Antihyperglycemic and antihyperlipidemic effects of guar gum on streptozotocin-induced diabetes in male rats

Evaluation of a mucoadhesive auto-nanoemulsifying drug delivery system (SNEDDS) for oral insulin administration

This study investigated the potential of self-nanoemulsifying drug delivery systems (SNEDDS) to optimize the oral bioavailability of insulin. Insulin complexes with phospholipids and enzymatically-modified phospholipids were developed and incorporated into the SNEDDS using Lauroglycol FCC as the oily phase and Cremophor EL and Labrafil M1944CS as the surfactant and co-surfactant, respectively. Additionally, mucoadhesive polysaccharides (sodium alginate and guar gum) were added further to enhance the bioavailability of insulin in these systems. The objective was to increase the bioavailability and bioactivity of an insulin-modified phosphatidylcholine complex by incorporating mucoadhesives into the SNEDDS. After polymer inclusion, the resulting nanoemulsions exhibited droplet diameters ranging from 57 to 83 nm. Cytotoxicity and apparent permeability tests were conducted on Caco-2 and NIH 3 T3 cell lines, revealing that toxicity was related to the concentrations of insulin and surfactant in the nanosystems-formulations containing guar gum as a mucoadhesive showed better tolerance to cell death in the Caco-2 line. In a murine diabetes model, the SNEDDS were observed to reduce glucose levels by up to 61.63 %, with a relative bioavailability of 2.25 % compared to subcutaneously administered insulin. These results suggest that SNEDDS incorporating mucoadhesives could represent a promising strategy for improving oral insulin delivery.

A review on the hypoglycemic effect, mechanism and application development of natural dietary polysaccharides

Diabetes mellitus (DM) as one chronic metabolic disease was greatly increased over recent decades. The major agents treating diabetes have noticeable side effects as well as the tolerability problems. The bioactive dietary polysaccharides from abundant natural resources exhibit good hypoglycemic effect with rare adverse effects, which might serve as a candidate to prevent and treat diabetes. However, the correlations between the hypoglycemic mechanism of polysaccharides and their structure were not mentioned in several studies, what's more, most of the current hypoglycemic studies on polysaccharides were based on in vitro and in vivo experiments, and there was a lack of knowledge about the effects in human clinical trials. The aim of this review is to discuss recent literature about the variety of dietary polysaccharides with hypoglycemic activity, as well the mechanism of action and the structure-function relationship are highlighted. Meanwhile, the application of dietary polysaccharides in functional foods and clinical medicine are realized with an in-depth understanding. So as to promote the exploration of dietary polysaccharides in low glycemic healthy foods or clinical medicine to prevent and treat diabetes.

Soluble Dietary Fibers as Antihyperlipidemic Agents: A Comprehensive Review to Maximize Their Health Benefits

The number of hypercholesterolemic people is increasing rapidly worldwide, with elevated lipid profiles representing a major risk factor of coronary heart diseases. Dietary intervention was shown to improve the lipid profile, thus enhancing the quality of life. Dietary fiber is a nondigestible form of carbohydrates, due to the lack of the digestive enzyme in humans required to digest fiber, and is classified according to its water solubility properties as either soluble (SDF) or insoluble dietary fiber (IDF). Consumption of SDF is associated with several health benefits such as reduced lipid levels, lower blood pressure, improved blood glucose control, improved immune function, and reduced inflammation. SDF has been shown to lower blood cholesterol by several action mechanisms including directly due to the gelling, mucilaginous, and viscous fiber nature, and indirectly due to its fermented products and modulation of the gut microbiome. This review aims to provide a holistic overview on how SDF impacts the lipid profile. We start by providing an overview of the chemical structure of the major SDFs including mucilage, gums (gum arabic and guar gum), pectin, and inulin.

