Effects of Gymnema sylvestre extract on the pharmacokinetics and pharmacodynamics of glimepiride in streptozotocin induced diabetic rats

Evaluation of pharmacokinetic herb-drug interaction of diabecon and losartan by UHPLC-MS/MS

The diabecon is an ayurvedic herbal formulation that contains a mixture of herbs traditionally used as antidiabetic which is reported in the ayurvedic pharmacopeia of India and Indian Materia medica. The diabetic population has a common co-morbidity of hypertension for which losartan drug is commonly used for the treatment of hypertension. However, there is a lack of research on the pharmacokinetics interaction between diabecon and losartan. This research aims to investigate the influence of diabecon on the pharmacokinetics of losartan drugs in rats by establishing a highly sensitive ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry (UHPLC-MS/MS) method. The method was validated according to the USFDA guidelines and was applied for the pharmacokinetic study. The lowest concentration of losartan detection in rat plasma was found to be 1 ng/mL and the accuracy and precision were within the linear range (1-1500 ng/mL). The results revealed that after 28 days of dosing diabecon, it has altered the pharmacokinetic parameters like area under the curve (AUC0-t), drug clearance (Cl/F), and rate of elimination (Ke) of losartan, which may happen due to enzyme induction. Although there was a change in the pharmacokinetic parameters of losartan when administered in the presence of diabecon, it was found to be nonsignificant in rats (p > 0.05). According to the best of our knowledge, this is the first article that discusses the pharmacokinetic herb-drug interaction between diabecon and losartan.

Effect of herbal formulation on glimepiride pharmacokinetics and pharmacodynamics in nicotinamide-streptozotocin-induced diabetic rats

BACKGROUND

Traditional medicinal herbs are widely consumed in developing countries to treat diabetes as they are perceived to be safer, less expensive, and have fewer side effects as compared to the conventional medicines. Diabecon (DB), Himalaya Herbal Healthcare, India is herbal over-the-counter formulation which contains several herbs that are reported in the traditional texts for the treatment of diabetes. The majority of these herbs have been investigated and found to interfere with the cytochrome pathway. The most common oral antihyperglycemic drug used today in clinical practice is Glimepiride (GP).The CYP2C9 enzyme is mainly responsible for the metabolism of GP. Herein we hypothesize that the co-administration of GP with DB may result in possible Herb-Drug Interactions (HDIs) as DB has the potential to significantly inhibit the CYP2C9 enzyme.

OBJECTIVE

In the current study, the pharmacokinetic and pharmacodynamic interactions of GP (0.82 mg/kg) with DB (110.95 mg/kg) was investigated in diabetes induced (Nicotinamide-STZ) rats by co-administering both drugs orally for 21 days.

MATERIALS AND METHODS

For the study of the HDI, Bioanalytical RP-HPLC/PDA method for quantifying GP in plasma of rats was developed and validated as per US-FDA guidelines. In vivo pharmacokinetic and pharmacodynamic parameters were studied on day 1 and day 21 post administration.

RESULTS

The RP-HPLC/PDA method was successfully employed for quantification of GP in the PK studies. The co-administration of GP and DB in diabetic rats resulted in beneficial pharmacodynamic interactions, but there were no notable changes in the pharmacokinetic parameters of GP.

CONCLUSION

This current investigation in an animal model suggests that co-administration of GP and DB may have significant therapeutic benefits in the treatment of diabetes; however, additional research, randomized clinical trials or case studies in humans, is needed.

