alpha-Amylase inhibitory activity of some Malaysian plants used to treat diabetes; with particular reference to Phyllanthus amarus

Swertiamarin and quercetin combination ameliorates hyperglycemia, hyperlipidemia and oxidative stress in streptozotocin-induced type 2 diabetes mellitus in wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Swertiamarin (Sw) and quercetin (Qu) have been isolated from different plants and are reported for their antidiabetic activities. The plants from which swertiamarin and quercetin were isolated are also traditionally used in the treatment of diabetes mellitus.

AIM OF THE STUDY

The present study is aimed to evaluate the synergistic effect of a combination of swertiamarin and quercetin (CSQ) on α-amylase in vitro and on streptozotocin (STZ) induced diabetes mellitus in vivo.

METHODS

Swertiamarin was isolated from the plant Enicostemma axillare and quercetin was procured in its pure form. Sw, Qu and CSQ were evaluated for in vitro α-amylase inhibitory activity. Based on the in vitro study results, CSQ was assessed for in vivo streptozotocin induced diabetes mellitus in Wistar rats. The effect of CSQ on blood glucose levels, body weight, serum biochemical parameters and antioxidant enzymes such as glutathione (GSH), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and lipid peroxide levels were estimated. The histopathological observations of pancreatic tissues were also made.

RESULTS

The purity of swertiamarin was confirmed by HPLC. The results showed that CSQ was found to possess high percentage of inhibition in an in vitro α-amylase inhibitory study. In a STZ-induced type 2 diabetes mellitus (T2DM), body weight of rats in CSQ treated and control groups were unaltered. A marked reduction in the blood glucose levels was observed in the CSQ treated groups on 14th and 28th day. Decrease in the levels of low-density lipoprotein (LDL), triglycerides, total cholesterol and an increase in high-density lipoprotein (HDL) cholesterol level was observed in a dose dependant in CSQ treated groups. However, CSQ treated groups could significantly improve antioxidant protection by increasing the levels of serum GSH, SOD, Catalase and GPx and decreasing the levels of lipid peroxide (p < 0.05). In the histopathological study, the pancreatic islets of Langerhans and vacuolization have shown significant increase in both the treated groups.

CONCLUSIONS

The combination of swertiamarin and quercetin (CSQ) has proven a preventive and therapeutic effect against T2DM and suggests that this is a potential combination of phytoconstituents for excellent hypoglycemic activity in T2DM.

Molecular dynamics simulation for screening phytochemicals as α-amylase inhibitors from medicinal plants

Diabetes mellitus (DM) is a complicated metabolic disorder with several enzymes, including α-amylase and α-glycosidase. The α-amylase is responsible for postprandial glucose levels; therefore, inhibiting its activity is helpful in diabetes management. Hence, to find natural inhibitors of α-amylase, we have prepared a 257 phytochemical library from selected medicinal plants with antidiabetic activity and conducted a virtual screening and molecular dynamics study. Seventy-nine phytochemicals were screened out of 257 phytochemicals based on binding energy, ranged from -10.1 kcal mol^-1 to -7.6 kcal mol^-1. The binding energies of screened compounds were lower or equal to the reference molecule (-7.6 kcal mol^-1). The binding affinity of six screened phytochemicals was re-scored by X-SCORE. These phytochemicals were subjected to ADMET and Drug-likeness analysis. After screening docking and drug-likeness analysis, six phytochemicals viz., Shahidine, Epicatechin, Quercetin, Isocolumbin, Ellagic acid, Luteolin and a reference molecule (Acarbose) were subjected to Molecular dynamics (MD) simulation to analyze the stability of the docked protein-ligand complex. The values of root mean square deviation, RMSF, RG, SASA, H-Bond, the interaction energy of all protein-ligand complexes were calculated after 30 ns of MD simulation. The results of screened complexes revealed good stability as compared to reference Acarbose. Pharmacophore features of the screened phytochemicals and α-amylase inhibitors showed many common pharmacophore features. Based on finding the screened phytochemicals, e.g. Shahidine, Epicatechin, Quercetin, Isocolumbin, Ellagic acid, and Luteolin, may be used as a potential inhibitors against α-amylase. These phytochemicals could be optimized and synthesized to develop potential drugs to manage and treat diabetes, targeting α-amylase.Communicated by Ramaswamy H. Sarma.

Screening chemical inhibitors for alpha-amylase from leaves extracts of Murraya koenigii (Linn.) and Aegle marmelos L

OBJECTIVES

Aqueous leaves extracts of Murraya koenigii (M. koenigii) and Aegle marmelos (A. marmelos) were prepared and effect of the extracts on inhibiting alpha-amylase playing essential roles on converting starch into glucose have been examined using in vitro assays.

METHODS

Alpha amylase inhibitory assay was used to asses the in vitro antidiabetic activity of the extracts. Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify the volatile molecules of the extracts. Identified molecule were converted as ligand and docked against human pancreatic α-amylase (0.95 Å; PDB ID: 5U3A) using Autodock tool.

RESULTS

The data analyzes suggested that the alpha-amylase inhibition potential of the extract obtained from M. koenigii was stronger than that of the A. marmelos at low concentrations (<1 mg/mL), whereas both the extracts depicted similar inhibition effects on the enzyme at high concentration (>1 mg/mL). The phytochemicals present in both the plant extracts were identified by using their respective GC-MS data and the data analyzes revealed that the extracts of M. koenigii and A. Marmelos seemed to consist of about 20 and 24 diverse chemical molecules, respectively. Through the molecular docking studies, azulene of M. koenigii and hydroxycyclodecadiene of A. marmelos showed higher binding affinity on alpha-amylase.

CONCLUSIONS

Concentration-dependent alpha-amylase inhibition effects of the extracts were observed and M. koenigii contains more alpha-amylase inhibitory effects due to the presence of azulene. This is primary lead to find out the better anti diabetic natural based drug to the society after clinical trial.

