Evaluation of In Vitro α -Amylase and α -Glucosidase Inhibitory Potentials of 14 Medicinal Plants Constituted in Thai Folk Antidiabetic Formularies

GC-MS analysis of n-hexane extract of Fagonia indica Burm.f. with hypoglycaemic potential

The present study was aimed at gas chromatography-mass spectrometry (GC-MS) analytical investigation of n-hexane extract of the aerial parts of Fagonia indica to identify hypoglycaemic compounds. Also, to investigate this extract for lactase enzyme inhibition responsible for hypoglycaemic activity. Phytochemical screening, GC-MS analysis and lactase inhibition of n-hexane extract was performed by the standard methods. GC-MS analytical study identified 15 compounds in this extract. The maximum percentage of lactase enzyme inhibition of n-hexane extract was 26.21 ± 1.25% (IC50 value of 311.2 ± 16.09 μg/mL) at 100 μg/mL concentration. The standard acarbose showed lactase inhibition of 63.21 ± 0.92% (IC50 value of 32.51 ± 0.85 µg/mL) at the same concentration. n-Hexane extract can be a potential source in the management of diabetes due to the presence of biologically active hypoglycaemic compounds.

Quality, Safety and Biological Studies on Campylanthus glaber Aerial Parts

In Cabo Verde, several endemic species are used in traditional medicine. However, no scientific studies have been conducted on the quality, efficacy, and safety of most of these plants. This study focused on establishing the botanical and chemical identification parameters required for a quality monograph of Campylanthus glaber Benth. aerial parts, a medicinal plant of Cabo Verde traditionally used to treat fever and muscular pain. In addition, in vitro antioxidant and antihyperglycemic activity, cytotoxicity, and genotoxicity were assessed for this medicinal plant. Optical microscopy, LC/UV-DAD-ESI/MS, and colorimetric assays were used for botanical, chemical, and biological studies, respectively. Cytotoxicity was assessed by the MTT assay with HepG2 cells, and genotoxicity by the Ames test. Microscopically, the xeromorphic leaf of C. glaber presents a thick cuticle (13.6-25.5 µm), thick-walled epidermal cells, anomocytic-type stomata, glandular trichomes (stalk length = 49.4-120.8 µm), and idioblasts containing calcium oxalate microcrystals. The chemical screening of aqueous and hydroethanolic extracts of this medicinal plant revealed the presence of organic acids, iridoids, phenylethanoids, and flavonoids as the main classes of marker compounds, with malic acid, citric acid, and verbascoside being the main marker compounds identified. Both extracts showed similar LC/UV-DAD/ESI-MS qualitative profiles and DPPH radical scavenger activity (IC50 = 130.9 ± 1.4; 134.3 ± 3.1 µg/mL). The hydroethanolic extract inhibited both α-amylase and α-glucosidase enzymes in a dose-dependent manner. Both extracts showed no cytotoxicity (up to 1000 µg/mL) by the MTT assay and no genotoxic potential with or without metabolic activation up to 5 mg /plate. The results obtained are an important contribution to the monographic quality assessment of C. glaber aerial parts and suggest that this medicinal plant may be safe and potentially used as an herbal drug raw material for pharmaceutical purposes.

Antidiabetic and antioxidant activities of Mitragyna speciosa (kratom) leaf extract in type 2 diabetic rats

Mitragyna speciosa is a medicinal plant with a reputation for treating pains, diabetes as well as increasing energy and sexual desires. However, there is no scientific evidence to validate the antidiabetic effect of M. speciosa. This study investigated the antidiabetic effects of M. speciosa (Krat) ethanolic extract on fructose and streptozocin (STZ)-induced type 2 diabetic rats. In vitro antioxidant and antidiabetic effects were evaluated using DPPH, ABST, FRAP and α-glucosidase inhibitory assays. Rats with fructose/STZ induced T2D were treated with Krat (100 and 400 mg/kg) or metformin (200 mg/kg) for 5 weeks via oral gavage. Krat showed good antioxidant activity and also displayed potent α-glucosidase inhibitory activity. Administration of Krat to the diabetic rats significantly improved body weight gain, restored alterations in blood glucose level, glucose tolerance, dyslipidemia (increased cholesterol, triglycerides, low-density lipoprotein-cholesterol and reduced high-density lipoprotein), hepatorenal biomarkers alterations (alanine transaminase, aspartate transaminase, alanine phosphatase, creatinine and blood urea nitrogen) and oxidative stress indices (superoxide dismutase, glutathione and malondialdehyde)in the treated diabetic rats. Furthermore, Krat also restored pancreatic histological and increased immunohistochemical aberrations in the diabetic rats. These results for the first time demonstrated the antidiabetic and antihyperlipidemic potentials of M. speciosa, thus providing scientific reinforcement for the traditional use of the plant in the treatment of diabetes.