Herb-drug interactions in diabetes mellitus: A review based on pre-clinical and clinical data

Global diabetes epidemic is the major cause of fatality and lethality. As per IDF 2019 report, diabetes caused 4.2 million deaths, approximately 463 million people are living with diabetes and by 2045, this will rise to 700 million. Nowadays, the physicians and common people in both developed and developing countries are using medicinal plants and their formulations to treat diseases with the postulation that organic commodities are safe for consumption. These plants may act as inhibitors or inducers of the Cytochrome P450 or transport and efflux proteins or both and may alter gastrointestinal, renal functions leading to Herb-Drug Interactions. This review intends to focus on the frequently employed medicinal plants, their traditional uses, their Cytochrome P450 inhibition or induction activity, phytochemical, and pharmacological effects, established HDI with the help of in vitro tools, in vivo pharmacokinetics and pharmacodynamics studies to understand the impact of herbs on ADME of the drug and whether it is beneficial, harmful or has no effect respectively. This review will help the physicians and other health care professionals as a reference guide to update their knowledge and expertise about HDI. However, more quality research in this area is needed to evaluate the efficacy of many herbal medicines, thereby reducing side effects and improving the safety of patients.

β-cell replenishment: Possible curative approaches for diabetes mellitus

AIMS

Diabetes mellitus (DM) is a disorder of heterogeneous etiology marked by persistent hyperglycemia. Exogenous insulin is the only treatment for type 1 diabetes (T1D). Islet transplantation is a potential long cure for T1D but is disapproved due to the possibility of immune rejection in the later stage. The approaches used for treating type 2 diabetes (T2D) include diet restrictions, weight management and pharmacological interventions. These procedures have not been able to boost the quality of life for diabetic patients owing to the complexity of the disorder.

DATA SYNTHESIS

Hence, research has embarked on permanent ways of managing, or even curing the disease. One of the possible approaches to restore the pancreas with new glucose-responsive β-cells is by their regeneration. Regeneration of β-cells include islet neogenesis, dedifferentiation, and trans-differentiation of the already differentiated cells.

CONCLUSIONS

This review briefly describes the islet development, functions of β-cells, mechanism and factors involved in β-cell death. It further elaborates on the potential of the existing and possible therapeutic modalities involved in the in-vivo replenishment of β-cells with a focus on exercise, diet, hormones, small molecules, and phytochemicals.

Pharmacokinetic Interaction of Green Rooibos Extract With Atorvastatin and Metformin in Rats

An aspalathin-rich green rooibos extract (Afriplex GRT™) has demonstrated anti-diabetic and hypolipidemic properties, while also moderately inhibiting CYP3A4 activity, suggesting a potential for herb-drug interaction. The present study, therefore, evaluated the effects of orally administered GRT on the pharmacokinetics of atorvastatin and metformin in Wistar rats. Wistar rats were orally treated with GRT (50 mg/kg BW), atorvastatin (40 mg/kg BW) or metformin (150 mg/kg BW) alone or 50 mg/kg BW GRT in combination with 40 mg/kg BW atorvastatin or 150 mg/kg BW metformin. Blood samples were collected at 0, 10, and 30 min and 1, 2, 4, 6, and 8 h and plasma samples obtained for Liquid chromatography-mass spectrometry (LC-MS/MS) analyses. Non-compartment and two-compartment pharmacokinetic parameters of atorvastatin and metformin in the presence or absence of GRT were determined by PKSolver version 2.0 software. Membrane transporter proteins, ATP-binding cassette sub-family C member 2 (Abcc2), solute carrier organic anion transporter family, member 1b2 (Slco1b2), ATP-binding cassette, sub-family B (MDR/TAP), member 1A (Abcb1a), and organic cation transporter 1 (Oct1) mRNA expression were determined using real-time PCR expression data normalized to β-actin and hypoxanthine-guanine phosphoribosyltransferase (HPRT), respectively. Co-administration of GRT with atorvastatin substantially increased the maximum plasma concentration (C_max) and area of the plasma concentration-time curve (AUC_0-8) of atorvastatin by 5.8-fold (p = 0.03) and 5.9-fold (p = 0.02), respectively. GRT had no effect on the plasma levels of metformin. GRT increased Abcc2 expression and metformin downregulated Abcb1a expression while the combination of GRT with atorvastatin or metformin did not significantly alter the expression of Slco1b1 or Oct1 did not significantly alter the expression of Sclo1b2 or Oct1. Co-administration of GRT with atorvastatin in rats may lead to higher plasma concentrations and, therefore, to an increase of the exposure to atorvastatin.

