Furostanol saponins from Asparagus racemosus as potential hypoglycemic agents

Antitubercular evaluation of dihydropyridine-triazole conjugates: design, synthesis, in vitro screening, SAR and in silico ADME predictions

This study investigates the potential of click chemistry for the development of novel anti-tuberculosis agents. A targeted library of 1,4-dihydropyridine-1,2,3-triazole conjugates was synthesized and evaluated for their in vitro activity against Mycobacterium tuberculosis H37Ra using the resazurin microtiter assay (REMA). Among the synthesized derivatives, compounds J10, J11, J14, J22 and J23 demonstrated significant antimycobacterial activity. These compounds exhibited low MIC values ranging from 6.24 to 6.64 μg mL-1, highlighting their promising potential as lead compounds for further developing novel tuberculosis therapeutics. In addition to the promising in vitro activity, structure-activity relationship (SAR) analysis revealed that electron-withdrawing groups on the aryl-substituted ring of the dihydropyridines (J10-J24), a triazole with an unsubstituted aryl ring or with electron-donating groups (methyl or methoxy), and a geminal dimethyl group are essential structural features for the observed antitubercular activity. Furthermore, in silico ADME (absorption, distribution, metabolism, and excretion) parameters and pharmacokinetic studies supported the potential of these conjugates for oral bioavailability. These findings collectively highlight the 1,4-dihydropyridine-1,2,3-triazole scaffold as a promising platform for developing novel orally active anti-tuberculosis drugs.

Design, Synthesis, and Biological Evaluation of 1,4-Dihydropyridine-Indole as a Potential Antidiabetic Agent via GLUT4 Translocation Stimulation

In the quest for the discovery of antidiabetic compounds, a series of 27 1,4-dihydropyridine-indole derivatives were synthesized using a diversity approach. These compounds were systematically evaluated for their antidiabetic activity, starting with an in vitro assessment for GLUT4 translocation stimulation in L6-GLUT4myc myotubes, followed by in vivo antihyperglycemic activity evaluation in a streptozotocin (STZ)-induced diabetic rat model. Among the synthesized compounds, 12, 14, 15, 16, 19, 27, and 35 demonstrated significant potential to stimulate GLUT4 translocation in skeletal muscle cells. Compound 19 exhibited the highest potency and was selected for in vivo evaluation. A notable reduction of 21.6% (p < 0.01) in blood glucose levels was observed after 5 h of treatment with compound 19 in STZ-induced diabetic rats. Furthermore, pharmacokinetic studies affirmed that compound 19 was favorable to oral exposure with suitable pharmacological parameters. Overall, compound 19 emerged as a promising lead compound for further structural modification and optimization.

Anti-obesity and anti-diabetic bioactive peptides: A comprehensive review of their sources, properties, and techno-functional challenges

The scourge of obesity arising from obesogens and poor dieting still ravages our planet as half of the global population may be overweight and obese by 2035. This metabolic disorder is intertwined with type 2 diabetes (T2D), both of which warrant alternative therapeutic options other than clinically approved drugs like orlistat with their tendency of abuse and side effects. In this review, we comprehensively describe the global obesity problem and its connection to T2D. Obesity, overconsumption of fats, the mechanism of fat digestion, obesogenic gut microbiota, inhibition of fat digestion, and natural anti-obesity compounds are discussed. Similar discussions are made for diabetes with regard to glucose regulation, the diabetic gut microbiota, and insulinotropic compounds. The sources and production of anti-obesity bioactive peptides (AOBPs) and anti-diabetic bioactive peptides (ADBPs) are also described while explaining their structure-function relationships, gastrointestinal behaviors, and action mechanisms. Finally, the techno-functional applications of AOBPs and ADBPs are highlighted.

A randomized double blind placebo controlled trial to assess the safety and efficacy of a patented fenugreek (Trigonella foenum-graecum) seed extract in Type 2 diabetics

Background

Fenugreek plant (Trigonella foenum-graecum) constitutes a traditionally acclaimed herbal remedy for many human ailments including diabetes, obesity, neurodegenerative diseases, and reproductive disorders. It is also used as an effective anti-oxidative, anti-inflammatory, antibacterial, and anti-fungal agent. The seed of the plant is especially enriched in several bioactive molecules including polyphenols, saponins, alkaloids, and flavonoids and has demonstrated potential to act as an antidiabetic phytotherapeutic. A novel patented formulation (Fenfuro®) was developed in our laboratory from the fenugreek seeds which contained >45% furostanolic saponins (HPLC).