Design, synthesis, and molecular docking studies of diphenylquinoxaline-6-carbohydrazide hybrids as potent α-glucosidase inhibitors

A novel series of diphenylquinoxaline-6-carbohydrazide hybrids 7a-o were rationally designed and synthesized as anti-diabetic agents. All synthesized compounds 7a-o were screened as possible α-glucosidase inhibitors and exhibited good inhibitory activity with IC50 values in the range of 110.6 ± 6.0 to 453.0 ± 4.7 µM in comparison with acarbose as the positive control (750.0 ± 10.5 µM). An exception in this trend came back to a compound 7k with IC50 value > 750 µM. Furthermore, the most potent derivative 7e bearing 3-fluorophenyl moiety was further explored by kinetic studies and showed the competitive type of inhibition. Additionally, the molecular docking of all derivatives was performed to get an insight into the binding mode of these derivatives within the active site of the enzyme. In silico assessments exhibited that 7e was well occupied in the binding pocket of the enzyme through favorable interactions with residues, correlating to the experimental results.

Neuroprotective potential of curcuminoids in modulating Alzheimer's Disease via multiple signaling pathways

Alzheimer's disease (AD) is a progressive and frequent neurodegenerative disease of elderly people. In the 21st century, owing to the increasing prevalence of AD, there is a crucial need for finding better and effective pharmacotherapeutic approaches. This review article demonstrated the various sources and possible metabolic pathways of curcuminoids obtained from Curcuma longa herb, to prevent and treat AD but the information related to the metabolic fate of curcuminoids is deficient. Different in vitro and in vivo research studies demonstrating the mechanisms by which curcuminoids attenuated AD have been summarized. Administration of curcuminoids has been indicated to inhibit hyperphosphorylation of tau protein, deposition, and oligomerization of amyloid beta plaques in several AD models. Curcuminoids also chelate metals and form complexes, have antioxidant properties, mediates neuroinflammatory signaling pathways by modifying microglial cells activity, inhibit acetylcholinesterase activities and also modulates other associated signaling pathways including insulin signaling pathways and heme-oxygenase pathway. Briefly curcuminoids exhibit the capability to be more productive and efficacious compared to many recent treatments due to their antioxidant, delayed neuron degeneration and anti-inflammatory potential. Although their effectiveness as a curative agent is considered to be reduced due to their low bioavailability, If the issue of curcuminoids' low bioavailability is resolved then curcuminoid-based medications are hopefully on the horizon against AD.

Comparative study of six antidiabetic polyherbal formulation for its multimodal approaches in diabetes management

Commercial antidiabetic polyherbal formulations (APH) are available with claimed hypoglycemic activities; yet they lack systematic scientific studies leading to their limited global acceptance. In the present study, six selected APH from the Indian market were evaluated for their phytochemical contents, anti-hyperglycemic, anti-hyperlipidemic, antioxidant activities and further identifying the major antidiabetic bioactive compound of "MA" by HPLC-ESI-MS/MS. Our results revealed highest TPC (136.97 ± 0.6 µg GAE/mg) and TFC (128.85 ± 0.74 µg QE/mg) in APH-DB and APH-SN, respectively. APH-MA has exhibited highest α-amylase 72.5% (IC₅₀-579.65 μg/ml), α-glucosidase 88.02% (IC₅₀-261.03 μg/ml) and moderate lipase inhibition 57.7% (IC₅₀ 159.57 μg/ml). A variable free radical scavenging activity was observed by all the tested APH. Further significant linear positive correlations were observed between TPC-Lipase (r ²-0.985****), TFC-α-amylase (r ²-0.868**) and DPPH-α-amylase inhibition (r ²-0.8098*). HPLC-ESI-MS/MS of MA showed the presence of anti-hyperglycemic compounds, Pheophorbide a and Pyropheophorbide a, as the major peaks. Among the tested extracts, MA exhibited better activities while BG, MH, SN, DB, and DT have showed comparable/mild anti-hyperglycemic, anti-hyperlipidemic and antioxidant potential. Hence the tested APH may be considered effective for DM management which can further be assessed for their other targets of inhibition.

