Indian herbs and herbal drugs used for the treatment of diabetes

Amelioration of hyperglycaemia and modulation of antioxidant status by Alcea rosea seeds in alloxan-induced diabetic rats

CONTEXT

Alcea rosea L. (Malvaceae) has various medicinal uses including anticancer, anti-inflammatory and analgesic properties. However, there is no report on its antidiabetic activity.

OBJECTIVE

Alcea rosea seed extracts were evaluated for antihyperglycaemic and antioxidative potential in diabetic rats.

MATERIALS AND METHODS

Single intra-peritoneal injection of alloxan (130 mg/kg b.w.) was used for induction of diabetes in Albino Wistar rats. Antihyperglycaemic and antioxidant activities of methanol and aqueous extracts of Alcea rosea seed (100 and 300 mg/kg b.w.), administered orally on daily basis for 15 days, were assessed in vivo for fasting blood glucose level and antioxidant status of liver and pancreas. Metformin was used as a positive control.

RESULTS

Aqueous and methanol extracts (300 mg/kg b.w.) decreased blood glucose level in diabetic rats by 24% and 46%, respectively. Administration of aqueous and methanol extracts at 300 mg/kg b.w. significantly (p < 0.01) modulated the antioxidant status of liver in diabetic rats by increasing levels of GR (22.5 ± 1.0, 24.4 ± 1.02 μg GSSG utilized/min/mg of protein), GPx (20.7 ± 1.2, 23.6 ± 2.04 μg GSH utilized/min/mg of protein), SOD (36.1 ± 1.7, 39.05 ± 1.5 units/mg of protein) and CAT (1744.5 ± 132.5, 1956.6 ± 125.2 nmol H₂O₂ decomposed/min/mg of protein), respectively. Similar results were observed for pancreas.

DISCUSSION AND CONCLUSIONS

Antihyperglycaemic and antioxidative potentials of Alcea rosea seeds suggest its usefulness in management of diabetes and its complications. This is the first report on antidiabetic activity of this plant.

Hypolipidemic activity of P-methoxycinnamic diester (PCO-C) isolated from Copernicia prunífera against Triton WR-1339 and hyperlipidemic diet in mice

Carnauba wax is extracted from the leaves of the Copernicia prunífera and contains approximately 80% of esters in its composition. The purpose of the present study was evaluate the hypolipidemic effect of p-methoxycinnamic diesters (PCO-C) extracted from Copernicia prunífera in a model of acute and chronic dyslipidemia in mice. The levels of total cholesterol and triglycerides were significantly reduced plasma levels in PCO-C at the dose of 100mg/kg in a model of acute and chronic dyslipidemia. Histological studies showed that PCO-C has no hepatotoxic effect and reduces hepatic steatosis in animals that consumed hyperlipidemic ration. Thus, it was concluded that PCO-C isolated from Copernicia Prunifera was effective in reducing total cholesterol and triglyceride levels in both dyslipidemia induction models. The finding indicates that PCO-C might be beneficial in treatment of hyperlipidemia and atherosclerosis.

Effects of butanol fraction of Ziziphus mucronata root ethanol extract on glucose homeostasis, serum insulin and other diabetes-related parameters in a murine model for type 2 diabetes

CONTEXT

Ziziphus mucronata Willd (Rhamnaceae) is currently used in Nigerian traditional treatment of diabetes mellitus. However, detailed information on the antidiabetic potential of the plant parts is presently unknown.

OBJECTIVES

The present study investigated the antidiabetic effects of the butanol fraction of Z. mucronata root (ZMBF) in a type 2 diabetes (T2D) model of rats.

MATERIALS AND METHODS

T2D was induced in rats by feeding a 10% fructose solution ad libitum for two weeks followed by an intraperitoneal injection of streptozotocin (40 mg/kg bw) and the animals were orally treated with ZMBF 150 or 300 mg/kg bw for five days a week for four weeks. Food and fluid intake, body weight changes and blood glucose levels were monitored during the experiment while other blood and organ specific diabetes-associated parameters were measured at the end of the experiment.

RESULTS

After four-week treatment, significantly (p < 0.05) lower blood glucose (19.24 vs 28.96 mmol/L), improved glucose tolerance ability (21.26 vs 28.56 mmol/L), higher serum insulin (131.37 vs 64.20 pmol/L) and liver glycogen (2.40 vs 1.54 mg/g tissue) were observed in the 300 mg/kg ZMBF ingested group compared with the diabetic control group. However, food and fluid intake, body weight gain, HOMA-β, HOMA-IR, serum fructosamine level, hepatic and renal function tests were not significantly (p > 0.05) affected by the treatment of ZMBF.

CONCLUSION

Results of this study suggest that ZMBF treatment, at 300 mg/kg bw, possess antidiabetic activity, but could not ameliorate some diabetes-related parameters in type 2 diabetic rats.

Ameliorative role of ethyl-acetate fraction of methanolic leaf extract of Camellia sinensis (green tea) on streptozotocin-induced diabetes linked testicular hypofunction in albino rat: A dose-dependent biochemical and genomic transection study

Background

The present investigation focuses the diabetes-induced testicular hypofunction and its possible correction by the effective dose of ethyl-acetate fraction of methanolic extract of

Methods

The androgenic, spermiological, oxidative stress and apoptosis sensors along with testicular genomic sensors were evaluated in a dose-dependent fashion (50 mg or 100 mg or 200 mg/kg body weight). Activities of hepatic transaminases for toxicity assessment were also measured.

Results

Increased level of fasting blood glucose, testicular cholesterol, seminal vesicular fructose along with a low count, motility and viability of epididymal sperm, low activities of testicular Δ5, 3β-hydroxy steroid dehydrogenase (HSD), 17β-HSD, testicular antioxidant enzymes (catalase and superoxide dismutase) and low plasma level of testosterone were noted in diabetic rat in respect to the control. After oral administration of said fraction to diabetic rat, levels of above sensors were resettled toward the control. A significant decrease in the number of different generations of germ cells at the stage VII of spermatogenesis in diabetic rat was noted which were recovered significantly toward the control in the fraction-treated diabetic group. It was supported by the correction in gene expression of testicular Δ5, 3β- HSD, 17β- HSD, Bcl-2 and Bax in the fraction-treated diabetic group.

