Antioxidant, antiglycation and insulinotrophic properties of Coccinia grandis (L.) in vitro: Possible role in prevention of diabetic complications

In Silico, In Vitro and Ex Vivo Evaluation of the Antihyperglycaemic, Antioxidant and Cytotoxic Properties of Coccinia grandis L. Leaf Extract

Research background

Coccinia grandis L. is traditionally used for the treatment of diabetes mellitus. Since the scientific evidence and mechanism of action have not yet been extensively investigated, this study aims to evaluate the antidiabetic and cytotoxic effects together with the optimisation and development of a scale-up process design for higher yields of bioactive phytocompounds from C. grandis.

Experimental approach

The in silico study was conducted to predict the binding affinity of phytocompounds of C. grandis for α-amylase and α-glucosidase enzymes involved in the pathophysiology of diabetes with pharmacokinetic assessment. Response surface methodology was used to determine the optimum total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC) and antioxidant activities (DPPH and FRAP) in 17 different experimental runs in which the parameters of microwave-assisted extraction such as temperature (50-70 °C), power (400-1000 W) and time (15-45 min) were varied. The phytocompounds were purified and identified using column chromatography, thin-layer chromatography (TLC), UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and liquid chromatography-mass spectrometry (LC-MS). The in vitro antidiabetic activity was determined by α-amylase and α-glucosidase enzymatic inhibitory assays, while cytotoxic investigations were done by measuring haemolytic activity, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and chorioallantoic membrane (CAM) assays.

Results and conclusions

The reported major bioactive compounds have shown an excellent binding affinity for α-amylase and α-glucosidase enzymes in the range of -14.28 to -36.12 kJ/mol with good pharmacokinetic properties and toxicities ranging from low to medium. The bioactive constituents such as total phenols, total flavonoids, total tannins and antioxidant activities such as DPPH and FRAP were found to be high and dependent on the optimised microwave-assisted extraction parameters such as temperature, time and power: 55 °C, 45 min and 763 W, respectively. Sixteen compounds were identified by FTIR and LC-MS spectra in the plant sample after preliminary identification, purification and TLC. The percentage of enzyme inhibition depended on the concentration of the extract (7.8-125.0 µg/mL) and was higher than that of acarbose. The haemolytic activity was in accordance with ISO standards and low toxicity was observed in the MTT and CAM assays in the range of 7.8-125.0 µg/mL, suggesting its potential use as an antidiabetic drug and for functional food development.

Novelty and scientific contribution

The results of the study open up new opportunities for researchers, scientists and entrepreneurs in the food and pharmaceutical sectors to develop antidiabetic foods and medicines that help diabetics to better control their condition and maintain overall health.

Genetic diversity, morphological traits, quality traits and antioxidants potentiality of Coccinia grandis germplasm under rainfed semi-arid region

The present study was conducted to evaluate the genetic variability for morphological and qualitative traits of Coccinia for development of trait specific lines at ICAR-Central Horticultural Experiment Station (CIAH-RS), Panchmahals (Godhra), Gujarat during 2020-2022. In this study, we evaluated 26 gynoecious accessions to assess the genetic divergence through principal component and cluster analysis. The experiment was carried out in a randomized complete block design with three replications under rainfed semi-arid conditions. High values of PCV and GCV were observed for variables such as NFFP (25.13 and 22.20), PL (23.14 and 20.69), FD (24.01 and 21.46), AFW (22.98 and 20.13), NFPY (26.38 and 24.40), FYP (37.57 and 31.29), FY (35.55 and 33.20), AsC (28.65 and 27.73), Ac (24.32 and 21.06), TSS (37.23 and 35.94), DPPHL (20.71 and 20.38), FRAPL (21.08 and 20.92), TPF(20.81 and 20.45) respectively. High heritability coupled with high genetic advance as per cent of mean was observed for vine length (VL), internodal length (IL), number of female flowers per plant (NFFP), fruit length (FL), peduncle length (PL), fruit diameter (FD), average fruit weight (AFW), number of fruit per plant per year (NFPY), fruit yield per plant (FYP), fruit yield (FY), ascorbic acid (AsC), acidity (Ac), total soluble solids (TSS), total phenols in leaves TPL), total flavonoids in leaves TFL, CUPRAC in leaves (CUPRACL), DPPH in leaves (DPPHL), FRAP in leaves (FRAPL), Total phenols in fruits (TPF), Total flavonoids in fruits (TFF), CUPRAC in fruits (CUPRACF) and DPPH in fruits (DPPHF). The FYP exhibited a significant positive correlation with variables like VL (0.6833), IL (0.2991), NFFP (0.8107), FD (0.5245), AFW (0.6766), NFPY (0.7659), ASC (0.4611), TSS (0.5004) and TPF (0.4281). The estimates of genetic parameters revealed scope for further improvement of fruit yield by selection. Of the eight principal components, PC-I through PC-VIII had eigen values greater than 1 and it accounts 85.02% of the total variation for 26 gynoecious accessions of Ivy gourd. The eigen values of PC-I comprised 5.775% of total variation followed by PC-II (4.250%), PC-III (3.175%), PC-IV (2.588%), PC-V (1.828%), PC-VI (1.447%), PC-VII (1.179%) and PC-VIII (1.013%).The cluster VI and cluster I having highest mean values for most of traits under study. Thus, genotypes from the distinct cluster like cluster VI and I for should be used for selection of parents and varietal improvement for further breeding programme in ivy gourd.