Pharmacokinetics of a novel microtubule inhibitor mHA11 in rats

mHA11, a 2-amino-4-phenyl-4H-chromene-3-carboxylate analog, is a microtubule-targeting agent discovered by our group through the modification of the Bcl-2 inhibitor HA14-1. mHA11 exhibits cytotoxicities against tumor cells with nM IC₅₀ values, whereas it has only a minimal effect on normal cells. We explored the plasma pharmacokinetics, tissue distribution, and excretion of mHA11 in rats using a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method. Next, we identified the metabolites of mHA11 and assessed the influence of cytochrome P450 (CYP) isozymes on mHA11 metabolism. We also examined the in vitro stability in rat plasma and rat liver microsomes (RLMs), the blood-to plasma (B/P) ratio, and the inhibitory effect on CYP isozyme activities. After oral administration at 5, 15, and 45 mg/kg, mHA11 was absorbed and eliminated rapidly. There was a linear correlation between the area under the concentration-time curve (AUC_0-∞) and the dose (R² = 0.983). The bioavailability of mHA11 was 4.1% at the oral dose of 15 mg/kg mHA11 was extensively distributed in various tissues and exhibited a high penetration into the brain. No significant parent drug was detected in urine or bile, and only 0.74% was recovered in feces, whereas two demethylated metabolites, M1 and M2, were found in the urine and feces, and further studies showed that CYP2C19 primarily contributed to metabolites formation. mHA11 was stable in rat plasma but degraded significantly in RLMs; its B/P ratio was 1.05 in rat blood. In addition, mHA11 dose-dependently inhibited the activities of rat CYP isozymes, including CYP1A2, CYP2C6, CYP2C11, CYP2D2, CYP2E1 and CYP3A2. The present study is the first report on the disposition of mHA11 in rats and provides important data for further research and development of this inhibitor.

Influence Factors of the Pharmacokinetics of Herbal Resourced Compounds in Clinical Practice

Herbal medicines have been used to prevent and cure diseases in eastern countries for thousands of years. In recent decades, these phytotherapies are becoming more and more popular in the West. As being nature-derived is the essential attribute of herbal medicines, people believe that taking them for diseases treatment is safe enough and has no side-effects. However, the efficacy of herbal resourced compounds (HRC) depends on the multiple constituents absorbed in the body and their pharmacokinetics. Thus, many factors will influence the clinical practice of HRC, i.e., their absorption, distribution, metabolism, and excretion (ADME). Among these factors, herb-drug interaction has been widely discussed, as these compounds may share the same drug-metabolizing enzymes and drug transporters. Meanwhile there are many other potential factors that can also change the ADME of HRC, including herb pretreatment, herb-herb interactions, pathological status, gender, age of patient, and chemical and physical modification of certain ingredients. With the aim of ensuring the efficacy of HRC and minimizing their clinical risks, this review provides and discusses the influence factors and artificial improvement of the pharmacokinetics of HRC.

Design, optimization, characterization and in-vivo evaluation of Quercetin enveloped Soluplus®/P407 micelles in diabetes treatment

Quercetin (Qu), is a flavonoid known to have anti-diabetic effects owing to its antioxidant property, thus promoting regeneration of the pancreatic islets, ultimately increasing insulin secretion. But the therapeutic application of Qu is hampered by its low oral bioavailability and its unfavourable physicochemical characteristics. The present work aimed at formulation of Quercetin loaded Soluplus® micelles (SMs) so as to enhance its bioavailability and provide prolonged release for the management of diabetes. Box-Behnken response surface methodology was employed to optimize the formulation prepared using co-solvent evaporation method. Physicochemical characterization confirmed the nano-spherical nature of Quercetin loaded Soluplus® micelles (Qu-SMs) with average particle size ranging from 85-108nm, encapsulation efficiency of 63-77%. Solid state characterization confirmed the encapsulation of Qu in the micelles without any incompatibilities. Moving forward, the results of in vitro study revealed prolonged and slow release of Qu from the developed formulations. The in vivo pharmacokinetic study revealed improved bioavailability by enveloping the drug in SMs. Moreover, the study performed to evaluate the efficiency in diabetes treatment revealed an enhanced anti-diabetic effect. Thus, Qu-SMs can serve as potential carriers aimed at improving the anti-diabetic property of Qu.