Conclusions

The threshold dose of ethyl-acetate fraction of methanolic extract of

Controversy of oral hypoglycemic agents in type 2 diabetes mellitus: Novel move towards combination therapies

AIM

As diabetes mellitus is multi-factorial disease, use of several oral hypoglycemic agents (OHAs) is the main stay of pharmacological treatment. The treatment has become more challenging and controversial as OHAs are heterogeneous in their mode of action that causes unwanted side effects. Complementary approaches such as use of medicinal plants and dietary polyunsaturated fatty acids (PUFA) with hypoglycemic and hypolipidemic activities are therefore imperative. A vast literature has independently documented the effects of OHAs, medicinal plants and PUFA for management of diabetes. In the present article, we have reviewed the current literature to describe the effects of commonly used OHAs, their mechanisms of action and reported controversies. The antidiabetic potential of herbs and/or formulations and omega-3 PUFA with its potential benefits and mode of action is also discussed.

METHODS

PUBMED, MEDLINE, Cochrane Library etc., were searched for relevant articles using appropriate terms (until February 2015). Human and animal studies were selected for the review. Data extraction was carried out by one author and checked by second author.

RESULTS

There is still controversy over the safety profile of OHAs. Medicinal herbs with hypoglycemic activities are increasingly sought because of its natural origin, active constituents and minimal side effects. The current literature suggests that supplementation with PUFA improves macro- and microvascular complications.

CONCLUSION

There is a need for best possible individualized treatment based on variations in biochemical parameters with combinational therapy of nutritional/herbal supplementations. Such a combination may be helpful for better management of diabetes and its complications.

Knowledge, attitude, and beliefs toward traditional herbal medicine use among diabetics in Jeddah Saudi Arabia

Herbs have long been used in the treatment of diabetes. Therefore, a cross-sectional study of a random sample of diabetic patients was conducted to assess their knowledge, attitude, and beliefs about the use of herbs to control diabetes. Approximately 64% of the patients had previously used herbs for controlling diabetes; 27%, 20.3%, 15.2%, and 10.8% used myrrh, black seeds, fenugreek, and aloe, respectively. Approximately 55.1% patients preferred using herbs to prescription drugs, while 75.2% used herbs with the prescribed medications. Only 38.3% patients informed their doctors about using herbs. Moreover, 54.2% of respondents experienced no side effects using herbs, and 64.5% noticed an improvement in blood sugar level while using herbs. No significant relationship between demographic characteristics and herbal medicine use was found. In conclusion, most diabetic patients exhibited low knowledge, attitude, and beliefs regarding herbal use. Therefore, the development of an awareness program is needed to improve these factors.

Investigation of morin-induced insulin secretion in cultured pancreatic cells

Morin is a flavonoid contained in guava that is known to reduce hyperglycemia in diabetes. Insulin secretion has been demonstrated to increase following the administration of morin. The present study is designed to investigate the potential mechanism(s) of morin-induced insulin secretion in the MIN6 cell line. First, we identified that morin induced a dose-dependent increase in insulin secretion and intracellular calcium content in MIN6 cells. Morin potentiated glucose-stimulated insulin secretion (GSIS). Additionally, we used siRNA for the ablation of imidazoline receptor protein (NISCH) expression in MIN6 cells. Interestingly, the effects of increased insulin secretion by morin and canavanine were markedly reduced in Si-NISCH cells. Moreover, we used KU14R to block imidazoline I₃ receptor (I-3R) that is known to enhance insulin release from the pancreatic β-cells. Without influence on the basal insulin secretion, KU14R dose-dependently inhibited the increased insulin secretion induced by morin or efaroxan in MIN6 cells. Additionally, effects of increased insulin secretion by morin or efaroxan were reduced by diazoxide at the dose sufficient to open K_ATP channels and attenuated by nifedipine at the dose used to inhibit L-type calcium channels. Otherwise, phospholipase C (PLC) is introduced to couple with imidazoline receptor (I-R). The PLC inhibitor dose-dependently inhibited the effects of morin in MIN6 cells. Similar blockade was also observed in protein kinase C (PKC) inhibitor-treated cells. Taken together, we found that morin increases insulin secretion via the activation of I-R in pancreatic cells. Therefore, morin would be useful to develop in the research and treatment of diabetic disorders.

Polarity based characterization of biologically active extracts of Ajuga bracteosa Wall. ex Benth. and RP-HPLC analysis

BACKGROUND

The concept of botanical therapeutics has revitalized due to wide importance of plant derived pharmaceuticals. Therefore, the ameliorative characteristics of Ajuga bracteosa were studied.

METHODS

Total phenolic content, flavonoid content, antioxidant capacity, reducing power and free-radical scavenging activity were determined colorimetrically. Specific polyphenols were quantified by RP-HPLC analysis. Preliminary cytotoxicity was tested using brine shrimp lethality assay while antiproliferative activity against THP-1 and Hep-G2 cell lines was determined by MTT and SRB protocols respectively. Antileishmanial potential was assessed via MTT colorimetric method. To investigate antidiabetic prospect, α-amylase inhibition assay was adopted whereas disc diffusion method was used to detect likely protein kinase inhibitory, antibacterial and antifungal activities.

RESULTS

Among fifteen different extracts, maximum total phenolic content (10.75 ± 0.70 μg GAE/mg DW), total reducing power (23.90 ± 0.70 μg AAE/mg DW) and total antioxidant capacity (11.30 ± 0.80 μg AAE/mg DW) were exhibited by methanol extract with superlative percent extract recovery (17.50 ± 0.80% w/w). Chloroform-methanol extract demonstrated maximum flavonoid content (4.10 ± 0.40 μg QE/mg DW) and ethanol extract exhibited greatest radical scavenging activity (IC50 14.40 ± 0.20 μg/ml). RP-HPLC based quantification confirmed polyphenols such as pyrocatechol, gallic acid, resorcinol, catechin, chlorogenic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, vanillic acid, coumarin, sinapinic acid, trans-cinnamic acid, rutin, quercetin and kaempferol. The brine shrimp lethality assay ranked 78.60% extracts as cytotoxic (LC50 ≤ 250 μg/ml) whereas significant THP-1 inhibition was shown by methanol-acetone extract (IC50 4.70 ± 0.43 μg/ml). The antiproliferative activity against Hep-G2 hepatoma cancer cell line was demonstrated by n-hexane, ethylacetate and methanol-distilled water (IC50 8.65-8.95 μg/ml) extracts. Methanol extract displayed prominent protein kinase inhibitory activity (MIC 12.5 μg/disc) while n-hexane extract revealed remarkable antileishmanial activity (IC50 4.69 ± 0.01 μg/ml). The antidiabetic potential was confirmed by n-hexane extract (44.70 ± 0.30% α-amylase inhibition at 200 μg/ml concentration) while a moderate antibacterial and antifungal activities were unveiled.

CONCLUSION

The variation in biological spectrum resulted due to use of multiple solvent systems for extraction. We also deduce that the valuable information gathered can be utilized for discovery of anticancer, antileishmanial, antioxidant and antidiabetic bioactive lead candidates.