Objective

A placebo-controlled clinical compliance study was designed to assess the effects of complementing Fenfuro® on a randomized group of human volunteers on antidiabetic therapy (Metformin and sulphonylurea) in controlling the glycemic index along with simultaneous safety assessment.

Study methodology and trial design

In a randomized double-blind, placebo-controlled trial, 42 individuals (21 male and 21 female volunteers) in the treatment group (out of 57 enrolled) and 39 individuals (17 male and 22 female volunteers) in the placebo group (out of 47 enrolled), all on antidiabetic therapy with Metformin/Metformin with sulphonyl urea within the age group of 18-65 years were administered either 1,000 mg (500 mg × 2) (Fenfuro®) capsules or placebo over a period of 12 consecutive weeks. Fasting and postprandial glucose along with glycated hemoglobin were determined as primary outcomes to assess the antidiabetic potential of the formulation. Moreover, in order to evaluate the safety of the formulation, C-peptide and Thyroid Stimulating Hormone (TSH) levels as well as immunohematological parameters were assessed between the treatment and placebo groups at the completion of the study.

Results

After 12 weeks of administration, both fasting as well as postprandial serum glucose levels decreased by 38 and 44% respectively in the treatment group. Simultaneously, a significant reduction in glycated hemoglobin by about 34.7% was also noted. The formulation did not have any adverse effect on the study subjects as there was no significant change in C- peptide level and TSH level; liver, kidney, and cardiovascular function was also found to be normal as assessed by serum levels of key immunohematological parameters. No adverse events were reported.

Conclusion

This clinical compliance study re-instated and established the safety and efficacy of Fenfuro® as an effective phytotherapeutic to treat hyperglycemia.

Characterization of Seven New Steroidal Saponins from Korean Oat Cultivars by UPLC-QTOF-MS and UPLC-MS/MS

Oat saponins are composed of triterpenoid and steroidal saponins, and their potential biological activities, such as antibacterial, antifungicidal, osteogenic, and anticancer activities, have been reported. In this study, qualitative and quantitative analyses of oat saponins were conducted by using UPLC-QToF-MS and UPLC-Triple Q-MS/MS. A total of 22 saponins were analyzed in seven Korean oat cultivars. Among them, 7 saponins were identified as new compounds in this source, which were tentatively confirmed as nuatigenin-type saponins with 26-O-diglucoside and 3-O-malonylglucoside forms and (25S)-furost-5-en-3β,22,26-triol-type saponins. In addition, the total content of these saponins ranged from 70.61 to 141.38 mg/100 g dry weight, and it was affected by the type of oat cultivar and the presence or absence of hulling. These detailed profiles will be suggested as fundamental data for breeding superior oat cultivars, evaluating of related products, and various industries.

Research progress on the hypoglycemic activity and mechanisms of natural polysaccharides

The incidence of diabetes, as a metabolic disease characterized by high blood sugar levels, is increasing every year. The predominantly western medicine treatment is associated with certain side effects, which has prompted people to turn their attention to natural active substances. Natural polysaccharide is a safe and low-toxic natural substance with various biological activities. Hypoglycemic activity is one of the important biological activities of natural polysaccharides, which has great potential for development. A systematic review of the latest research progress and possible molecular mechanisms of hypoglycemic activity of natural polysaccharides is of great significance for better understanding them. In this review, we systematically reviewed the relationship between the hypoglycemic activity of polysaccharides and their structure in terms of molecular weight, monosaccharide composition, and glycosidic bonds, and summarized underlying molecular mechanisms the hypoglycemic activity of natural polysaccharides. In addition, the potential mechanisms of natural polysaccharides improving the complications of diabetes were analyzed and discussed. This paper provides some valuable insights and important guidance for further research on the hypoglycemic mechanisms of natural polysaccharides.