Active phytoconstituents for diabetes management: A review

Diabetes is a metabolic syndrome increasing rapidly due to occupational stress, lack of physical activity, sedentary lifestyle and increasing occurrence of obesity, associated with rapidly growing urbanization and industrialization. Due to erroneous carbohydrate metabolism, diabetics are more prone to chronic complications like nephropathy, neuropathy, retinopathy, coronary artery disease and peripheral arterial disease resulting in tissue damage. Current treatment protocols to these problems produce more serious adverse effects and are costly too. Medicinal plants provide an alternative of safe, reliable and cost-effective pharmacological source to all these ailments. This review provides the compiled data of isolated active phytoconstituents of 22 potent antidiabetic plants with their plant-part used, which might be useful for drug development.

Risk assessment of substances used in food supplements: the example of the botanical Gymnema sylvestre

Botanicals and preparations derived from these are among the substances frequently added to foods and food supplements, yet the safety of many botanicals has not been systematically assessed. In the context of the EU‐FORA fellowship programme, the fellow performed an assessment on the safety of the botanical Gymnema sylvestre, in accordance with EFSA's guidance on the assessment of safety of botanicals. Although preparations of G. sylvestre are marketed as food supplements, they may appeal to people who are suffering from metabolic syndrome and/or diabetes mellitus. A scientific literature search was carried out using PubMed/MEDLINE and EMBASE electronic databases. Experience was gained by the fellow in systematic data extraction from scientific publications, structuring of the data and evaluating toxicological key parameters, outcomes of clinical significance, pharmacokinetic and pharmacodynamic interactions, uncertainties and methodological shortcomings of studies. Limited evidence from toxicological in vivo studies and human clinical studies suggested lack of relevant adverse effects of this botanical. However, human studies provided some indications that certain Gymnema extracts may enhance the glucose‐lowering effects of certain antidiabetic drugs. Considering the uncertainties for the composition of different Gymnema preparations, potential herb–drug interactions and the indications of glucose lowering or hypoglycaemic effects, the use of Gymnema‐based food supplements in combination with authorised antidiabetic drugs may be associated with risks. The procedures learned for the safety evaluation of Gymnema may be similarly applied by the fellow for the risk assessment of other substances with nutritional or physiological effect added to foods and food supplements. Furthermore, apart from learning by conducting exercises in risk assessment, the fellow was able to develop other skills (e.g. communication skills), diversify his competencies and expand his network of scientific connections for future collaborations in the field of nutritional risk assessment.

In vivo pharmacokinetic interaction by ethanolic extract of Gymnema sylvestre with CYP2C9 (Tolbutamide), CYP3A4 (Amlodipine) and CYP1A2 (Phenacetin) in rats

