is depleting significantly with the decrease in age and increase in educational level.

CONCLUSION

The results of present ethnobotanical survey reveal the rich wealth of indigenous knowledge associated with the villagers of Udhampur district. A number of plants with a high citation values have given some leads for the further pharmocological research. Apart from these highly cited plants, studies need to be done on some other promising plants like Anagallis arvensis, Euphorbia hirta, Ficus benghalensis, Fumaria indica, Prunus persica, Rubus ellipticus, Taraxacum officinale, Tribulus terrestris etc.

Analgesic, anti-inflammatory, and antipyretic effects of Ixora coccinea

Abstract Background: The present study was carried out to explore the potential of the ethanol extract of Ixora coccinea L. (IC) leaves as analgesic, anti-inflammatory and antipyretic agents using the hot-plate, acetic acid-induced writhing, carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests in rodents. Methods: The extract was prepared by soaking the dried powdered leaves of IC in ethanol for 2 days. The filtrate thus obtained by filtration and evaporation was considered as a stock solution and was used in all experimental models. Results: Oral administration of IC (250 and 500 mg/kg) significantly (p<0.05) increased the reaction time in the hot-plate test. Ixora coccinea (250 and 500 mg/kg) produced 56.14% and 63.16% inhibition (p<0.05) in acetic acid-induced writhing. It also (250 and 500 mg/kg) produced significant (p<0.05) inhibition of paw edema pronounced at 6 h after carrageenan injection. Intraperitoneal administration of IC (250 and 500 mg/kg) lowered the body temperature in brewer's yeast-induced hyperthermia. Conclusions: Based on the findings, it may be concluded that the IC leaves possessed analgesic, anti-inflammatory, and antipyretic activities. Phytochemical constituents of IC leaves such as flavonoids, tannins, and triterpenes in ethanol extract could be correlated with its observed biological activities.

Determination of antioxidant activity of spices and their active principles by differential pulse voltammetry

The anodic oxidation of mercury in the presence of hydrogen peroxide in differential pulse voltammetry (DPV) was used to determine the antioxidant (AO) character of radical scavengers. Hydroperoxide radical is formed at the potentials of the oxidation peak on mercury electrodes, such radical reacting with the antioxidants in different extension. The parameter C10 (antioxidant concentration at which the peak area decreases by 10%) is used to measure the scavenging activity of the individual antioxidants. To establish the scavenging activity of antioxidant mixtures as a whole, the parameter, μ10 as the reverse of V10, V10 being the volume necessary to decrease the peak area in DPV by 10%, was selected. Higher μ10 values correspond to higher scavenging activity. The studies have been extended to aqueous extracts of some species. The results may be useful in explaining the effect of spices in vitro and in vivo studies.

Modulatory effects of morin on hyperglycemia by attenuating the hepatic key enzymes of carbohydrate metabolism and β-cell function in streptozotocin-induced diabetic rats

The present study was aimed to evaluate the effect of morin on blood glucose, insulin level, hepatic glucose regulating enzyme activities and glycogen level in experimental diabetes. Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (STZ) (50 mg/kg b.w.). Five days after STZ injection, diabetic rats received morin (25 and 50 mg/kg b.w.) orally for 30 days. Glibenclamide was used as reference drug. Morin treatment significantly reduced the blood glucose and improved the serum insulin levels. Further, a dose-dependent reduction in glucose-6-phosphatase and fructose-1,6-bisphosphatase was observed along with the increase in liver hexokinase and glucose-6-phosphate dehydrogenase activities. Morin supplement were found to be effective in preserving the normal histological appearance of pancreatic islets as well as to preserve insulin-positive β-cells in STZ-rats. Therefore, these findings suggest that morin displays beneficial effects in the treatment of diabetes, mediated through the regulation of carbohydrate metabolic enzyme activities.

Effect of NR-Salacia on post-prandial hyperglycemia: A randomized double blind, placebo-controlled, crossover study in healthy volunteers

BACKGROUND

Salacia chinensis (S. chinensis) is widely distributed in India and Sri Lanka. Most of the species of genus Salacia are known to have effects on blood glucose levels; however, the effects of S. chinensis on glucose levels are seldom reported.

OBJECTIVE

To evaluate the oral hypoglycemic activity of NR- Salacia (1000 mg extract of S. chinensis) in healthy adults.

MATERIALS AND METHODS

Randomized, double-blind, placebo-controlled, cross-over study was conducted in healthy volunteers. Single dose of NR-Salacia (1000 mg extract of Salacia chinensis) and placebo were administered before carbohydrate-rich diet. A 6-point plasma glucose profile was performed at different time intervals up to 180 min.