Identification of morin as an agonist of imidazoline I-3 receptor for insulin secretion in diabetic rats

Morin is a flavonoid contained in guava that is known to reduce hyperglycemia in diabetics. Morin has been demonstrated to increase plasma insulin. However, the mechanism(s) remains unknown. The present study is designed to investigate the effect of morin on the imidazoline receptor (I-R) that regulates insulin secretion. We used Chinese hamster ovary (CHO) cells transfected with an I-R expression construct (NISCH-CHO-K1 cells) to identify the direct effect of morin on the I-R. Moreover, the imidazoline I₃ receptor (I-3R) is known to be present in pancreatic β cells and involved in insulin secretion. Therefore, we applied a specific antagonist (KU14R) to block I-3R in diabetic rats. Additionally, the effect of morin on insulin secretion was characterized in isolated pancreatic islets. Morin decreased blood glucose levels by increasing plasma insulin levels in diabetic rats. In CHO cells expressing an I-R, morin increased calcium influx in a dose-dependent manner. Additionally, KU14R dose-dependently inhibited the morin-induced effects, including hypoglycemia and the increase in insulin secretion and plasma C-peptide levels, in diabetic rats. Furthermore, morin enhanced insulin secretion from isolated pancreatic islets, and this effect was also dose-dependently inhibited by KU14R. Phospholipase C (PLC) is known to couple with the I-R, and a PLC inhibitor dose-dependently attenuated the insulin secretion induced by morin in isolated pancreatic islets. Taken together, these data suggest that morin can activate I-3R to enhance insulin secretion. Therefore, it would be useful to develop morin into a treatment for diabetic disorders.

Rapid Development and Validation of Improved Reversed-Phase High-performance Liquid Chromatography Method for the Quantification of Mangiferin, a Polyphenol Xanthone Glycoside in Mangifera indica

Mangiferin, a polyphenolic xanthone glycoside from Mangifera indica, is used as traditional medicine for the treatment of numerous diseases. The present study was aimed to develop and validate a reversed-phase high-performance liquid chromatography (RP-HPLC) method for the quantification of mangiferin from the bark extract of M. indica. RP-HPLC analysis was performed by isocratic elution with a low-pressure gradient using 0.1% formic acid: acetonitrile (87:13) as a mobile phase with a flow rate of 1.5 ml/min. The separation was done at 26°C using a Kinetex XB-C18 column as stationary phase and the detection wavelength at 256 nm. The proposed method was validated for linearity, precision, accuracy, limit of detection, limit of quantification, and robustness by the International Conference on Harmonisation guidelines. In linearity, the excellent correlation coefficient more than 0.999 indicated good fitting of the curve and also good linearity. The intra- and inter-day precision showed < 1% of relative standard deviation of peak area indicated high reliability and reproducibility of the method. The recovery values at three different levels (50%, 100%, and 150%) of spiked samples were found to be 100.47, 100.89, and 100.99, respectively, and low standard deviation value < 1% shows high accuracy of the method. In robustness, the results remain unaffected by small variation in the analytical parameters, which shows the robustness of the method. Liquid chromatography–mass spectrometry analysis confirmed the presence of mangiferin with M/Z value of 421. The assay developed by HPLC method is a simple, rapid, and reliable for the determination of mangiferin from M. indica.

Potential of Lichen Compounds as Antidiabetic Agents with Antioxidative Properties: A Review

The advancement in the knowledge of potent antioxidants has uncovered the way for greater insight in the treatment of diabetic complications. Lichens are a rich resource of novel bioactive compounds and their antioxidant potential is well documented. Herein we review the antidiabetic potential of lichens which have received considerable attention, in the recent past. We have correlated the antidiabetic and the antioxidant potential of lichen compounds. The study shows a good accordance between antioxidant and antidiabetic activity of lichens and points out the need to look into gathering the scarce and scattered data on biological activities for effective utilization. The review establishes that the lichen extracts, especially of Parmotrema sp. and Ramalina sp. have shown promising potential in both antidiabetic and antioxidant assays. Ubiquitous compounds, namely, zeorin, methylorsellinate, methyl-β-orcinol carboxylate, methyl haematommate, lecanoric acid, salazinic acid, sekikaic acid, usnic acid, gyrophoric acid, and lobaric acid have shown promising potential in both antidiabetic as well as antioxidant assays highlighting their potential for effective treatment of diabetic mellitus and its associated complications. The available compilation of this data provides the future perspectives and highlight the need for further studies of this potent herbal source to harvest more beneficial therapeutic antidiabetic drugs.

Review of antidiabetic fruits, vegetables, beverages, oils and spices commonly consumed in the diet

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes is the most common type of diabetes and its prevalence is rapidly increasing throughout the world. Modifications of lifestyle such as suitable diet and exercise programs along with pharmacotherapy and education of patients are beneficial therapies for patients with type 2 diabetes. The ethnopharmacological use of herbal medicines, many of them part of our diet as spices, vegetables and fruits, has been developed for the treatment of diabetes due to inexpensiveness, easy availability and few side effects.

AIM OF THE STUDY

Our aim is to present a review for researchers who are interested in the biologically active dietary plants traditionally utilized in the treatment of diabetes.

MATERIALS AND METHODS

Information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed, Sci Finder and Cochrane. Common and scientific name of the fruits, vegetables, beverages, oils and spices and the words 'antidiabetic', 'hypoglycemic', 'anti-hyperglycemic', 'type 2 diabetes' were used as keywords for search.

RESULTS

Certain fruits and vegetables are functional foods and their consumption reduces the incidence of type 2 diabetes. Hypoglycemic effects of fruits and vegetables may be due to their inducing nature on pancreatic β-cells for insulin secretion, or bioactive compounds such as flavonoids, alkaloids and anthocyanins, which act as insulin-like molecules or insulin secretagogues.

CONCLUSION

This write-up covers hypoglycemic, anti-hyperglycemic and anti-diabetic activities of some dietary fruits, vegetables, beverages, oils and spices and their active hypoglycemic constituents. Including such plant species in the diet might improve management of type 2 diabetes.

Ethnobiological treatments of neurological conditions in the Chota Nagpur Plateau, India

ETHNOPHARMACOLOGICAL RELEVANCE

World Health Organization (WHO) has recognized the contribution of traditional medicine in the primary health care system. WHO also considers neurological disorders as one of the prime concern to the public health. Inadequate and inaccessible health facilities in the rural and underprivileged areas have forced the various tribal and non-tribal communities to use ethno-phyto and ethno-zoo therapeutics against different ailments. Chota Nagpur Plateau, India is one of the richest in India in terms of plant and animal diversity, and houses a number of indigenous communities often practising their own ethnobiological medicines. These undocumented indigenous treasure must be preserved and could be utilized in discovering lead compounds against human ailments including neuroprotective and psychoactive disorders.