Traditional Herbal Medications Utilized in the Indian Medical System forthe Management of Diabetes: An Updated Review and Clinical Implications

Phytomedicine, also called botanical medicine, is the practice of using plants to treat disease. Diabetes, for example, has been treated and prevented with herbal medication for a lot longer than Western medicine. Worldwide, diabetes has become a major health concern. The management of diabetes and hyperglycemia, two of the most common public health threats, is far from ideal. When hyperglycemia persists or is not under control, diabetes-related complications, like blindness, lower limb amputations, renal disease, and cardiovascular disease, play a significant role in the morbidity and mortality of the disease. Although chemicals and biochemical agents can assist in managing diabetes, there is currently no complete cure for the disease. Herbal remedies are one of many methods that can be used to treat and prevent diabetes and its subsequent problems. Numerous traditional treatments have been discovered for diabetes as a result of extensive research efforts. However, there are many factors to consider when deciding which herbs to use, such as the patient's financial status, the presence or absence of co-morbidities, and the accessibility, cost-effectiveness, and safety profile of the herbs. This article focuses on the use of herbal and natural remedies in the treatment and prevention of diabetes, the mechanisms by which these remedies lower blood glucose levels, and the specific herbal items now utilized in the management of diabetes.

Controlling diabetes with the aid of medicinal herbs: a critical compilation of a decade of research

Diabetes is a metabolic disorder owing to the insulin faulty production or the resistance to the action mechanism where the accumulation of glucose is the major side effect in the body in the case of diabetes. Numerous herbs with the potential of reducing glucose production along with combating the secondary ailments associated with it but >1% out of 250,000 have been pharmacologically validated. Affordability and historical usage of these herbal remedies often result in patients' preference as primary or as adjunctive to conventional therapies. Clinical trials conducted with herbs are necessary for determining the efficacy of the herbs against diabetes. Additional benefits of herbal employment include the treatment of secondary ailments in patients along with diabetes including triglyceride reduction, cholesterol level management, body mass index, and cardiovascular disease control. Any individual extract marketed as antidiabetic formulations requires clinical validation before adoption but with ongoing disease status, quick validation in protocols and testing is needed to understand, isolate and cross-verify the status of the bioactive ingredient in individual herb and the polyherb extract formulations. Standardization, characterization, long-term role and impact on the human body, efficacy status, and toxicity profile need to be addressed fully for each active ingredient before it is advanced for production. Therefore, after trials, the related regulatory bodies will be approached to confirm the safety status and efficacy of the prepared concoction.

Ethnomedicines for the treatment of scorpion stings: A perspective study

ETHNOPHARMACOLOGICAL RELEVANCE

Scorpion sting is a public health concern with limited clinical symptomatic treatment. The clinical treatment uses anti-scorpion antivenom and prazosin (α-adrenergic inhibitor), often in combination with insulin, to reduce scorpion venom-induced hyperglycemia and other complications. However, these therapies also possess some limitations, necessitating urgent exploration of ethnomedicines, mainly traditional medicinal plants, to treat scorpion stings. Unfortunately, several conventional treatments are not scientifically validated, thus raising questions about their quality and utility. Therefore, pharmacological re-assessment of such medicinal plants to alleviate scorpion stings' complications is essential.

AIM OF THE STUDY

The principal objectives of this study are to provide a brief overview of medically important scorpions of the world, outline the extant traditional practices, and comprehensively review plants used in conventional ethnic medicines to treat scorpion stings over time. Modern technological advances in identifying and characterizing plant bioactive molecules are also mentioned in this review.

MATERIALS AND METHODS

The traditionally used medicinal plants against scorpion stings were reviewed from the available literature in the database. The Plant List (http://www.theplantlist.org/) was used to validate the scientific names of the plants mentioned in this study. The search targeted literature on conventional treatments and crude plant extracts or their bioactive components with proven neutralization capacity against scorpion stings. Search words used were 'scorpion sting,' 'treatment for a scorpion sting,' 'antivenom and scorpion sting,' 'traditional treatment for scorpion stings, and 'natural compounds against scorpion stings'.

RESULTS

A list of more than 200 medicinal plants traditionally used in several countries for treating scorpion stings is presented in this review. Though some myth-based remedies are practiced to treat scorpion stings, no empirical evidence exists to validate this aspect of traditional knowledge. Only 38 traditional medicinal plant extracts have been tested under in-vivo and in-vitro conditions to determine their neutralization potency of scorpion envenomation. Although a few bioactive plant constituents showing scorpion venom neutralization potency have been characterized, they are not yet commercially available for clinical application.

CONCLUSIONS

There is tremendous potential locked in medicinal plants' traditional knowledge for scorpion envenomation treatment. Translating this knowledge into the clinical application will require pharmacological reassessment, in tandem with isolation and characterization of active compounds to prove their prophylactic prowess. Almost equally important would be the formulation of stringent strategies to conserve such medicinal plants from overexploitation.

