In Vitro Antidiabetic Effects of Isolated Triterpene Glycoside Fraction from Gymnema sylvestre

Nine undescribed pregnane glycosides from Gymnema sylvestre and their glucose uptake and GLUT4 translocation activities

A phytochemical investigation on the ethyl acetate fraction of Gymnema sylvestre led to the production of nine previously undescribed C21 steroidal glycosides sylvepregosides F-N (1-9), as well as ten known analogues, prosapogenin (10), 20-O-benzoyl-12-O-cinnamoyl-3β,5α,8β,12β,14β,17β,20-heptahydroxy-(20S)-pregn-6-ene (11), 12-O-cinnamoyl-3β,5α,8β,12β,14β,17β,20-heptahydroxy- (20S)-pregn-6-ene (12), stephanoside K (13), gymnepregoside C (14), gymnepregoside D (15), stephanoside O (16), isokidjoladinin (17), gymsyloside D (18) and gymsyloside C (19). The structures of these isolated compounds were elucidated based on extensive 1D and 2D nuclear magnetic resonance (NMR) spectra with mass spectrometry data. The biological activities screening demonstrated that compounds 1, 3-6, 8-10, 12-14, 17, and 18 promoted glucose uptake by the range of 1.06-1.97 folds. In addition, compounds 3-6, 8, 13, 14, and 19 could promote GLUT-4 translocation to the plasma membrane in L6 cells.

Elucidating the therapeutic efficacy of polyherbal formulation for the management of diabetes through endogenous pancreatic β-cell regeneration

Diabetes mellitus is characterized by the progressive loss of pancreatic β-cells. Owing to the adverse side effects of conventional antidiabetic, ethnopharmacological agents have emerged as adjunct therapies for their management. The present study aims to validate the antidiabetic activity of an aqueous polyherbal extract (APE) via in silico, in vitro, and in vivo models. UHPLC-Q-TOF-MS and HPLC analysis of APE were performed to identify bioactive secondary plant metabolites. In silico approaches implemented to predict the binding efficacy of the active phytoconstituents. Biochemical estimation, antioxidant activity, and in vitro and in vivo antidiabetic activities of APE were performed. Histomorphological and immunohistological studies of the pancreatic islets were carried out in diabetic animals for microarchitectural study. UHPLC-Q-TOF-MS identified a total of 60 compounds in APE, of which 39 were reported to have antidiabetic activity, and 16 marker compounds were identified via high-performance liquid chromatography (HPLC). An in silico study revealed a strong interaction of verbacoside B with the target proteins. APE is characterized by high flavonoid and phenolic contents with strong antioxidant properties. In an in vitro enzymatic assay, APE significantly inhibited α-amylase and α-glucosidase enzymes, with calculated IC50 values of 54.26 ± 0.14 and 26.47 ± 0.12 μg/ml, respectively. An in vitro glucose uptake assay revealed increased uptake with APE treatment in a dose-dependent manner. APE significantly decreased blood glucose and HbA1c levels and had no side effects on liver or kidney function, as measured from blood parameters. Immunohistological observation revealed 47% regeneration of pancreatic β-cells with APE treatment in diabetic animals.

Gymnema sylvestre as a Potential Anti-Inflammatory and Anti-Biofilm Agent Against Anaerobic Infections: An In Vitro Study