Hesperidin: Enrichment, forced degradation, and structural elucidation of potential degradation products using spectral techniques

RATIONALE

Hesperidin (HES) is a well-known citrus bioflavonoid phyto-nutraceutical agent with polypharmacological properties. After 2019, HES was widely used for prophylaxis and COVID-19 treatment. Moreover, it is commonly prescribed for treating varicose veins and other diseases in routine clinical practice. Pharmaceutical impurities and degradation products (DP) impact the drug's quality and safety and thus its effectiveness. Therefore, forced degradation studies help study drug stability, degradation mechanisms, and their DPs. This study was performed because stress stability studies using detailed structural characterization of hesperidin are currently unavailable in the literature.

METHODS

In the HES enrichment method crude HES was converted to its pure form (98% purity) using column chromatography and then subjected to forced degradation under acid, base, and neutral hydrolyses followed by oxidative, reductive, photolytic, and thermal stress testing (International Conference on Harmonization guidelines). The stability-indicating analytical method (SIAM) was developed to determine DPs using reversed-phase high-performance liquid chromatography (C18 column with methanol and 0.1% v/v acetic acid in deionized water [70:30, v/v] at 284 nm). Further, structural characterization of DPs was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and nuclear magnetic resonance (NMR) spectroscopy. In addition, in silico toxicity predictions were performed using pKCSM and DataWarior freeware.

RESULTS

HES was found to be susceptible to acidic and basic hydrolytic conditions and yielded three DPs in each, which were detected using designed SIAM. Of six DPs, three were pseudo-DPs (short lived), and the remaining were characterized using LC-MS/MS and NMR spectroscopy. The tentative mechanism of the formation of proposed DPs was explained. The proposed DPs were found inactive from in silico toxicity predictions.

CONCLUSIONS

Hesperidin was labile under acidic and basic stress conditions. The potential DPs were characterized using LC-ESI-MS/MS and NMR spectral techniques. The proposed mechanism of formation was hypothesized. In addition, to identify and characterize the DPs, a SIAM, which has broad biomedical applications, was successfully developed.

Antileishmanial evaluation of triazole-butenolide conjugates: design, synthesis, in vitro screening, SAR and in silico ADME predictions

In the quest to discover novel scaffolds with leishmanicidal effects, a series of 23 compounds containing the most promising 1,2,3-triazole and highly potent butenolide in one framework were synthesized. The synthesized conjugates were screened against Leishmania donovani parasite; five of them showed moderate antileishmanial activity against promastigotes (IC50 30.6 to 35.5 μM) and eight of them exhibited significant activity against amastigotes (IC50 ≤12 μM). Compound 10u was found to be the most active (IC50 8.4 ± 0.12 μM) with the highest safety index (20.47). The series was further evaluated against Plasmodium falciparum (3D7 strain) and seven compounds were found to be moderately active. Among them, again 10u emerged as the most active compound (IC50 3.65 μM). In antifilarial assays against adult female Brugia malayi, five compounds showed grade II inhibition (50-74%). Structure-activity relationship (SAR) analysis suggested a substituted phenyl ring, triazole and butenolide as essential structural features for bioactivity. Moreover, the results of in silico ADME parameter and pharmacokinetic studies indicated that the synthesized triazole-butenolide conjugates abide by the required criteria for the development of orally active drugs, and thus this scaffold can be used as a pharmacologically active framework that should be considered for the development of potential antileishmanial hits.

Design, synthesis and evaluation of novel pyrrole-hydroxybutenolide hybrids as promising antiplasmodial and anti-inflammatory agents

In the pursuance of novel scaffolds with promising antiplasmodial and anti-inflammatory activity, a series of twenty-one compounds embraced with most promising penta-substituted pyrrole and biodynamic hydroxybutenolide in single skeleton was designed and synthesized. These pyrrole-hydroxybutenolide hybrids were evaluated against Plasmodium falciparum parasite. Four hybrids 5b, 5d, 5t and 5u exhibited good activity with IC₅₀ of 0.60, 0.88, 0.97 and 0.96 μM for chloroquine sensitive (Pf3D7) strain and 3.92, 4.31, 4.21 and 1.67 μM for chloroquine resistant (PfK1) strain, respectively. In vivo efficacy of 5b, 5d, 5t and 5u was studied against the P. yoelii nigeriensis N67 (a chloroquine-resistant) parasite in Swiss mice at a dose of 100 mg/kg/day for 4 days via oral route. 5u was found to show maximum 100% parasite inhibition with considerably increased mean survival time. Simultaneously, the series of compounds was screened for anti-inflammatory potential. In preliminary assays, nine compounds showed more than 85% inhibition in hu-TNFα cytokine levels in LPS stimulated THP-1 monocytes and seven compounds showed more than 40% decrease in fold induction in reporter gene activity analyzed via Luciferase assay. 5p and 5t were found to be most promising amongst the series, thus were taken up for further in vivo studies. Wherein, mice pre-treated with them showed a dose dependent inhibition in carrageenan induced paw swelling. Moreover, the results of in vitro and in vivo pharmacokinetic parameters indicated that the synthesized pyrrole-hydroxybutenolide conjugates abide by the required criteria for the development of orally active drug and thus this scaffold can be used as pharmacologically active framework that should be considered for the development of potential antiplasmodial and anti-inflammatory agents.