Gymnema sylvestre (GS) is a medicinal herb used for diabetes mellitus (DM). Herbs are gaining popularity as medicines in DM for its safety purpose. The aim of the present study was to evaluate in vivo pharmacokinetic (PK) interaction between allopathic drugs tolbutamide (TOLBU), amlodipine (AMLO), and phenacetin (PHENA) at low (L) and high (H) doses with ethanolic extract (EL) from GS. EL was extracted and subjected to TLC, total triterpenoid content (19.76 ± 0.02 W/W) and sterol content (0.1837 ± 0.0046 W/W) estimation followed by identification of phytoconstituents using HRLC-MS and GC-MS. PK interaction study with CYP2C9, CYP3A4 and CYP1A2 enzymes were assessed using TOLBU, AMLO and PHENA respectively to index cytochrome (CYP) mediated interaction in rats after concomitant administration of EL extract (400 mg/kg) from GS for 7 days. The rats were divided into four groups for each PK study where, group I and II were positive control for low and high dose of test drugs (CYP substrates) while group II and IV were orally administered EL. The PK study result of PHENA indicated that area under the plasma concentration-time curve (AUC_0-24) was significantly (P < 0.0001) increased by 1.4 (L) and 1.3-fold (H), plasma concentration (C_max) was significantly (P < 0.001) increased by 1.6 (L) and 1.4-fold (H). Whereas for TOLBU; clearance rate (CL) was significantly (P < 0.0001) decreased by 2.4 (L) and 2.3-fold (H), C_max, was significantly (P < 0.001) decreased by 26.5% (L) and 50.4% (H) and AUC_0-24 was significantly (P < 0.0001) decreased by 59.8% (L) and 57.5% (H). Thus, EL is seen to be interacting with CYP1A2 by inhibiting its metabolic activity. HRLC-MS and GC-MS helped identify the presence of gymnemic acid (GA), triterpenoids and steroids in EL which could be the reason for PK interaction of CYP1A2 and CYP2C9. Also, in silico structure based site of metabolism study showed Fe accessibility and intrinsic activity for GA-IV, GA-VI, GA-VII and GA-X with CYP2C9. PK parameters of AMLO were not significantly affected by pre-treatment of EL. Thereby our findings indicate that co-administration of GS with drugs that are metabolized by CYP2C9 and CYP1A2 could lead to potential HDI.

An Overview of Herbal Products and Secondary Metabolites Used for Management of Type Two Diabetes

Diabetes mellitus is a common effect of uncontrolled high blood sugar and it is associated with long-term damage, dysfunction, and failure of various organs. In the adult population, the global prevalence of diabetes has nearly doubled since 1980. Without effective prevention and management programs, the continuing significant rise in diabetes will have grave consequences on the health and lifespan of the world population, and also on the world economy. Supplements can be used to correct nutritional deficiencies or to maintain an adequate intake of certain nutrients. These are often used as treatments for diabetes, sometimes because they have lower costs, or are more accessible or "natural" compared to prescribed medications. Several vitamins, minerals, botanicals, and secondary metabolites have been reported to elicit beneficial effects in hypoglycemic actions in vivo and in vitro; however, the data remain conflicting. Many pharmaceuticals commonly used today are structurally derived from natural compounds from traditional medicinal plants. Botanicals that are most frequently used to help manage blood glucose include: bitter melon (Momordica charantia), fenugreek (Trigonella foenum graecum), gurmar (Gymnema sylvestre), ivy gourd (Coccinia indica), nopal (Opuntia spp.), ginseng, Russian tarragon (Artemisia dracunculus), cinnamon (Cinnamomum cassia), psyllium (Plantago ovata), and garlic (Allium sativum). In majority of the herbal products and secondary metabolites used in treating diabetes, the mechanisms of action involve regulation of insulin signaling pathways, translocation of GLUT-4 receptor and/or activation the PPARγ. Several flavonoids inhibit glucose absorption by inhibiting intestinal α-amylase and α-glucosidase. In-depth studies to validate the efficacies and safeties of extracts of these traditional medicinal plants are needed, and large, well designed, clinical studies need to be carried out before the use of such preparations can be recommended for treatment and/or prevention of diabetes. The main focus of this review is to describe what we know to date of the active compounds in these, along with their glucose-lowering mechanisms, which are either through insulin-mimicking activity or enhanced glucose uptake.

Recent advances in pharmacokinetics approach for herbal medicine

Traditional Chinese Medicine (TCM), an indispensable part of herbal medicine, has been used for treating many diseases and/or symptoms for thousands of years.