RESULTS

NR-Salacia treatment significantly lowered plasma glucose level at 90 min, and the percentage reduction in glucose concentration was found to be 13.32 as compared to placebo group. A 33.85% decrease in the plasma glucose positive incremental area under curve (AUC) (0 to 180 min) was observed in comparison to placebo. No adverse events were recorded throughout the study period, except for some mild cases of abdominal discomforts like cramping and distention, vomiting, and headache in both placebo and NR-Salacia-treated groups.

CONCLUSION

The study findings revealed that NR-Salacia lowered the post-prandial plasma glucose levels after a carbohydrate-rich meal and can be used as an oral hypoglycemic agent.

Underestimating the toxicological challenges associated with the use of herbal medicinal products in developing countries

Various reports suggest a high contemporaneous prevalence of herb-drug use in both developed and developing countries. The World Health Organisation indicates that 80% of the Asian and African populations rely on traditional medicine as the primary method for their health care needs. Since time immemorial and despite the beneficial and traditional roles of herbs in different communities, the toxicity and herb-drug interactions that emanate from this practice have led to severe adverse effects and fatalities. As a result of the perception that herbal medicinal products have low risk, consumers usually disregard any association between their use and any adverse reactions hence leading to underreporting of adverse reactions. This is particularly common in developing countries and has led to a paucity of scientific data regarding the toxicity and interactions of locally used traditional herbal medicine. Other factors like general lack of compositional and toxicological information of herbs and poor quality of adverse reaction case reports present hurdles which are highly underestimated by the population in the developing world. This review paper addresses these toxicological challenges and calls for natural health product regulations as well as for protocols and guidance documents on safety and toxicity testing of herbal medicinal products.

Development of polyherbal antidiabetic formulation encapsulated in the phospholipids vesicle system

Multifactorial metabolic diseases, for instance diabetes develop several complications like hyperlipidemia, hepatic toxicity, immunodeficiency etc., Hence, instead of mono-drug therapy the management of the disease requires the combination of herbs. Marketed herbal drugs comprise of irrational combinations, which makes their quality control more difficult. Phytoconstituents, despite having excellent bioactivity in vitro demonstrate less or no in vivo actions due to their poor lipid solubility, resulting in high therapeutic dose regimen; phospholipids encapsulation can overcome this problem. Hence, present study was designed to develop a phospholipids encapsulated polyherbal anti-diabetic formulation. In the present study, polyherbal formulation comprises of lyophilized hydro-alcoholic (50% v/v) extracts of Momordica charantia, Trigonella foenum-graecum and Withania somnifera 2:2:1, respectively, named HA, optimized based on oral glucose tolerance test model in normal Wistar rats. The optimized formulation (HA) entrapped in the phosphatidylcholine and cholesterol (8:2) vesicle system is named HA lipids (HAL). The vesicles were characterized for shape, morphology, entrapment efficiency, polar-dispersity index and release profile in the gastric pH. The antidiabetic potential of HA, marketed polyherbal formulation (D-fit) and HAL was compared in streptozotocin-induced diabetic rat model of 21 days study. The parameters evaluated were behavioral changes, body weight, serum glucose level, lipid profile and oxidative stress. The antidiabetic potential of HA (1000 mg/kg) was at par with the D-fit (1000 mg/kg). However, the potential was enhanced by phospholipids encapsulation; as HAL (500 mg/kg) has shown more significant (P < 0.05) potential in comparison to HA (1000 mg/kg) and at par with metformin (500 mg/kg).

Evidence based herbal drug standardization approach in coping with challenges of holistic management of diabetes: a dreadful lifestyle disorder of 21st century

Plants by virtue of its composition of containing multiple constituents developed during its growth under various environmental stresses providing a plethora of chemical families with medicinal utility. Researchers are exploring this wealth and trying to decode its utility for enhancing health standards of human beings. Diabetes is dreadful lifestyle disorder of 21st century caused due to lack of insulin production or insulin physiological unresponsiveness. The chronic impact of untreated diabetes significantly affects vital organs. The allopathic medicines have five classes of drugs, or otherwise insulin in Type I diabetes, targeting insulin secretion, decreasing effect of glucagon, sensitization of receptors for enhanced glucose uptake etc. In addition, diet management, increased food fiber intake, Resistant Starch intake and routine exercise aid in managing such dangerous metabolic disorder. One of the key factors that limit commercial utility of herbal drugs is standardization. Standardization poses numerous challenges related to marker identification, active principle(s), lack of defined regulations, non-availability of universally acceptable technical standards for testing and implementation of quality control/safety standard (toxicological testing). The present study proposed an integrated herbal drug development & standardization model which is an amalgamation of Classical Approach of Ayurvedic Therapeutics, Reverse Pharmacological Approach based on Observational Therapeutics, Technical Standards for complete product cycle, Chemi-informatics, Herbal Qualitative Structure Activity Relationship and Pharmacophore modeling and, Post-Launch Market Analysis. Further studies are warranted to ensure that an effective herbal drug standardization methodology will be developed, backed by a regulatory standard guide the future research endeavors in more focused manner.