Function of selected natural antidiabetic compounds with potential against cancer via modulation of the PI3K/AKT/mTOR cascade

Diabetes mellitus (DM) is a metabolic disorder with growing global incidence, as 387 million people were diagnosed in 2014 with an expected projection of 642 million in 2040. Several complications are associated with DM including heart attack, stroke, kidney failure, blindness, and cancer. The latter is the second leading cause of death worldwide accounting for one in every six deaths, with liver, pancreas, and endometrium cancers are the most abundant among patients with diabetes. Phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway plays a vital role in developing a wide array of pathological disorders, among them diabetes and cancer. Natural secondary metabolites that counteract the deleterious effects of reactive oxygen species (ROS) and modulate PI3K/Akt/mTOR pathway could be a promising approach in cancer therapy. Here, 717 medicinal plants with antidiabetic activities were highlighted along with 357 bioactive compounds responsible for the antidiabetic activity. Also, 43 individual plant compounds with potential antidiabetic activities against cancer via the modulation of PI3K/Akt/mTOR cascade were identified. Taken together, the available data give an insight of the potential of repurposing medicinal plants and/or the individual secondary metabolites with antidiabetic activities for cancer therapy.

Chemical Group Profiling, In Vitro and In Silico Evaluation of Aristolochia ringens on α-Amylase and α-Glucosidase Activity

Diabetes mellitus (DM) has become a global scourge, and there is a continuous search for novel compounds as viable alternatives to synthetic drugs which are often accompanied by severe adverse effects. Aristolochia ringens is among the scientifically implicated botanicals effective in the management of several degenerative diseases including DM. The current study evaluated the inhibitory mechanism(s) of root extract of A. ringens on α-amylase and α-glucosidase in vitro and in silico, while its constituents were characterized using liquid chromatography-mass spectrometric technique. The extract had concentration-dependent inhibitory effect on the study enzymes, and the inhibition compared well with that of standard drug (acarbose) with respective IC₅₀ values of 0.67 mg/mL (α-amylase) and 0.57 mg/mL (α-glucosidase) compared with that of the extract (0.63 and 0.54 mg/mL). The extract competitively and uncompetitively inhibited α-amylase and α-glucosidase, respectively. Of the identified compounds, dianoside G (−12.4, −12.5 kcal/mol) and trilobine (−10.0, −10.0 kcal/mol) had significant interactions with α-amylase and α-glucosidase, respectively, while magnoflorine and asiatic acid also interacted keenly with both enzymes, with quercetin 3-O-glucuronide and strictosidine showing better affinity towards α-glucosidase. These observations are suggestive of involvement of these compounds as probable ligands contributing to antidiabetic potential of the extract. While studies are underway to demystify the yet to be identified compounds in the extract, the data presented have lent scientific credence to the acclaimed in vivo antidiabetic potential of the extract and suggested it as a viable source of oral hypoglycaemic agent.

Significant effects of Ganoderma lucidum polysaccharide on lipid metabolism in diabetes may be associated with the activation of the FAM3C-HSF1-CAM signaling pathway

Diabetes is a threat to patient health worldwide. Type 2 diabetes (T2DM), one of the two main types of diabetes, is a long-term metabolic disease caused by heredity and environmental factors. It has been reported that Ganoderma lucidum polysaccharide (GLP) significantly decreased the concentration of blood glucose, promoted insulin secretion, improved glucose tolerance and regulated the concentration of blood lipids. In the present study, a T2DM model was established in db/db mice, following which T2DM mice were treated with GLP (100 and 400 mg/kg) for 8 weeks, with MET used as the positive control. The glycosylated hemoglobin (HbAlc) and fasting blood glucose (FBG) levels, and diabetes-associated clinical chemistry indexes were detected in the blood and serum of each mouse. Hematoxylin and eosin, and oil red O staining were performed on the livers of each mouse to evaluate the level of liver fat. The expression levels of family with sequence similarity 3 (FAM3C), heat shock factor 1 (HSF1), calmodulin (CaM), AKT and phosphorylated (p)-AKT were detected in the hepatocytes of T2DM mice using reverse transcription-quantitative PCR and western blotting. The results demonstrated that the unbalanced levels of HbAlc, FBG and diabetes-related index in T2DM mice were significantly improved by treatment with GLP. Lipid droplets in the hepatocytes of mice shrank in the GLP groups compared with the model control group. The expression levels of FAM3C, HSF1, CaM and p-AKT/AKT in the hepatocytes of T2DM mice were significantly increased following treatment with GLP. In conclusion, GLP exerted significant effects on lipid metabolism in diabetes, which may be associated with the activation of the FAM3C-HSF1-CaM signaling pathway.