Recent advances on the regulation of bacterial biofilm formation by herbal medicines

Biofilm formation is a fundamental part of life cycles of bacteria which affects various aspects of bacterial-host interactions including the development of drug resistance and chronic infections. In clinical settings, biofilm-related infections are becoming increasingly difficult to treat due to tolerance to antibiotics. Bacterial biofilm formation is regulated by different external and internal factors, among which quorum sensing (QS) signals and nucleotide-based second messengers play important roles. In recent years, different kinds of anti-biofilm agents have been discovered, among which are the Chinese herbal medicines (CHMs). CHMs or traditional Chinese medicines have long been utilized to combat various diseases around the world and many of them have the ability to inhibit, impair or decrease bacterial biofilm formation either through regulation of bacterial QS system or nucleotide-based second messengers. In this review, we describe the research progresses of different chemical classes of CHMs on the regulation of bacterial biofilm formation. Though the molecular mechanisms on the regulation of bacterial biofilm formation by CHMs have not been fully understood and there are still a lot of work that need to be performed, these studies contribute to the development of effective biofilm inhibitors and will provide a novel treatment strategy to control biofilm-related infections.

Effect of Codonopsis Radix and Polygonati Rhizoma on the regulation of the IRS1/PI3K/AKT signaling pathway in type 2 diabetic mice

OBJECTIVE

Codonopsis Radix and Polygonati Rhizoma (CRPR) has a good hypoglycemic effect. The aims of the present study were to investigate the effect of CRPR on high-fat/high-sugar diet (HFHSD)- and streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) mice as well as to investigate the involved mechanism.

METHODS

A T2DM mouse model was generated by combining HFHSD and STZ. After the model was established, normal and model groups received the same volume of normal saline intragastrically, and the negative control group was treated with metformin (200 mg/kg·BW). The low, medium, and high CRPR groups received four consecutive weeks of oral gavage with CRPR doses of 2.5, 5, and 10 g/kg·BW, respectively, during the course of the study. Body weight and fasting blood glucose (FBG) were measured on a weekly basis. Enzyme-linked immunosorbent assay (ELISAs) were used to evaluate the serum and liver samples. Hematoxylin and eosin (H&E) staining was utilized to observe the pathological status of the liver and pancreas. Western blot (WB) analysis was performed to evaluate the protein expression levels of PI3K, p-PI3K, AKT, and p-AKT.

RESULTS

Compared to model mice, each treatment group had significantly elevated levels of FBG, total cholesterol (TC), and triacylglycerol (TG) (P<0.01 and P<0.05, respectively). The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly reduced in the treatment groups compared to the model group (P<0.01). Compared to the model group, fasting insulin (FINS) levels were elevated in all groups of CRPR (P<0.05), and there were significantly higher levels of high-density lipoprotein cholesterol (HDL-C) in both the low-dose and high-dose CRPR groups (P<0.05). H&E staining indicated that CRPR treatment reduced organ enlargement, improved liver lipid accumulation, and repaired islet injury in T2DM mice. Moreover, WB analysis demonstrated that all CRPR groups significantly upregulated the protein expression of IRS1, p-GSK3β, PI3K, p-Akt and p-FOXO1(P<0.05) as well as significantly downregulated p-IRS1 and FOXO1 protein expression (P<0.05).

CONCLUSION

The present study demonstrated that CRPR effectively improves the metabolic disturbance of lipids, repairs damaged liver tissues, repairs damaged pancreatic tissues, and reduces insulin resistance (IR) in T2DM mice. The mechanism of action may be associated with upregulation of the IRS1/PI3K/AKT signaling pathway and inhibition of IRS1 phosphorylation.