Spray-Drying Microencapsulation of High Concentration of Bioactive Compounds Fragments from Euphorbia hirta L. Extract and Their Effect on Diabetes Mellitus

The present study was performed to spray-dry the high concentration of bioactive compounds from Euphorbia hirta L. extracts that have antidiabetic activity. The total phenolic content (TPC) and total flavonoid content (TFC) of four different extracts (crude extract, petroleum ether extract, chloroform extract and ethyl acetate extract) from the dried powder of Euphorbia hirta L. were determined using a spectrophotometer. After that, the fragment containing a high number of bioactive compounds underwent spray-dried microencapsulation to produce powder which had antidiabetic potential. The total phenolic content values of the crude extract, petroleum ether extract, chloroform extract and ethyl acetate extract were 194.55 ± 0.82, 51.85 ± 3.12, 81.56 ± 1.72 and 214.21 ± 2.53 mg/g extract, expressed as gallic acid equivalents. Crude extract, petroleum ether extract, chloroform extract and ethyl acetate extracts showed total flavonoids 40.56 ± 7.27, 29.49 ± 1.66, 64.99 ± 2.60 and 91.69 ± 1.67 mg/g extract, as rutin equivalents. Ethyl acetate extract was mixed with 20% maltodextrin in a ratio of 1:10 to spray-dry microencapsulation. The results revealed that the moisture content, bulk density, color characteristic, solubility and hygroscopicity of the samples were 4.9567 ± 0.00577%, 0.3715 ± 0.01286 g/mL, 3.7367 ± 0.1424 Hue, 95.83 ± 1.44% and 9.9890 ± 1.4538 g H₂O/100 g, respectively. The spray powder was inhibited 51.19% α-amylase at 10 mg/mL and reduced 51% in fast blood glucose (FBG) after 4 h treatment. Furthermore, the administration of spray powder for 15 days significantly lowered the fast blood glucose level in streptozotocin-diabetic mice by 23.32%, whereas, acarbose—a standard antidiabetic drug—and distilled water reduced the fast blood glucose level by 30.87% and 16.89%. Our results show that obtained Euphorbia hirta L. powder has potential antidiabetic activity.

Evaluation of the alpha-amylase inhibitory activity of Nepalese medicinal plants used in the treatment of diabetes mellitus

Background

α-Amylase catalyses the hydrolysis of starch and ultimately producing glucose. Controlling the catalytic activity of this enzyme reduces glucose production in the postprandial stage, which could be a therapeutic benefit for people with diabetes. This study was conducted to evaluate α-amylase inhibition for utilizing the crude extracts of some medicinal plants traditionally used in Nepal for the treatment of diabetes and its related complications.

Methods

Microtiter plate approach has been used to assess inhibitory activities of in vitro α-amylase of methanolic extracts of thirty-two medicinal plants. A starch tolerance test was used in rats to investigate the in vivo study of the methanolic extract concerning glibenclamide as the positive control.

Results

Acacia catechu, Dioscorea bulbifera, and Swertia chirata exhibited inhibitory activity against α-amylase and with IC50 values; 49.9, 296.1, and 413.5 μg/mL, respectively. Kinetics study revealed that all the extracts displayed a mixed type of inhibition pattern, with Ki values ranging from 26.6–204.2 μg/mL. Free radical scavenging activity was again re-examined and found prominent in extracts of A. catechu. Likewise, A. catechu and S. chirata showed significant reduction of blood glucose concentration up to 30 min after oral dose of 250 mg/kg (F (4, 20) = 4.1, p = .048), and (F (4, 20) = 4.1, p = .036), respectively.

Conclusions

Enzymatic assay for α-amylase inhibition using extracts was successfully evaluated. Also, the in-vitro and in-vivo study model revealed that medicinal plants could be a potent source of α-amylase inhibition. So, they could serve as potential candidates for future drug development strategies for curing diabetes with minimal or no adverse side effects.

Multimodal α-Glucosidase and α-Amylase Inhibition and Antioxidant Effect of the Aqueous and Methanol Extracts from the Trunk Bark of Ceiba pentandra

Postprandial hyperglycemia and oxidative stress are important factors that worsen the health condition of patients with type 2 diabetes. We recently showed that extracts from Ceiba pentandra mitigate hyperglycemia in dexamethasone- and high diet/streptozotocin-induced diabetes. Herein, we evaluated the postprandial regulatory properties and the antioxidant effects of the aqueous (AE) and methanol (ME) extracts from the stem bark of Ceiba pentandra. The phytochemical analysis of AE and ME was performed using the LC-MS technique and the total phenolic and flavonoid assays. Both extracts were tested for their ability to inhibit superoxide anion (O2 •ـ), hydrogen peroxide (H2O2), protein oxidation, alpha-amylase, and alpha-glucosidase activities. The mode of enzyme inhibition was also determined in a kinetic study. AE and ME were both rich in phenolic and flavonoid compounds. ME was 2.13 and 1.91 times more concentrated than AE in phenolic and flavonoid compounds, respectively. LC-MS allowed the identification of 5 compounds in both extracts. ME and AE inhibited O2 •ـ with IC50 of 51.81 and 34.26 μg/ml, respectively. On H2O2, they exhibited IC50 of 44.84 and 1.78 μg/ml, respectively. Finally, they exhibited IC50 of 120.60 and 140.40 μg/ml, respectively, in the inhibition of protein oxidation induced by H2O2, while showing IC50 of 39.26 and 97.95 μg/ml on the protein oxidation induced by AAPH. ME and AE inhibited alpha-amylase with IC50 of 6.15 and 54.52 μg/ml, respectively. These extracts also inhibited alpha-glucosidase, demonstrating IC50 of 76.61 and 86.49 μg/ml. AE exhibited a mixed noncompetitive inhibition on both enzymes, whereas ME exhibited a competitive inhibition on α-amylase and a pure noncompetitive inhibition on α-glucosidase. These results demonstrate that ME and AE scavenge reactive oxygen species and prevent their effects on biomolecules. Besides, ME and AE inhibit carbohydrate digestive enzymes. These properties may contribute to reduce postprandial hyperglycemia and regulate glycemia in diabetic patients.