MATERIALS AND METHODS

A number of ethnobiological surveys were carried out during 2012-2015 in the three districts of the Bengal part of Manbhum region, Chota Nagpur Plateau via conducting open and semi-structured interviews among the traditional medicine men (65:59 males and 6 females aged between 22 and 85 years). This dataset was statistically analysed by calculating seven quantitative indexes such as use value (UV), informants' consensus factor (ICF), fidelity level (FL), relative importance (RI), cultural importance index (CII), index of agreement on remedies (IAR) and cultural agreement index (CAI).

RESULTS

Sixty five traditional medicine men (TMM) reported 47 traditional formulations involving 58 plant species and 17 animal species used against 13 neurological and psychological disorders and as pro-cognitives. Fabaceae was represented by the highest number of medicinal plant species (9 species) whereas herbs (48%) and roots (28%) represented the most common plant habit and plant part, respectively. Quantitative ethnobiology revealed the frequency and coherence of ethnomedicinal reports. The plant Piper nigrum (1.35) and the animal, Spilostethus hospes (0.50) showed the highest UV. Among the ethnobotanicals, maximum RI value was noted for Hemidesmus indicus (0.91) and IAR was found to be maximum (1.00) for 8 plant species. Among the ethnozoologicals, Spilostethus hospes (0.67) displayed maximum RI value whereas Axis axis (2.32) displayed maximum CAI value.

CONCLUSION

TMM possessed knowledge on preparations, dose dependence, administration, safety, possible toxicity and side effects of using traditional formulations. TMM practising age old traditional therapeutics serve as alternative medical option for the underprivileged rural ethnic people in these remote areas of the country.

Socio-cultural contribution to medicinal plants assessment and sustainable development: case of antidiabetic and antihypertensive plants in Cameroon

Diabetes and hypertension rank among human diseases that are very difficult to control. The medicinal material of Cameroon can provide much information on ethnic folklore practices and traditional aspects of therapeutically important natural products. Cameroon has a very rich cultural diversity with different traditional systems of medicine that need more evidence-based studies on both crude extracts and purified phytomolecules. Therefore, an ethnobotanical study was conducted on 58 socio-cultural population groups living in different phytogeographic units of Cameroon in order to collect various medicinal plants or recipes. A two by two comparison of social-cultural groups of the same phytogeographic unit indicated a significant difference in 86.97% of medicinal plants or recipes comparisons' cases. A total of two hundred and eight recipes were identified, among which 75 were used for diabetes and hypertension treatment, 74 for hypertension alone, and 59 for diabetes alone. Also, two hundred and three plants were identified among which 33 were cultivated and marketed by 25 farming families engaged in integrated agriculture and selling of antidiabetic and antihypertensive plants to enhance their socio-economic status.

Gallic Acid, the Active Ingredient of Terminalia bellirica, Enhances Adipocyte Differentiation and Adiponectin Secretion

Visceral obesity induces the onset of metabolic disorders such as insulin resistance and diabetes mellitus. Adipose tissue is considered as a potential pharmacological target for treating metabolic disorders. The fruit of Terminalia bellirica is extensively used in Ayurvedic medicine to treat patients with diseases such as diabetes mellitus. We previously investigated the effects of a hot water extract of T. bellirica fruit (TB) on obesity and insulin resistance in spontaneously obese type 2 diabetic mice. To determine the active ingredients of TB and their molecular mechanisms, we focused on adipocyte differentiation using mouse 3T3-L1 cells, which are widely used to study adipocyte physiology. We show here that TB enhanced the differentiation of 3T3-L1 cells to mature adipocytes and that one of the active main components was identified as gallic acid. Gallic acid (10-30 µM) enhanced the expression and secretion of adiponectin via adipocyte differentiation and also that of fatty acid binding protein-4, which is the target of peroxisome proliferator-activated receptor gamma (PPARγ), although it does not alter the expression of the upstream genes PPARγ and CCAAT enhancer binding protein alpha. In the PPARγ ligand assay, the binding of gallic acid to PPARγ was undetectable. These findings indicate that gallic acid mediates the therapeutic effects of TB on metabolic disorders by regulating adipocyte differentiation. Therefore, TB shows promise as a candidate for preventing and treating patients with metabolic syndrome.

Phytotherapy in reducing glycemic index and testicular oxidative stress resulting from induced diabetes: a review

Oxidative stress plays a main role in the development of diabetes complications. The impairment of gonadal antioxidant potential and endocrine disturbance in diabetic males causes testicular damage and failure in sperm production. Plants have been widely used to control diabetes due their hypoglycemic and antioxidant potential, contributing towards the recovery of testicular function. Current study comprises a review of the literature on the main medicinal plants used in the recovery of testicular oxidative damage in animals with experimental diabetes. Eighteen plant species in the nineteen studies selected from the search strategy were evaluated. Plant extracts were evaluated according to their effects on blood glucose and insulin levels, antioxidant enzymes and oxidant levels, lipid peroxidation, total protein, testosterone levels, gonadosomatic index, diameter of seminiferous tubules, seminiferous epithelium height and integrity, number of germ cells at stage VII and apoptosis in the seminiferous epithelium, sperm production, motility, viability and morphology. After the analysis of the studies, it was observed that plant species, used alone or in combination, may control testicular oxidative damage triggered by diabetes. The antioxidant potential varies among species, with some plants proving to have a better performance in the recovery of reproduction parameters than others.

Pragmatic dietary advice for diabetes during Navratris

Navratri is one of the most common religious fasts observed among Hindus. A large number of people with diabetes follow Navratris fast irrespective of its health implications, often without proper education and medical advice. The quest for the scientific research on dietary advices for Hindu fasts including Navratris shows paucity of literature comparative to the dietary advices advocated during Ramadan. The eating and physical activity patterns during different fasts vary a lot depending up on social and cultural factors. Even eating pattern is not uniform among all persons following Navratris and is modified as per their region, local culture, and religious beliefs. Dietary advice during Navratris depends upon pattern of fasting, religious beliefs, and local sociocultural factors. In this review, efforts are made to provide pragmatic dietary advice for people with diabetes, modifications in the menus and cooking practices, and timings of the meals for successful blood glucose management during Navratris. This review will also help plan diet and physical activity advice for persons observing other fasts as well.

Functional food supplements to ameliorate the secondary complications in high fructose fed diabetic rats

Poly-herbal functional food supplements inhibited high fructose induced glycation in diabetic rats and showed promise for effective management of secondary complications of diabetes such as improved lipid profile, kidney function and reduction of oxidative stress.