Effect of Protease Type and Peptide Size on the In Vitro Antioxidant, Antihypertensive and Anti-Diabetic Activities of Eggplant Leaf Protein Hydrolysates

Solanum macrocarpon (eggplant) leaf protein isolate (ELI) was hydrolyzed using four different enzymes to produce hydrolysates from alcalase (AH), chymotrypsin (CH) pepsin (PH) and trypsin (TH). CH had an overall stronger antioxidant property and was separated using ultrafiltration membranes into <1, 1–3 and 3–5 kDa peptide fractions. Gel-permeation chromatography confirmed conversion of the ELI (average of 22 kDa) into protein hydrolysates that contained smaller peptides (<6 kDa). A total of 23 peptides consisting of tri and tetrapeptides were identified from the CH, which is a wider spectrum when compared to seven for AH and four each for TH and PH. CH exhibited stronger scavenging activities against DPPH and hydroxyl radicals. CH and TH exhibited the strongest inhibitions against angiotensin-converting enzyme. In contrast, AH was the strongest inhibitor of α-amylase while AH and PH had strong inhibitory activities against α-glucosidase when compared with other hydrolysates. Ultrafiltration fractionation produced peptides that were stronger (p < 0.05) scavengers of DPPH, and hydroxyl radicals, in addition to better metal-chelating and enzyme inhibition agents. The study concluded that the eggplant protein hydrolysates and the UF fractions may find applications in tackling oxidative stress-related diseases and conditions involving excessive activities of the metabolic enzymes.

Caffeic acid derivatives (CAFDs) as inhibitors of SARS-CoV-2: CAFDs-based functional foods as a potential alternative approach to combat COVID-19

BACKGROUND

SARS-CoV-2, an emerging strain of coronavirus, has affected millions of people from all the continents of world and received worldwide attention. This emerging health crisis calls for the urgent development of specific therapeutics against COVID-19 to potentially reduce the burden of this emerging pandemic.

PURPOSE

This study aims to evaluate the anti-viral efficacy of natural bioactive entities against COVID-19 via molecular docking and molecular dynamics simulation.

METHODS

A library of 27 caffeic-acid derivatives was screened against 5 proteins of SARS-CoV-2 by using Molegro Virtual Docker 7 to obtain the binding energies and interactions between compounds and SARS-CoV-2 proteins. ADME properties and toxicity profiles were investigated via www.swissadme.ch web tools and Toxtree respectively. Molecular dynamics simulation was performed to determine the stability of the lead-protein interactions.

RESULTS

Our obtained results has uncovered khainaoside C, 6-O-Caffeoylarbutin, khainaoside B, khainaoside C and vitexfolin A as potent modulators of COVID-19 possessing more binding energies than nelfinavir against COVID-19 M^pro, Nsp15, SARS-CoV-2 spike S2 subunit, spike open state and closed state structure respectively. While Calceolarioside B was identified as pan inhibitor, showing strong molecular interactions with all proteins except SARS-CoV-2 spike glycoprotein closed state. The results are supported by 20 ns molecular dynamics simulations of the best complexes.

CONCLUSION

This study will hopefully pave a way for development of phytonutrients-based antiviral therapeutic for treatment or prevention of COVID-19 and further studies are recommended to evaluate the antiviral effects of these phytochemicals against SARS-CoV-2 in in vitro and in vivo models.

GC–MS analysis of phytocompounds and antihyperglycemic property of Hydrocotyle sibthorpioides Lam