This study evaluates the antimicrobial activity of the glycolic extract of G. sylvestre against anaerobic pathogens, along with its cytotoxicity, genotoxicity, anti-inflammatory activity, antioxidant effects, and phytochemical composition. Phytochemical analysis was conducted using high-performance liquid chromatography and liquid chromatography-mass spectrometry, while the antioxidant effect was assessed through a DPPH assay. Antimicrobial action was tested on planktonic cultures and biofilms of Porphyromonas gingivalis, Porphyromonas endodontalis, Parvimonas micra, and Fusobacterium nucleatum. Cytotoxicity was evaluated using mouse macrophages (RAW 264.7), rat fibroblasts (L929), and human keratinocytes (HaCaT). Anti-inflammatory effects were measured by an immunoenzymatic assay (ELISA) on RAW 264.7 cells. Statistical analysis was performed using a one-way ANOVA and Tukey's test. Phytochemical analysis revealed the presence of phenolic compounds and flavonoids. The extract demonstrated a reduction of over 95% in biofilms of P. gingivalis, P. micra, and F. nucleatum within 5 min of treatment. Cell viability (HaCaT) remained above 80%. Antioxidant activity showed an EC50 of 353.43 µg/mL, achieving a 50% reduction in free radicals. A significant decrease in TNF-α (a pro-inflammatory cytokine) and an increase in IL-10 (an anti-inflammatory cytokine) were observed. In conclusion, the extract of G. sylvestre exhibits promising potential as a therapeutic agent for treating anaerobic infections, inflammation, and oxidative stress.

Insulinotropic and anti-obesity properties of ethno-medicinal plants: pharmacology-based and in-silico predictions

The herbal extracts of four traditional plants; namely Gymnema sylvestre leaves, Garcinia cambogia fruits, Cleome droserifolia leaves, and Nigella sativa seeds, were identified for their main constituents using UHPLC/QTOF-MS/MS. Then, a pharmacology-based analysis and molecular docking verification were established targeting the evaluation of each individual herbal extract for their antidiabetic/anti-obesity potential besides their safety. Streptozotocin-induced diabetic rats were used to evaluate antiobesity and insulinotropic effects against insulin (10 U/Kg, IP) and metformin (100 mg/Kg, per oral) as standard regimens. Levels of insulin and fasting blood glucose as well as body weight were assessed, together with certain histopathological, hematological, and biochemical parameters to establish safety profiles. The four herbal extracts exhibited an increase in insulin secretion in-vivo, which is confirmed by docking studies. The herbal extracts (100 mg/kg per oral, daily) demonstrated a significant weight decrease. Each individual herbal extract markedly improved the streptozotocin-induced indices alterations.

Exploring the potential of semi-synthetic Swertiamarin analogues for GLUT facilitation and insulin secretion in NIT-1 cell lines: a molecular docking and in-vitro study

Synthesis, characterisation, and anti-diabetic potential of swertiamarin analogues against DPP-4 enzymatic inhibition was done prior to this study. However, swertiamarin and its analogues inhibited DPP-4 enzyme significantly. Semisynthetic swertiamarin analogues have been studied for antidiabetic potential and mechanism of action utilising molecular docking and in-vitro techniques. The mechanism of action for swertiamarin analogues was determined by in-silico molecular docking studies using glucose-transporters, GLUT-1 (PDB ID: 4PYP), GLUT-3 (PDB ID: 7SPS), and GLUT-4 (PDB ID: 7WSM) along with in-vitro glucose uptake and glucose-induced insulin secretion assays. These studies found that synthesised swertiamarin analogues SNIPERSV3, SNIPERSV4, and SNIPERSV7 shown better docking score against different GLUTs and better anti-diabetic effects on glucose uptake and insulin secretion in NIT-1 cell line than standard glibenclamide and swertiamarin. Thus, swertiamarin analogues might be studied for diabetes therapy in the future.

Phytochemical profiling, human insulin stability and alpha glucosidase inhibition of Gymnema latifolium leaves aqueous extract: Exploring through experimental and in silico approach