Selection and optimisation of extraction technique for the preparation of phenolic- and flavonoid-rich extract of leafy vegetable, Coccinia grandis (Linn.) Voigt

Coccinia grandis (L.) Voigt (family: Cucurbitaceae) is a popular leafy vegetable in Sri Lankan diet. C. grandis is high in phenolics and flavonoids. The present work attempted to determine a suitable extraction technique, and further optimise it to obtain phenolic- and flavonoid-rich extract from C. grandis leaves, with an aim at developing a nutraceutical targeting the dietary management of diabetes mellitus. Acetone extraction (AE), methanol extraction (ME), pre-warmed water extraction (PWE), electric shake extraction (ESE), reflux extraction (RE), ultrasonication with water (UEw), ultrasonication with ethanol (UEe), ultrasonic assisted-reflux extraction (URE), and reflux assisted-ultrasonic extraction (RUE) were chosen as the extraction techniques. URE was selected as a satisfactory extraction technique for further optimisation for the preparation of phenolic- and flavonoid-rich extract based on the contents of phenolics (32.97 ± 0.41 mg of equivalent gallic acid/g of extract) and flavonoids (4.50 ± 0.04 mg equivalent quercetin/g of extract). The highest yield of 32.8% was obtained by the URE technique. The optimal extraction conditions for URE were determined with an ultrasonic time of 19 min, refluxing time of 168 min, and liquid:solid ratio of 16.4 mL/g. This is the first attempt to investigate the selection and optimisation of an extraction technique for obtaining phenolic- and flavonoid-rich extract from C. grandis leaves. The present findings would be useful in the development of a commercially viable nutraceutical using a phenolic- and flavonoid-rich extract of C. grandis.

The antioxidant and antiglycation activities of selected spices and other edible plant materials and their decay in sugar-protein systems under thermal stress

Antiglycation activities of herbs and spices, have been described in relation to their in vivo anti-diabetic or anti-aging activity at physiological temperature. Under the hypothesis that those natural antioxidants may inhibit the formation of Maillard intermediates, the behavior of several hydroalcoholic plant extracts was analyzed in sugar-protein systems. Allspice, thyme, green pepper and black pepper extracts were the most efficient inhibitors, decreasing furosine formation by 60, 45, 40 and 30%, respectively. 5-hydroxymethyl-2-furfural formation decreased in the presence of the extracts and protein glycation was inhibited by the thyme extract in advanced stages. Antiglycation activities were related to polyphenols content, to radical scavenging and to iron-reducing power. In the protein-sugar systems studied at the time in which 4000 ppm of furosine were formed, the antioxidant activity dropped between 30 and 40%. Polyphenols inhibit Maillard intermediates formation, revealing the incidence of oxidative pathways, but they are depleted as a function of time.

LC-QTOF-MS/MS Based Molecular Networking Approach for the Isolation of α-Glucosidase Inhibitors and Virucidal Agents from Coccinia grandis (L.) Voigt

Coccinia grandis or ivy gourd is an edible plant. Its leaves and fruits are used as vegetable in many countries. Many works on antidiabetic activity of a crude extract of C. grandis, i.e., in vitro, in vivo, and clinical trials studies, have been reported. Profiles of the antidiabetic compounds were previously proposed by using LC-MS or GC-MS. However, the compounds responsible for antidiabetic activity have rarely been isolated and characterized by analysis of 1D and 2D NMR data. In the present work, UHPLC-ESI-QTOF-MS/MS analysis and GNPS molecular networking were used to guide the isolation of α-glucosidase inhibitors from an extract of C. grandis leaves. Seven flavonoid glycosides including rutin (1), kaempferol 3-O-rutinoside (2) or nicotiflorin, kaempferol 3-O-robinobioside (3), quercetin 3-O-robinobioside (4), quercetin 3-O-β-D-apiofuranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (5) or CTN-986, kaempferol 3-O-β-D-api-furanosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (6), and kaempferol 3-O-β-D-apiofuranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (7) were isolated from C. grandis leaves. This is the first report of glycosides containing apiose sugar in the genus Coccinia. These glycosides exhibited remarkable α-glucosidase inhibitory activity, being 4.4–10.3 times more potent than acarbose. Moreover, they also displayed virucidal activity against influenza A virus H1N1, as revealed by the ASTM E1053-20 method.

Antioxidant properties of extract combination of Coccinia grandis and Blumea balsamifera: An in vitro synergistic effect

Introduction: As single extracts, Coccinia grandis and Blumea balsamifera have been known to have potent antioxidant activities. However, the synergistic antioxidant effect of the combination of these plant extracts was unknown. In this study, the combination of C. grandis and B. balsamifera extracts was investigated for its antioxidant and synergistic properties. Methods: Separately, C. grandis and B. balsamifera leaves were extracted with ethanol. After evaporation, the thick extracts were assayed for their total phenolic content (TPC) and total flavonoid content (TFC). The antioxidant properties of single and combined extracts were measured using the molybdenum(VI) reducing power, ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. The possible synergism effect was evaluated using the checkerboard method and the combination index values were also calculated. Results: The TPC and TFC of the B. balsamifera extracts were much greater than that of C. grandis extract. In the molybdenum(VI) reducing power and FRAP assay, the reducing power of the extract combination increased as B. balsamifera extract concentration increased (P < 0.05). In the ABTS+ and DPPH radical scavenging assays, B. balsamifera extract demonstrated a higher antioxidant activity than C. grandis extract (P < 0.05). When combined, increasing the concentration of B. balsamifera caused an increase in the radical scavenging activity (P < 0.05). Synergism was observed in the combination of the extracts with low concentration ratios. Conclusion: In this study, we showed that the combination of C. grandis and B. balsamifera leaf extracts possessed synergistic antioxidant properties.