Ashanti pepper (Piper guineense Schumach et Thonn) attenuates carbohydrate hydrolyzing, blood pressure regulating and cholinergic enzymes in experimental type 2 diabetes rat model

BACKGROUND

Ashanti pepper (Piper guineense Schumach et Thonn) seed is well known in folkloric medicine in the management of type 2 diabetes (T2DM) with little or no scientific documentation for its action. This study investigated the effect of Ashanti pepper seed on some enzymes relevant to carbohydrate hydrolysis, blood regulation and the cholinergic system, as well as the blood glucose level, lipid profile, antioxidant parameters, and hepatic and renal function markers in T2DM rats.

METHODS

T2DM was induced by feeding rats with high-fat diet (HFD) for 14 days followed by a single intraperitoneal dose of 35 mg/kg body weight of streptozotocin (STZ). Three days after STZ induction, diabetic rats were placed on a dietary regimen containing 2%-4% Ashanti pepper.

RESULTS

Reduced blood glucose level with decreased α-amylase, α-glucosidase and angiotensin I converting enzyme (ACE) activities were observed in Ashanti pepper seed and acarbose-treated rat groups when compared to that of the diabetic control rat group. Furthermore, the results revealed that inclusion of 2%-4% Ashanti pepper seed in diabetic rat fed group diets may ameliorate the lipid profile, antioxidant status, and hepatic and renal function in T2DM rats as much as in the acarbose-treated groups. In addition, a chromatographic profile of the seed revealed the presence of quercitrin (116.51 mg/g), capsaicin (113.94 mg/g), dihydrocapsaicin (88.29 mg/g) and isoquercitrin (74.89 mg/g).

CONCLUSIONS

The results from this study clearly suggest that Ashanti pepper could serve as a promising source of phenolic compounds with great alternative therapeutic potentials in the management of T2DM.

Circulating levels of reactive oxygen species in patients with nonproliferative diabetic retinopathy and the influence of antioxidant supplementation: 6-month follow-up

Aims:

The aim was to evaluate circulating levels of reactive oxygen species (ROS) and changes in central macular thickness (CMT) in patients with nonproliferative diabetic retinopathy (NPDR) after antioxidant supplementation.

Materials and Methods:

A total of 68 patients (68 eyes) with NPDR were enrolled. Patients were randomly divided into two groups: Treated with antioxidant supplement (Group A) and untreated control group (Group B). Each tablet, for oral administration, containing pycnogenol 50 mg, Vitamin E 30 mg and coenzyme Q10 20 mg. CMT and free oxygen radical test (FORT) were analyzed at baseline (T0), 3 (T1) and 6 (T2) months in both groups.

Results:

In Group A, FORT levels and CMT were significantly reduced over time (P < 0.001 for both). In Group B, FORT levels were increased (P < 0.001) and CMT did not vary significantly (P = 0.81) over 3 time points.

Conclusions:

This is the first study showing the reduction of ROS levels in patients with NPDR thanks to antioxidant therapy. Moreover, our findings have suggested also an influence on retinal thickness.

Effect of root-extracts of Ficus benghalensis (Banyan) in memory, anxiety, muscle co-ordination and seizure in animal models

Background

Ficus benghalensis L. (Banyan) is a commonly found tree in Eastern Nepal. Its different plant parts are used for various neurological ailments. This study was performed in mice to see its effects in various neuropharmacological parameters.

Methods

Passive-avoidance (memory), Open-field (anxiety), Pentobarbital-induced Sleep potentiation (sleep), Rota-rod (muscle-co-ordination), Pentylenetetrazol-Induced and Maximal Electroshock Seizure Tests were performed. Sample size was calculated using G*Power 3.1.9.2. Aqueous root extracts (Soxhlet method) of Ficus benghalensis 100 mg/kg and 200 mg/kg with negative and positive controls were used. The experimental results were represented as Mean ± SD. P-value was set at <0.05. Oneway analysis of variance (ANOVA) or Mann-Whitney U test was appropriately used.

Results

Passive-avoidance test showed 200 mg/kg group spent significantly less. Time (0.00s + 0.00s) in shock-zone than Normal Saline-group (9.67 s + 14.36 s, P = 0.000) or Diazepam-group (41.07 s + 88.24 s, P = 0.000).

Open-field test showed 200 mg/kg group spent significantly longer Time (24.77 s + 12.23 s) in central-square than either Normal Saline group (15.08 s + 6.81 s, P = 0.000) or Diazepam-group (15.32 s + 5.12 s, P = 0.000).

In Rota-rod test, 200 mg/kg group fell off the rod significantly (P = 0.000) earlier (33.01 s + 43.61 s) than both Normal Saline (>120 s) and Diazepam (62.07 s + 43.83 s) PTZ model showed that 100 mg/kg significantly (P = 0.004) delayed seizure-onset (184.40s + 36.36 s) compared to Normal Saline (101.79 s + 22.81 s), however, in MES model 200 mg/kg significantly (P = 0.000) prolonged tonic hind-limb extension (17.57 s + 2.15 s) compared to Normal Saline (13.55 s + 2.75 s) or Phenytoin (00.00s + 00.00s).

Conclusion

Aerial roots of Ficus benghalensis have memory-enhancing, anxiolytic, musclerelaxant, and seizure-modifying effect.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1413-5) contains supplementary material, which is available to authorized users.

The Role of Anethum graveolens L. (Dill) in the Management of Diabetes

Aim. There is evidence that Anethum graveolens (AG) has been used for centuries in Asian traditional medicine, and its constituents have useful effects on the control and management of diabetes and cardiovascular disorders. AG has many useful effects, including hypolipidemic and hypoglycemic effects, and it has been reported to reduce the incidence of diabetic complications. It acts mainly by affecting antioxidant capacity and change in some genes in glucose and lipid pathways. The aim of the present paper was to summarize pharmacological effects of AG in the management of diabetes. Methods. To prepare this review, a pharmacological and phytochemical literature survey was performed using Scopus, PubMed, and Web of Science. Also, some historical and ethnopharmacological literature sources were used. Results. This review plans to provide readers with an assessment of the pharmacological effects of AG, especially in diabetes. Conclusion. The paper highlights the therapeutic effects of AG which would aid in supporting their safe use in the management of diabetes and cardiovascular diseases.

