Reducing the intestinal side effects of acarbose by baicalein through the regulation of gut microbiota: An in vitro study

Quercetin slow-release system delays starch digestion via inhibiting transporters and enzymes

This study investigates the potential of a quercetin-based emulsion system to moderate starch digestion and manage blood glucose levels, addressing the lack of in vivo research. By enhancing quercetin bioaccessibility and targeting release in the small intestine, the emulsion system demonstrates significant inhibition of starch digestion and glucose spikes through both in vitro and in vivo experiments. The system inhibits α-amylase and α-glucosidase via competitive and mixed inhibition mechanisms, primarily involving hydrogen bonds and van der Waals forces, leading to static fluorescence quenching. Additionally, this system downregulates the protein expression and gene transcription of SGLT1 and GLUT2. These findings offer a novel approach to sustaining glucose equilibrium, providing a valuable foundation for further application of quercetin emulsion in food science.

Fabrication and characterization of responsible approach for targeted intestinal releasing and enhancing the effectivity of kidney tea saponin upon porous starch /xanthan gum /sodium alginate-based hydrogel bead

To enhance the intestinal targeted release of kidney tea saponins, a simple delivery system was designed through the use of porous starch (PS), sodium alginate (ALG) and xanthan gum (XG). Porous starch was prepared by hydrolysis with a combination of α-amylase and amyloglucosidase and it was characterized by scanning electron microscopy, which revealed the formation of porous structures in the starch granules. The results of one-way optimisation illustrated that this unique delivery system achieved 79.00 ± 1.22 % of the optimal encapsulation rate. The carrier structure was subjected to analysis using Fourier transform infrared spectroscopy and X-ray diffraction. The α-glucosidase inhibition assay showed better inhibition of kidney tea saponin compared to the positive control acarbose. In addition, the effectiveness of this delivery design was confirmed via an in vitro simulated digestion method. It was showed that only a 15.57 ± 1.27 % release rate of kidney tea saponin was observed in the upper gastrointestinal tract, whereas release rates of 17.51 ± 1.29 % and 41.07 ± 0.76 % were observed for xanthan gum/sodium alginate/kidney tea saponin and sodium alginate/kidney tea saponin beads, respectively. It was concluded that the utilization of PS and a xanthan gum/sodium alginate coating represents an efficacious methodology for the development of an intestinal targeted delivery system.

Discovery of novel dihydro-pyrimidine hybrids: insight into the design, synthesis, biological evaluation and absorption, distribution, metabolism and excretion studies

Aim: By keeping in aspects, the pharmacological potential of heterocyclic compounds, pyrimidine-based compounds were designed, synthesized and evaluated for α-amylase inhibitory potential.Materials & methods: Five new series 1a-l, 2a-d, 3a-d, 4a-d and 5a-d of 1,2,3,4-tetrahydroprimidine-5-carboxylate derivatives were designed by de novo method by taking Alogliptin as reference compound. Here in we describe synthesis and characterization of compounds as potential α-amylase inhibitor.Results: Structure activity relationship (SAR), in vitro analysis and molecular modelling approaches generate compounds 1 h, 1i, 1k and 4c as potential lead with good α-amylase inhibitory selection. However, compound 1k failed the criteria of optimization as drug lead by ADME studies while all other compounds showed optimum range for all in silico ADME parameters.Conclusion: Therefore, these compounds can serve as potential lead candidate in developing anti-diabetic therapy.

Enzymolysis Modes Trigger Diversity in Inhibitor-α-Amylase Aggregating Behaviors and Activity Inhibition: A New Insight Into Enzyme Inhibition

