Medicinal plants and phytochemicals for diabetes mellitus: pharmacokinetic characteristics and herb-drug interactions

Characterization of Plant-Derived Natural Inhibitors of Dipeptidyl Peptidase-4 as Potential Antidiabetic Agents: A Computational Study

Diabetes, characterized by elevated blood sugar levels, poses significant health and economic risks, correlating with complications like cardiovascular disease, kidney failure, and blindness. Dipeptidyl peptidase-4 (DPP-4), also referred to as T-cell activation antigen CD26 (EC 3.4.14.5.), plays a crucial role in glucose metabolism and immune function. Inhibiting DPP-4 was anticipated as a potential new therapy for diabetes. Therefore, identification of plant-based natural inhibitors of DPP-4 would help in eradicating diabetes worldwide. Here, for the identification of the potential natural inhibitors of DPP-4, we developed a phytochemicals library consisting of over 6000 phytochemicals detected in 81 medicinal plants that exhibited anti-diabetic potency. The library has been docked against the target proteins, where isorhamnetin, Benzyl 5-Amino-5-deoxy-2,3-O-isopropyl-alpha-D-mannofuranoside (DTXSID90724586), and 5-Oxo-7-[4-(trifluoromethyl) phenyl]-4H,6H,7H-[1,2]thiazolo[4,5-b]pyridine 3-carboxylic acid (CHEMBL3446108) showed binding affinities of -8.5, -8.3, and -8.3 kcal/mol, respectively. These compounds exhibiting strong interactions with DPP-4 active sites (Glu205, Glu206, Tyr547, Trp629, Ser630, Tyr662, His740) were identified. ADME/T and bioactivity predictions affirmed their pharmacological safety. Density functional theory calculations assessed stability and reactivity, while molecular dynamics simulations demonstrated persistent stability. Analyzing parameters like RMSD, RG, RMSF, SASA, H-bonds, MM-PBSA, and FEL confirmed stable protein-ligand compound formation. Principal component analysis provided structural variation insights. Our findings suggest that those compounds might be possible candidates for developing novel inhibitors targeting DPP-4 for treating diabetes.

Microwave-Promoted Total Synthesis of Puniceloid D for Modulating the Liver X Receptor

A growing global health concern is metabolic syndrome, which is defined by low HDL, diabetes, hypertension, and abdominal obesity. Nuclear receptors are attractive targets for treatment of diseases associated with metabolic syndrome. Liver X receptors (LXRs) have become one of the most significant pharmacological targets among nuclear receptors. Multiple research studies emphasize the essential function of the liver X receptor (LXR) in the pathophysiology of metabolic syndrome. Puniceloid D, among natural products, demonstrated promising effects on LXRα. However, attempts at the total synthesis of natural products were faced with challenges, including long synthetic steps and low yields, requiring a more efficient approach. In this study, for the first time, we successfully synthesized puniceloid D through a seven-step process and conducted docking studies to gain a comprehensive understanding of the interactions involved in the binding of puniceloid D to LXR within different heterodimeric contexts. Our understanding of the pathophysiology of metabolic syndrome could be improved by these findings, which might assist with the development of novel treatment strategies.

The antidiabetic effect of methanolic extract of Holarrhena pubescens seeds is mediated through multiple mechanisms of action

Holarrhena pubescens is widely used in Indian and Chinese medicine in the treatment of diabetes. The current work determined the oral hypoglycemic and antidiabetic effects of seed extract in rats. The probable mechanism of action was evaluated in-vitro by α - glucosidase inhibition, glucose metabolism in insulinoma (INS-1) cells to reflect secretion of insulin, and protein glycation inhibition. Its potential for herb-drug interaction was evaluated in the cytochrome P450 3A4 (CYP3A4) inhibition assay. The seed extract increased serum insulin levels and reduced serum blood glucose levels in the oral glucose tolerance test. It also reduced the serum glucose levels in streptozocin-induced diabetes. The extract also inhibited α -glucosidase enzyme activity and demonstrated that it can increase the secretion of insulin from INS to 1-rat insulinoma cell line cells in-vitro in a concentration-dependent manner. However, it had a very weak inhibitory effect on protein glycation and it did not affect the activity of CYP3A4. The results of the study showed that H. pubescens seed extract increases insulin secretion and inhibits glucose absorption both in-vivo and in-vitro with a weak protein glycation inhibitory effect. The herb is devoid of CYP3A4 inhibitory effect indicating that it may not have pharmacokinetic interaction with the drug metabolized by this enzyme.