Arylsulfonyl histamine derivatives as powerful and selective α-glucosidase inhibitors

A series of simple N-arylbenzenesulfonyl histamine derivatives were prepared and screened against α-glucosidase. Inhibition was in the micromolar range for several N α,N τ-di-arylsulfonyl compounds, with N α,N τ-di-4-trifluorobenzenesulfonyl histamine (IId) being the best inhibitor. Compound IId is a reversible and competitive α-glucosidase inhibitor, and presented good selectivity with respect to other target enzymes, including β-glucosidase and α-amylase, and interesting predicted physicochemical properties. Docking studies have been run to postulate ligand-enzyme interactions to account for the experimental results. In vivo, compound IId produced a similar hypoglycemic effect to acarbose with half of its dose.

Plant food anti-nutritional factors and their reduction strategies: an overview

Abstract

Legumes and cereals contain high amounts of macronutrients and micronutrients but also anti-nutritional factors. Major anti-nutritional factors, which are found in edible crops include saponins, tannins, phytic acid, gossypol, lectins, protease inhibitors, amylase inhibitor, and goitrogens. Anti-nutritional factors combine with nutrients and act as the major concern because of reduced nutrient bioavailability. Various other factors like trypsin inhibitors and phytates, which are present mainly in legumes and cereals, reduce the digestibility of proteins and mineral absorption. Anti-nutrients are one of the key factors, which reduce the bioavailability of various components of the cereals and legumes. These factors can cause micronutrient malnutrition and mineral deficiencies. There are various traditional methods and technologies, which can be used to reduce the levels of these anti-nutrient factors. Several processing techniques and methods such as fermentation, germination, debranning, autoclaving, soaking etc. are used to reduce the anti-nutrient contents in foods. By using various methods alone or in combinations, it is possible to reduce the level of anti-nutrients in foods. This review is focused on different types of anti-nutrients, and possible processing methods that can be used to reduce the level of these factors in food products.

Graphical abstract

A brief overview of beneficial effects of anti-nutrients and reduction strategy.

High-performance thin-layer chromatography linked with (bio)assays and FTIR-ATR spectroscopy as a method for discovery and quantification of bioactive components in native Australian plants

Many native Australian plants have a long history of use as medicinal and culinary herbs and some are considered to be equivalents to the Mediterranean herbs. However, while therapeutic properties of Mediterranean herbs are well documented, there is limited information on the medicinal use of the Australian native herbs. Extracts of five native Australian plants were characterised with FTIR-ATR spectroscopy in the fingerprint region and screened for enzyme inhibitory and antioxidant activities via effect-directed analysis (EDA) based on bioautography. High-performance thin-layer chromatography (HPTLC) coupled with microchemical and biochemical derivatization assays was used for EDA screening. Detected compounds with biological activities were identified via FTIR-ATR spectroscopy. All herbs showed antioxidant activity with lemon myrtle being the most active. The α-amylase inhibition, observed in native thyme, sea parsley and native bush was associated with the presence of phenolic acids, chlorogenic acid and caffeic acid. The investigation of botanicals by a fast, hyphenated HPTLC method, has allowed an effect-directed high-throughput screening, fast characterization of complex mixtures and detection of biologically active phytochemicals (bioprofiling).

Ameliorative effects of Hydrolea zeylanica in streptozotocin-induced oxidative stress and metabolic changes in diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Hydrolea zeylanica L. Vahl. (Hydroleaceae) is an aquatic medicinal plant used as leafy vegetable in some parts of India. In south Odisha and Hazaribag district of Jharkhand, India, decoction of leaves is used as household remedy for diabetes. To our knowledge, no prior studies have examined the antidiabetic activity of H. zeylanica to validate its ethnomedicinal claim.

PURPOSE

With this aim in mind, we examined the bioactivity of hydroalcohol fraction of leaves of H. zeylanica (HAHZ) in streptozotocin-induced oxidative stress in diabetic rats.

MATERIALS AND METHODS

In vitro antidiabetic and free radical scavenging activities of different fractions of H. zeylanica were performed. The most effective bioactive fraction e.g. HAHZ was considered for kinetic studies to understand the mode of inhibition of α-glucosidase and α-amylase. To understand the chemical composition, GC-MS/MS and LC-MS/MS analysis of HAHZ were performed. To find out the molecular mechanism of action of HAHZ, streptozotocin-induced oxidative stress and metabolic changes in diabetic rats were studied.

RESULTS

HAHZ demonstrated significantly higher radical scavenging and antidiabetic activities. Kinetic analysis revealed that HAHZ inhibited α-glucosidase competitively, and α-amylase mixed competitively. To understand the chemical composition, GC-MS/MS and LC-MS/MS analysis of HAHZ identified 32 compounds and among which R-limonene (0.52%), perillartine (0.41%), N-formyl-L-lysine (1.49%), limonen-6-ol, pivalate (1.43%), lidocaine (1.70%) and gamolenic acid (2.80%) were reported to have antioxidant and antidiabetic activities. HAHZ-400 mg/kg showed significant (p < 0.001) improvement in serum markers (SGOT, SGPT, ALP, total bilirubin, total protein, triglycerides, total cholesterol, HDL-C, LDL-C) and oxidative markers (MDA, SOD, CAT, GSH) in serum, liver and pancreas at effective dose dependent manner. In histopathological observation, HAHZ-400 mg/kg showed marked improvement in restoring cellular architecture of liver and pancreas.

CONCLUSION

In diabetic rats, the improvement in glycemic control mechanism was achieved upon stimulating insulin secretion by R-limonene, perillartine, N-formyl-L-lysine, limonen-6-ol, pivalate, lidocaine and gamolenic acid of HAHZ.