The effects of guar gum supplementation on lipid profile in adults: a GRADE-assessed systematic review, meta-regression and dose-response meta-analysis of randomised placebo-controlled trials

Recent meta-analytic work indicated that guar gum supplementation might improve lipid profile markers in different populations. However, critical methodological limitations such as the use of some unreliable data and the lack of inclusion of several relevant studies, and the scarcity in assessments of regression and dose-specific effects make it difficult to draw meaningful conclusions from the meta-analysis. Therefore, current evidence regarding the effects of guar gum supplementation on lipid profile remains unclear. The present systematic review, meta-regression and dose-response meta-analysis aimed to examine the effects of guar gum supplementation on lipid profile (total cholesterol (TC), LDL, TAG and HDL) in adults. Relevant studies were obtained by searching the PubMed, SCOPUS, Embase and Web of Science databases (from inception to September 2021). Weighted mean differences (WMD) and 95 % CI were estimated via a random-effects model. Heterogeneity, sensitivity analysis and publication bias were reported using standard methods. Pooled analysis of nineteen randomised controlled trials (RCT) revealed that guar gum supplementation led to significant reductions in TC (WMD: -19·34 mg/dl, 95 % CI -26·18, -12·49, P < 0·001) and LDL (WMD: -16·19 mg/dl, 95 % CI -25·54, -6·83, P = 0·001). However, there was no effect on TAG and HDL among adults in comparison with control group. Our outcomes suggest that guar gum supplementation lowers TC and LDL in adults. Future large RCT on various populations are needed to show further beneficial effects of guar gum supplementation on lipid profile and establish guidelines for clinical practice.

Extraction and Optimization of Active Metabolites From Cluster Bean: An In Vitro Biological and Phytochemical Investigation

The current study aimed to explore active metabolites of locally recognized and high yielding cultivar cluster bean (BR-99) with a wide range of adaptability having antioxidant, antidiabetic, antimicrobial, and cytotoxic potential. Six solvents were used (crude methanol, n-hexane, chloroform, ethyl acetate, butanol, and aqueous) with escalating polarity for colorimetric determination of antioxidants such as total phenolic contents (TPC), total flavonoid contents (TFC), and free radical scavenging activity (FRSA) by DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay. Moreover, an antidiabetic and anticancer study was conducted by α-amylase inhibition and MTT (3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-tetrazolium bromide) assay. Biological investigations were carried out against the most commonly found infectious microbial strains. The significant results (P ≤ .001) of each activity were seen among six tested solvent extracts. The ethyl acetate and methanol extract have more antioxidant potential with the highest TPC (16.38 ± .13 mg GAE/g) and TFC (8.15 ± .24 mg CE/g), respectively. Similarly, methanol extract presented the highest free radical scavenging activity (46.31 ± .91%), followed by ethyl acetate, butanol, chloroform, aqueous, and n-hexane extract. However, the maximum α-amylase inhibition (62.54 ± 1.47%) and anticancer activity against human lung cancer cells were congregated (78.31 ± 1.46%) in butanol and chloroform, respectively. A positive correlation was seen between TPC with TFC (R²= .8356), FRSA (R²= .8381), and anti-diabetic activity (R²= .8082), which highlights the phenolic contents as strong anti-oxidant agents especially flavonoids. Each extract of cluster bean (BR-99) showed significant antimicrobial activities for all tested bacterial strains except B. cereus and E. coli. The profound results of maximum antibacterial activity were witnessed by chloroform extract while ethyl acetate extracts showed great antifungal potential against all tested fungal strains. The HPLC quantitative analysis results of cluster bean (BR-99) revealed the presence of active phytochemicals such as gallic acid, HB acid, vanillic acid, kaempferol, sinapic acid, ferulic acid, salicylic acid, coumarins, quercetin, rutin, p-coumaric acid, and catechin, and the variation in both phytochemical and biological spectrums envisioned the cluster bean (BR-99) used in future as a cheap, safer, and potent source of bioactive drugs.