Complementary alternative medicine use among patients with type 2 diabetes mellitus in the primary care setting: a cross-sectional study in Malaysia

BACKGROUND

Limited study on the use of complementary alternative medicine (CAM) among patients with diabetes mellitus (DM), particularly in primary -care settings. This study seeks to understand the prevalence, types, expenditures, attitudes, beliefs, and perceptions of CAM use among patients with DM visiting outpatient primary care clinics.

METHODS

This is a descriptive, cross-sectional study of 240 diabetic patients. CAM is defined as a group of diverse medical and healthcare systems, practices, and products that are not generally considered part of conventional Western medicine. Data analysis was done using SPSS v. 19 and multiple logistic regressions were used to identify predictors of CAM use.

RESULTS

The prevalence of CAM use was 62.5 percent. Female were 1.8 times more likely than male in using CAM. Malays (75%) were the most frequent users, followed Indians (18%) and Chinese (6%). Biological therapy (50.0%) were the most widely used, followed by manipulative-body based systems (9.2%), energy system (8.8%), alternative medicine systems (4.6%) and mind-body system (1.7%). In biological therapy, a total of 30.4 percent, 24.2 percent, 13.3 percent, and 7.9 percent of diabetic patients consumed bitter gourd (Momordica Charantia), followed by Misai Kucing (Orthosiphon Stamineus Benth), garlic (Allium Sativum), and Sabah snake grass (Clinacanthus Nutans Lindau) respectively. The mean of the expenditure on CAM usage was RM 52.8 ± 101.9 (US $16.9 ± 32.5) per month. According to multiple logistic regression analyses, being Muslim (OR 5.258, 95 percent CI 2.952-9.368) had significant positive association with CAM use.

CONCLUSIONS

The prevalence of CAM use was high among diabetics. Islam faith is predictor for CAM use among Type 2 DM patients. The most-common herbs used were bitter gourd (Momordica Charantia) and Misai Kucing (Orthosiphon Stamineus, Benth). Further studies on the anti-glycemic activity of the isolated compound may be needed in the future.

Traditional Indian medicines used for the management of diabetes mellitus

Plants have always been a source of drugs for humans since time immemorial. The Indian traditional system of medicine is replete with the use of plants for the management of diabetic conditions. According to the World Health Organization, up to 90% of population in developing countries use plants and its products as traditional medicine for primary health care. There are about 800 plants which have been reported to show antidiabetic potential. The present review is aimed at providing in-depth information about the antidiabetic potential and bioactive compounds present in Ficus religiosa, Pterocarpus marsupium, Gymnema sylvestre, Allium sativum, Eugenia jambolana, Momordica charantia, and Trigonella foenum-graecum. The review provides a starting point for future studies aimed at isolation, purification, and characterization of bioactive antidiabetic compounds present in these plants.

Kalpaamruthaa modulates oxidative stress in cardiovascular complication associated with type 2 diabetes mellitus through PKC-β/Akt signaling

This study aimed at investigating the efficacy of Kalpaamruthaa (KA) on cardiovascular damage (CVD) associated with type 2 diabetes mellitus in experimental rats by reducing oxidative stress and the modulation of the protein kinase C-β (PKC-β)/Akt signaling pathway. CVD-induced rats were treated with KA (200 mg·(kg body mass)(-1)·(day)(-1)) orally for 4 weeks. KA effectively reduced insulin resistance with alterations in blood glucose, hemoglobin, and glycosylated hemoglobin in CVD-induced rats. Elevated levels of lipids in CVD-induced rats were decreased upon KA administration. In CVD-induced rats the levels of lipoproteins were returned to normal by KA treatment. KA effectively reduced the lipid peroxidative product and protein carbonyl content in liver of CVD-induced rats. KA increased the activities and (or) levels of enzymatic and nonenzymatic antioxidants in liver of CVD-induced rats. KA treatment reduced the fatty inclusion and mast cell infiltration in liver of CVD-induced rats. Further, treatment with KA reduced the chromatin condensation and marginization in myocardium of CVD-induced rats. KA alters insulin signaling by decreasing PKC-β and increasing p-Akt and GLUT4 expressions in heart of CVD-induced rats. The above findings suggest that KA renders protection against CVD induced by type 2 diabetes mellitus by augmenting the cellular antioxidant defense capacity and modulating PKC-β and the p-Akt signaling pathway.

Syzygium cumini (L.) Skeels., a novel therapeutic agent for diabetes: folk medicinal and pharmacological evidences

OBJECTIVES

During the past few decades numerous folk medicinal and scientific investigations on the antidiabetic effects of jambolan (Syzygium cumini (L.) Skeels) have been reported. However no comprehensive evidence-based review is available. Hence this review was aimed to summarize the antidiabetic effects of different parts and active principles of jambolan.