Bioactive Compounds from Ephedra fragilis: Extraction Optimization, Chemical Characterization, Antioxidant and AntiGlycation Activities

Response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize the extraction of bioactive compounds from Ephedra fragilis. The results suggested that extraction with 61.93% ethanol at 44.43 °C for 15.84 h was the best solution for this combination of variables. The crude ethanol extract (CEE) obtained under optimum extraction conditions was sequentially fractionated with solvents of increasing polarity. The content of total phenolic (TP) and total flavonoid (TF) as well as the antioxidant and antiglycation activities were measured. The phytochemical fingerprint profile of the fraction with the highest activity was characterized by using RP-HPLC. The ethyl acetate fraction (EAF) had the highest TP and TF contents and exhibited the most potent antioxidant and antiglycation activities. The Pearson correlation analysis results showed that TP and TF contents were highly significantly correlated with the antioxidant and antiglycation activities. Totally, six compounds were identified in the EAF of E. fragilis, including four phenolic acids and two flavonoids. Additionally, molecular docking analysis also showed the possible connection between identified bioactive compounds and their mechanisms of action. Our results suggest new evidence on the antioxidant and antiglycation activities of E. fragilis bioactive compounds that may be applied in the treatment and prevention of aging and glycation-associated complications.

The effect of Salaciareticulata, Syzygiumcumini, Artocarpusheterophyllus, and Cassiaauriculata on controlling the rapid formation of advanced glycation end-products

BACKGROUND

The excessive formation of Advanced Glycation End-products (AGEs) by non-enzymatic glycation mediates many health complications in the human body and the formation of AGEs largely accelerated under the hyperglycaemic condition.

OBJECTIVE

The prospect of the study to assess the strength of inhibiting the rapid AGE formations in four Ayurvedic medicinal plants, namely; Salacia reticulata (stems), Syzygium cumini (barks), Artocarpus heterophyllus (mature leaves) and, Cassia auriculata (flowers).

MATERIALS AND METHODS

Herbal decoctions of four medicinal plant materials were prepared by simmering with hot water as prescribed by the Ayurvedic medicine. The effectiveness of the decoctions was analyzed in vitro based on their Anti-AGE formation activity, glycation reversing, and anti-oxidant potentials.

RESULTS

According to the results, the decoctions of S. reticulata, A. heterophyllus and C. auriculata indicated the strong Anti-AGE forming (IC₅₀: 23.01 ± 2.70, 32.01 ± 2.09, 43.66 ± 2.11 mg/mL, respectively), glycation reversing (EC₅₀: 183.15 ± 7.67, 91.85 ± 1.93, 252.35 ± 4.03 mg/mL, respectively) and antioxidant potentials in terms of total polyphenol content (TPC), total flavonoid content (TFC), ferric ion reducing power (FRAP), ABTS and DPPH radical scavenging activities. However, the decoction of S. cumini reported the significantly high (p < 0.05) Anti-AGE forming, (IC₅₀: 9.75 ± 0.32 mg/mL), glycation reversing (EC₅₀: 66.45 ± 4.51 mg/mL), and antioxidant potentials against the decoctions of the other three plant materials.

CONCLUSION

S. cumini bark extract was identified as the best source in controlling the formation of AGEs excessively. Further, the other three plant extracts can also be effectively used as potential therapeutic agents to control the pathological conditions associated with AGEs-mediated health complications.

The Taming of Nuclear Factor Erythroid-2-Related Factor-2 (Nrf2) Deglycation by Fructosamine-3-Kinase (FN3K)-Inhibitors-A Novel Strategy to Combat Cancers

Simple Summary

Aim of this review is to provide an overview on (a) Fructosamine-3-Kinase (FN3K) and its role in regulating Nuclear Factor Erythorid-2-Related Factor-2 (Nrf2); (b) the role of glycation and deglycation mechanisms in modulating the functional properties of proteins, in particular, the Nrf2; (c) the dual role of Nrf2 in the prevention and treatment of cancers. Since controlling the glycation of Nrf2 is one of the key mechanisms determining the fate of a cell; whether to get transformed into a cancerous one or to stay as a normal one, it is important to regulate Nrf2 and deglycating FN3K using pharmacological agents. Inhibitors of FN3K are being explored currently to modulate Nrf2 activity thereby control the cancers.

Abstract

Glycated stress is mediated by the advanced glycation end products (AGE) and the binding of AGEs to the receptors for advanced glycation end products (RAGEs) in cancer cells. RAGEs are involved in mediating tumorigenesis of multiple cancers through the modulation of several downstream signaling cascades. Glycated stress modulates various signaling pathways that include p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor kappa–B (NF-κB), tumor necrosis factor (TNF)-α, etc., which further foster the uncontrolled proliferation, growth, metastasis, angiogenesis, drug resistance, and evasion of apoptosis in several cancers. In this review, a balanced overview on the role of glycation and deglycation in modulating several signaling cascades that are involved in the progression of cancers was discussed. Further, we have highlighted the functional role of deglycating enzyme fructosamine-3-kinase (FN3K) on Nrf2-driven cancers. The activity of FN3K is attributed to its ability to deglycate Nrf2, a master regulator of oxidative stress in cells. FN3K is a unique protein that mediates deglycation by phosphorylating basic amino acids lysine and arginine in various proteins such as Nrf2. Deglycated Nrf2 is stable and binds to small musculoaponeurotic fibrosarcoma (sMAF) proteins, thereby activating cellular antioxidant mechanisms to protect cells from oxidative stress. This cellular protection offered by Nrf2 activation, in one way, prevents the transformation of a normal cell into a cancer cell; however, in the other way, it helps a cancer cell not only to survive under hypoxic conditions but also, to stay protected from various chemo- and radio-therapeutic treatments. Therefore, the activation of Nrf2 is similar to a double-edged sword and, if not controlled properly, can lead to the development of many solid tumors. Hence, there is a need to develop novel small molecule modulators/phytochemicals that can regulate FN3K activity, thereby maintaining Nrf2 in a controlled activation state.