Hydrocotyle sibthorpioides Lam. is a popular medicinal plant of Assam having several ethnomedicinal values. The present study investigated the metallic content, phytochemical contents, α-amylase, and α-glucosidase enzymes inhibitory property of H. sibthorpioides using in-vitro and in-silico methods. Heavy metal contents were analyzed using Atomic Absorption Spectroscopy. GC–MS was used to analyze the phytochemical compounds of the plant. Enzyme inhibition study was carried out by Spectrophotometry methods. The drug-likeness and toxicity properties of the phytocompounds were studied using SwissADME and ADMETlab databases. Docking and molecular visualizations were performed in AutoDock vina and Discovery studio tools. The study found that the extract of H. sibthorpioides contains a negligible amount of toxic elements. GC–MS analysis detected four compounds from the methanolic extract of the plant. Biochemical study showed considerable α-amylase and α-glucosidase enzyme inhibitory property of the crude extract of H. sibthorpioides. The IC50 of the plant extracts were found to be 1.27 mg/ml and 430.39 µg/ml for α-amylase and α-glucosidase enzymes, respectively. All four compounds were predicted to have potential drug-likeness properties with high cell membrane permeability, intestinal absorption, and less toxic effects. The docking study also showed strong binding affinities between the plant compounds and enzymes. Plant compound C2 showed an almost similar binding affinity with the α-amylase enzyme as compared to standard acarbose. The present study, thus, suggests the antihyperglycemic property of H. sibthorpioides and can be a potential source of antidiabetic drug candidates.

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

ETHNOPHARMACOLOGICAL RELEVANCE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

In-vitro anti-diabetic activity and in-silico studies of binding energies of palmatine with alpha-amylase, alpha-glucosidase and DPP-IV enzymes

Palmatine a protoberberine alkaloid has been previously reported to possess in vivo antidiabetic and antioxidant property. The aim of the experiment is to evaluate the in vitro antidiabetic activity and in-silico studies of the binding energies of Palmatine, acarbose, and Sitagliptin with the three enzymes of alpha-amylase, alpha-glucosidase, and dipeptidyl peptidase-IV (DPP-IV). The in vitro antidiabetic study was done by evaluating the inhibitory effect of palmatine on the activities of alpha-amylase, alpha-glucosidase, and DPP-IV. Acarbose, and sitagliptin was used as standard drug. The molecular docking study was performed to study the binding interactions of palmatine with alpha-glucosidase, a-amylase, and DPP-IV. The binding interactions were compared with the standard compounds Sitagliptin and acarbose. Palmatine with IC50 (1.31 ± 0.27 µM) showed significant difference of (&lt; 0.0001) higher inhibiting effect on alpha-amylase and weak inhibiting effect on alpha-glucosidase enzyme with IC50 (9.39 ± 0.27 µM) and DPP-IV with IC50 (8.7 ± 1.82 µM). Palmatine possess inhibition effect on the three enzymes.

Identification of Major Compounds and α-Amylase and α-Glucosidase Inhibitory Activity of Rhizome of Musa balbisiana Colla: An In-vitro and insilico Study

BACKGROUND

α-Amylase and α-glucosidase inhibitors are widely used to suppress postprandial glycemia in the treatment of type 2 diabetes.

OBJECTIVES

To evaluate the metallic content, major phytoconstituents, and α-amylase and α-glucosidase inhibitory activity of Musa balbisiana rhizome using in-vitro and in-silico methods.

MATERIALS AND METHODS

Heavy metal content was detected by AAS following standard protocol. Major phytochemicals of the plant were analysed by GC-MS technique. Enzyme inhibition study was carried out by UV/VIS spectrophotometric methods. The druglikeness and bioavailability properties of major compounds were carried out using computer-aided tools - SwissADME and ADMElab. Docking and visualization were performed in AutoDock vina and Discovery studio tools.

RESULTS

The study found that the fruits of M. balbisiana contain negligible amount toxic elements. GC-MS analysis showed five major compounds from the rhizome of M. balbisiana. In-vitro enzyme assays revealed strong α-amylase and αglucosidase inhibitory property of the plant. All the five compounds were predicted to have druglikeness property with high cell membrane permeability and bioavailability. The compounds were also predicted to have low to moderate toxicity property. The Docking study showed strong binding affinities of plant compounds with α-amylase and α-glucosidase. Out of five compounds, C5 showed best binding affinity with active pockets of α-amylase and α-glucosidase.

CONCLUSION

The present in-vitro and in-silico study suggests the antihyperglycemic property of the rhizome of Musa balbisiana and possible candidate for therapeutic antidiabetic agent(s).

Identification of bioactive compounds by GC-MS and α-amylase and α-glucosidase inhibitory activity of Rauvolfia tetraphylla L. and Oroxylum indicum (L.) Kurz: an in vitro and in silico approach

Background

The practice of ethnomedicine remains to be the primary source of healthcare in many parts of the world, especially among the tribal communities. However, there is a lack of scientific outlook and investigation to authenticate and validate their medicinal values.