Guar (Cyamopsis tetragonoloba L.) plant gum: From biological applications to advanced nanomedicine

Natural polymers are an efficient class of eco-friendly and biodegradable polymers, because they are readily available, come from natural sources, inexpensive and can be chemically modified with the correct reagents. Guar gum (GG) is a natural polymer with great potential to be used in pharmaceutical formulations due to its unique composition and lack of toxicity. GG can be designed to suit the needs of the biological and medical engineering sectors. In the development of innovative drug delivery systems, GG is commonly utilized as a rate-controlling excipient. In this review, different properties of GG including chemical composition, extraction methods and its usefulness in diabetes, cholesterol lowering, weight control, tablet formulations as well as its food application were discussed. The other purpose of this study is to evaluate potential use of GG and its derivatives for advanced nanomedicine such as drug delivery, tissue engineering and nanosensing. It should be noted that some applicable patents in medical area have also been included in the rest of this survey to extend knowledge about guar gum and its polymeric nature.

Insight in the Recent Application of Polyphenols From Biomass

Biomass polyphenols are bio-active macromolecules with distinct chemical structures in a variety of biomass. In recent years, the study of biomass polyphenols and their application in food and medicine fields has become a research hotspot, which predominantly focuses on the preparation, purification, structural identifications, and measurements of biological activities. Many studies describe methodologies for extraction and application of polyphenols, but comprehensive work to review its physiological activities like drugs and health products are lacking. This paper comprehensively unlocks the bioactivities of antioxidant, antibacterial, antitumor, anticancer, neuroprotection, control of blood sugar, regulation of blood fat, and promotion of gastrointestinal health functions of polyphenols from different biomass sources. This review will serve as an illuminating resource for the global scientific community, especially for those who are actively working to promote the advances of the polyphenols research field.

Nephroprotective potential of Anogeissus latifolia Roxb. (Dhava) against gentamicin-induced nephrotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Stem bark of Anogeissus latifolia Roxb. (Family: Combretaceae) is used traditionally and ethnomedicinally for correction of kidney disorders.

AIM OF THE STUDY

The present study demonstrates the nephroprotective potential of stem bark of A. latifolia Roxb.

MATERIALS AND METHODS

The HPTLC fingerprint and HPLC analysis were carried out to standardize the ethanolic extract of stem bark of A. latifolia (ALEE) using ellagic acid as a marker. Nephrotoxicity was induced in adult Wistar albino rats by gentamicin (100 mg/kg, intraperitoneally for 8 days) and they were treated with ALEE (100, 200 and 400 mg/kg, orally for 8 days), ellagic acid (10 mg/kg, orally for 8 days) and cystone syrup (5 ml/kg, orally), a standard reference a polyherbal formulation. Urine volume, serum and urine levels of creatinine, urea and uric acid, oxidative stress parameters (lipid peroxidation, catalase, superoxide dismutase and reduced glutathione), inflammatory markers (TNF-α and IL-6) and kidney weight along with its histological changes were studied in experimental animals.

RESULTS

HPTLC, HPLC and LC-MS analysis of ALEE revealed the presence of ellagic acid and other various phytoconstituents. Administration of gentamicin caused significant increase in urine output and kidney weight, elevated biochemical, inflammatory and oxidative stress parameters as well as caused histological damage in the kidney tissue. These parameters were attenuated by the concurrent treatment with ALEE and ellagic acid. The effects were comparable to cystone.

CONCLUSION

Present investigations concluded that ALEE exhibited nephroprotective potential and validated the traditional use of stem bark of A. latifolia in kidney disorders. The nephroprotective effect may be attributed to the antioxidant and anti-inflammatory phytoconstituents in ALEE.

Comparative transcriptome and metabolome profiling in the maturing seeds of contrasting cluster bean (Cyamopsis tetragonoloba L. Taub) cultivars identified key molecular variations leading to increased gum accumulation

Cluster bean (Guar) is the major source of industrial gum. Knowledge on the molecular events regulating galactomannan gum accumulation in guar will pave way for accelerated development of gummy guar genotypes. RNA Seq analysis in the immature seeds of contrasting cluster bean genotypes HGS 563 (gum type) and Pusa Navbahar (vegetable type) resulted in the generation of 19,855,490 and 21,488,472 quality reads. Data analysis identified 4938 differentially expressed genes between the gummy vs vegetable genotypes. A set of 2241 genes were up-regulated and 2587 genes were down-regulated in gummy guar. Significant up-regulation of genes involved in the biosynthesis of galactomannan and cell wall storage polysaccharides was observed in the gummy HGS 563. Genes involved in carotenoids, flavonoids, non mevalonic acid, terpenoids, and wax metabolism were also up-regulated in HGS 563. Mannose and galactose were the major nucleotide sugars in Pusa Navbahar and HGS 563 immature seeds. Immature seeds of HGS 563 showed high concentration of mannose and galactose accumulation compared to Pusa Navbahar. qRT-PCR analysis of selected genes confirmed the findings of transcriptome data.