METHODS

The review is based on the available electronic literature indexed in the PubMed. The search terms were: Syzygium cumini, Eugenia jambolana, jambolan, jamun, and java plum with and without antidiabetic effect.

RESULTS

Based on experimental studies and folk medicinal evidences, we summarized an up to date and comprehensive report on the antidiabetic activity of jambolan. The mode of action of some of the parts and active principles is also included. Preclinical and clinical studies suggest that, different parts of this plant especially fruits, seeds and stem bark were reported for promising activity against diabetes.

CONCLUSIONS

Till date no review is available for the evidence based preclinical/clinical study of jambolan with its antidiabetic effect. There is an immediate attention need for detailed analysis to identify its active principles. It could be used to produce safer drugs to treat diabetes.

Clinical efficacy of Shankhapushpi and a herbo-mineral compound in type-II diabetes

Diabetic population is more than 245 million worldwide and expected to be b380 million by 2025. One of the main causes of increasing rate of diabetes is stress and tension in day-to-day life, disturbing the homeostasis of positive and negative emotions to initiate pathophysiology of stress-induced diabetes. In the present study, in Group A of 34 patients, a herbo-mineral compound containing Shuddha Shilajatu, Shuddha Guggulu, Vijayasara Ghana, Saptarangi Ghana, and Triphala Ghana was administered in the dose of 3 gm/day in three divided doses with luke-warm water before meal for the duration of 8 weeks, which significantly relieved symptoms (60.52%) like Prabhuta Mutrata (54.55%), Avila Mutrata (66.67%), Daurbalya (61.36%), Shrama (59.32%), etc. with fasting blood sugar (4.05%) and postprandial blood sugar (9.95%). In another series of 34 patients (Group B), where psychological health promoting drug Shankhapushpi was administered in the dose of 1.5 gm/day in three divided doses for 8 weeks along with herbo-mineral compound. The percentage relief was found to be more better on symptoms (71.13%) like Prabhuta Mutrata (76.92%), Avila Mutrata (83.33%), Daurbalya (75%), Shrama (70.37%), fasting blood sugar (18.04%) and postprandial blood sugar (27.75%). Group B showed better results on psychological parameters like disturbed Manasabhava (29.16%) and Brief Psychiatry Rating Scale (38.28%). The high significance of χ(2) (15.50) on overall effect of therapy indicated better results in group B.

The antidiabetic effects of an herbal formula composed of Alnus hirsuta, Rosa davurica, Acanthopanax senticosus and Panax schinseng in the streptozotocin-induced diabetic rats

A folk prescription consisting of Alnus hirsuta, Rosa davurica, Acanthopanax senticosus and Panax schinseng has been used in the treatment of diabetes mellitus. The aim of the present investigation was to evaluate the antidiabetic effects of the herb formula extract (HFE) composed of Alnus hirsuta, Rosa davurica, Acanthopanax senticosus and Panax schinseng in the streptozotocin (STZ)-induced diabetic rats. The HFE was mixed in the food supply of the healthy and STZ-induced diabetic male Sprague-Dawley rats, and its effects on the body weight, water and food intake, hyperglycemia, hypolipidemic and islet structure were studied. The treatment of the rats with STZ for 6 weeks resulted in marasmus, polydipsia, polyphagia, hyperglycemia and hypoinsulinemia. In addition, the diabetic rats showed an apparent decrease in the insulin immunoreactivity and the number of β-cells in the pancreas. The addition of the HFE to the rats' food supply significantly lowered the serum glucose and the serum triglycerides level and preserved the normal histological appearance of the pancreatic islets. These results indicate that the HEF have a strong antidiabetic potential along with the significant hypoglycemic and hypolipidemic effects, which may be applicable in the pharmaceutical industry.

Effects of Syzygium aromaticum-derived oleanolic acid on glucose transport and glycogen synthesis in the rat small intestine

BACKGROUND

In the present study, we investigated the effects of oleanolic acid (OA), which has hypoglycemic properties, on glucose transport and glycogen synthesis in the small intestine, an organ that secretes enzymes involved in carbohydrate metabolism.

METHODS

The OA was isolated from Syzygium aromaticum ethyl acetate-soluble fractions followed by recrystallization with ethanol. It was diluted to required concentrations in freshly prepared dimethyl sulfoxide (2 mL) and normal saline (19 mL) before being administered to rats (p.o.). Glycogen concentrations were determined in isolated small intestines from fasted and non-fasted non-diabetic and streptozotocin-diabetic rats after 18 h treatment with 80 mg/kg, p.o., OA or standard hypoglycemic drugs (i.e. 100 μg/kg, s.c., insulin; 500 mg/kg, p.o., metformin). In a separate series of experiments, the effects of 30-min incubation with graded concentrations of OA (0.82-6.56 mmol/L) on d-glucose were evaluated by monitoring changes in glucose concentrations inside and outside of intestinal sacs isolated from fasted, non-diabetic rats and mounted in an organ bath containing Krebs-Henseleit bicarbonate buffer.