Diabetes mellitus Type 2 (DM2T) is a rapidly expanding metabolic endocrine disorder worldwide. It is caused due to inadequate insulin secretion by pancreatic beta cells as well as development of insulin resistance. This study aimed to investigate the anti-α-glucosidase, insulin stabilization effect, and non-cytotoxic nature of Gymnema latifolium leaf aqueous extract (GLAE). FTIR analysis revealed the functional groups of compounds present in GLAE. Through LC/ESI-MS/MS analysis, about 12 compounds which belongs to different classes, triterpene glycosides, flavonoids, phenolics, stilbene glycosides and chlorophenolic glycosides were identified. GLAE showed in vitro antioxidant activity. GLAE stabilized insulin by increasing its α-helical content. GLAE inhibited the mammalian α-glucosidase (IC50 = 144 μg/mL) activity through competitive mode (Ki = 61.30 µg/mL). GLAE did not affect the viability of normal cell line (Vero cell line) which shows its non-toxic nature. Molecular docking of phytocompounds identified in GLAE was done with human α-glucosidase and insulin. The top 2 compounds [Gymnema saponin V (GSV) and quercetin 3-(2-galloylglucoside) (QGG) with α-glucosidase; GSV and Z)-resveratrol 3,4'-diglucoside (RDG) with human insulin] with low binding free energy were subjected to 100 ns molecular dynamics simulation to ascertain the stable binding of ligand with protein. The MM/GBSA analysis revealed binding free energy of GSV/α-glucosidase and QGG /α-glucosidase to be - 20.9935 and, - 30.9461 kcal/mol, respectively. Altogether GLAE is valuable source of anti-α-glucosidase inhibitors and insulin stabilizing compounds, suggesting potential lead for further exploration as complementary medicine against DM2T.

An Overview of Herbal-Based Antidiabetic Drug Delivery Systems: Focus on Lipid- and Inorganic-Based Nanoformulations

Diabetes is a metabolic pathology with chronic high blood glucose levels that occurs when the pancreas does not produce enough insulin or the body does not properly use the insulin it produces. Diabetes management is a puzzle and focuses on a healthy lifestyle, physical exercise, and medication. Thus far, the condition remains incurable; management just helps to control it. Its medical treatment is expensive and is to be followed for the long term, which is why people, especially from low-income countries, resort to herbal medicines. However, many active compounds isolated from plants (phytocompounds) are poorly bioavailable due to their low solubility, low permeability, or rapid elimination. To overcome these impediments and to alleviate the cost burden on disadvantaged populations, plant nanomedicines are being studied. Nanoparticulate formulations containing antidiabetic plant extracts or phytocompounds have shown promising results. We herein aimed to provide an overview of the use of lipid- and inorganic-based nanoparticulate delivery systems with plant extracts or phytocompounds for the treatment of diabetes while highlighting their advantages and limitations for clinical application. The findings from the reviewed works showed that these nanoparticulate formulations resulted in high antidiabetic activity at low doses compared to the corresponding plant extracts or phytocompounds alone. Moreover, it was shown that nanoparticulate systems address the poor bioavailability of herbal medicines, but the lack of enough preclinical and clinical pharmacokinetic and/or pharmacodynamic trials still delays their use in diabetic patients.

Lipid Flip-Flop-Inducing Antimicrobial Phytochemicals from Gymnema sylvestre are Bacterial Membrane Permeability Enhancers

An amphiphilic phytochemical fraction isolated from methanol extract of Gymnema sylvestre leaf powder contained six terpenoids, two flavonoids, and one alkaloid that induced rapid flip-flop of fluorescent phospholipid analog in the phosphatidyl choline bilayer. Lipid-flipping activity of the methanol-extracted fraction of G. sylvestre (MEFGS) was dose-dependent and time-dependent with a rate constant k = (12.09 ± 0.94) mg^-1 min^-1 that was saturable at (40 ± 1) % flipping of the fluorescent lipid analogue. Interactions of MEFGS phytochemicals with large unilamelar vesicles led to time-dependent change in their rounded morphology into irregular shapes, indicating their membrane-destabilizing activity. MEFGS exhibited antibacterial activity on Escherichia coli (MTCC-118), Staphylococcus aureus (MTCC-212), and Pseudomonas aeruginosa (MTCC-1035) with IC₅₀ values 0.5, 0.35, and 0.1 mg/mL, respectively. Phytochemicals in MEFGS increased membrane permeabilization in all three bacteria, as indicated by 23, 17, and 17% increase in the uptake of crystal violet, respectively. MEFGS enhanced membrane damage, resulting in a 3-5 fold increase in leakage of cytosolic ions, 0.5-2 fold increase in leakage of PO₄ ^-, and 15-20% increase in loss of cellular proteins. MEFGS synergistically increased the efficacy of curcumin, amoxillin, ampicillin, and cefotaxime on S. aureus probably by enhancing their permeability into the bacterium. For the first time, our study reveals that phytochemicals from G. sylvestre enhance the permeability of the bacterial plasma membrane by facilitating flip-flop of membrane lipids. Lipid-flipping phytochemicals from G. sylvestre can be used as adjuvant therapeutics to enhance the efficacy of antibacterials by increasing their bioavailability in the target bacteria.