Dietary Fiber: An Opportunity for a Global Control of Hyperlipidemia

Dietary fiber has a long history in the intervention study of hyperlipidemia. In this review, current understandings of structures, sources, and natures of various kinds of dietary fibers (DFs) were analyzed first. Available evidences for the use of different varieties of DFs in the lipid-lowering action both in vitro and in vivo were subsequently classified, including both soluble ones, such as glucans, pectins, and gums, and insoluble ones, including arabinooxylans and chitosans, in order to draw a primary conclusion of their dose and molecular weight relationship with lipid-lowering effect. Their potential mechanisms, especially the related molecular mechanism of protective action in the treatment and prevention of hyperlipidemia, were summarized at last. Five major mechanisms are believed to be responsible for the antihyperlipidemic benefits of DFs, including low levels of energy, bulking effect, viscosity, binding capacity, and fermentation thus ameliorating the symptoms of hyperlipidemia. From the molecular level, DFs could possibly affect the activities of HMG-CoA reductase, LDL receptors, CYP7A1, and MAPK signaling pathway as well as other lipid metabolism-related target genes. In summary, dietary fibers could be used as alternative supplements to exert certain lipid-lowering effects on humans. However, more clinical evidence is needed to strengthen this proposal and its fully underlying mechanism still requires more investigation.

Anti-diabetic effects of the soluble dietary fiber from tartary buckwheat bran in diabetic mice and their potential mechanisms

Background

Tartary buckwheat has beneficial effects on glucose and lipid metabolism of patients with type 2 diabetes mellitus. However, the physiological effects of a soluble dietary fiber (SDF) from tartary buckwheat have rarely been studied, especially in vivo.

Objective

This study aimed to examine the hypoglycemic and hypolipidemic effects of SDF from tartary buckwheat bran on high-fat diet/streptozotocin-induced diabetic mice.

Design

The SDF of tartary buckwheat bran was collected according to the Association of Official Analytical Chemists method 991.43. Diabetic mice were treated with high-fat diets supplemented with 0.5, 1, and 2% SDF for 8 weeks. Parameters related to glucose and lipid metabolism and relevant mechanisms, including the excretion of short-chain fatty acids and the glycemic signaling pathway in the liver, were investigated. In addition, the structural characterization of a purified polysaccharide from SDF of tartary buckwheat bran was illustrated.

Result

Supplementation with SDF in the diet resulted in reduced levels of fasting blood glucose, improved oral glucose tolerance, increased levels of liver glycogen and insulin, as well as improved lipid profiles in both the serum and liver, in diabetic mice. The amelioration of glucose and lipid metabolism by SDF was accompanied by an increase in the short-chain fatty acid levels in the cecum and co-regulated by hepatic adenosine-5′-monophosphate-activated protein kinase (AMPK) phosphorylation. A neutral tartary buckwheat polysaccharide with an average molecular weight of 19.6 kDa was purified from the SDF, which consisted mainly of glucose with α-glycosidic bonds.

Conclusions

The SDF of tartary buckwheat bran exhibits hypoglycemic and hypolipidemic effects in diabetic mice, contributing to the anti-diabetic mechanisms of tartary buckwheat.