RESULTS

All in vivo treatments increased the glycogen concentration in rat small intestine, although the effects of metformin treatment in non-fasted diabetic rats failed to reach statistical significance. In vitro, both OA (1.64-6.56 mmol/L) and phlorizin (10(-5) -10(-3) mol/L) decreased glucose transport from the mucosa to the serosa.

CONCLUSION

The data suggest that OA may be a potential alternative drug treatment for postprandial hyperglycemia because of its inhibition of glucose uptake across the small intestine and its concomitant conversion of glucose to glycogen in the intestinal wall.

Identification of PPARgamma partial agonists of natural origin (II): in silico prediction in natural extracts with known antidiabetic activity

Background

Natural extracts have played an important role in the prevention and treatment of diseases and are important sources for drug discovery. However, to be effectively used in these processes, natural extracts must be characterized through the identification of their active compounds and their modes of action.

Methodology/Principal Findings

From an initial set of 29,779 natural products that are annotated with their natural source and using a previously developed virtual screening procedure (carefully validated experimentally), we have predicted as potential peroxisome proliferators-activated receptor gamma (PPARγ) partial agonists 12 molecules from 11 extracts known to have antidiabetic activity. Six of these molecules are similar to molecules with described antidiabetic activity but whose mechanism of action is unknown. Therefore, it is plausible that these 12 molecules could be the bioactive molecules responsible, at least in part, for the antidiabetic activity of the extracts containing them. In addition, we have also identified as potential PPARγ partial agonists 10 molecules from 16 plants with undescribed antidiabetic activity but that are related (i.e., they are from the same genus) to plants with known antidiabetic properties. None of the 22 molecules that we predict as PPARγ partial agonists show chemical similarity with a group of 211 known PPARγ partial agonists obtained from the literature.

Conclusions/Significance

Our results provide a new hypothesis about the active molecules of natural extracts with antidiabetic properties and their mode of action. We also suggest plants with undescribed antidiabetic activity that may contain PPARγ partial agonists. These plants represent a new source of potential antidiabetic extracts. Consequently, our work opens the door to the discovery of new antidiabetic extracts and molecules that can be of use, for instance, in the design of new antidiabetic drugs or functional foods focused towards the prevention/treatment of type 2 Diabetes Mellitus.

Use of traditional medicine for the treatment of diabetes in Eastern Uganda: a qualitative exploration of reasons for choice

BACKGROUND

While there are biomedical drugs for managing diabetes mellitus, some patients with diabetes use traditional medicine. The aim of the study was to explore why patients with diabetes use traditional medicine for the treatment of diabetes.

METHODS

The study was conducted in Iganga and Bugiri districts in Eastern Uganda using four focus group discussions (FGDs) with patients with diabetes; two with female patients and two with male patients, thirteen key informant interviews (KIIs); nine with health workers working with patients with diabetes and four with herbalists. FGDs and KIIs focused on what respondents perceived as reasons for patients with diabetes taking traditional medicine. Analysis was done using content analysis.

RESULTS

Reasons for taking traditional medicine included finding difficulties accessing hospitals, diabetic drugs being out of stock, traditional medicine being acceptable and available within community, as well as being supplied in big quantities. Others were traditional medicine being cheaper than biomedical treatment and payment for it being done in installments. Traditional medicine was also more convenient to take and was marketed aggressively by the herbalists. Influence of family and friends as well as traditional healers contributed to use of traditional medicine.

CONCLUSIONS

Possibilities of putting diabetic drugs at facilities closer to patients need to be considered and health facilities should have a constant supply of diabetic drugs. Community members need to be sensitized on the proper treatment for diabetes mellitus and on the dangers of taking traditional medicine.

Effect of Withania somnifera Extracts on Some Selective Biochemical, Hematological, and Immunological Parameters in Guinea Pigs Experimental Infected with E. coli

Fifty 1-2-month-old Guinea pigs were divided into 5 equal groups, 10 each. Control (Gp1) did receive neither viable bacteria nor treatment. Each animal from the other groups (Gp2-5) was challenged with (1-2 × 10(8)) viable E. coli in 200  μ L normal saline (0.9%) through IP route. GP2 infected group was treated with 200  μ L saline IP and kept as positive control group. Gp3-4 are infected and treated with Withania somnifera (ethanol root extract) with doses 50 and 100 mg/kg. BW, respectively. Gp5 infected treated group was treated with cefoperazone antibiotic at dose 35 mg/Kg BW. The treatment by drug or the extracted medicinal plant was started 72 h after infection for 7 successive days. Serum and whole blood sample were collected from all groups 14 days after treatment to evaluate some hematological and biochemical changes as well as immunomodulatory cytokine tumor necrosis factor-alpha (TNF- α ). Oral treatment of the plant extract caused significant benefit results in infected Guinea pig appeared in the correction of some hematological and biochemical parameters also try to suppressed inflammatory cytokine response represent in TNF- α . It could be concluded that W. somnifera extract has potent antibacterial activity, and this appears in the correction with hematological, biochemical, and immunological results.