Inhibitors of α-amylase have been developed to regulate postprandial blood glucose fluctuation. The enzyme inhibition arises from direct or indirect inhibitor-enzyme interactions, depending on inhibitor structures. However, an ignored factor, substrate, may also influence or even decide the enzyme inhibition. In this work, it is innovatively found that the difference in substrate enzymolysis modes, i.e., structural composition and concentration of α-1,4-glucosidic bonds, triggers the diversity in inhibitor-enzyme aggregating behaviors and α-amylase inhibition. For competitive inhibition, there exists an equilibrium between α-amylase-substrate catalytic affinity and inhibitor-α-amylase binding affinity; therefore, a higher enzymolysis affinity and concentration of α-1,4-glucosidic structures interferes the balance, unfavoring inhibitor-enzyme aggregate formation and thus weakening α-amylase inhibition. For uncompetitive inhibition, the presence of macromolecular starch is necessary instead of micromolecular GalG2CNP, which not only binds with active site but with an assistant flexible loop (involving Gly304-Gly309) near the site. Hence, the refined enzyme structure due to the molecular flexibility more likely favors the inhibitor binding with the non-active loop, forming an inhibitor-enzyme-starch ternary aggregate. Conclusively, this study provides a novel insight into the evaluation of α-amylase inhibition regarding the participating role of substrate in inhibitor-enzyme aggregating interactions, emphasizing the selection of appropriate substrates in the development and screening of α-amylase inhibitors.

The inhibitory effects of free and bound phenolics from Phyllanthus emblica Linn. on α-amylase: a comparison study

BACKGROUND

Phyllanthus emblica Linn. (PE) is rich in polyphenols, which can be categorized into free and bound phenolics (PEFP and PEBP). This study evaluated the inhibitory effect of PEFB and PEBP on α-amylase for the first time. The mechanism of the inhibition effect of PEFP and PEBP on α-amylase was investigated by enzyme inhibition kinetics, multispectral analysis, thermodynamics, and molecular docking.

RESULTS

Free and bound phenolics inhibited α-amylase activity effectively in a mixed type of inhibition. Fluorescence quenching and thermodynamic analyses showed that the binding of PEFP and PEBP to α-amylase occurred through a static quenching process (Kq = 6.94 × 10¹² and 5.74 × 10¹² L mol-1 s-1), which was accompanied by a redshift (λem from 343 to 347 nm), leading to a change in the microenvironment. This process was found to be a spontaneous exothermic reaction (ΔG < 0). Circular dichroism (CD) analysis confirms that the secondary structure of α-amylase was altered, in particular a decrease in α-helixes and an increase in random coils. Molecular docking studies showed that PEFP and PEBP interacted with α-amylase through hydrogen bonding and hydrophobic interactions.

CONCLUSION

The present study provides valuable insights into the mechanism of action of PEFP and PEBP on α-amylase, which will provide a theoretical basis for their possible use as novel natural α-amylase inhibitors. © 2024 Society of Chemical Industry.

Macroalgae-derived bioactive compounds for functional food and pharmaceutical applications-a critical review

The rising demand for global food resources, combined with an overreliance on land-based agroecosystems, poses a significant challenge for the sustainable production of food products. Macroalgae cultivation is a promising approach to mitigate impending global food insecurities due to several key factors: independence from terrestrial farming, rapid growth rates, unique biochemical makeup, and carbon capture potential. Furthermore, macroalgae are rich in vitamins, minerals, essential amino acids, polyunsaturated fatty acids and fiber, demonstrating significant potential as sustainable alternatives for enhancing dietary diversity and fulfilling nutritional requirements. This review provides an overview of the nutritional composition and functional properties of commercially cultivated macroalgae species, with emphasis on their viability as value additions to the functional food market. Furthermore, the review discusses the technological aspects of integrating macroalgae into food products, covering both innovative solutions and existing challenges. Macroalgae, beyond being nutritional powerhouses, contain a plethora of bioactive compounds with varied biological activities, including anti-diabetic, anti-cancer, cardioprotective, and neuroprotective properties, making them excellent candidates in developing novel pharmaceuticals. Thus, this review also summarizes the pharmaceutical applications of macroalgae, identifies research gaps and proposes potential strategies for incorporating macroalgae-derived bioactive compounds into therapeutic products.