The Antioxidant Activities of Betula etnensis Rafin. Ethanolic Extract Exert Protective and Anti-diabetic Effects on Streptozotocin-Induced Diabetes in Rats

Pathophysiological mechanisms correlating diabetes mellitus with associated complications are still not completely clear, even though oxidative stress seems to play a pivotal role. Literature data suggest that cell damages induced by hyperglycemia, although multifactorial, have a common pathway in oxidative/nitrosative stress. The present study evaluated the effects of Betula etnensis Raf. bark extract, a plant belonging to the Betulaceae family endemic to Sicily, on oxidative stress and in preventing and/or retarding diabetes-associated complications in streptozotocin diabetic rats treated with the extract at dose of 0.5 g/kg body weight per day for 28 consecutive days. The extract administration significant decreased food and water intake, fasting blood glucose, weight loss and polyuria, compared with untreated diabetic animals. Furthermore, oxidative stress markers particularly, lipid hydroperoxides (LOOH) and nitrite/nitrate levels, non-proteic thiol groups (RSH), γ-glutamyl-cysteine-synthetase (γ-GCS) activities and expression, heme oxygenase-1 (HO-1), endothelial and inducible nitric oxide synthases (i-NOS e-NOS) expression, significantly changed by streptozocin treatment, were markedly restored both in plasma and tissues together with nuclear sirtuins activity (Sirt1). Results suggested that B. etnensis bark alcoholic extract is able to counteract oxidative stress and to ameliorate some general parameters related to diabetes.

Hypolipidaemic Effects of High Resistant Starch Sago and Red Bean Flour- based Analog Rice on Diabetic Rats

INTRODUCTION

Sago analog rice had known as an example of food with high resistant starch. Recent research shows that sago analog rice and red bean flour also had a low glycemic index (GI). However, Identification of hypolipidaemic mechanism based on the nutrigenomic analysis remains unknown.

AIM

This study aims to determine the effects of hypolipidaemic in diabetic rats with analog rice treatment.

MATERIAL AND METHODS

Thirty-five male Wistar rats were divided into 5 groups with different food treatment, such as standard dietary food (STD) group, and four groups of diabetic rats with standard dietary food (STDD), mentik wangi rice diet (MWRD), sago analog rice (SARD) and sago analog rice with 10% red bean flour (SARKBD). Lipid profile was observed every week for a month. Measurement of insulin and blood glucose was performed twice at the beginning and end of treatment. Atherogenic index (AI) was also investigated. Then, the pancreas was collected for histological analysis.

RESULTS

SARD group showed the highest effect of decreasing the total cholesterol (47.74%) which followed by SARKBD (34.62%). The triglyceride level in SARD group was also significantly decreased (31.14%), followed by SARKBD (19.32%). However, the HDL increase in SARD (48.66%), followed by SARKBD (36.00%). The LDL level in SARD and SARKBD group were significantly decreased, respectively 32.89% and 22.19%. SARD atherogenic index levels lower than SARKBD; 1.00 and 2.06.

CONCLUSION

The improvement of insulin resistance by SARD and SARKBD were generated by role of resistant starch through the mechanism of bile acid binding, insulin sensitivity escalation and SCFA effect.

Antihyperglycemic and Antihyperlipidemic Effects of Low-molecular-weight Carrageenan in Rats

This study investigated the antihyperglycemic and antihyperlipidemic effects of low-molecular-weight carrageenan (LC) on rats fed a high-fat diet. Wistar rats were divided into five groups: normal control group (NC), high-fat diet control group (HC), carrageenan-treated control group (CC), 1% LC group (1% LC), and 3% LC-groups (3% LC). Body weight, food intake, fecal weight, blood glucose, and serum lipid levels were measured. After 30 days, body weight significantly decreased in the LC-treated groups than in the HC group. Moreover, in the LC-treated groups, postprandial blood glucose, total cholesterol, triglyceride, and low-density lipoprotein cholesterol (LDL-C) levels decreased, whereas high-density lipoprotein cholesterol (HDL-C) levels increased. From this study, our data suggest that LC has antihyperglycemic and hypolipidemic effects when compared to carrageenan, likely related to its increased absorption due to its lower molecular weight.