Doctors' and nurses' views on patient care for type 2 diabetes: an interview study in primary health care in Oman

Aim

This study aimed at exploring the experiences of primary health-care providers of their encounters with patients with type 2 diabetes, and their preferences and suggestions for future improvement of diabetes care.

Background

Barriers to good diabetes care could be related to problems from health-care providers’ side, patients’ side or the health-care system of the country. Treatment of patients with type 2 diabetes has become a huge challenge in Oman, where the prevalence has increased to high levels.

Method

Semi-structured interviews were conducted with 26 health-care professionals, 19 doctors and seven nurses, who worked in primary health care in Oman. Qualitative content analysis was applied.

Findings

Organizational barriers and barriers related to patients and health-care providers were identified. These included workload and lack of teamwork approach. Poor patients’ management adherence and influence of culture on their attitudes towards illness were identified. From the providers’ side, language barriers, providers’ frustration and aggressive attitudes towards the patients were reflected. Decreasing the workload, availability of competent teams with diabetes specialist nurses and continuity of care were suggested. Furthermore, changing professional behaviours towards a more patient-centred approach and need for health education to the patients, especially on self-management, were addressed. Appropriate training for health-care providers in communication skills with emphasis on self-care education and individualization of care according to each patient's needs are important for improvement of diabetes care in Oman.

Chronic administration of a combination of six herbs inhibits the progression of hyperglycemia and decreases serum lipids and aspartate amino transferase activity in diabetic rats

The effects of a polyherbal compound, containing six plants (Allium sativum, Cinnamomum zeylanicum, Nigella sativa, Punica granatum, Salvia officinalis and Teucrium polium) were tested on biochemical parameters in streptozotocin-induced diabetic rats. Streptozotocin caused an approximately 3-fold increase in fasting blood sugar level after 2 days. The diabetic control rats showed further increase in blood glucose after 30 days (384 ± 25 mg/dl in day 30 versus 280 ± 12 mg/dl in day 2, P < 0.001). Administration of the compound blocked the increase of blood glucose (272 ± 7 and 269 ± 48 mg/dl at day 2 and day 30, respectively). Also, there was significant difference in the level of triglyceride (60 ± 9 versus 158 ± 37 mg/dl, P < 0.01), total cholesterol (55 ± 2 versus 97 ± 11 mg/dl, P < 0.01) and aspartate amino transferase activity (75 ± 12 versus 129 ± 18 U/L, P < 0.05) between treated rats and diabetic control group. In conclusion, the MSEC inhibited the progression of hyperglycemia and decreased serum lipids and hepatic enzyme activity in diabetic rats. Therefore, it has the potential to be used as a natural product for the management of diabetes.

Efficacy and safety of 'true' cinnamon (Cinnamomum zeylanicum) as a pharmaceutical agent in diabetes: a systematic review and meta-analysis

AIMS

Diabetes is a leading cause of morbidity and mortality worldwide. Studies have frequently looked at dietary components beneficial in treatment and prevention. We aim to systematically evaluate the literature on the safety and efficacy of Cinnamomum zeylanicum on diabetes.

METHODS

A comprehensive search of the literature was conducted in the following databases; PubMed, Web of Science, Biological Abstracts, SciVerse Scopus, SciVerse ScienceDierect, CINAHL and The Cochrane Library. A meta-analysis of studies examining the effect of C. zeylanicum extracts on clinical and biochemical parameters was conducted. Data were analysed using RevMan v5.1.2.

RESULTS

The literature search identified 16 studies on C. zeylanicum (five in-vitro, six in-vivo and five in-vivo/in-vitro). However, there were no human studies. In-vitro C. zeylanicum demonstrated a potential for reducing post-prandial intestinal glucose absorption by inhibiting pancreatic α-amylase and α-glucosidase, stimulating cellular glucose uptake by membrane translocation of glucose transporter-4, stimulating glucose metabolism and glycogen synthesis, inhibiting gluconeogenesis and stimulating insulin release and potentiating insulin receptor activity. The beneficial effects of C. zeylanicum in animals include attenuation of diabetes associated weight loss, reduction of fasting blood glucose, LDL and HbA(1c) , increasing HDL cholesterol and increasing circulating insulin levels. Cinnamomum zeylanicum also significantly improved metabolic derangements associated with insulin resistance. It also showed beneficial effects against diabetic neuropathy and nephropathy, with no significant toxic effects on liver and kidney and a significantly high therapeutic window.