Isolation of flavonoids from Musa acuminata Colla (Simili radjah, ABB) and the in vitro inhibitory effects of its leaf and fruit fractions on free radicals, acetylcholinesterase, 15-lipoxygenase, and carbohydrate hydrolyzing enzymes

Musa species are used traditionally for the management of many diseases. The study evaluated and compared anticholinesterase, anti-inflammatory, antioxidant, and antidiabetic activities of Musa acuminata (Simili radjah, ABB) fruits and leaves fractions and characterized the bioactive compounds using HPTLC-HRMS and NMR. Leaf fractions gave the higher biological activities than the fruit. Ethyl acetate fraction of the leaf had the highest total phenolic content (911.9 ± 1.7 mg GAE/g) and highest 2,2-diphenyl-1-picrylhydrazyl (DPPH^· ) scavenging activity (IC_50, 9.0 ± 0.4 µg/ml). It also gave the most effective inhibition of acetylcholinesterase (IC_50, 404.4 ± 8.0 µg/ml) and α-glucosidase (IC_50, 4.9 ± 1.6 µg/ml), but a moderate α-amylase inhibition (IC_50, 444.3 ± 4.0 µg/ml). The anti-inflammatory activity of n-butanol (IC_50, 34.1 ± 2.6 µg/ml) and ethyl acetate fractions (IC₅₀ , 43.1 ± 11.3 µg/ml) of the leaf were higher than the positive control, quercetin (IC₅₀ , 54.8 ± 17.1 µg/ml). Kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside (rutin) were identified as the bioactive compounds with antioxidant and antidiabetic activities from the ethyl acetate fraction of M. acuminata leaf. PRACTICAL APPLICATIONS: All parts of Musa acuminata are known to be useful ethnomedicinally even as food. The leaves are mostly used to serve food and used for wrapping purposes. However, this study concluded that M. acuminata leaf is rich in bioactive flavonoids such as kaempferol-3-O-rutinoside and rutin, with relatively high antioxidative, antidiabetic, and anti-inflammatory activities. Therefore, aside the fact that the leaves can serve as potential drug leads for pharmaceutical industries, it can also be embraced in the food sector to produce supplements and/or nutraceuticals in the management of Alzheimer's, diabetes and other inflammatory diseases.

An Insight of Alpha-amylase Inhibitors as a Valuable Tool in the Management of Type 2 Diabetes Mellitus

BACKGROUND

Among the millions of people around the world, the most prevalent metabolic disorder is diabetes mellitus. Due to the drawbacks which are associated with commercially available antidiabetic agents, new therapeutic approaches are needed to be considered. Alpha-amylase is a membrane- bound enzyme which is responsible for the breakdown of polysaccharides such as starch to monosaccharides which can be absorbed.

METHODS

We searched the scientific database using alpha-amylase, diabetes, antidiabetic agents as the keywords. Here in, only peer-reviewed research articles were collected which were useful to our current work.

RESULTS

To overcome the research gap, the alpha-amylase enzyme is regarded as a good target for antidiabetic agents to design the drug and provide an alternate approach for the treatment of type 2 diabetes mellitus. Basically, alpha-amylase inhibitors are classified into two groups: proteinaceous inhibitors, and non-proteinaceous inhibitors. Recently, non-proteinaceous inhibitors are being explored which includes chalcones, flavones, benzothiazoles, etc. as the potential antidiabetic agents.

CONCLUSION

Herein, we discuss various potential antidiabetic agents which are strategically targeted alpha-amylase enzyme. These are having lesser side effects as compared to other antidiabetic agents, and are proposed to prevent the digestion and absorption of glucose leading to a decrease in the blood glucose level.

C-glucosidic ellagitannins and galloylated glucoses as potential functional food ingredients with anti-diabetic properties: a study of α-glucosidase and α-amylase inhibition

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia, which can be counteracted by inhibition of α-glucosidase and α-amylase, both involved in the carbohydrate metabolism. Fourteen C-glucosidic ellagitannins and three galloylated glucoses were studied as potential α-glucosidase and α-amylase inhibitors. Most of the compounds were found to be moderate inhibitors of α-amylase, but potent inhibitors of α-glucosidase, showing low-micromolar IC₅₀ values, far lower than that of the antidiabetic drug acarbose. This selectivity can be an advantage for their possible application as functional food ingredients with anti-diabetic properties because strong α-amylase inhibition generally causes undesired side effects. The best inhibitors were selected for further studies. Intrinsic fluorescence measurements confirmed their high affinity towards α-glucosidase, highlighting a static quenching mechanism. Circular dichroism measurements and kinetics of inhibition indicated that the most active C-glucosidic ellagitannin roburin D (RobD) is a competitive inhibitor, whereas α-pentagalloylglucose (α-PGG) acts as a mixed-type inhibitor.

The Influence of In Vitro Gastrointestinal Digestion on the Chemical Composition and Antioxidant and Enzyme Inhibitory Capacities of Carob Liqueurs Obtained with Different Elaboration Techniques

Carob liqueur is a traditional Mediterranean alcoholic beverage obtained via a wide range of production techniques contributing to the different organoleptic attributes of the final product. The aim of this research was to evaluate the stability of the chemical composition and biological capacities (antioxidant and enzyme inhibition) under in vitro simulated gastrointestinal digestion of liqueurs prepared by flavouring the fig spirit with carob pulp by maceration, distillation, percolation, or aqueous and hydro-alcoholic infusions. For this purpose, the phenolic and furanic compositions, the total phenolic (TPC) and flavonoid (TFC) contents, antioxidant capacity (AC), and enzyme inhibitory potential against acethylcholinesterase, tyrosinase, α-glucosidase and α-amylase enzymes were evaluated. The content of gallic acid decreased after gastrointestinal digestion, while TPC, TFC, and AC significantly increased after each digestion phase. Overall, no significantly different enzyme inhibitions (p < 0.05) were observed among digested liqueurs, with moderate inhibition against acethylcholinesterase and tyrosinase (enzymes related with neurodegenerative diseases), and potent and low inhibitory capacities for α-glucosidase and α-amylase, respectively (ideal conditions employed in antidiabetic therapy). The study indicates that hydro-alcoholic infusion and maceration were the most appropriate methods to obtain liqueurs with higher values of the aforementioned parameters and safe levels of toxic furanics.

The Promising Role of Plant Tannins as Bioactive Antidiabetic Agents

BACKGROUND

Plant tannins are polyphenolic substances with various molecular weights and a variable complexity. Due to the beneficial effects for controlling chronic disorders particularly diabetes mellitus, this class of secondary metabolites has gained more interest in the recent years.