A multicenter clinical study to determine the efficacy of a novel fenugreek seed (Trigonella foenum-graecum) extract (Fenfuro™) in patients with type 2 diabetes

Background

Trigonella foenum-graecum (fenugreek) seeds are known to exhibit potent antioxidant, hypoglycemic, and nephroprotective activities, as well as serve as excellent membrane stabilizers especially because of their content of novel furostanolic saponins. Our previous studies exhibited the broad spectrum safety and efficacy of Fenfuro, a novel T. foenum-graecum seed extract enriched in furostanolic saponins, in type 2 diabetes (T2D) in rats.

Design

This multicenter, randomized, placebo-controlled, double-blind, add-on clinical study evaluated over a period of 90 consecutive days the efficacy of Fenfuro (daily dosage: 500 mg bid) in 154 subjects (male: 108; female: 46; age: 25–60 years) with T2D.

Methods

This study examined the body weight, blood pressure, and pulse rate, as well as the efficacy of Fenfuro on fasting and post-prandial plasma sugar (mg/dL), glycosylated hemoglobin (HbA1c), and fasting and post-prandial C-peptide levels.

Results

Fenfuro caused significant reduction in both fasting plasma and post-prandial blood sugar levels. Approximately 83% of the subjects reported decreases in fasting plasma sugar levels in the Fenfuro-treated group as compared to 62% in the placebo group, while 89% of the subjects demonstrated reduction in post-prandial plasma sugar levels in the Fenfuro-treated group as compared to 72% in the placebo group. HbA1c levels were reduced in both placebo and treatment groups. The decrease in HbA1c levels was significant in both groups as compared to respective baseline values. A significant increase in fasting and post-prandial C-peptide levels compared to the respective baseline values was observed, while no significant changes in fasting and post-prandial C-peptide levels were observed between the two groups. No significant adverse effects were observed by blood chemistry analyses. Furthermore, 48.8% of the subjects reported reduced dosage of anti-diabetic therapy in the Fenfuro-treated group, whereas 18.05% reported reduced dosage of anti-diabetic therapy in the placebo group.

Conclusion

In summary, Fenfuro proved safe and efficacious in ameliorating the symptoms of T2D in humans.

Multivariate analysis and molecular interaction of curcumin with PPARγ in high fructose diet induced insulin resistance in rats

To investigate the effect of curcumin on the multivariate and docking analysis on peroxisome proliferator activated receptor-γ, the rats were fed with high fructose diet (Group 2) to induce insulin resistance and curcumin was co-administered orally (Group 4) for a period of 8 weeks and measured the biochemical parameters in blood, kidney and liver tissues. The results showed a significant (p ≤ 0.05) increase in the level of creatinine, glucose, insulin, low density lipoprotein, total cholesterol, triglyceride, urea, uric acid, very low density lipoprotein and decreased albumin, high density lipoprotein and total protein level in the blood of Group 2 when compared with Group 1 control rats. Further, analysis on liver and kidney tissues showed a significant decrease in antioxidants, hexokinase and increased glucose 6-phosphatase and fructose 1,6-bisphosphatase, hydroperoxides and TBARS in Group 2 rats. Furthermore, the multivariate and loading coefficient analysis showed that albumin, HDL, catalase, glutathione reductase, hexokinase and vitamin E are the most contributing factors in blood, liver and kidney. Subsequently, molecular docking was carried out to determine the binding efficiency of curcumin as agonist of PPARγ showed high affinity compared to pioglitazone. The histology of liver and kidney were also studied and the administration of curcumin along with fructose protects the organs from the abnormal changes and also prevents the fat accumulation. Overall, these results demonstrate the preventive role of curcumin on diet induced insulin resistant in rats by ameliorating the altered levels of metabolic changes and potential binding of curcumin with PPARγ as agonist in the treatment of insulin resistance.

Prunus mume leaf extract lowers blood glucose level in diabetic mice

Context Diabetes is a common metabolic disease with long-term complications. Prunus mume Sieb. et Zucc. (Rosaceae) fruits have shown to ameliorate glucose intolerance. However, the antidiabetic effects of P. mume leaves have not been investigated. Objective This study evaluated the effects of P. mume leaf 70% ethanol extract (PMLE) on alleviating diabetes in vivo and in vitro. Materials and methods PMLE was fractionated into n-hexane, dichloromethane (CH2Cl2), ethyl acetate (EtOAc), n-butanol (BuOH) and water. Polyphenol and flavonoid contents in PMLE fractions were determined using Folin-Ciocalteu reagent and the aluminium chloride colorimetric method, respectively. We evaluated α-glucosidase inhibition using a microplate reader at 400 nm. Adipocyte differentiation by lipid accumulation was measured using Nile Red staining. Male imprinting control region (ICR) mice were injected with streptozotocin (STZ, 100 mg/kg, i.p.). High-fat diets were provided for three weeks prior to PMLE treatments to induce type 2 diabetes. PMLE (0, 5, 25 or 50 mg/kg) was administrated for four weeks with high-fat diets. Results The EtOAc fraction of PMLE inhibited α-glucosidase activity (IC50 = 68.2 μg/mL) and contained 883.5 ± 14.9 mg/g of polyphenols and 820.1 ± 7.7 mg/g of flavonoids. The 50 mg/kg PMLE supplement reduced 40% of blood glucose level compared to obese/diabetes mice. Obese/diabetic mice treated with 50 mg/kg PMLE showed a lower level of triacylglycerol (320.7 ± 20.73 mg/dL) compared to obese/diabetes mice (494.9 ± 14.80 mg/dL). Conclusion The data demonstrate that P. mume leaves exert antidiabetic effects that may be attributable to high concentrations of polyphenols and flavonoids.

Biological actions and molecular effects of resveratrol, pterostilbene, and 3'-hydroxypterostilbene

Stilbenes are a class of polyphenolic compounds, naturally found in a wide variety of dietary sources such as grapes, berries, peanuts, red wine, and some medicinal plants. There are several well-known stilbenes including trans-resveratrol, pterostilbene, and 3′-hydroxypterostilbene. The core chemical structure of stilbene compounds is 1,2-diphenylethylene. Recently, stilbenes have attracted extensive attention and interest due to their wide range of health-beneficial effects such as anti-inflammation, -carcinogenic, -diabetes, and -dyslipidemia activities. Moreover, accumulating in vitro and in vivo studies have reported that stilbene compounds act as inducers of multiple cell-death pathways such as apoptosis, cell cycle arrest, and autophagy for chemopreventive and chemotherapeutic agents in several types of cancer cells. The aim of this review is to highlight recent molecular findings and biological actions of trans-resveratrol, pterostilbene, and 3′-hydroxypterostilbene.

Hypoglycemic and anti-hyperglycemic activity of Triphalādi granules in mice

Background:

Triphalādi kvātha is well known herbal Ayurvedic formulation used in Prameha (~type 2 diabetes mellitus). In the present study, kvātha was converted into granules and assessed for its hypoglycemic and anti-hyperglycemic effects in albino mice.