Objective

The present study investigated the trace and heavy metal content, bioactive compounds, α-amylase, and α-glucosidase inhibitory activity of Rauvolfia tetraphylla and Oroxylum indicum using in vitro and in silico methods.

Methods

Trace and heavy metal content of Rauvolfia tetraphylla and Oroxylum indicum were detected using Atomic Absorption Spectroscopy. Bioactive compounds were analyzed and identified by the GC-MS technique. α-Amylase and α-glucosidase inhibitory activity of the plants were studied using the spectrophotometric method using UV/VIS-Spectrophotometer. In silico molecular docking was carried out in AutoDock vina and the structures visualized using PyMol and Biovia Discovery Studio software. Statistical and graphical representations were performed using Excel and OriginPro.

Results

The trace and heavy metallic content such as Zn, Ni, Pb, Cr, Cu, and Mn were reported from both the plant. No Cd was detected in both the plants. GC-MS analysis revealed four major compounds in R. tetraphylla and seven in O. indicum. Biochemical studies showed that the leaf extract of O. indicum posses the strongest α-amylase and α-glucosidase inhibitory activity. R. tetraphylla showed weaker enzyme inhibition. Molecular docking study revealed that three compounds from O. indicum (O2, O3, and O6) and two from R. tetraphylla (R1 and R2) showed strong binding affinity to α-amylase and α-glucosidase. However, leaf extract of O. indicum showed better binding affinity with the enzymes compared to R. tetraphylla.

Conclusion

Inhibition of α-amylase and α-glucosidase in an important strategy of diabetes control. The present study revealed the in vitro α-amylase and α-glucosidase inhibitory activity of Rauvolfia tetraphylla and Oroxylum indicum. In conclusion, the study identified that the leaf extract of O. indicum as a potential inhibitor of glucose metabolizing enzymes and could be a source of antidiabetic agents.

An overview on the role of bioactive α-glucosidase inhibitors in ameliorating diabetic complications

Recently the use of bioactive α-glucosidase inhibitors for the treatment of diabetes have been proven to be the most efficient remedy for controlling postprandial hyperglycemia and its detrimental physiological complications, especially in type 2 diabetes. The carbohydrate hydrolysing enzyme, α-glucosidase, is generally competitively inhibited by the α-glucosidase inhibitors and results in the delayed glucose absorption in small intestine, ultimately controlling the postprandial hyperglycemia. Here we have reviewed the most recent updates in the bioactive α-glucosidase inhibitors category. This review provides an overview of the α-glucosidase inhibitory potentials and efficiency of controlling postprandial hyperglycemia of various bioactive compounds such as flavonoids, phenolic compound, polysaccharide, betulinic acid, tannins, anthocyanins, steroids, polyol, polyphenols, galangin, procyanidins, hydroxyl-α-sanshool, hydroxyl-β-sanshool, erythritol, ganomycin, caffeoylquinic acid, resin glycosides, saponins, avicularin, oleanolic acids, urasolic acid, ethanolic extracts etc., from various dietary and non-dietary naturally occurring sources.

Chemistry, Biological Activities and In Silico Bioprospection of Sterols and Triterpenes from Mexican Columnar Cactaceae

The Cactaceae family is an important source of triterpenes and sterols. The wide uses of those plants include food, gathering, medicinal, and live fences. Several studies have led to the isolation and characterization of many bioactive compounds. This review is focused on the chemistry and biological properties of sterols and triterpenes isolated mainly from some species with columnar and arborescent growth forms of Mexican Cactaceae. Regarding the biological properties of those compounds, apart from a few cases, their molecular mechanisms displayed are not still fully understand. To contribute to the above, computational chemistry tools have given a boost to traditional methods used in natural products research, allowing a more comprehensive exploration of chemistry and biological activities of isolated compounds and extracts. From this information an in silico bioprospection was carried out. The results suggest that sterols and triterpenoids present in Cactaceae have interesting substitution patterns that allow them to interact with some bio targets related to inflammation, metabolic diseases, and neurodegenerative processes. Thus, they should be considered as attractive leads for the development of drugs for the management of chronic degenerative diseases.

A Comprehensive Review on Preclinical Diabetic Models

BACKGROUND

Preclinical experimental models historically play a critical role in the exploration and characterization of disease pathophysiology. Further, these in-vivo and in-vitro preclinical experiments help in target identification, evaluation of novel therapeutic agents and validation of treatments.