OBJECTIVE

We aimed through this review to collect, analyze and discuss all available information related to the antidiabetic effect of isolated tannins (including both condensed and hydrolysable varieties) and tannin-rich plants as well as the possible mechanisms of action involved in this antidiabetic activity.

METHODS AND RESULTS

Our bibliographic research was conducted to gather more than 41 medicinal plants containing tannins and 19 isolated tannins and tannin-rich crud extracts which were revealed to possess glucose lowering effect according to pharmacological studies.

CONCLUSION

Hence, according to findings of the present review, tannins could be useful for prevention and management of diabetes mellitus and its associated complications and these natural products could be promising compounds for the discovery of new hypoglycemic agents.

Antidiabetic activity of root tubers of Asparagus gonoclados Baker in streptozotocin induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Asparagus gonoclados Baker is a traditional folk remedy used for diabetes, diuretic, galactogogue, gastric ulcer activities etc. AIM: The present investigation was intended to evaluate the beneficial effect of the A.gonoclados (Lilliaceae) root tubers against diabetes mellitus.

MATERIALS AND METHODS

Different solvent extracts of root tubers of A. gonoclados were used to study the antihyperglycemic activity in streptozotocin (45 mg/kg.wt) induced diabetic rats. Oral glucose tolerance test was performed in diabetic and normal rats treated with A.gonoclados. Total phenolic content (TPC), total flavanoid content (TFC) and total steroidal saponins content (TSSC) were measured in different solvent extracts. Following bioassay guided fractionation method antihyperglycemic active fraction of A. gonoclados (AGAF) was isolated from the ethanol extract (AGEE) by silica gel column chromatography. We further tested relationship between insulin stimulation effect and the influence of active fraction on K⁺-ATP and Ca²⁺ channels opening in normal and diabetic rats. The characterization of AGAF was carried out by LC-ESI-MS/MS.

RESULTS

Among the different solvent extracts, the ethanol extract (AGEE) at a dose of 500 mg/kg b.wt has produced maximum (67%) reduction in fasting blood glucose levels (FBG) in diabetic treated rats after 6 h of oral administration when compared to the standard drug glibenclamide (40%). AGEE also showed dose-dependent inhibitory effect on the activities of α-glucosidase (74.73%) and α-amylase (76.47%), which is comparable to the activity of standard drug acarbose (88.42%). AGEE was found to have the richest quantity of TPCs (138.4 ± 0.39 μg/mg gallic acid equivalents), TFCs (64.8 ± 0.54 μg/mg quercetin equivalents) and TSSCs (12.9 ± 0.11μg/mg sarasapogenin equivalents). We identified 8 potential antihyperglycemic compounds in AGAF by LC-ESI-MS/MS analysis.

CONCLUSION

From our current study we confirm that A. gonoclados root tubers have potent antihyperglycemic activity and it can be a unique drug/formulation for the management of diabetes mellitus.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Iso-Mukaadial Acetate from Warburgia salutaris Enhances Glucose Uptake in the L6 Rat Myoblast Cell Line

Diabetes mellitus (DM) is a chronic metabolic disorder which has become a major risk to the health of humankind, as its global prevalence is increasing rapidly. Currently available treatment options in modern medicine have several adverse effects. Thus, there is an urgent need to develop alternative cost-effective, safe, and active treatments for diabetes. In this regard, medicinal plants provide the best option for new therapeutic remedies desired to be effective and safe. Recently, we focused our attention on drimane sesquiterpenes as potential sources of antimalarial and antidiabetic agents. In this study, iso-mukaadial acetate (Iso) (1), a drimane-type sesquiterpenoid from the ground stem bark of Warburgia salutaris, was investigated for glucose uptake enhancement in the L6 rat myoblast cell line. In vitro assays with L6 skeletal muscle cells were used to test for cytotoxicity, glucose utilisation, and western blot analysis. Additionally, the inhibition of carbohydrate digestive enzymes and 1,1-diphenyl-2- picrylhydrazyl (DPPH) scavenging activity were analysed in vitro. The cell viability effect of iso-mukaadial acetate was the highest at 3 µg/mL with a percentage of 98.4. Iso-mukaadial acetate also significantly and dose-dependently increased glucose utilisation up to 215.18% (12.5 µg/mL). The increase in glucose utilisation was accompanied by enhanced 5' adenosine monophosphate-activated protein kinase (AMPK)and protein kinase B (AKT) in dose-dependent manner. Furthermore, iso-mukaadial acetate dose-dependently inhibited the enzymes α-amylase and α-glucosidase. Scavenging activity against DPPH was displayed by iso-mukaadial acetate in a concentration-dependent manner. The findings indicate the apparent therapeutic efficacy of iso-mukaadial acetate isolated from W. salutaris as a potential new antidiabetic agent.

Antioxidant, metabolic enzymes inhibitory ability of Torreya grandis kernels, and phytochemical profiling identified by HPLC-QTOF-MS/MS

In this study, the antioxidant activities, α-glucosidase and tyrosinase inhibitory ability of Torreya grandis kernels (TGK) were performed. Samples were extracted with various polarity of ethanol, and the major phytochemical profile was characterized. The results showed that 70% of ethanol extract gave the richest phenolics and flavonoids. The strongest DPPH· and ABTS·⁺ scavenging ability, as well as the best inhibition on tyrosinase and α-glucosidase was also detected on 70% of ethanol extract. Among the fractions of 70% of ethanol extract, the ethyl acetate fraction (EAF) owned the highest phenolics, flavonoids, and the best DPPH· and ABTS·⁺ scavenging ability, and tyrosinase inhibition. Unexpectedly, the dichloromethane fraction possessed the strongest inhibition on α-glucosidase, which was much greater than that of acarbose. HPLC-QTOF-MS/MS analysis result to the characterization of 19 compounds from EAF. The results implied that TGK can be a potential source of natural antioxidants, α-glucosidase and tyrosinase inhibitors. Practical applications The kernels of T. grandis are one of the precious nuts in the world, and the extracts were advertised to show a variety of biological activities and pharmacological effects. However, researches on the phytochemical constituents and bioactivities are fewer. In this study, TGK was found to show good potency in antioxidant, α-glucosidase and tyrosinase inhibitory activities. The 70% ethanol is the best solvent for extracting above mentioned active components, and ethyl acetate can be the suitable enriching solvent. In addition, the predominant phytochemical compounds in EAF were characterized. Therefore, this research can help to the performance of further research and application of TGK in functional products.