Regulation of reactive oxygen species by phytochemicals for the management of cancer and diabetes

Cancer and diabetes mellitus are served as typical life-threatening diseases with common risk factors. Developing therapeutic measures in cancers and diabetes have aroused attention for a long time. However, the problems with conventional treatments are in challenge, including side effects, economic burdens, and patient compliance. It is essential to secure safe and efficient therapeutic methods to overcome these issues. As an alternative method, antioxidant and pro-oxidant properties of phytochemicals from edible plants have come to the fore. Phytochemicals are naturally occurring compounds, considered promising agent applicable in treatment of various diseases with beneficial effects. Either antioxidative or pro-oxidative activity of various phytochemicals were found to contribute to regulation of cell proliferation, differentiation, cell cycle arrest, and apoptosis, which can exert preventive and therapeutic effects against cancer and diabetes. In this article, the antioxidant or pro-oxidant effects and underlying mechanisms of flavonoids, alkaloids, and saponins in cancer or diabetic models demonstrated by the recent studies are summarized.

Possible Synergistic Antidiabetic Effects of Quantified Artemisia judaica Extract and Glyburide in Streptozotocin-Induced Diabetic Rats via Restoration of PPAR-α mRNA Expression

Simple Summary

A considerable number of diabetic patients are in favour of using oral antidiabetic drugs in combination with certain herbs instead of using oral antidiabetic drugs alone. Artemisia judaica (AJ) is one of the herbs documented to have antidiabetic effects. This study examined the effect of using combination of A. judaica extract (AJE) and the oral hypoglycemic drug glyburide (GLB, 5 mg/kg) on diabetic rats. Fasting blood glucose (FBG), insulin levels, glycated hemoglobin (HbA1c) percentage, serum lipid profile, and oxidative stress biomarkers were estimated. The histopathological examination of the pancreas and the immunohistochemical analysis of anti-insulin, anti-glucagon, and anti-somatostatin protein expressions were also performed. The analysis of the hepatic mRNA expression of peroxisome proliferator-activated receptor α (PPAR-α) and nuclear factor erythroid 2-related factor-2 (Nrf2) genes was performed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Combination of GLB and 500 mg/kg of AJE highly improved FBG, insulin levels, HbA1c, and lipid profile in blood when compared with GLB monotherapy. Furthermore, GLB plus 500 mg/kg of AJE combination was the most successful in restoring insulin content in the β-cells and diminished the levels of glucagon and somatostatin of the α- and δ-endocrine cells in the pancreatic islets, restoring PPAR-α and Nrf2 mRNA expression in the liver. In conclusion, these data indicate that GLB plus 500 mg/kg of AJE combination gives greater glycemic improvement than GLB monotherapy.

Abstract

Several members of the genus Artemisia are used in both Western and African traditional medicine for the control of diabetes. A considerable number of diabetic patients switch to using oral antidiabetic drugs in combination with certain herbs instead of using oral antidiabetic drugs alone. This study examined the effect of Artemisia judaica extract (AJE) on the antidiabetic activity of glyburide (GLB) in streptozotocin (STZ)-induced diabetes. Forty-two male Wistar rats were divided into seven equal groups. Normal rats of the first group were treated with the vehicle. The diabetic rats in the second–fifth groups received vehicle, GLB (5 mg/kg), AJE low dose (250 mg/kg), and AJE high dose (500 mg/kg), respectively. Groups sixth–seventh were treated with combinations of GLB plus the lower dose of AJE and GLB plus the higher dose of AJE, respectively. All administrations were done orally for eight weeks. Fasting blood glucose (FBG) and insulin levels, glycated hemoglobin (HbA1c) percentage, serum lipid profile, and biomarkers of oxidative stress were estimated. The histopathological examination of the pancreas and the immunohistochemical analysis of anti-insulin, anti-glucagon, and anti-somatostatin protein expressions were also performed. The analysis of the hepatic mRNA expression of PPAR-α and Nrf2 genes were performed using quantitative RT-PCR. All treatments significantly lowered FBG levels when compared with the STZ-control group with the highest percentage reduction exhibited by the GLB plus AJE high dose combination. This combination highly improved insulin levels, HbA1c, and lipid profile in blood of diabetic rats compared to GLB monotherapy. In addition, all medicaments restored insulin content in the β-cells and diminished the levels of glucagon and somatostatin of the α- and δ-endocrine cells in the pancreatic islets. Furthermore, the GLB plus AJE high dose combination was the most successful in restoring PPAR-α and Nrf2 mRNA expression in the liver. In conclusion, these data indicate that the GLB plus AJE high dose combination gives greater glycemic improvement in male Wistar rats than GLB monotherapy.