INTRODUCTION

Diabetes mellitus (DM) is a multifaceted metabolic disorder of multidimensional aetiologies with the cardinal feature of chronic hyperglycemia. To avoid or minimize late complications of diabetes and related costs, primary prevention and early treatment are therefore necessary. Due to its chronic manifestations, new treatment strategies need to be developed, because of the limited effectiveness of the current therapies.

METHODS

The study included electronic databases such as Pubmed, Web of Science and Scopus. The datasets were searched for entries of studies up to June, 2018.

RESULTS

A large number of in-vivo and in-vitro models have been presented for evaluating the mechanism of anti-hyperglycaemic effect of drugs in hormone-, chemically-, pathogen-induced animal models of diabetes mellitus. The advantages and limitations of each model have also been addressed in this review.

CONCLUSION

This review encompasses the wide pathophysiological and molecular mechanisms associated with diabetes, particularly focusing on the challenges associated with the evaluation and predictive validation of these models as ideal animal models for preclinical assessments and discovering new drugs and therapeutic agents for translational application in humans. This review may further contribute to discover a novel drug to treat diabetes more efficaciously with minimum or no side effects. Furthermore, it also highlights ongoing research and considers the future perspectives in the field of diabetes.

In Vitro Antidiabetic Activity Affecting Glucose Uptake in HepG2 Cells Following Their Exposure to Extracts of Lauridia tetragona (L.f.) R.H. Archer

The incidence of diabetes is on the rise and one of the medically active plants used for the treatment of diabetes in South Africa is Lauridia tetragona. The aim of this study is to investigate the antidiabetic property of the polyphenolics (PP) compounds isolated from the methanolic extract of Lauridia tetragona. The α-amylase, α-glucosidase, dipeptidyl peptidase IV (DPPIV), lipase inhibitory activities, and glucose uptake in HepG2 were investigated. The methanolic extract fractions of L. tetragona yielded six fractions (PP1–PP6) all of which showed weak inhibition against DPPIV and lipase compared to the standards. However, PP4 and PP6 showed the best inhibition against α-amylase (IC50 of 359.3 ± 2.11 and 416.82 ± 2.58 μg/mL, respectively) and α-glucosidase (IC50 of 95.93 ± 2.34 and 104.49 ± 2.21 μg/mL, respectively) and only PP4 (173.6%) resulted in enhanced glucose uptake in HepG2 cells compared to berberine (129.89%) and metformin (187.16%) used as positive controls. The previous investigation on PP4 and PP6 showed the presence of polyphenolics such as ferulic acid, coumaric acid, and caffeic acid. The results of this study suggest that L. tetragona could be suitable as an antidiabetic agent and justifies the folkloric use of the plant to treat diabetes.

Rhinacanthins-rich extract and rhinacanthin C ameliorate oxidative stress and inflammation in streptozotocin-nicotinamide-induced diabetic nephropathy

In this present study, rhinacanthins-rich extract (RRE) and rhinacanthin C (RC) the main bioactive constituent of Rhinacanthus nasutus was investigated for their protective effect against diabetic nephropathy (DN). Diabetes was induced by administering nicotinamide (100 mg/kg, i.p.)/streptozotocin (60 mg/kg, i.p.) and diabetic rats were orally administered with RRE and RC for 4 weeks. RRE and RC significantly reduced the kidney index, renal oxidative stress markers, and pro-inflammatory cytokines. Furthermore, RRE and RC increased renal levels of glutathione, superoxide dismutase, catalase, and attenuated diabetic induced renal damages. In conclusion, RRE and RC confer protective effect against DN through the inhibition of oxidative stress and inflammation and could be a potential medicinal or nutritional supplement for the prevention of DN. PRACTICAL APPLICATIONS: Rhinacanthus nasutus is a medicinal plant that is extensively used in Thai traditional medicine as an antibacterial, antifungal, antidiabetic, and anti-inflammatory agent. The plant is rich in naphthoquinones, which confer it with several excellent bioactivities. The rich extract of the leaves was prepared with three major bioactive components and the extract was evaluated for its renoprotective effect in diabetic rats. The results from this study provides valuable pharmacological information that supports the use of the plant, especially the rich extract in the prevention and treatment of diabetes and diabetic complications.