Nephroprotective effect of Ferulago angulata flowers on N-nitrosodimethylamine-induced nephrotoxicity in rats and its phytochemical profile

The present study was designed to assess the phytochemical content of Ferulago angulata (FA) and possible in vivo nephroprotective effect of FA administration on trace elements, minerals, MDA and GSH in kidney and liver tissue samples, serum vitamin (α-tocopherol, retinol, cholecalciferol, phylloquinone), TSA, and LSA in a rat model of DMN-induced nephrotoxicity. In the study, Wistar albino rats were assigned to six groups: Control (0.9% NaCl), (DMN 10 mg/kg), (FA 150 mg/kg), (DMN + FA 150 mg/kg), (FA 300 mg/kg), and (DMN + FA 300 mg/kg). Rats were intraperitoneally given DMN for the first 7 days. Renal injury caused by DMN was proved by the histopathological alterations. The FA (300 mg/kg) treatment significantly normalized Se, Cr, Ca levels in liver and Co level in kidney tissue samples. These observed positive effects are due to the phytochemical content of the plant. The flower extract of FA (300 mg/kg) can be used for the prevention of kidney damage. PRACTICAL APPLICATIONS: Ferulago angulata flowers are used in traditional medicine for treat kidney and liver digestive system diseases. This species is endemic taxa of the family Apiaceae, which has been used both as food and therapeutics because of their phytochemical composition. In this study, the phenolic characterization of FA flower was used to a new RP-HPLC method, as well as the biological activity of FA flower and possible in vivo nephroprotective effect of FA flowers on trace elements, minerals, MDA and GSH in kidney and liver tissue samples and vitamins, TSA, and LSA in serum samples a rat model of DMN-induced nephrotoxicity. It was found that high level of phenolic compounds (chlorogenic acid, vanillic acid, 2-hydroxycinnamic acid) present in the flower extract of F. angulata has positive effects and antioxidant properties. Due to its phenolic content, FA flower extract could protect for kidney damage and can be used as antioxidants in the food additive and pharmaceutical industry.

Comparison of pharmacological properties and phytochemical constituents of in vitro propagated and naturally occurring liverwort Lunularia cruciata

BACKGROUND

Study of phytochemicals and pharmacological properties of bryophytes has been neglected for a long time because of the three main reasons i.e. (i) difficulty in collection in large amount for analysis; (ii) their availablility only in particular season and (iii) their restricted geographic distribution. So, the aim of this work was to propagate Lunularia cruciata under in vitro condition for comparing its pharmacological properties and phytocmecial constituents with naturally grown counterparts.

METHOD

Axenic culture of L. cruciata was established by propagating gemmae under in vitro condition. Appropriate culture conditions, media, and the effect of hormones on growth and development were studied. The phytochemical composition was determined by GC-MS analysis and pharmacological activity was evaluated by assessing the antioxidant and anti-diabetic activities. For the antioxidant activity ABTS⁺ [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)], DPPH^• (2,2-diphenyl-1-picrylhydrazyl) and metal chelating assays were done and for evaluation of the in vitro anti-diabetic activity α-glucosidase and α-amylase inhibitory activities were done.

RESULT

Growth of L. cruciata was recorded in half strength MS media. Benzylaminopurine (BAP: 2 mg/L) and 1-Naphtheleneacetic acid (NAA: 0.5 mg/L) were the successful hormonal combination. GC-MS analysis revealed the existence of nine key compounds in both in vitro and naturally grown L. cruciata. Result of antioxidant and anti-diabetic activity showed that in vitro grown L. cruciata has a more or less similar antioxidant and anti-diabetic activities as naturally grown ones. This result confirms the possibility of using in vitro grown plants in place of naturally grown plants for research and clinical purposes.

Comprehensive Chemical Profiling and Multidirectional Biological Investigation of Two Wild Anthemis Species (Anthemis tinctoria var. Pallida and A. cretica subsp. tenuiloba): Focus on Neuroprotective Effects

Ethyl acetate (EA), methanol (MeOH), and aqueous extracts of aerial parts of Anthemis tinctoria var. pallida (ATP) and A. cretica subsp. tenuiloba (ACT) were investigated for their phenol and flavonoid content, antioxidant, and key enzyme inhibitory potentials. All extracts displayed antiradical effects, with MeOH and aqueous extracts being a superior source of antioxidants. On the other hand, EA and MeOH extracts were potent against AChE and BChE. Enzyme inhibitory effects against tyrosinase and α-glucosidase were observed, as well. We also studied Anthemis extracts in an ex vivo experimental neurotoxicity paradigm. We assayed extract influence on oxidative stress and neurotransmission biomarkers, including lactate dehydrogenase (LDH) and serotonin (5-HT), in isolated rat cortex challenged with K⁺ 60 mM Krebs-Ringer buffer (excitotoxicity stimulus). An untargeted proteomic analysis was finally performed in order to explore the putative mechanism in the brain. The pharmacological study highlighted the capability of ACT water extract to blunt K⁺ 60 mM increase in LDH level and 5-HT turnover, and restore physiological activity of specific proteins involved in neuron morphology and neurotransmission, including NEFMs, VAMP-2, and PKCγ, thus further supporting the neuroprotective role of ACT water extract.