Materials and Methods:

Triphalādi granules (650 mg/kg, p.o.) were administered in normal albino mice for assessment of hypoglycemic activity. Anti-hyperglycemic activity of Triphalādi granules was assessed in glucose (5 g/kg, p.o.) solution overloaded mice. The blood sugar level (BSL) was measured with the help of one touch easy glucometer.

Results:

Triphalādi granules produced significant decrease in blood glucose level after one hour in comparison to initial values while decreasing BSL by 27.92% in comparison to control group in normal albino mice. In hyperglycemic study, Triphalādi granules produced significant decrease the BSL after 2 hr. of administration compared to control group.

Conclusion:

Triphalādi granules have significant hypoglycemic and anti-hyperglycemic activity in mice with minimal effect on BSL below normal range. The studies suggest the potential role of Triphalādi granules as an alternative adjuvant therapy in diabetic individuals for the control of the blood glucose level.

Antioxidant and antimicrobial capacities of ethanolic extract of Pergularia daemia leaves: a possible substitute in diabetic management

BACKGROUND

The leaves of Pergularia daemia Forsk (family Asclepidaceae) provide alternative plant-based treatments for the management of diabetes mellitus and diarrhoea in both humans and indigenous poultry species like the Guinea fowls (Numida meleagris). However, no scientific investigations to validate its usefulness in Ghana have been established. This study therefore sought to investigate the anti-hyperglycaemic activity of the 70 % ethanolic extract of P. daemia using streptozotocin (STZ)-induced diabetic male Sprague-Dawley rats. Additionally, the antioxidant and antimicrobial properties of the extract were investigated.

METHODS

The total phenolic content, total flavonoids content, radical scavenging activity and reducing power assays were estimated using Folin-Ciocalteu method, aluminium chloride colorimetric assay, Fe3+ reduction assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays, respectively.

RESULTS

The results showed that P. daemia extract caused anti-hyperglycaemic activity in the STZ-induced rats at doses of 30, 60 and 90 mg/kg body weight with significant reduction in blood glucose levels. The phytosterols, saponins, phenols, alkaloids, tannins and triterpenes found in the extract may be responsible for the observed anti-hyperglycaemia and antioxidant activities. The extract also showed antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis.

CONCLUSIONS

These findings justify the folkloric use of P. daemia as an anti-diabetic and antibacterial agents for susceptible species.

Chemical and Biological Aspects of Extracts from Medicinal Plants with Antidiabetic Effects

Diabetes mellitus is a chronic disease and a leading cause of death in western countries. Despite advancements in the clinical management of the disease, it is not possible to control the late complications of diabetes. The main characteristic feature of diabetes is hyperglycemia, which reflects the deterioration in the use of glucose due to a faulty or poor response to insulin secretion. Alloxan and streptozotocin (STZ) are the chemical tools that are most commonly used to study the disease in rodents. Many plant species have been used in ethnopharmacology or to treat experimentally symptoms of this disease. When evaluated pharmacologically, most of the plants employed as antidiabetic substances have been shown to exhibit hypoglycemic and antihyperglycemic activities, and to contain chemical constituents that may be used as new antidiabetic agents. There are many substances extracted from plants that offer antidiabetic potential, whereas others may result in hypoglycemia as a side effect due to their toxicity, particularly their hepatotoxicity. In this article we present an updated overview of the studies on extracts from medicinal plants, relating the mechanisms of action by which these substances act and the natural principles of antidiabetic activity.

Health-promoting and disease-preventive potential of Trianthema portulacastrum Linn. (Gadabani) -An Indian medicinal and dietary plant

It is estimated that 80% of the world population depends on traditional medicine for primary healthcare need. Trianthema portulacastrum Linn. (family: Aizoaceae) is a small perennial weed found in the Americas, Africa, India, and other regions of the world. This plant is used extensively in Indian traditional medicines and is also consumed as a vegetable throughout Asia for its perceived health benefits. Phytochemical analysis of T. portulacastrum reveals the presence of alkaloids, flavonoids, terpenoids, saponins, and phenolic compounds. Emerging studies demonstrate that crude extracts as well as bioactive phytoconstituents of T. portulacastrum exhibit potent antioxidant, anti-infective, analgesic, and anti-inflammatory activities. A growing number of in vitro and in vivo studies demonstrate various biological and pharmacological activities, including prevention and amelioration of hepatotoxicity, nephrotoxicity, hyperglycemia, hyperlipidemia, infectious diseases and cancer. This review aims to present and analyze available literature to understand the full potential of T. portulacastrum in health promotion and disease prevention. Current limitations and future directions of research on this medicinal and dietary plant are also critically discussed.

Reactive oxygen species: sources, consequences and targeted therapy in type 2 diabetes

Oxidative stress has been considered as a central mediator in the progression of diabetic complication. The intracellular reactive oxygen species (ROS) leads to oxidative stress and it is raised from the mitochondria as well as by activation of five major pathways: increased polyol pathway flux, activation of protein kinase C (PKC) pathway, increased formation of advanced glycation end products (AGEs), over activity of hexosamine pathway and increased production of angiotensin II. The increased ROS through these pathways leads to β-cell dysfunction and insulin resistance, responsible for cell damage and death. This review not only highlights the sources of ROS production and their involvement in the progression of diabetes, but also emphasizes on pharmacological interventions and targeting of ROS in type 2 diabetes. This review summarizes the ROS as potential therapeutic targets, based on a putative mechanism in the progression of the diabetes. It also summarizes current knowledge of ROS activation in type 2 diabetes as well as ROS as a possible target for its treatment. Eventually, it would be a promising target for various strategies and drugs to modulate ROS levels in diabetes.

The Protective Effect of Antioxidants Consumption on Diabetes and Vascular Complications

Obesity and diabetes is generally accompanied by a chronic state of oxidative stress, disequilibrium in the redox balance, implicated in the development and progression of complications such as micro- and macro-angiopathies. Disorders in the inner layer of blood vessels, the endothelium, play an early and critical role in the development of these complications. Blunted endothelium-dependent relaxation and/or contractions are quietly associated to oxidative stress. Thus, preserving endothelial function and oxidative stress seems to be an optimization strategy in the prevention of vascular complications associated with diabetes. Diet is a major lifestyle factor that can greatly influence the incidence and the progression of type 2 diabetes and cardiovascular complications. The notion that foods not only provide basic nutrition but can also prevent diseases and ensure good health and longevity is now attained greater prominence. Some dietary and lifestyle modifications associated to antioxidative supply could be an effective prophylactic means to fight against oxidative stress in diabesity and complications. A significant benefit of phytochemicals (polyphenols in wine, grape, teas), vitamins (ascorbate, tocopherol), minerals (selenium, magnesium), and fruits and vegetables in foods is thought to be capable of scavenging free radicals, lowering the incidence of chronic diseases. In this review, we discuss the role of oxidative stress in diabetes and complications, highlight the endothelial dysfunction, and examine the impact of antioxidant foods, plants, fruits, and vegetables, currently used medication with antioxidant properties, in relation to the development and progression of diabetes and cardiovascular complications.