CONCLUSION

Cinnamomum zeylanicum demonstrates numerous beneficial effects both in vitro and in vivo as a potential therapeutic agent for diabetes. However, further randomized clinical trials are required to establish therapeutic safety and efficacy.

Management of diabetes in Guinean traditional medicine: an ethnobotanical investigation in the coastal lowlands

ETHNOPHARMACOLOGICAL RELEVANCE

This survey was carried out in the coastal lowlands of Guinea-Conakry in order to make an inventory of plants used by traditional healers, herbalists and diabetic patients for the management of diabetes mellitus.

MATERIALS AND METHODS

Frequent ethnomedical and ethnobotanical investigations were conducted from June 2008 to December 2009 in Conakry, Kindia, Forécariah, Dubréka, Boke, Fria and Boffa. It is a cross-sectional survey and data collection is based on the interactive method. During this period a total of 112 people aged from 39 to 76 years old were interviewed.

RESULTS

During this investigation 146 plant species belonging to 55 families were collected. The most cited plants were Anacardium occidentale L. and Ficus spp., while the Fabaceae family was the most represented, followed by the Euphorbiaceae and Rubiaceae. The most frequently plant parts used by the traditional healers and the herbalists were the stem-bark and decoctions the most common preparation mode.

CONCLUSIONS

It is clear that a variety of plants is used in the management and treatment of diabetes. Due to the increasing prevalence of type 2 diabetes, there is an urgent need for scientific investigations to rationalise the use of these traditional remedies, which could represent accessible alternative medicines for the Guinean populations.

Safety Profile of a Polyherbal Formulation (Gynocare capsules) in Female Rats by Subchronic Oral Toxicity Study

Gynocare capsules, is a polyherbal formulation, are used as uterine tonic and for treating gynaecological ailments like infertility, leucorrhea, and menstrual disorders. The formulation contains ingredients of herbal origin, such as, extracts of Ashoka, Vasaka, Durva, Chandan, Musk, and so on. It was evaluated for its safety at the therapeutic dose level by a repeated dose oral toxicity study in albino Wistar rats. The herbal formulation was administered orally at a therapeutic dose of 100 mg/kg/day, for 90 days. All animals were monitored daily for their health status and signs of abnormalities. The body weight, water consumption, and food intake were measured once weekly. At the end of the experimental period, various hematological and biochemical parameters were estimated and histopathologies of selected organs were conducted. The study resulted from the long-term oral administration of Gynocare capsules (100 mg/kg), did not cause any relevant signs of toxicity nor significant changes in the physical, hematological and biochemical parameters. However, statistically significant differences were seen in the relative organ weights of adrenal gland, ovary, and serum creatinine levels. The reduction in ovary weight revealed the possibility of the drug targeting the ovary. Moreover, no pathological features were identified in the treated group as monitored by the histopathological analysis of the internal organs. The study established that Gynocare capsules at the dose given (100 mg/kg) did not induce any remarkable or significant toxic effects, indicating that it was safe in rats following oral administration for 90 consecutive days.

Identification of novel human dipeptidyl peptidase-IV inhibitors of natural origin (Part II): in silico prediction in antidiabetic extracts

BACKGROUND

Natural extracts play an important role in traditional medicines for the treatment of diabetes mellitus and are also an essential resource for new drug discovery. Dipeptidyl peptidase IV (DPP-IV) inhibitors are potential candidates for the treatment of type 2 diabetes mellitus, and the effectiveness of certain antidiabetic extracts of natural origin could be, at least partially, explained by the inhibition of DPP-IV.

METHODOLOGY/PRINCIPAL FINDINGS

Using an initial set of 29,779 natural products that are annotated with their natural source and an experimentally validated virtual screening procedure previously developed in our lab (Guasch et al.; 2012) [1], we have predicted 12 potential DPP-IV inhibitors from 12 different plant extracts that are known to have antidiabetic activity. Seven of these molecules are identical or similar to molecules with described antidiabetic activity (although their role as DPP-IV inhibitors has not been suggested as an explanation for their bioactivity). Therefore, it is plausible that these 12 molecules could be responsible, at least in part, for the antidiabetic activity of these extracts through their inhibitory effect on DPP-IV. In addition, we also identified as potential DPP-IV inhibitors 6 molecules from 6 different plants with no described antidiabetic activity but that share the same genus as plants with known antidiabetic properties. Moreover, none of the 18 molecules that we predicted as DPP-IV inhibitors exhibits chemical similarity with a group of 2,342 known DPP-IV inhibitors.

CONCLUSIONS/SIGNIFICANCE

Our study identified 18 potential DPP-IV inhibitors in 18 different plant extracts (12 of these plants have known antidiabetic properties, whereas, for the remaining 6, antidiabetic activity has been reported for other plant species from the same genus). Moreover, none of the 18 molecules exhibits chemical similarity with a large group of known DPP-IV inhibitors.