Flavonoids from Morus alba L. Leaves: Optimization of Extraction by Response Surface Methodology and Comprehensive Evaluation of Their Antioxidant, Antimicrobial, and Inhibition of α-Amylase Activities through Analytical Hierarchy Process

To explore the flavonoids from Morus alba L. leaves (MLF), the process of extracting was optimized by a response surface methodology and the antimicrobial and antioxidant activities were evaluated in vitro. The yield of flavonoids reached 50.52 mg g^-1 under the optimized extraction conditions (i.e., extraction temperature, 70.85 °C; solvent concentration, 39.30%; extraction time, 120.18 min; and liquid/solid ratio, 34.60:1). The total flavonoids were extracted in organic solvents with various polarities, including petroleum ether (MLF_p), ethyl acetate (MLF_e), and n-butanol (MLF_b). In vitro, the four MLF samples exhibited good antioxidant activities for scavenging of 2, 2'-azinobis-(3-ethylbenz-thiazoline-6-sulphonate) radical, 1, 1-diphenyl-2-picrylhydrazyl radical, and total reducing power. Regarding antimicrobial efficacy, the MLF samples suppressed the development of Staphylococcus aureus, Bacillus subtilis, and Bacillus pumilus. The MLF samples inhibited α-amylase activity to a certain extent. The analytical hierarchy process (AHP) was used to evaluate comprehensively the bioactivities of the MLF samples. The AHP results revealed that the bioactivity comprehensive score (78.83 μg mL^-1) of MLF_e was optimal among the four MLF samples. Morus alba L. leaves also exhibited non-hemolytic properties. All bioactivities suggested the potential of MLF_e as a candidate resource in the food and drug industries.

Bioactive compounds in plant materials for the prevention of diabetesand obesity

Plant materials have been widely studied for their preventive and therapeutic effects for type 2 diabetes mellitus (T2DM) and obesity. The effect of a plant material arises from its constituents, and the study of these bioactive compounds is important to achieve a deeper understanding of its effect at the molecular level. In particular, the study of the effects of such bioactive compounds on various biological processes, from digestion to cellular responses, is required to fully understand the overall effects of plant materials in these health contexts. In this review, I summarize the bioactive compounds we have recently studied in our research group that target digestive enzymes, dipeptidyl peptidase-4, myocyte glucose uptake, and lipid accumulation in adipocytes.

Abbreviations: AC: adenylyl cyclase; AMPK: AMP-activated protein kinase; βAR: β-adrenergic receptor; CA: catecholamine; cAMP: cyclic adenosine monophosphate; cGMP: cyclic guanosine monophosphate; DPP-4: dipeptidyl peptidase-4; ERK: extracellular signal-regulated kinase; GC: guanylyl cyclase; GH: growth hormone; GLP-1: glucagon-like peptide-1; GLUT: glucose transporter; HSL: hormone-sensitive lipase; IR: insulin receptor; IRS: insulin receptor substrate; MAPK: mitogen-activated protein kinase; MEK: MAPK/ERK kinase; MG: maltase-glucoamylase; NP: natriuretic peptide; NPR: natriuretic peptide receptor; mTORC2: mechanistic target of rapamycin complex-2; PC: proanthocyanidin; PI3K: phosphoinositide 3-kinase; PKA: cAMP-dependent protein kinase; PKB (AKT): protein kinase B; PKG: cGMP-dependent protein kinase; PPARγ: peroxisome proliferator-activated receptor-γ; SGLT1: sodium-dependent glucose transporter 1; SI: sucrase-isomaltase; T2DM: type 2 diabetes mellitus; TNFα: tumor necrosis factor-α.

Analyzing hedyotis diffusa mechanisms of action from the genomics perspective

BACKGROUND AND OBJECTIVE

Hedyotis diffusa is an herb used for anti-cancer, anti-oxidant, anti-inflammatory, and anti-fibroblast treatment in the clinical practice of Traditional Chinese Medicine. However, its pharmacological mechanisms have not been fully established and there is a lack of modern scientific verification. One of the best ways to further understand Hedyotis diffusa's mechanisms of action is to analyze it from the genomics perspective.

METHODS

In this study, we used network pharmacology approaches to infer the herb-gene interactions, the herb-pathway interactions, and the gene families. We then analyzed Hedyotis diffusa's mechanisms of action using the genomics context combined with the Traditional Chinese Medicine clinical practice and the pharmacological research.

RESULTS

The results obtained in the pathway and gene family analysis were consistent with the Traditional Chinese Medicine clinical experience and the pharmacological activities of Hedyotis diffusa.

CONCLUSIONS

Our approach can identify related genes and pathways correctly with little a priori knowledge, and provide potential directions to facilitate further research.

Effect of Xylocarpus granatum Bark Extract on Amelioration of Hyperglycaemia and Oxidative Stress Associated Complications in STZ-Induced Diabetic Mice

Xylocarpus granatum is a medicinal mangrove plant, traditionally used for the treatment of diarrhoea, cholera, fever, dyslipidaemia, inflammation, etc. The present study was aimed to evaluate the in vitro antidiabetic (α-glucosidase inhibition assay) and antioxidant (ABTS scavenging and metal chelating assay) activities of ethanol, methanol, and aqueous extracts of leaves and barks of X. granatum followed by in vivo antidiabetic and antioxidant evaluation of ethanol bark extracts in streptozotocin- (STZ-) induced diabetic mice. The in vitro evaluation revealed higher α-amylase inhibition and ABTS scavenging activities in ethanol bark extracts of X. granatum (XGEB). Administration of XGEB at 100 and 200 mg/kg BW doses to STZ-induced diabetic mice resulted in significant decrease (P < 0.05) in blood glucose, triglyceride (TG), total cholesterol (TC), serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transminase (SGPT), and urea levels in the serum of the extract administered groups as compared to diabetic control group. The levels of SOD, CAT, GPx, GR, and GST in liver along with LPx, SOD, GST, and GR activities in brain tissues were found to be ameliorated in XGEB treated diabetic mice. Histopathological alternations of liver tissues were also found to be restored in XGEB treated diabetic groups. The HPLC fingerprint analysis of XGEB revealed the presence of simple polyphenols, isoflavone, and flavonol-like compounds. The DSC and UV-VIS analysis also confirmed the presence of phenolic compounds in XGEB. The GC-MS analysis of XGEB showed the presence of a number of bioactive compounds. These results demonstrated the beneficial effect of XGEB in controlling hyperglycaemia and ameliorating oxidative stress associated complications associated with diabetes.