In silico evaluation of naturally isolated triterpene glycosides (TG) from Gymnema sylvestre towards diabetic treatment

Diabetes is a metabolic disorder which is characterised by high levels of blood glucose. Most of the oral drugs available today for the treatment of diabetes are associated with various side-effects. Herbal medicines are considered relatively safer alternatives and Gymnema sylvestre (GS) is one such known traditional medicinal plant widely used for the treatment of diabetes. In our previous work, we isolated active triterpene glycosides (TG) from Gymnema sylvestre (GS) and screened for yeast α-glucosidase inhibitory activity in vitro. The present study aims to use in silico techniques to understand and predict the inhibitory role of the isolated triterpene glycosides (TG); Gymnemic acid I, IV, VII and gymnemagenin against disaccharidase enzymes. enzyme kinetic analysis using Lineweaver-Burk plot indicated that TG competitively inhibited yeast α-glucosidase at IC50 concentration with Ki 0.0028 μM. TG also exhibited significant inhibitory activity against mammalian sucrase and maltase respectively, compared to control.

PRACTICAL APPLICATIONS

The molecular docking simulation reveals that TG is capable of docking well with crystallographic structures of the selected enzyme targets. Inhibition of α-glucosidases could delay the absorption of glucose in the blood during post-meal digestion. Thus the current study highlights the dietary intervention of TG towards the selected enzyme targets, thus making TG a potential nutraceutical candidate towards management of blood glucose.

Inhibitory effects of Gymnema inodorum (Lour.) Decne leaf extracts and its triterpene saponin on carbohydrate digestion and intestinal glucose absorption

ETHNOPHARMACOLOGICAL RELEVANCE

Chiang-Da, Gymnema inodorum (Lour.) Decne. (GI), is an ethnomedicinal plant that has been used for diabetic treatment since ancient times. One of the anti-diabetic mechanisms is possibly related to the actions of triterpene glycoside, (3β, 16β)-16,28-dihydroxyolean-12-en-3-yl-O-β-D-glucopyranosyl-β-D-glucopyranosiduronic acid (GIA1) in decreasing carbohydrate digestive enzymes and intestinal glucose absorption in the gut system.

AIMS OF THE STUDY

To observe the amount of GIA1 in GI leaf extracts obtained from different ethanol concentrations and to investigate the anti-hyperglycemic mechanisms of the extracts and GIA1.

MATERIALS AND METHODS

The crude extracts were prepared using 50%v/v to 95%v/v ethanol solutions and used for GIA1 isolation. The anti-hyperglycemic models included in our study examined the inhibitory activities of α-amylase/α-glucosidase and intestinal glucose absorption related to sodium glucose cotransporter type 1 (SGLT1) using Caco-2 cells.

RESULTS

GIA1 was found about 8%w/w to 18%w/w in the GI extract depending on ethanol concentrations. The GI extracts and GIA1 showed less inhibitory activities on α-amylase. The extracts from 75%v/v and 95%v/v ethanol and GIA1 significantly delayed the glycemic absorption by lowering α-glucosidase activity and glucose transportation of SGLT1. However, the 50%v/v ethanolic extract markedly decreased the α-glucosidase activity than the SGLT1 function.

CONCLUSION

Differences in the GIA1 contents and anti-glycemic properties of the GI leaf extract was dependent on ethanol concentrations. Furthermore, the inhibitory effects of the 75%v/v and 95%v/v ethanolic extracts on α-glucosidase and SGLT1 were relevant to GIA1 content.