Phenolic compounds and bioactivity evaluation of aqueous and methanol extracts of Allium mongolicum Regel

Allium mongolicum Regel (AM), widely distributed in western China, is a traditional Mongolian medicine herb. Two different solvents as water and methanol were used to extract AM, and their antioxidant capacity and inhibitory effects against key enzymes related to metabolic syndrome were assessed. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS and reducing power assays. In addition, the total phenolic content and total flavonoids content were quantificated and analyzed. Aqueous extract, having higher phenolic content (10.20 mg GAE/g DW) and flavonoid content (4.02 mg QE/g DW), showed better antioxidant and inhibitory effects against lipase and angiotensin-converting enzyme (ACE); as for α-glucosidase, the extract made by methanol showed better ability. In general, the aqueous extract of A. mongolicum Regel has the potential to be used as a functional food or nutraceutical in prevention and treatment of obesity and hypertension due to the high antioxidant and sound inhibitory potential against vital enzymes relevant to obesity and hypertension.

Recently isolated antidiabetic hydrolysates and peptides from multiple food sources: a review

Diabetes, a metabolic syndrome of global importance has been on a progressive rise in recent years. Several pharmacological approaches have been made, which have proved effective, but with underlying side effects. Bioactive hydrolysates (BHs) and peptides (BPs) from food sources, however, have shown the relative advantage of imparting less adverse effects. Furthermore, BHs and BPs from food have been discovered to impart their antidiabetic potentials through one or more mechanisms such as inhibition of digestive enzymes, inhibition of the antigenic enzyme - Dipeptyl peptidase IV (DPP-IV), decrease in blood glucose levels and increase in insulin uptake. Several plants and animal sources have been used as protein sources for the isolation of antidiabetic hydrolysates and peptides through different mechanisms and analytical techniques. This review integrates recent research information about several popular and unconventional food sources of BHs and BPs, their isolation techniques, antidiabetic effects and protein profiles. In addition, the fractionation technique(s) employed in each study and inhibition potentials of BHs and BPs are reviewed. This article is intended to supplement accessible scholarly literature and intellectual awareness on the subject of food-oriented approach for the management of diabetes.

Microfluidization trends in the development of nanodelivery systems and applications in chronic disease treatments

Plant bioactive compounds are known for their extensive health benefits and therefore have been used for generations in traditional and modern medicine to improve the health of humans. Processing and storage instabilities of the plant bioactive compounds, however, limit their bioavailability and bioaccessibility and thus lead researchers in search of novel encapsulation systems with enhanced stability, bioavailability, and bioaccessibility of encapsulated plant bioactive compounds. Recently many varieties of encapsulation methods have been used; among them, microfluidization has emerged as a novel method used for the development of delivery systems including solid lipid nanocarriers, nanoemulsions, liposomes, and so on with enhanced stability and bioavailability of encapsulated plant bioactive compounds. Therefore, the nanodelivery systems developed using microfluidization techniques have received much attention from the medical industry for their ability to facilitate controlled delivery with enhanced health benefits in the treatment of various chronic diseases. Many researchers have focused on plant bioactive compound-based delivery systems using microfluidization to enhance the bioavailability and bioaccessibility of encapsulated bioactive compounds in the treatment of various chronic diseases. This review focuses on various nanodelivery systems developed using microfluidization techniques and applications in various chronic disease treatments.

Evaluation of the Anti-Diabetic Activity of Polysaccharide from Cordyceps cicadae in Experimental Diabetic Rats

Cordyceps cicadae is a medicinal fungus used in treating night sweat, childhood convulsions, vision improvement and pain. This study was designed to evaluate the anti-diabetic activity of the crude polysaccharide (SHF) from the mycelium and body portion of C. cicadae. Diabetes mellitus was induced in the rat with a single intravenous injection of alloxan monohydrate (150 mg/kg). In other to evaluate the anti-diabetic effects of C. cicadae polysaccharide in alloxan-induced diabetic rats, the crude polysaccharide (SHF at 100, 200 and 400 mg/kg body weight) and glibenclamide were administered orally to diabetic rats for 30 days. Blood glucose level, total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphate (ALP), creatinine (CREA), urea, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH) were determined. SHF showed significant reduction in blood glucose in diabetic rats. Treatment of diabetic rats also resulted an improvement in body weights, increased HDL, SOD and GSH, as well as decreased TC, TG, LDL, MDA, urea, CREA, ALT, AST and ALP. These results suggested that C. cicadae polysaccharide displayed anti-hyperglycemic, anti-hyperlipidemic and antioxidant activities and could be a promising therapeutic source in managing diabetes mellitus and its associated complications.