α-Glucosidase Inhibitory Activity of Prenylated Pyranocoumarins from Clausena excavata: Mechanism of Action, ADMET and Molecular Docking

Three naturally occurring prenylated pyranocoumarins, nordentatin (1), dentatin (2), and clausarin (3), isolated from the roots of Clausena excavata (Family Rutaceae), and O-methylclausarin (4) which was obtained by methylation of 3, were investigated for their α-glucosidase inhibitory activity. The mechanism of action and the in silico prediction of their physicochemical and ADMET properties as well as the molecular docking were also studied. Compounds 1-4 exhibited stronger α-glucosidase inhibitory activity than the positive control, acarbose, through a non-competitive mechanism. Among them, 3 exhibited the highest activity, with an IC50 of 8.36 μM, which is significantly stronger than that of acarbose (IC50=430.35 μM). The prenyl group on C-3 and the hydroxyl group on C-5 in 3 may play important roles in enhancing the activity. Calculated physicochemical and ADMET parameters of 1-4 satisfied the Lipinski's and Veber's rules. Molecular simulation analysis indicated they are promising drug candidates with no hepatotoxicity. Compound 3 exhibited potent activity in the experiment and demonstrated good drug properties based on the calculations. A molecular docking study revealed that 3 showed H-bonding and π-π stacking interactions with selective Phe321, as well as interactions with thirteen other amino acid residues of the α-glucosidase.

Antibacterial Activity Potential of Industrial Food Production Waste Extracts against Pathogenic Bacteria: Comparative Analysis and Characterization

The Food and Agricultural Organization estimates a 17% loss in the food production chain, making it imperative to adopt scientific and technological approaches to address this issue for sustainability. Industrial food production waste and its value-added applications, particularly in relation to a wide variety of pathogenic microorganisms and the health-related effects have not been thoroughly investigated. This study explores the potential of food production waste extracts-lemon peel (LP), hot trub (HT), and coffee silverskin (CSS) as sources of bioactive compounds. Extraction was conducted using hydro-methanolic extraction with yields in LP (482 mg/1 g) > HT (332 mg/1 g) > CSS (20 mg/1 g). The agar diffusion assay revealed the substantial antibacterial activity of all three extracts against Erwinia Amylovora, Escherichia coli, Bacillus subtilis, and Bacillus aquimaris. All extracts demonstrated activity against Gram-positive and Gram-negative bacteria, displaying minimum inhibitory concentrations effective against pathogenic bacteria like Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus, and Salmonella enterica. Total phenolic content (TPC in mg GAE/1g) was 100, 20, and 100 for CSS, HT, and LP, respectively. Antioxidant activity by ABTS indicated IC50 of 3.09, 13.09, and 2.61 for LP, HT, and CSS, respectively. Also, the antioxidant activity of the extracts was further confirmed by DPPH assay with the best activity in CSS (9.84 GAEg-1) and LP (9.77 mg of GAEg-1) rather than in HT (1.45 GAEg-1). No adverse cytotoxic effects on HaCaT cells were observed. Pancreatic amylase inhibition demonstrated antidiabetic potential, with LP showing the highest levels (92%). LC-MS characterization identified polyphenols as the main compounds in CSS, prenylated compounds in HT, and flavanols in LP. The findings imply the potential sustainable use of food production waste in industry.

Computational investigation of 2, 4-Di Tert Butyl Phenol as alpha amylase inhibitor isolated from Coccinia grandis (L.) Voigt using molecular docking, and ADMET parameters

INTRODUCTION

Diabetes Mellitus is the metabolic disorder most prevalent globally, accounting for a substantial morbidity rate. The conventional drugs available for the management of diabetes are either expensive or lack the required efficacy. The purpose of this research is to isolate and characterize an active phytoconstituent from Coccinia grandis and assess its anti-diabetic properties.

METHODS AND MATERIALS

Stems of Coccinia grandis are subjected to successive extraction and isolation. The isolated compound by column chromatography was characterized by FTIR (fourier-transform infrared), 1 H NMR (proton nuclear magnetic resonance), and Mass spectroscopy. The antidiabetic potential of the isolated compound was evaluated by in-vitro alpha-amylase inhibitory activity. Further, the compound was subjected to molecular docking studies to study its interaction with the human pancreatic alpha-amylase (Molegro Virtual Docker) as well to determine the pharmacokinetic and toxicity profile using computational techniques (OSIRIS property explorer, Swiss ADME, pkCSM, and PreADMET).