Cyamopsis tetragonoloba type 1 metallothionein (CtMT1) gene is upregulated under drought stress and its protein product has an additional C-X-C motif and unique metal binding pattern

Metallothioneins (MTs) are involved in cellular homeostasis of essential metal ions and detoxification of nonessential metal ions. We report here the identification of four MT genes, CtMT1, CtMT2, CtMT3 and CtMT4, encoding CtMT1, CtMT2, CtMT3 and CtMT4 proteins, respectively, from the industrial guar crop. The primary structures of last three proteins were similar to those of respective MT proteins of other plants but the CtMT1 protein primary structure was different from the other plant MT1 proteins in having an additional C-X-C motif. The four MT genes showed tissue specific expression patterns suggesting their specific roles in different tissues. High expression of CtMT1 gene was observed in roots and nodules whereas CtMT2 and CtMT3 genes showed high expression in leaves. The expression of CtMT4 gene was high in seeds. The qRT-PCR studies revealed upregulation in expression of CtMT1 gene under drought stress. Recombinant CtMT1 protein was produced in E. coli Rosetta cells and purified by metal affinity chromatography. The purified protein showed antioxidant property and the order of its metal ion binding affinities was Cu²⁺ > Zn²⁺ > Fe²⁺ > Cd²⁺. This information about CtMT1 protein is expected to be useful in understanding its role in drought tolerance and other physiological processes of guar.

Catechin Treatment Ameliorates Diabetes and Its Complications in Streptozotocin-Induced Diabetic Rats

CONTEXT

Diabetes mellitus causes atherosclerosis and lipid abnormalities. Hypolipidemic and antioxidative properties of catechin (CTN) have been reported in several studies.

OBJECTIVE

This study assesses the possible protective effects of CTN against oxidative damage in the diabetic rats.

MATERIALS AND METHODS

The rats were divided into the control, untreated diabetic, and 3 CTN-treated diabetic groups (20, 40, and 80 mg/kg/d, intraperitoneal). The diabetic rats were induced by streptozotocin. Catechin was injected for 4 weeks. At the end of the experimental period, glucose, lipid profile, apoprotein A-I (apo A-I), apoprotein B (apo B), malondialdehyde (MDA) levels, and antioxidant enzymes including glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) activities were determined in serum. Statistical analyses were performed using the InStat 3.0 program.

RESULTS

Streptozotocin caused an elevation of glucose, MDA, triglycerides (TGs), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and apo B with reduction in high-density lipoprotein cholesterol (HDL-C), apo A-I, SOD, CAT, and GST in the serum (P < .05). The findings showed that the significant elevation in the body weight, glucose, MDA, TG, TC, LDL-C, and apo B and reduction in HDL-C, apo A-I, SOD, CAT, and GST were ameliorated in the CTN-treated diabetic groups versus the untreated group, in a dose-dependent manner (P < .05).

CONCLUSION

The present investigation proposes that CTN may ameliorate diabetes and its complications by modification of oxidative stress.

Effect of crocin on aged rat kidney through inhibition of oxidative stress and proinflammatory state

This study evaluated whether crocin, a bioactive component of saffron, has a protective effect on kidney through reducing the oxidative stress and inflammatory response in aged rats. In this study the changes in activities of antioxidant enzymes, lipid peroxidation, glutathione (GSH) levels and the expression of pro-inflammatory cytokines in the serum and renal tissue were evaluated by ELISA and RT-PCR, respectively. The middle and aged rats were given intraperitoneal injections of crocin (10, 20, 30 mg/kg/day) for 4 weeks. After 4 weeks, animals were anesthetized with diethyl ether. The kidney samples were taken for biochemical analysis. The results revealed the aging was associated with a significant decrease in the activities of antioxidant enzymes, and GSH content with increase in lipid peroxidation level in kidney of the aged rats (p < 0.001). The increased levels of serum renal functional parameter, oxidative parameters (p < 0.01) and also pro-inflammatory cytokine levels were significantly reduced by crocin administration (p < 0.05). The aged rats exhibited a dysregulation of the oxidative stress, and inflammation in the kidneys, but crocin treatment significantly reduced the expression of the inflammatory genes. These results provide pivotal documentation that crocin has a renoprotective effects against the development of oxidative stress and inflammation in the kidney of old rats. Copyright © 2016 John Wiley & Sons, Ltd.