Development of an antidiabetic formulation (ADJ6) and its inhibitory activity against α-amylase and α-glucosidase

There has recently been much advancement in the diagnosis, treatment, and research of metabolic disorders, especially diabetes. Current research around the world is focused on finding an alternative source of treatment from natural resources for diabetic management, apart from the available synthetic medicines. The present study is a preliminary study of a polyherbal formulation using edible natural resources and an assessment of its antidiabetic activity. The formulation was screened for its phytochemical constituents, total phenols, flavonoids, and vitamin C content. It was also analyzed for its inhibitory effect against the digestive enzymes α-amylase and α-glucosidase, compared with the standard drug acarbose. The formulation showed the presence of major constituents such as steroids, cardiac glycosides, phenols, flavonoids, and saponins. It also had a high level of phenols (340 ± 2.5 mg/g), flavonoids (235.4 ± 8.3 mg/g), and vitamin C (470.8 ± 16.6 mg/g), and showed a half-maximal inhibitory concentration (IC50) value of 0.41 ± 0.03 mg/mL and 0.51 ± 0.01 mg/mL for amylase and glucosidase, respectively. The results showed that ADJ6 had a significant inhibitory activity on α-amylase and α-glucosidase; however, its inhibitory activity was less than that of acarbose. The plants that are formulated in ADJ6 possess potent antidiabetic activity. Thus, we found that ADJ6 is a potent lead for effective diabetic management; however, an evaluation of the formulation must be illustrated using an in vivo model.

Efficacy of Aloe Vera Supplementation on Prediabetes and Early Non-Treated Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The aim of this study was to evaluate evidence for the efficacy of aloe vera on managing prediabetes and early non-treated diabetes mellitus. We performed a systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials until 28 January 2016. A total of five randomized controlled trials (RCTs) involving 415 participants were included. Compared with the controls, aloe vera supplementation significantly reduced the concentrations of fasting blood glucose (FBG) (p = 0.02; weighed mean difference [WMD]: −30.05 mg/dL; 95% confidence interval [CI]: −54.87 to −5.23 mg/dL), glycosylated hemoglobin A1c (HbA1c) (p < 0.00001; WMD: −0.41%; 95% CI: −0.55% to −0.27%), triglyceride (p = 0.0001), total cholesterol (TC) (p < 0.00001), and low density lipoprotein-cholesterol (LDL-C) (p < 0.00001). Aloe vera was superior to placebo in increasing serum high density lipoprotein-cholesterol (HDL-C) levels (p = 0.04). Only one adverse event was reported. The evidence from RCTs showed that aloe vera might effectively reduce the levels of FBG, HbA1c, triglyceride, TC and LDL-C, and increase the levels of HDL-C on prediabetes and early non-treated diabetic patients. Limited evidence exists about the safety of aloe vera. Given the small number and poor quality of RCTs included in the meta-analysis, these results are inconclusive. A large-scale, well-designed RCT is needed to further address this issue.

Terminalia bellirica Extract Inhibits Low-Density Lipoprotein Oxidation and Macrophage Inflammatory Response in Vitro

The deciduous tree Terminalia bellirica found in Southeast Asia is extensively used in traditional Indian Ayurvedic medicine for the treatment of hypertension, rheumatism, and diabetes. The anti-atherogenic effect of Terminalia bellirica fruit has not been fully elucidated. Here, we investigated the effect of Terminalia bellirica extract (TBE) on low-density lipoprotein (LDL) oxidation and inflammation in macrophages. TBE showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (EC₅₀: 7.2 ± 1.2 μg/mL) and 15-lipoxygenase inhibitory activity. TBE also significantly inhibited free radical-induced LDL oxidation compared to the solvent control in vitro. In THP-1 macrophages, TBE treatment resulted in significant decreases of the mRNA expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and lectin-like oxidized LDL receptor-1 (LOX-1). TBE also reduced matrix metalloproteinase (MMP)-9 secretion and intracellular reactive oxygen species (ROS) production in THP-1 macrophages. These results show that TBE has the inhibitory effects on LDL oxidation and macrophage inflammatory response in vitro, suggesting that its in vivo use might inhibit atherosclerosis plaque progression.

Kinetics of α-amylase and α-glucosidase inhibitory potential of Zea mays Linnaeus (Poaceae), Stigma maydis aqueous extract: An in vitro assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Corn silk (Zea mays L., Stigma maydis) is an important herb used traditionally in many parts of the world to treat array of diseases including diabetes mellitus. Inhibitors of α-amylase and α-glucosidase offer an effective strategy to modulate levels of post prandial hyperglycaemia via control of starch metabolism.

AIM OF THE STUDY

This study evaluated α-amylase and α-glucosidase inhibitory potentials of corn silk aqueous extract. Active principles and antioxidant attributes of the extract were also analysed.

MATERIALS AND METHODS

The α-amylase inhibitory potential of the extract was investigated by reacting its different concentrations with α-amylase and starch solution, while α-glucosidase inhibition was determined by pre-incubating α-glucosidase with different concentrations of the extract followed by addition of p-nitrophenylglucopyranoside. The mode(s) of inhibition of the enzymes were determined using Lineweaver-Burke plot.

RESULTS

In vitro analysis of the extract showed that it exhibited potent and moderate inhibitory potential against α-amylase and α-glucosidase, respectively. The inhibition was concentration-dependent with respective half-maximal inhibitory concentration (IC50) values of 5.89 and 0.93mg/mL. Phytochemical analyses revealed the presence of alkaloids, flavonoids, phenols, saponins, tannins and phytosterols as probable inhibitory constituents. Furthermore, the extract remarkably scavenges reactive oxygen species like DPPH and nitric oxide radicals, elicited good reducing power and a significant metal chelating attributes.

CONCLUSION

Overall, the non-competitive and uncompetitive mechanism of action of corn silk extract is due to its inhibitory effects on α-amylase and α-glucosidase, respectively. Consequently, this will reduce the rate of starch hydrolysis, enhance palliated glucose levels, and thus, lending credence to hypoglycaemic candidature of corn silk.