Pharmacological Inhibition of O-GlcNAc Transferase Promotes mTOR-Dependent Autophagy in Rat Cortical Neurons

O-GlcNAc transferase (OGT) is a ubiquitous enzyme that regulates the addition of β-N-acetylglucosamine (O-GlcNAc) to serine and threonine residues of target proteins. Autophagy is a cellular process of self-digestion, in which cytoplasmic resources, such as aggregate proteins, toxic compounds, damaged organelles, mitochondria, and lipid molecules, are degraded and recycled. Here, we examined how three different OGT inhibitors, alloxan, BXZ2, and OSMI-1, modulate O-GlcNAcylation in rat cortical neurons, and their autophagic effects were determined by immunoblot and immunofluorescence assays. We found that the treatment of cortical neurons with an OGT inhibitor decreased O-GlcNAcylation levels and increased LC3-II expression. Interestingly, the pre-treatment with rapamycin, an mTOR inhibitor, further increased the expression levels of LC3-II induced by OGT inhibition, implicating the involvement of mTOR signaling in O-GlcNAcylation-dependent autophagy. In contrast, OGT inhibitor-mediated autophagy was significantly attenuated by 3-methyladenine (3-MA), a blocker of autophagosome formation. However, when pre-treated with chloroquine (CQ), a lysosomotropic agent and a late-stage autophagy inhibitor, OGT inhibitors significantly increased LC3-II levels along with LC3 puncta formation, indicating the stimulation of autophagic flux. Lastly, we found that OGT inhibitors significantly decreased the levels of the autophagy substrate p62/SQSTM1 while increasing the expression of lysosome-associated membrane protein 1 (LAMP1). Together, our study reveals that the modulation of O-GlcNAcylation by OGT inhibition regulates mTOR-dependent autophagy in rat cortical neurons.

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.

An Electrochemical Chip to Monitor In Vitro Glycation of Proteins and Screening of Antiglycation Potential of Drugs

Hyperglycemia and the production of advanced glycation end products (AGEs) are the primary factors for the development of chronic complications in diabetes. The level of protein glycation is proportional to the glucose concentration and represents mean glycemia. In this study, we present an electrochemical chip-based method for in vitro glycation monitoring and the efficacy evaluation of an antiglycation compound. An electrochemical chip consisting of five microchambers and embedded microelectrodes was designed for parallel measurements of capacitance signals from multiple solutions at different concentrations. The feasibility of glycation monitoring was then investigated by measuring the capacitance signal at 0.13 MHz with bovine serum albumin and gelatin samples in the presence of various glucose concentrations over 28 days. A significant change in the capacitance due to protein glycation was observed through measurements conducted within 30 s and 21 days of incubation. Finally, we demonstrated that the chip-based capacitance measurement can be utilized for the selection of an antiglycation compound by supplementing the protein solution and hyperglycemic concentration of glucose with an inhibitory concentration of the standard antiglycation agent aspirin. The lack of a significant change in the capacitance over 28 days proved that aspirin is capable of inhibiting protein glycation. Thus, a strong relationship exists between glycation and capacitance, suggesting the application of an electrochemical chip for evaluating glycation and novel antiglycation agents.

In vitro evaluation of anti-methylglyoxal/glyoxal activity of three phytosterols using glycated bovine serum albumin models

Reactive intermediate dicarbonyls, such as methylglyoxal (MGO) and glyoxal (GO), have received extensive attention recently due to their high reactivity and capability to form advanced glycation end products (AGEs) in foods, which have been implicated in the progression of age-related complaints. We aimed to investigate the effects of three structurally different phytosterols (PS), including stigmasterol (SS), β-sitosterol (βS), and γ-oryzanol (γO), on AGEs-formation by measuring their anti-GO/MGO activity. The glycoxidation-based products, SDS-PAGE intensity, free lysine, protein thiols, fluorescence microscopy clicks, scavenging of dicarbonyl activity, and protein aggregation in bovine serum albumin (BSA) models were therefore measured. The results showed that PS could strongly inhibit fluorescent-AGEs, lysine residues, intermediate di-carbonyls, beside their disaggregation effects in a dose and structure dependent manner. Additionally, γ-oryzanol strongly inhibited AGEs more than the other PS, mostly due to its distinctive structure. Our results will provide a new foundation for development of different structure of PS as natural AGEs-inhibitors.

Antiglycation and Antioxidant Properties of Ficus deltoidea Varieties

The present study aimed to evaluate the potential of standardized methanolic extracts from seven Ficus deltoidea varieties in inhibiting the formation of AGEs, protein oxidation, and their antioxidant effects. The antiglycation activity was analyzed based on the inhibition of AGEs, fructosamine, and thiol groups level followed by the inhibition of protein carbonyl formation. The antioxidant activity (DPPH radical scavenging activity and reducing power assay) and total phenolic contents were evaluated. After 28 days of induction, all varieties of Ficus deltoidea extracts significantly restrained the formation of fluorescence AGEs by 4.55–5.14 fold. The extracts also reduced the fructosamine levels by 47.0–86.5%, increased the thiol group levels by 64.3–83.7%, and inhibited the formation of protein carbonyl by 1.36–1.76 fold. DPPH radical scavenging activity showed an IC₅₀ value of 66.81–288.04 μg/ml and reducing power activity depicted at 0.02–0.24 μg/ml. The extent of phenolic compounds present in the extracts ranged from 70.90 to 299.78 mg·GAE/g. Apart from that, correlation studies between the activities were observed. This study revealed that seven varieties of Ficus deltoidea have the potential to inhibit AGEs formation and possess antioxidant activity that might be attributed to the presence of phenolic compounds.