Guar gum as a promising starting material for diverse applications: A review

Guar gum is the powdered endosperm of the seeds of the Cyamopsis tetragonolobus which is a leguminous crop. The endosperm contains a complex polysaccharide called galactomannan, which is a polymer of d-galactose and d-mannose. This hydroxyl group rich polymer when added to water forms hydrogen bonding imparting significant viscosity and thickening to the solution. Due to its thickening, emulsifying, binding and gelling properties, quick solubility in cold water, wide pH stability, film forming ability and biodegradability, it finds applications in large number of industries. In last few decades a lot of research has been done on guar gum to fit it into particular application, as such or by its structural modifications. This review gives an overview of the nature, chemistry and properties of guar gum and discusses recent developments in its modifications and applications in major industries like hydraulic fracturing, explosives, food, agriculture, textile, paper, cosmetics, bioremediation, drug delivery, medical and pharmaceuticals. This article would help researchers engaged in biopolymer area and other end-users who want to begin research in natural polysaccharides.

Diabetes mellitus and its management with medicinal plants: A perspective based on Iranian research

ETHNOPHARMACOLOGICAL RELEVANCE

Complementary and alternative medicine has been increasingly used to treat chronic illnesses, such as diabetes mellitus. However, various limitations in terms of their application and efficacies exist. Furthermore, there is still much to be done to discover the right herbal medicine for diabetes.

AIM OF THE STUDY

This paper aims to evaluate previous herbal studies on the management of diabetes mellitus, to address their strengths and weaknesses and propose a general framework for future studies.

APPROACH AND METHODS

Data sources such as PubMed, ScienceDirect, Scopus, SpringerLink, and Wiley were searched, limited to Iran, using 36 search terms such as herbal, traditional, medicine, and phytopharmacy in combination with diabetes and related complications. Reviewed articles were evaluated regarding the use of botanical nomenclature and included information on (1) identity of plants and plant parts used, (2) the processing procedure, and (3) the extraction process. The main outcomes were extracted and then surveyed in terms of the efficacies of herbs in the management of diabetes mellitus. Then a comparative study was performed between Iranian and non-Iranian studies with respect to herbs best studied in Iran.

RESULTS

Of the 82 herbs studied in Iran, only six herbs were endemic and 19 were studied in detail. Although most of the reviewed herbs were found to decrease the level of blood glucose (BG) and/or glycated hemoglobin (HbA1C) in both Iranian and non-Iranian studies, information on their pharmacological mechanisms is scarce. However, the level of HbA1C was measured in a limited number of clinical trials or animal studies. Available information on both short- and long-term use of studied herbs on diabetes related complications and functions of involved organs as well as comorbid depression and/or simultaneous changes in lifestyle is also insufficient. Furthermore, little or no information on their phytochemical, toxicological, and herb-drug interaction properties is available. It is worth noting that the efficacy of the reviewed herbs has been studied scarcely in both humans and animals regarding both Iranian and non-Iranian studies. A significant number of reviewed articles failed to cite the scientific name of herbs and include information on the processing procedure and the extraction process.

CONCLUSIONS

Treatment of diabetes mellitus as a multifactorial disease using herbal medicines requires a comprehensive approach. In order to discover the right herbal medicine for the management of diabetes many other important factors than the levels of BG, HbA1C and insulin should be considered. According to our criteria, all the reviewed herbs suffered from inadequate investigation in human, animal and in vitro models in this respect, whereas they are worth investigating further. However, more research on endemic plants and the traditional history of herbal medicine is warranted. In our opinion, the pharmacological, toxicological, and phytochemical information should be obtained before clinical trials. Furthermore, information such as botanical scientific nomenclature, side effects, and toxicity will improve the quality and validity of publications in herbal research. In particular, designing a database covering all valid information about herbs and/or diseases will decrease unnecessary costs and increase the efficiency of research.