Assessment of Metabolic Interaction between Repaglinide and Quercetin via Mixed Inhibition in the Liver: In Vitro and In Vivo

Repaglinide (RPG), a rapid-acting meglitinide analog, is an oral hypoglycemic agent for patients with type 2 diabetes mellitus. Quercetin (QCT) is a well-known antioxidant and antidiabetic flavonoid that has been used as an important ingredient in many functional foods and complementary medicines. This study aimed to comprehensively investigate the effects of QCT on the metabolism of RPG and its underlying mechanisms. The mean (range) IC₅₀ of QCT on the microsomal metabolism of RPG was estimated to be 16.7 (13.0–18.6) μM in the rat liver microsome (RLM) and 3.0 (1.53–5.44) μM in the human liver microsome (HLM). The type of inhibition exhibited by QCT on RPG metabolism was determined to be a mixed inhibition with a K_i of 72.0 μM in RLM and 24.2 μM in HLM as obtained through relevant graphical and enzyme inhibition model-based analyses. Furthermore, the area under the plasma concentration versus time curve (AUC) and peak plasma concentration (C_max) of RPG administered intravenously and orally in rats were significantly increased by 1.83- and 1.88-fold, respectively, after concurrent administration with QCT. As the protein binding and blood distribution of RPG were observed to be unaltered by QCT, it is plausible that the hepatic first-pass and systemic metabolism of RPG could have been inhibited by QCT, resulting in the increased systemic exposure (AUC and C_max) of RPG. These results suggest that there is a possibility that clinically significant pharmacokinetic interactions between QCT and RPG could occur, depending on the extent and duration of QCT intake from foods and dietary supplements.

Impacts of Drug Interactions on Pharmacokinetics and the Brain Transporters: A Recent Review of Natural Compound-Drug Interactions in Brain Disorders

Natural compounds such as herbal medicines and/or phyto-compounds from foods, have frequently been used to exert synergistic therapeutic effects with anti-brain disorder drugs, supplement the effects of nutrients, and boost the immune system. However, co-administration of natural compounds with the drugs can cause synergistic toxicity or impeditive drug interactions due to changes in pharmacokinetic properties (e.g., absorption, metabolism, and excretion) and various drug transporters, particularly brain transporters. In this review, natural compound–drug interactions (NDIs), which can occur during the treatment of brain disorders, are emphasized from the perspective of pharmacokinetics and cellular transport. In addition, the challenges emanating from NDIs and recent approaches are discussed.

Onion Extract Encapsulated on Nano Chitosan: a Promising Anticancer Agent

BACKGROUND

Onion (Allium cepa) is very rich in nutritional and pharmaceutical components, such as saponins, tannins, alkaloids, steroids, and phenols. Many recent researches approved its anticancer activity against various cancer cell lines. In this paper, we attempt to improve its anticancer activity with encapsulation on nano chitosan. On the best of our knowledge, this is considered the first study that tries to increase the anticancer activity of the onion extract on nano chitosan.

METHODS

An aqueous extract of the onion was prepared and the extract efficiency as anticancer agent was enhanced by encapsulating the extract on nano chitosan. The antioxidant capacity and the functional ingredients such as alkaloid, tannin, saponin, steroid, phenolic, and flavonoid in either the free or encapsulated one were estimated. Also, the anticancer activity of the two extracts was tested against different cell lines.

RESULTS

Encapsulation of the extract on chitosan nano particles decreased IC₅₀ in different cell lines and induced apoptosis through decreasing BCL-2 level and increasing caspase-3 and caspase-9 activity.

CONCLUSION

Onion extract encapsulated on nano chitosan can be used as protective agents from cancer, antitumor, or act synergistically with the cancer chemotherapy. This greatly participates in improving the use of natural products in cancer therapy instead of chemotherapy.

Phenolome of Asian Agrimony Tea (Agrimonia asiatica Juz., Rosaceae): LC-MS Profile, α-Glucosidase Inhibitory Potential and Stability

Functional beverages constitute the rapidly increasing part of the functional food section and represent an area with a wide range of products including herbal-based beverages. We carried out screening investigations of the extracts of 85 Rosaceous tea plants. Among the extracts analyzed Agrimonia asiatica herb extract demonstrated the highest inhibitory activity against the enzyme α-glucosidase (20.29 µg/mL). As a result of chromato-mass-spectrometric profiling of A. asiatica herb with high-performance liquid chromatography with photodiode array and electrospray triple quadrupole mass-spectrometric detection (HPLC-PDA-ESI-tQ-MS) 60 compounds were identified, including catechins, ellagitannins, flavones, flavonols, gallotannins, hydroxycinnamates, procyanidins, most for the very first time. The analysis of the seasonal variation of metabolites in A. asiatica herb demonstrated that the phenolic content was highest in summer samples and lower in spring and autumn. HPLC activity-based profiling was utilized to identify compounds of A. asiatica herb with the maximal α-glucosidase inhibitory activity. The most pronounced inhibition of α-glucosidase was observed for agrimoniin, while less significant results of inhibition were revealed for ellagic acid and isoquercitrin. The evaluation of phenolic content in A. asiatica herbal teas with the subsequent determination of α-glucosidase inhibiting potential was discovered. Maximum inhibition of α-glucosidase was observed for hot infusion (75.33 µg/mL) and the minimum for 30 min decoction (159.14 µg/mL). Our study demonstrated that A. asiatica herbal tea is a prospective functional beverage in which dietary intake may help to reduce blood glucose.