RESULTS

The characterization of the compound suggests the structure to be 2,4-ditertiary butyl phenol. The in-vitro alpha-amylase inhibitory study indicated a concentration-dependent inhibition and the IC50 (median lethal dose) value of the isolated compound was found to be 64.36 μg/ml. The docking study with the A chain of receptor 5EMY yielded a favorable docking score of -81.48 Kcal mol-1, suggesting that the compound binds to the receptor with high affinity through electrostatic, hydrophobic, and hydrogen bonds. Furthermore, the silico ADME analysis of the compound revealed improved metabolism, a skin permeability of -3.87 cm/s, gastrointestinal absorption of 95.48 %, and a total clearance of 0.984 log ml min-1 kg-1. In silico toxicity analysis also predicted cutaneous irritations but no carcinogenicity, mutagenicity, or hepatotoxicity.

CONCLUSION

The data suggested that the isolated compound (2, 4-tertiary butyl phenol) has the potential to inhibit the alpha-amylase activity and possess optimal ADME properties as well as tolerable side effects.

Synthesis of obovatol and related neolignan analogues as α-glucosidase and α-amylase inhibitors

Diabetes mellitus is a metabolic disease characterized by hyperglycemia, which can be counteracted by the inhibition of α-glucosidase (α-Glu) and α-amylase (α-Amy), enzymes responsible for the hydrolysis of carbohydrates. In recent decades, many natural compounds and their bioinspired analogues have been studied as α-Glu and α-Amy inhibitors. However, no studies have been devoted to the evaluation of α-Glu and α-Amy inhibition by the neolignan obovatol (1). In this work, we report the synthesis of 1 and a library of new analogues. The synthesis of these compounds was achieved by implementing methodologies based on: phenol allylation, Claisen/Cope rearrangements, methylation, Ullmann coupling, demethylation, phenol oxidation and Michael-type addition. Obovatol (1) and ten analogues were evaluated for their in vitro inhibitory activity towards α-Glu and α-Amy. Our investigation highlighted that the naturally occurring 1 and four neolignan analogues (11, 22, 26 and 27) were more effective inhibitors than the hypoglycemic drug acarbose (α-Amy: 34.6 µM; α-Glu: 248.3 µM) with IC5O value of 6.2-23.6 µM toward α-Amy and 39.8-124.6 µM toward α-Glu. Docking investigations validated the inhibition outcomes, highlighting optimal compatibility between synthesized neolignans and both the enzymes. Concurrently circular dichroism spectroscopy detected the conformational changes in α-Glu induced by its interaction with the studied neolignans. Detailed studies through fluorescence measurements and kinetics of α-Glu and α-Amy inhibition also indicated that 1, 11, 22, 26 and 27 have the greatest affinity for α-Glu and 1, 11 and 27 for α-Amy. Surface plasmon resonance imaging (SPRI) measurements confirmed that among the compounds studied, the neolignan 27 has the greater affinity for both enzymes, thus corroborating the results obtained by kinetics and fluorescence quenching. Finally, in vitro cytotoxicity of the investigated compounds was tested on human colon cancer cell line (HCT-116). All these results demonstrate that these obovatol-based neolignan analogues constitute promising candidates in the pursuit of developing novel hypoglycemic drugs.

Rhodiola rosea: a review in the context of PPPM approach

A natural "medicine and food" plant, Rhodiola rosea (RR) is primarily made up of organic acids, phenolic compounds, sterols, glycosides, vitamins, lipids, proteins, amino acids, trace elements, and other physiologically active substances. In vitro, non-clinical and clinical studies confirmed that it exerts anti-inflammatory, antioxidant, and immune regulatory effects, balances the gut microbiota, and alleviates vascular circulatory disorders. RR can prolong life and has great application potential in preventing and treating suboptimal health, non-communicable diseases, and COVID-19. This narrative review discusses the effects of RR in preventing organ damage (such as the liver, lung, heart, brain, kidneys, intestines, and blood vessels) in non-communicable diseases from the perspective of predictive, preventive, and personalised medicine (PPPM/3PM). In conclusion, as an adaptogen, RR can provide personalised health strategies to improve the quality of life and overall health status.