LC-QTOF-MS-based metabolite profiling and evaluation of α-glucosidase inhibitory kinetics of Coccinia grandis fruit

Coccinia grandis is an important food crop of the Cucurbitaceae family, widely used for culinary purposes in India. It is reported to possess hypoglycemic, hypolipidemic and antioxidant activities. The current study was aimed to explore the inhibition kinetics as well as major constituents of the active fraction of C. grandis against α-glucosidase. The kinetic study was performed through spectrophotometric assay, with p-nitrophenyl-α-d-glucopyranoside as a substrate with varying concentrations. An in vitro antioxidant study was performed by DPPH assay. In addition, UPLC-QTOF-MS analysis was carried out for metabolite profiling of the bioactive fraction of C. grandis. The results showed that the difference between the α-glucosidase inhibitory activity of the ethyl acetate fraction of C. grandis (EFCG) (IC₅₀ 2.43 ± 0.27 mg/ml), and standard inhibitor, acarbose (2.08 ± 0.19 mg/ml), was not statistically significant at a P-value of 0.05. The enzyme kinetics confirmed the inhibition mode in a mixed manner. The EFCG also showed the highest antioxidant activity (101.74 ± 1.95 μg/ml) among all of the fractions. A significant correlation between antioxidant and α-glucosidase inhibitory activity of EFCG was observed. The LC-QTOF-MS study of the EFCG putatively identified 35 metabolites, which may be responsible for its antioxidant and α-glucosidase inhibitory properties. Thus, C. grandis fruits can serve as a functional food to address diabetes-related disorders associated with α-glucosidase.

Potential anti-inflammatory and anti-apoptotic effect of Coccinia grandis plant extract in LPS stimulated-THP-1 cells

Coccinia grandis (C. grandis) L is an Indian medicinal plant from the Cucurbitaceae family whose extracts possess anti-oxidant, anti-infective, and anti-inflammatory properties. The objective of the present study was to probe the potential immunomodulatory of C. grandis crude extract on different pathways in THP-1 cells as probed by changes in expression of several proteins. THP-1 cells were differentiated into macrophages after treatment with phorbol-12-myristate 13-acetate, followed by exposure to lipopolysaccharide (LPS) with or without 50 or 100 μg/ml of C. grandis extract. Treatment of the cells with the extract significantly downregulated the expression and release of pro-inflammatory cytokines (IL-6, IL-1β, CCL2, CCL22, CXCL10/IP-10, CX3CL1 and CXCL8/IL-8), proteins (ERK5, BAX, BCL2, Cyclin D, ERK1, NF-κB, P-IκBα,P- NF-κB and P-p38) and molecular signaling pathways (NF-κB, p38 MAPK, ERK1/2 and IL-6/JAK/STAT3 signaling cascades). This study is the first to highlight the ability of C. grandis extract to modulate several pathways, including proliferation, the expression of inflammatory cytokines, phagocytosis, migration properties and apoptosis, in human monocytic THP-1 cells.

Chemical ingredients and antioxidant activities of underutilized wild fruits

This study evaluated nutritional values, bioactive constituents and antioxidant activities of the five wild underutilized fruits in the mountains of southwest Saudi Arabia (Coccinia grandis (L.) Voigt, Diospyros mespiliformis Hochst. Ex A.Dc., Cissus rotundifolius (L.), Ephedra foeminea Forssk., and Grewia villosa Willd.). The moisture content, crude fibers, total protein, total lipids, total hydrolyzable carbohydrate, total soluble sugars, and total free amino acids were analyzed. The results showed varying amounts among fruits of the five study species. In addition, the mineral composition, amino acid content, phenolic compounds, vitamins, and antioxidant activity were assessed. The highest content of total phenolic and total tannins was measured in D. mespiliformis (20.69 mg/g and 3.84 mg/g) and the lowest in E. foeminea (10.83 mg/g and 1.44 mg/g), respectively. The methanol extract (1 mg/ml) of D. mespiliformis displayed higher percentage of DPPH radical scavenging activity (87.36%). The methanol extract (1 mg/ml) of C. grandis exhibited the highest effect of total antioxidant activity and hydrogen peroxide scavenging activity (71.53%). The sufficient nutritional and antioxidant value of these wild fruits provide healthy food source for the local residents, much the same as many cultivated fruits and vegetables.

Polysaccharide from Okra (Abelmoschus esculentus (L.) Moench) Improves Antioxidant Capacity via PI3K/AKT Pathways and Nrf2 Translocation in a Type 2 Diabetes Model

Polysaccharide extracted from okra (Abelmoschus esculentus (L.) Moench), a traditional functional food, is a biologically active substance reported to possess hypoglycemic and anti-oxidative qualities. However, it is unknown which polysaccharides play a role and have the potential mechanism. This present study is to assess the possible impacts of a novel polysaccharide isolated from okra (OP) on mice fed with a high-fat diet (HFD) combined with an intraperitoneal injection (i.p.) of 100 mg/kg streptozotocin (STZ) twice, to induce type 2 diabetes mellitus (T2DM). We found that an eight-week administration of OP at 200 or 400 mg/kg body weight significantly alleviated the symptoms, with elevations in blood glucose, triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), as well as reducing high-density lipoprotein cholesterol (HDL-C), body weight, food, and water consumption. The OP treatment increased the hepatic glycogen and decreased the mussy hepatic cords and liver fibrosis in the T2DM mice. The decreases of ROS and MDA and the increases of SOD, GSH-Px and CAT in liver were observed after administration of OP. OP alleviated the T2DM characteristics through the activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3 beta (GSK3β) pathway, and enhanced the nuclear factor erythroid-2 (Nrf2) expression and promoted Nrf2-medicated heme oxygenase-1(HO-1) and superoxide dismutase 2 (SOD2) expression. OP also relieved mitochondrial dysfunction by inhibiting NOX2 activation. Taken together, these findings suggest that a polysaccharide isolated from okra exerts anti-T2DM effects partly by modulating oxidative stress through PI3K/AKT/GSK3β pathway-medicated Nrf2 transport. We have determined that a polysaccharide possesses hypoglycemic activity, as well as its underlying mechanism.