Hypolipidemic activity of a hydroalcoholic extract of Cyperus scariosus Linn. root in guinea pigs fed with a high cholesterol diet

Lipid-lowering and antioxidant activities of a hydroalcoholic extract of Cyperus scariosus Linn. root (HCS) were evaluated in guinea pigs fed with a high cholesterol diet. Serum lipid profile (total cholesterol, triglycerides, LDL-C, VLDL-C, and HDL-C), atherogenic indices and serum enzymes (ALT, AST, ALP, LDH, and CK-MB) were performed in each group at 0 days and at the end of 60 days. Histological study of liver and kidney was done in groups 1, 2, 5, 6 and 7. The total phenolic and flavonoid content in HCS and its antioxidant activity were evaluated by the DPPH assay. Both doses of HCS decreased serum lipid profile and atherogenic indices (P < 0.05). HCS has lipid lowering, immunosuppressive and antioxidant properties, and mays have value in atherosclerosis prevention. The higher dose of HCS also reduced serum AST, ALP, and LDH levels and rosuvastatin increased AST and ALP levels (P < 0.05). Histology of the liver showed decreased lipid accumulation and improvement in hepatocytes in HCS-treated animals. The antioxidant activity of HCS may be responsible for its lipid lowering and cytoprotective action. HCS had significant lipid lowering and antioxidant activity, which; may be due to the phenolic compounds. HCS may be a safe and cost effective alternative to current statin therapy for patients with dyslipidaemia.

Anti-diabetic effect of Capparis spinosa L. root extract in diabetic rats

OBJECTIVE

Diabetes mellitus is the most common metabolic disorders with severe impact on quality of life. Reducing serum glucose levels and normalization of serum lipid is of great clinical importance for treating diabetes. To our knowledge, there are not any evidences about the anti-diabetic action of capparis spinosa root. In the present study the effects of the C. spinosa root extract on diabetic metabolic disorders have been studied in experimental diabetes.

MATERIALS AND METHODS

Rats were divided into six groups: normal control (NC), diabetic control (DC), diabetic rats receiving 0.2, 0.4 g/kg of plant extract or 0.6 mg/kg glibenclamide (groups D0.2, D0.4 or DG respectively). A normal group of rats was also designed to receive 0.2 g/kg of plant extract (N0.2). Rats were rendered diabetic (streptozotocin 60 mg/kg, i.p.) and treated with 0.2, 0.4 g/ kg of plant extract or glibenclamide for four weeks. At the end of the experiment, blood was drawn through heart puncture under deep anesthesia. Weight was measured weekly, glucose levels were measured at the first and fourth week and lipid profiles, insulin and liver enzymes at the end of the study.

RESULTS

Glucose levels significantly decreased after treating with plant extract (p=0.003). However, insulin levels did not increase in any treating groups. Plant extract could significantly raise HDL and reduce levels of LDL and liver enzymes (ALT and ALP).

CONCLUSION

These results showed that C. spinosa root extract could improve diabetic related metabolic derangement such as hyperglycemia, dyslipidemia, and elevated liver markers in an insulin-independent manner.

Ameliorative effect of saffron aqueous extract on hyperglycemia, hyperlipidemia, and oxidative stress on diabetic encephalopathy in streptozotocin induced experimental diabetes mellitus

Diabetic encephalopathy is one of the severe complications in patients with diabetes mellitus. Findings indicate that saffron extract has antioxidant properties but its underlying beneficial effects on diabetic encephalopathy were unclear. In the present study, the protective activities of saffron were evaluated in diabetic encephalopathy. Saffron at 40 and 80 mg/kg significantly increased body weight and serum TNF-α and decreased blood glucose levels, glycosylated serum proteins, and serum advanced glycation endproducts (AGEs) levels. Furthermore, significant increase in HDL and decrease (P<0.05) in cholesterol, triglyceride, and LDL were observed after 28 days of treatment. At the end of experiments, the hippocampus tissue was used for determination of glutathione content (GSH), superoxide dismutase (SOD), and catalase (CAT) activities. Furthermore, saffron significantly increased GSH, SOD, and CAT but remarkably decreased cognitive deficit, serum TNF-α, and induced nitric oxide synthase (iNOS) activity in hippocampus tissue. Our findings indicated that saffron extract may reduce hyperglycemia and hyperlipidemia risk and also reduce the oxidative stress in diabetic encephalopathy rats. This study suggested that saffron extract might be a promising candidate for the improvement of chemically induced diabetes and its complications.

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.