Extraction, identification, and molecular mechanisms of α-glucosidase inhibitory peptides from defatted Antarctic krill (Euphausia superba) powder hydrolysates

The objective of this study was to explore the potential of Antarctic krill-derived peptides as α-glucosidase inhibitors for the treatment of type 2 diabetes. The enzymolysis conditions of α-glucosidase inhibitory peptides were optimized by response surface methodology (RSM), a statistical method that efficiently determines optimal conditions with a limited number of experiments. Gel chromatography and LC-MS/MS techniques were utilized to determine the molecular weight (Mw) distribution and sequences of the hydrolysates. The identification and analysis of the mechanism behind α-glucosidase inhibitory peptides were conducted through conventional and computer-assisted techniques. The binding affinities between peptides and α-glucosidase were further validated using BLI (biolayer interferometry) assay. The results revealed that hydrolysates generated by neutrase exhibited the highest α-glucosidase inhibition rate. Optimal conditions for hydrolysis were determined to be an enzyme concentration of 6 × 103 U/g, hydrolysis time of 5.4 h, and hydrolysis temperature of 45 °C. Four peptides (LPFQR, PSFD, PSFDF, VPFPR) with strong binding affinities to the active site of α-glucosidase, primarily through hydrogen bonding and hydrophobic interactions. This study highlights the prospective utility of Antarctic krill-derived peptides in curtailing α-glucosidase activity, offering a theoretical foundation for the development of novel α-glucosidase inhibitors and related functional foods to enhance diabetes management.

Utilizing bio-affinity ultrafiltration combined with UHPLC Q-Exactive Plus Orbitrap HRMS to detect potential α-glucosidase inhibitors in Oxalis corniculate L

Oxalis corniculate L. (O. corniculate) was used to treat diabetes in Chinese folk as a popular tea drink. In this work, 31 compounds from O. corniculate were screened and identified as potential α-Glucosidase inhibitors (α-GIs). Among them, 6 compounds displayed stronger inhibitory activity than acarbose (IC50 = 212.9 ± 5.98 μg/mL). Especially, the most effective compounds quercetin (Qu, IC50 = 4.70 ± 0.40 μg/mL) and luteolin (Lu, IC50 = 15.72 ± 0.75 μg/mL) inhibited α-Glu in competitive and mixed manners, respectively. Moreover, fluorescence quenching, circular dichroism (CD), and molecular docking study revealed that they can arouse the changes in the secondary structure and hydrophobic micro-environment of the enzyme mainly through a hydrophobic binding. Furthermore, it was observed that oral administration of Qu (20 mg/kg) can significantly reduce postprandial blood glucose (PBG) levels in mice vs. the control group. To sum up, the above research confirmed that O. corniculate could prevent and treat postprandial hyperglycemia as a good tea drink, and the plant was an excellent source to obtain natural α-GIs.

Anti-Diabetic Potential of Sargassum horneri and Ulva australis Extracts In Vitro and In Vivo

Sargassum horneri (SH) and Ulva australis (UA) are marine waste resources that cause environmental and economic problems when entering or multiplying the coastal waters of Jeju Island. We analyzed their anti-diabetic efficacy to assess their reusability as functional additives. The alpha-glucosidase inhibitory activity of SH and UA extracts was confirmed, and the effect of UA extract was higher than that of SH. After the induction of insulin-resistant HepG2 cells, the effects of the two marine extracts on oxidative stress, intracellular glucose uptake, and glycogen content were compared to the positive control, metformin. Treatment of insulin-resistant HepG2 cells with SH and UA resulted in a concentration-dependent decrease in oxidative stress and increased intracellular glucose uptake and glycogen content. Moreover, SH and UA treatment upregulated the expression of IRS-1, AKT, and GLUT4, which are suppressed in insulin resistance, to a similar degree to metformin, and suppressed the expression of FoxO1, PEPCK involved in gluconeogenesis, and GSK-3β involved in glycogen metabolism. The oral administration of these extracts to rats with streptozotocin-induced diabetes led to a higher weight gain than that in the diabetic group. Insulin resistance and oral glucose tolerance are alleviated by the regulation of blood glucose. Thus, the SH and UA extracts may be used in the development of therapeutic agents or supplements to improve insulin resistance.