A systematic review of antiglycation medicinal plants

BACKGROUND AND OBJECTIVES

The present review shows a list of anti-glycation plants with their anti-glycation activity mechanisms that can attract the attention of pharmacologist for further scientific research towards finding better remedy for diabetic complications.

MATERIALS

Google scholar, Pubmed, Web of Science and Scopus were searched. The terms were advanced glycation end products (AGEs), medicinal plants, antiglycation products.

RESULTS

plants that studied in this review inhibit glycation in several possible mechanisms. Some of these plants inhibit the production of shiff base and amadori products. The others inhibit the generation of amadori products in the advanced phase. Some others blocked the aggregation of AGEs and some plants have antioxidant activity and reduce AGEs formation by preventing oxidation of amadori product and metal-catalyzed glucoxidation.

CONCLUSION

This review can help pharmacologist to find antiglycation natural substance that can be useful in treatment of diabetic complications.

Recent advances in the pathogenesis of microvascular complications in diabetes

Millions of people worldwide have diabetes, which is diagnosed by fasting blood glucose levels exceeding 126 mg/dL. Regardless of the type of diabetes, prolonged hyperglycemia is damaging to several organs including eyes, kidneys, nerve, and/or heart. The damages are associated with a high risk of morbidity and mortality. Diabetes has been implicated in ischemia in the microvasculature of the target tissues, which occurs due to the insufficient perfusion of tissues. The resulting occlusion and pain affect the quality of life. Multiple therapeutic approaches have been proposed for a long time to overcome these vascular complications. Apart from systemically controlling high glucose levels, other therapeutic strategies are not well understood. In this review, we summarize the recent literature for biochemical/cellular targets that are being utilized for the treatment of diabetic microvascular diseases. These targets, which are closely associated with mitochondrial dysfunction, include the polyol and diacylglycerol-protein kinase C pathways, oxidative stress, non-enzymatic glycation and the formation of advanced glycation end products, and immune dysregulation/inflammation.

Cassia grandis Lf nanodispersion is a hypoglycemic product with a potent α-glucosidase and pancreatic lipase inhibitor effect

Purpose

This study aimed to evaluate the hypoglycemic effect, antioxidant, α-glucosidase and lipase inhibitory activity, and the cytotoxicity of the Cassia grandis nanodispersion (CgND).

Methods

The hypoglycemic effect was evaluated in alloxan-induced diabetic mice. The particle size, polydispersion index, ζ-potential, and conductivity, as well as the drug-loaded content, were monitored in shelf-live, along a year. The delivery profile was evaluated in simulated intestinal fluids at pH 6.5 and 7.4. The antioxidant effect was evaluated as DPPH and ABTS inhibition. The murine α-glucosidase inhibitory activity and the lipase-inhibitory effect were evaluated in vitro. Cytotoxicity was evaluated by the Alamar blue test.

Results

CgND remained stable for a year in shelf conditions. The hypoglycemic effect in a dose of 10 mg/kg was not statistically different from glibenclamide 25 mg/kg. Nanoparticles released 100% of extract in 120 min at pH 6.5 and 7.4. Nanodispersion exhibited a potent α-glucosidase and lipase-inhibitory effect with IC₅₀ of 3.96 and 0.58 µg/mL, respectively. A strong antioxidant activity against DPPH (IC₅₀ 0.65 µg/mL) and ABTS (0.48 µg/mL) was also observed. The hypoglycemic effect could occur, at least in part, via antioxidant and α-glucosidase inhibition. CgND is non-cytotoxic in MRC-5 line cell. This nanodispersion is a promising nanotechnological product that could be used in pharmaceuticals for the treatment of Type II diabetes and related complications as obesity.

An update on natural compounds in the remedy of diabetes mellitus: A systematic review

Herbal medicine, phytomedicine or botanical medicine are synonymous, utilizes plants intended for medicinal purposes. Medicinal use of herbal medicine in the treatment and prevention of diseases including diabetes has a long history compared to conventional medicine. Diabetes is one of the major public health concerns over the world. Diabetes or hyperglycemia is considered to be one of the common public health hazard; optimal control of which is still not possible. Persistent hyperglycemia or uncontrolled diabetes has the potential to cause serious complications such as kidney disease, vision loss, cardiovascular disease, and lower-limb amputations which contributed towards morbidity and mortality in diabetes. There are various approaches to treat and prevent diabetes as well as its secondary complications, one of it is herbal medicines. However, the selection of herbs might depends on several factors, which include the stage of progression of diabetes, types of comorbidities that the patients are having, availability, affordability as well as the safety profile of the herbs. This review focuses on the herbal and natural remedies that play the role in the treatment or prevention of this morbid disorder - diabetes, including their underlying mechanisms for the blood glucose-lowering property and the herbal products already been marketed for the remedial action of diabetes.