In Silico Analysis of Microarray-Based Gene Expression Profiles Predicts Tumor Cell Response to Withanolides

Withania somnifera (L.) Dunal (Indian ginseng, winter cherry, Solanaceae) is widely used in traditional medicine. Roots are either chewed or used to prepare beverages (aqueous decocts). The major secondary metabolites of Withania somnifera are the withanolides, which are C-28-steroidal lactone triterpenoids. Withania somnifera extracts exert chemopreventive and anticancer activities in vitro and in vivo. The aims of the present in silico study were, firstly, to investigate whether tumor cells develop cross-resistance between standard anticancer drugs and withanolides and, secondly, to elucidate the molecular determinants of sensitivity and resistance of tumor cells towards withanolides. Using IC₅₀ concentrations of eight different withanolides (withaferin A, withaferin A diacetate, 3-azerininylwithaferin A, withafastuosin D diacetate, 4-B-hydroxy-withanolide E, isowithanololide E, withafastuosin E, and withaperuvin) and 19 established anticancer drugs, we analyzed the cross-resistance profile of 60 tumor cell lines. The cell lines revealed cross-resistance between the eight withanolides. Consistent cross-resistance between withanolides and nitrosoureas (carmustin, lomustin, and semimustin) was also observed. Then, we performed transcriptomic microarray-based COMPARE and hierarchical cluster analyses of mRNA expression to identify mRNA expression profiles predicting sensitivity or resistance towards withanolides. Genes from diverse functional groups were significantly associated with response of tumor cells to withaferin A diacetate, e.g. genes functioning in DNA damage and repair, stress response, cell growth regulation, extracellular matrix components, cell adhesion and cell migration, constituents of the ribosome, cytoskeletal organization and regulation, signal transduction, transcription factors, and others.

Improvement of the bioavailability and glycaemic metabolism of cinnamon oil in rats by liquid loadable tablets

The purpose of this study is to investigate the bioavailability and glycaemic metabolism of cinnamon oil (CIO) carried by liquid-loadable tablets (CIO-LLTs), the carrier of a CIO self-emulsifying formulation (CIO-LS). The results of tests performed to evaluate the physical properties of the CIO-LLT complied with Chinese Pharmacopeia (2010). The release profile suggested that the CIO-LLT preserved the enhancement of in vitro dissolution of cio. After orally administration, the plasma concentration-time profile and pharmacokinetic parameters suggested that a significant increase (P < 0.0001) in the C_max, AUC and F were observed in the CIO-LLT. The blood glucose and the HbA1c were significantly decreased in alloxan-induced hyperglycemic rats (P < 0.05, P < 0.01, resp.), while the level of insulin secretion was markedly elevated in alloxan-induced hyperglycemic rats (P < 0.05). The alloxan-damaged pancreatic β-cells of the rats were partly recovered gradually after the rats were administered with CIO-LLT 45 days later. CIO-LLT could improve the bioavailability and glycaemic metabolism of CIO.

Antihyperglycemic effect of Annona squamosa hexane extract in type 2 diabetes animal model: PTP1B inhibition, a possible mechanism of action?

AIM

The mechanism of action of Annona squamosa hexane extract in mediating antihyperglycemic and antitriglyceridimic effect were investigated in this study.

MATERIALS AND METHODS

The effects of extract on glucose uptake, insulin receptor-β (IR-β), insulin receptor substrate-1 (IRS-1) phosphorylation and glucose transporter type 4 (GLUT4) and phosphoinositide 3-kinase (PI3 kinase) mRNA expression were studied in L6 myotubes. The in vitro mechanism of action was tested in protein-tyrosine phosphatase 1B (PTP1B), G-protein-coupled receptor 40 (GPR40), silent mating type information regulation 2 homolog 1 (SIRT1) and dipeptidyl peptidase-IV (DPP-IV) assays. The in vivo efficacy was characterized in ob/ob mice after an oral administration of the extract for 21 days.

RESULTS

The effect of extract promoted glucose uptake, IR-β and IRS-1 phosphorylation and GLUT4 and PI3 kinase mRNA upregulation in L6 myotubes. The extract inhibited PTP1B with an IC(50) 17.4 μg/ml and did not modulate GPR40, SIRT1 or DPP-IV activities. An oral administration of extract in ob/ob mice for 21 days improved random blood glucose, triglyceride and oral glucose tolerance. Further, the extract did not result in body weight gain before and after treatment (29.3 vs. 33.6 g) compared to rosiglitazone where significant body weight gain was observed (28.4 vs. 44.5 g; *P<0.05 after treatment compared to before treatment).

CONCLUSION

The results suggest that Annona squamosa hexane extract exerts its action by modulating insulin signaling through inhibition of PTP1B.