Bioactivity guided isolation of antidiabetic and antioxidant compound from Xylocarpus granatum J. Koenig bark

The present study was designed to identify antidiabetic and antioxidant constituents from ethanol bark extract of a medicinally important mangrove plant Xylocarpus granatum J. Koenig, using in vitro bioactivity-guided fractionation. The repeated fractionation of X. granatum ethanol bark extract (XGEB) by silica gel column chromatography yielded a compound with strong antidiabetic and antioxidant potential. The bioactive compounds likely to be present in the XGEB fraction were identified by FT-IR, ¹H & ¹³C NMR and MS analysis and determined as a limonoid derivative Xyloccensin-I, by comparing spectral data with the literature reports. The isolated compound demonstrated excellent in vitro antidiabetic potential IC₅₀ values of 0.25 and 0.16 mg/ml, respectively for α-amylase and α-glucosidase inhibition study. The antioxidant potential assayed by DPPH, ABTS, superoxide and hydrogen peroxide scavenging studies exhibited that the isolated compound could scavenge these free radicals with IC₅₀ values of 0.041, 0.039, 0.096 and 0.235 mg/ml, respectively. Further, in silico study was performed to find the antidiabetic activity of Xyloccensin-I by docking it against α-glucosidase enzyme. The study demonstrated that Xyloccensin-I have satisfactory interactions and binding energies when docked into target which further confirms the possible mode of antidiabetic action of the isolated compound. The bioactivity assays further asserts the antidiabetic and antioxidant efficacy of the isolated compound which strongly suggests that Xyloccensin-I holds promise in the pharmaceutical industry. The results from this study provide new mechanistic evidence justifying, at least in part, the traditional use of X. granatum extract for antidiabetic and antioxidants activities.

Molecular Insight and Mode of Inhibition of α-Glucosidase and α-Amylase by Pahangensin A from Alpinia pahangensis Ridl

The inhibition of carbohydrate-hydrolyzing enzymes in human digestive organs is crucial in controlling blood sugar levels, which is important in treating type 2 diabetes. In the current study, pahangensin A (1), a bis-labdanic diterpene characterized previously in the rhizomes of Alpinia pahangensis Ridl., was identified as an active dual inhibitor for α-amylase (IC₅₀ =114.80 μm) and α-glucosidase (IC₅₀ =153.87 μm). This is the first report on the dual α-amylase and α-glucosidase inhibitory activities of a bis-labdanic diterpene. The Lineweaver-Burk plots of compound 1 indicate that it is a mixed-type inhibitor with regard to both enzymes. Based on molecular docking studies, compound 1 docked in a non-active site of both enzymes. The dual inhibitory activity of compound 1 makes it a suitable natural alternative in the treatment of type 2 diabetes.

Suppressive effect of ascophyllan HS on postprandial blood sugar level through the inhibition of α-glucosidase and stimulation of glucagon-like peptide-1 (GLP-1) secretion

A sulfated polysaccharide ascophyllan inhibited α-glucosidase in a concentration dependent manner, and >90% activity was inhibited at 1.0 mg/mL. The inhibitory activity was much higher than that of acarbose. No significant inhibitory effect of ascophyllan on α-amylase was observed up to 10.0 mg/mL. Ascophyllan HS, a commercially available ascophyllan preparation showed even higher inhibitory effect on α-glucosidase than ascophyllan. Interestingly, ascophyllan and ascophyllan HS induced the secretion of glucagon-like peptide-1 (GLP-1) from human intestinal NCI-H716 cell line in a concentration dependent manner (10-100 ng/mL). The oral glucose tolerance tests revealed that after continuous 8-week ingestion of ascophyllan HS at 100 mg/day, the glucose area under the curve values of the ascophyllan HS ingested group were significantly lower than placebo ingested group. Serum glycosylated hemoglobin (HbA1c) level in ascophyllan HS ingested group tended to decrease after 8-week ingestion, whereas no significant change was observed in placebo ingested group. This is the first report indicating that ascophyllan can induce the secretion of GLP-1 from human intestinal cell line (NCI-H716), besides the potent inhibitory effect on α-glucosidase. Furthermore, clinical trial suggested that ascophyllan HS may be a practically applicable blood glucose controlling agent in humans.

Anti-hyperglycemic and genotoxic studies of 1-O-methyl chrysophanol, a new anthraquinone isolated from Amycolatopsis thermoflava strain SFMA-103

The compound 1-O-methyl chrysophanol (OMC) which belongs to a class of hydroxyanthraquinones was isolated from Amycolatopsis thermoflava strain SFMA-103 and studied for their anti-diabetic properties. OMC was evaluated as an anti-diabetic agent based on in silico studies which initially predicted the binding energy with α-amylase (-188.81 KJ mol^-1) and with α-glucosidase (70.53 KJ mol^-1). Further, these results were validated based on enzyme inhibition assays where OMC demonstrated enzyme inhibitory activity towards α-amylase (IC₅₀ 3.4 mg mL^-1) and α-glucosidase (IC₅₀ 38.49 μg mL^-1). To confirm the anti-diabetic activity, in vivo studies (oral dose in Wistar rats) revealed that OMC inhibited significantly the increase in glucose concentration at 100 mg/kg as compared to starch control (p < 0.05). Further, to understand the safety of OMC as a therapeutic agent, the genotoxic analysis was performed in both in vitro Chinese Hamster Ovary cells (250, 500, and 1000 µM/mL) and in vivo Swiss albino mice (250, 500, and 1000 mg/kg). In vitro results showed that OMC concentration of up to 250 µM/mL did not elicit significant changes in CAs, MI, and MN counts in CHO cells. Similarly, in mice experiments (i.p. injection), no significant changes in CAs, MI, and MN induction were observed till 500 mg/kg of OMC when compared with chrysophanic acid (Cy) (200 mg/kg). In addition, mice that received the lowest dose of OMC (250 mg/kg) did not show any histological changes in liver, kidney, and heart. The study concluded that five times higher therapeutic dose (100 mg/kg) of OMC can be utilized against hyperglycemia with no genotoxic effects.