Phytochemical profile, aldose reductase inhibitory, and antioxidant activities of Indian traditional medicinal Coccinia grandis (L.) fruit extract

Coccinia grandis (L.) fruits (CGFs) are commonly used for culinary purposes and has several therapeutic applications in the Southeast Asia. The aim of this work was to evaluate phytochemical profile, aldose reductase inhibitory (ARI), and antioxidant activities of CGF extract. The CGFs were extracted with different solvents including petroleum ether, dichloromethane, acetone, methanol, and water. The highest yield of total extractable compounds (34.82%) and phenolic content (11.7 ± 0.43 mg of GAE/g dried extract) was found in methanol extract, whereas water extract showed the maximum content of total flavonoids (82.8 ± 7.8 mg QE/g dried extract). Gas chromatography-mass spectroscopy (GC-MS) analysis of methanol and water extract revealed the presence of flavonoids, phenolic compounds, alkaloids, and glycosides in the CGFs. Results of the in vitro ARI activity against partially purified bovine lens aldose reductase showed that methanol extract of CGFs exhibited 96.6% ARI activity at IC₅₀ value 6.12 µg/mL followed by water extract 89.1% with the IC₅₀ value 6.50 µg/mL. In addition, methanol and water extracts of CGF showed strong antioxidant activities including ABTS^*+ scavenging, DPPH* scavenging, and hydroxyl radical scavenging. Our results suggest that high percentage of both flavonoids and phenolic contents in the CGFs are correlated with the ARI and antioxidant activities. The fruits of C. grandis are thus potential bifunctional agents with ARI and antioxidant activities that can be used for the prevention and management of DM and associated diseases.

Influence of Flavonoids on Mechanism of Modulation of Insulin Secretion

BACKGROUND

The development of alternatives for insulin secretion control in vivo or in vitro represents an important aspect to be investigated. In this direction, natural products have been progressively explored with this aim. In particular, flavonoids are potential candidates to act as insulin secretagogue.

OBJECTIVE

To study the influence of flavonoid on overall modulation mechanisms of insulin secretion.

METHODS

The research was conducted in the following databases and platforms: PubMed, Scopus, ISI Web of Knowledge, SciELO, LILACS, and ScienceDirect, and the MeSH terms used for the search were flavonoids, flavones, islets of Langerhans, and insulin-secreting cells.

RESULTS

Twelve articles were included and represent the basis of discussion on mechanisms of insulin secretion of flavonoids. Papers in ISI Web of Knowledge were in number of 1, Scopus 44, PubMed 264, ScienceDirect 511, and no papers from LILACS and SciELO databases.

CONCLUSION

According to the literature, the majority of flavonoid subclasses can modulate insulin secretion through several pathways, in an indication that corresponding molecule is a potential candidate for active materials to be applied in the treatment of diabetes.

SUMMARY

The action of natural products on insulin secretion represents an important investigation topic due to their importance in the diabetes controlIn addition to their typical antioxidant properties, flavonoids contribute to the insulin secretionThe modulation of insulin secretion is induced by flavonoids according to different mechanisms. Abbreviations used: KATP channels: ATP-sensitive K+ channels, GLUT4: Glucose transporter 4, ERK1/2: Extracellular signal-regulated protein kinases 1 and 2, L-VDCCs: L-type voltage-dependent Ca+2 channels, GLUT1: Glucose transporter 1, AMPK: Adenosine monophosphate-activated protein kinase, PTP1B: Protein tyrosine phosphatase 1B, GLUT2: Glucose transporter 2, cAMP: Cyclic adenosine monophosphate, PKA: Protein kinase A, PTK: Protein tyrosine kinase, CaMK II: Ca2+/calmodulin-dependent protein kinase II, GSIS: Glucose-stimulated insulin secretion, Insig-1: Insulin-induced gene 1, IRS-2: Insulin receptor substrate 2, PDX-1: Pancreatic and duodenal homeobox 1, SREBP-1c: Sterol regulatory element binding protein-1c, DMC: Dihydroxy-6'-methoxy-3',5'-dimethylchalcone, GLP-1: Glucagon-like peptide-1, GLP-1R: Glucagon-like peptide 1 receptor.

Evaluation of the antidiabetic property of aqueous leaves extract of Zanthoxylum armatum DC. using in vivo and in vitro approaches

The present study was designed to evaluate the antidiabetic potential of the aqueous leaves extract of Zanthoxylum armatum DC. leaves using in vivo and in vitro approaches. For in vivo studies, blood glucose level was monitored at different intervals after administration of varying doses of the extract for its hypoglycemic (100–6000 mg/kg b.w.) and antihyperglycemic (250 mg/kg b.w.) effect in normoglycemic and diabetic mice. In vitro enzymatic inhibition activity was tested against α-amylase, α- and β-glucosidase and lipase. Additionally hydroxyl radical, hydrogen peroxide scavenging assay and phytochemical screening were also performed. Element analysis of the plant was studied by Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The plant extract showed significant hypoglycemic and antihyperglycemic effect in normoglycemic and diabetic mice. The IC₅₀ values of extract for α-amylase, β-glucosidase, lipase, hydroxyl radical scavenging activity, hydrogen peroxide scavenging activity were 7.40 mg/ml, 0.30 mg/ml, 8.35 mg/ml, 3.25 mg/ml, 9.62 mg/ml respectively and the percentage of inhibition for α-glucosidase was 79.82% at 0.8 mg/ml. In vitro studies were compared with their respective standards. Elemental analysis revealed the presence of essential elements such as Mg, V, Fe, Cr, Zn, Cu, Mo, Mn, K, Ca, P and Sr which are all known to play a role in regulating blood glucose. The results demonstrate that Z. armatum aqueous leaves extract possess antidiabetic property in both in vivo and in vitro condition.