Plant-Based Antidiabetic Nanoformulations: The Emerging Paradigm for Effective Therapy

Diabetes mellitus is a life-threatening metabolic syndrome. Over the past few decades, the incidence of diabetes has climbed exponentially. Several therapeutic approaches have been undertaken, but the occurrence and risk still remain unabated. Several plant-derived small molecules have been proposed to be effective against diabetes and associated vascular complications via acting on several therapeutic targets. In addition, the biocompatibility of these phytochemicals increasingly enhances the interest of exploiting them as therapeutic negotiators. However, poor pharmacokinetic and biopharmaceutical attributes of these phytochemicals largely restrict their clinical usefulness as therapeutic agents. Several pharmaceutical attempts have been undertaken to enhance their compliance and therapeutic efficacy. In this regard, the application of nanotechnology has been proven to be the best approach to improve the compliance and clinical efficacy by overturning the pharmacokinetic and biopharmaceutical obstacles associated with the plant-derived antidiabetic agents. This review gives a comprehensive and up-to-date overview of the nanoformulations of phytochemicals in the management of diabetes and associated complications. The effects of nanosizing on pharmacokinetic, biopharmaceutical and therapeutic profiles of plant-derived small molecules, such as curcumin, resveratrol, naringenin, quercetin, apigenin, baicalin, luteolin, rosmarinic acid, berberine, gymnemic acid, emodin, scutellarin, catechins, thymoquinone, ferulic acid, stevioside, and others have been discussed comprehensively in this review.

Comprehensive Review on Phytochemicals, Pharmacological and Clinical Potentials of Gymnema sylvestre

Gymnema sylvestre is a plant included in Apocynaceae family and is located in many regions of Asia, Africa and Australia. This plant is widely used as a traditional therapy for different purposes. Even now it is being used as a dietary supplement due to its numerous therapeutic uses. It is known to have blood glucose lowering potential and, thus, is widely used in traditional and Ayurvedic systems of medicine. It renders glucose lowering activity due to the presence of phytochemicals, such as gurmarin, gymnemic acid as well as gymnemasaponins. Gymnema sylvestre is also known to have anti-oxidant, antibiotic, anti-inflammatory, antiviral, gastro and hepatoprotective, anticancer and lipid-lowering activities. This review discusses in details on different pharmacological and clinical potentials of Gymnema sylvestre and its chemical constituents associated with its therapeutic potentials.

Impact of Copper Oxide Nanoparticles on Enhancement of Bioactive Compounds Using Cell Suspension Cultures of Gymnema sylvestre (Retz.) R. Br

Gymnema sylvestre is a plant that is enriched in bioactive compounds. In particular, gymnemic acids (GA) and phenolic compounds (PC) are pharmaceutically important. There is a commercial demand for naturally occurring bioactive compounds, but their availability is limited due to geographical and seasonal variations. The elicitation approach can enhance the biosynthesis of phytochemicals during in vitro culture of G. sylvestre. Here, to further improve gymnemic acid II (GA II) and phenolic compounds (PC) production by G. sylvestre, cell suspension cultures (CSC), which has attracted attention for the production of essential phytochemicals, was explored using copper oxide nanoparticles (CuO NPs). Callus was obtained on MS medium containing 2,4-dichlorophenoxyacetic acid, kinetin, phytoagar, and sucrose. Agar-free MS medium was used to initiate CSC, which was treated with three concentrations of CuO NPs (1, 3 or 5 mg/L). Treatment for 48 h with 3 mg/L CuO NPs resulted in the greatest yields of GA II, total phenolics, and flavonoids. The cultures also displayed pronounced antioxidant, antidiabetic, anti-inflammatory, antibacterial, antifungal, and anticancer activities. The use of CuO NPs (3 mg/L) significantly increased the production of GA II (nine-fold) and PC compared to unamended CSC. We propose that CSC and use of nanoparticles (NPs) as a new generation of elicitors, offer a suitable prospect for the production of bioactive compounds.