Dendrobium officinale Polysaccharide Prevents Diabetes via the Regulation of Gut Microbiota in Prediabetic Mice

Dendrobium officinale polysaccharide (DOP), which serves as a prebiotic, exhibits a variety of biological activities, including hypoglycemic activities. However, the effects of DOP on diabetes prevention and its hypoglycemic mechanisms are still unclear. In this study, the effects of DOP treatment on the prediabetic mice model were studied and the mechanism was investigated. The results showed that 200 mg/kg/d of DOP reduced the relative risk of type 2 diabetes mellitus (T2DM) from prediabetes by 63.7%. Meanwhile, DOP decreased the level of LPS and inhibited the expression of TLR4 by regulating the composition of the gut microbiota, consequently relieving the inflammation and alleviating insulin resistance. In addition, DOP increased the abundance of SCFA (short chain fatty acid)-producing bacteria in the intestine, increased the levels of intestinal SCFAs, promoted the expression of short-chain fatty acid receptors FFAR2/FFAR3, and increased the secretion of the intestinal hormones GLP-1 and PYY, which helped to repair islet damage, suppress appetite, and improve insulin resistance. Our results suggested that DOP is a promising functional food supplement for the prevention of T2DM.

(1'S)-1'-Acetoxyeugenol Acetate Enhances Glucose-Stimulated Insulin Secretion

Alpinia galanga have been widely used as spice or traditional medicine in East Asia, commonly known as Thai ginger. In the present study, seven major phenylpropanoids, (±)-1'-hydoxychavicol acetate (1; HCA), (1'S)-1'-acetoxychavicol acetate (2; ACA), (1'S)-1'-acetoxyeugenol acetate (3; AEA), eugenyl acetate (4), trans-p-coumaraldehyde (5), trans-p-acetoxycinnamyl alcohol (6), and trans-p-coumaryl diacetate (7), were isolated from the 95% EtOH and hot water extracts of the rhizomes of A. galanga by chromatographic method. Phenylpropanoids 1-7 were evaluated for glucose-stimulated insulin secretion (GSIS) effect and α-glucosidase inhibitory activity. Phenylpropanoids 1-4 increase GSIS effect without cytotoxicity in rat INS-1 pancreatic β-cells. In addition, INS-1 cells were treated with AEA (3) to determine a plausible mechanism of β-cell function and insulin secretion through determining the activation of insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, and pancreatic and duodenal homeobox-1 (PDX-1). Upon treatment with AEA (3), INS-1 cells showed an increase in these protein expressions. Meanwhile, AEA (3) exhibited α-glucosidase inhibitory activity. On the basis of the above findings, we suggest AEA (3) as a potential antidiabetic agent.

Scutellaria baicalensis georgi is a promising candidate for the treatment of autoimmune diseases

Autoimmune diseases a group of disorders elicited by unexpected outcome of lymphocytes self-tolerance failure, and the common members of which include multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease, rheumatoid arthritis, and type 1 diabetes mellitus, etc. The pathogenesis of autoimmune diseases is not fully understood and the current therapeutic regimen’s inefficacy in certain cases coupled with low rates of success, exorbitant financial burden, as well as numerous side effects, which do open new avenues for the role of natural products as novel therapeutic agents for auto-inflammatory disorders. Scutellaria baicalensis Georgi is a well-known and widely-recognized herbal medicine with certain ameliorative effect on diverse inflammation-involved dysfunction. Though recent advances do highlight its potential to be applied in the fight against autoimmune diseases, the specific mechanism and the related opinion on the exploring possibility are still limited which hampered the further progress. Here in this timeline review, we traced and collected the evidence of how Scutellaria baicalensis Georgi and its bioactive contents, namely baicalin, baicalein, wogonoside and wogonin affect autoimmune diseases. Moreover, we also discussed the clinical implications and therapeutic potential of Scutellaria baicalensis Georgi and its bioactive contents in autoimmune diseases treatment.