Genetic engineering of novel super long-acting Exendin-4 chimeric protein for effective treatment of metabolic and cognitive complications of obesity

A common bottleneck challenge for many therapeutic proteins lies in their short plasma half-lives, which often makes the treatment far less compliant or even disables achieving sufficient therapeutic efficacy. To address this problem, we introduce a novel drug delivery strategy based on the genetic fusion of an albumin binding domain (ABD) and an anti-neonatal Fc receptor (FcRn) affibody (AFF) to therapeutic proteins. This ABD-AFF fusion strategy can provide a synergistic effect on extending the plasma residence time by, on one hand, preventing the rapid glomerular filtration via ABD-mediated albumin binding and, on the other hand, increasing the efficiency of FcRn-mediated recycling by AFF-mediated high-affinity binding to the FcRn. In this research, we explored the feasibility of applying the ABD-AFF fusion strategy to exendin-4 (EX), a clinically available anti-diabetic peptide possessing a short plasma half-life. The EX-ABD-AFF produced from the E. coli displayed a remarkably (241-fold) longer plasma half-life than the SUMO tagged-EX (SUMO-EX) (0.7 h) in mice. Furthermore, in high-fat diet (HFD)-fed obese mice model, the EX-ABD-AFF could provide significant hypoglycemic effects for over 12 days, accompanied by a reduction of body weight. In the long-term study, the EX-ABD-AFF could significantly reverse the obesity-related metabolic complications (hyperglycemia, hyperlipidemia, and hepatic steatosis) and, moreover, improve cognitive deficits. Overall, this study demonstrated that the ABD-AFF fusion could be an effective strategy to greatly increase the plasma half-lives of therapeutic proteins and thus markedly improve their druggability.

Enhanced oral delivery of insulin via the colon-targeted nanocomposite system of organoclay/glycol chitosan/Eudragit®S100

This study aimed to develop a ternary nanocomposite system of organoclay, glycol-chitosan, and Eudragit^®S100 as an effective colon targeted drug delivery carrier to enhance the oral absorption of insulin. A nanocomplex of insulin and aminoclay was prepared via spontaneous co-assembly, which was then coated with glycol-chitosan and Eudragit S^®100 (EGAC-Ins). The double coated nanocomplex, EGAC-Ins demonstrated a high entrapment efficiency of greater than 90% and a pH-dependent drug release. The conformational stability of insulin entrapped in EGAC-Ins was effectively maintained in the presence of proteolytic enzymes. When compared to a free insulin solution, EGAC-Ins enhanced drug permeability by approximately sevenfold in Caco-2 cells and enhanced colonic drug absorption in rats. Accordingly, oral EGAC-Ins significantly reduced blood glucose levels in diabetic rats while the hypoglycemic effect of an oral insulin solution was negligible. In conclusion, EGAC-Ins should be a promising colonic delivery system for improving the oral absorption of insulin.

Antihyperlipidemic and Antioxidative Properties of Pistacia atlantica subsp. kurdica in Streptozotocin-Induced Diabetic Mice

INTRODUCTION

Pistacia atlantica subsp. kurdica is an important food source and a well-known medicinal plant in the Zagros Mountains of Iran. The present study aimed to investigate the effect of P. atlantica extract and essential oil in streptozotocin-induced diabetic mice.

MATERIALS AND METHODS

Different doses of hydroalcoholic extract and essential oil of P. atlantica subsp. kurdica (50, 100, and 200 mg/kg) were given to streptozotocin-induced diabetic mice in separate groups for three weeks. At the end of treatment, blood samples were collected; then, oxidative stress markers, TNF-α, and lipid profile were determined in its serum samples.

RESULTS

Our findings showed that the administration of P. atlantica extract for three consecutive weeks significantly improved the lipid profile, oxidative stress, and inflammation process by reducing lipid peroxidation and increasing total antioxidant capacity.

CONCLUSION

This study showed that P. atlantica subsp. kurdica has antioxidant and blood lipid-lowering effects that can be used as a supplement to improve diabetes complications.