Carbohydrate Digestive Enzymes Research Articles

Identification of bioactive compounds in Brassica oleracea var. capitata L. with enzyme-inhibitory activity against postprandial hyperglycemia.

Postprandial hyperglycemia is a hallmark of diabetes, and inhibition of key carbohydrate digestion enzymes such as α-amylase (α-AMY) and α-glucosidase (α-GLU) is an effective therapeutic target. A potential unexplored source of inhibitory compounds of these enzymes is Brassica oleracea var. capitata L (BOCE). This study explored the in vitro inhibition mechanism of BOCE and studied in silico the interaction of its compounds identified and quantified by UPLC-QTOF-MS on α-AMY and α-GLU. BOCE demonstrated IC50 values of 3.08 mg/mL for α-AMY and 22.63 mg/mL for α-GLU, indicating competitive and mixed-type inhibitions, respectively. Untargeted metabolomics identified 21 compounds, primarily phenolic acids such as t-cinnamic, sinapic, and caffeoylquinic acid. In the targeted analysis, 11 compounds were quantified, mainly phenolic acids. The most impactful biosynthetic pathways identified were phenylpropanoids and brassinosteroids. In silico analysis revealed that for α-AMY and α-GLU, castasterone and 26-hydroxybrassinolide displayed the lowest binding free energies with specific hydrogen bond patterns to catalytic residues in the binding site, respectively. B. oleracea is a promising source of compounds with the ability to modulate key enzymes related to hyperglycemia. Specifically, compounds such as castasterone and 26-hydroxybrassinolide show potential against α-AMY and α-GLU inhibition, offering a novel approach to diabetes.

AntiT2DMP-Pred: Leveraging feature fusion and optimization for superior machine learning prediction of type 2 diabetes mellitus.

Pancreatic α-amylase breaks down starch into isomaltose and maltose, which are further hydrolyzed by α-glucosidase in the intestine into monosaccharides, rapidly raising blood sugar levels and contributing to type 2 diabetes mellitus (T2DM). Synthetic inhibitors of carbohydrate-digesting enzymes are used to manage T2DM but may harm organ function over time. Bioactive peptides offer a safer alternative, avoiding such adverse effects. Computational methods for predicting antidiabetic peptides (ADPs) can significantly reduce the time and cost of experimental testing. While machine learning (ML) has been applied to identify ADPs, advancements in data analysis and algorithms continue to drive progress in the field. To address this, we developed AntiT2DMP-Pred, the first ML-based tool specifically designed for predicting type 2 antidiabetic peptides (T2ADPs). This tool employs a feature fusion strategy, combining ten highly discriminative feature descriptors chosen from a pool of 32 descriptors and eight ML algorithms, tested across a range of baseline models. AntiT2DMP-Pred demonstrated excellent performance, surpassing both baseline and feature-optimized models, with an accuracy (ACC) and Matthews' correlation coefficient (MCC) of 0.976 and 0.953 on the training dataset, and an ACC and MCC of 0.957 and 0.851 on the independent dataset. The web server (https://balalab-skku.org/AntiT2DMP-Pred) is freely accessible, enabling researchers worldwide to utilize it in their experimental workflows and contribute to the discovery and understanding of T2ADPs, ultimately supporting peptide-based therapeutic development for diabetes management.

A Supramolecular Gel-Based Protocol for the Detection of α-Glycosidases for Screening Potential Drugs.

α-Glycosidases are carbohydrate-digesting enzymes that catalyze the hydrolysis of α-1,4-glycopyranoside bonds from oligosaccharides and disaccharides. α-Glucosidase is an important biomarker for the diagnosis of type-II diabetes, Azoospermia and Pompe diseases. Additionally, the mutations in α-galactosidase lead to Fabry disease. Inhibitors targeting these enzymes are prescribed as anti-diabetic medications and as effective chaperones for Fabry disease. Comprehending the function - regulation of α-glycosidases requires accurate quantification methods. In this work, we highlight the design of a simple luminescent 'turn-on' assay for sensing these two α-glycosidases in a supramolecular TbCh hydrogel matrix using 1-α-glycosides as pro-sensitizers. The protocol offers a cost-effective method for selectively sensing α-glycosidases in the detection limit of the subnanomolar range. Importantly, the developed enzyme sensors functioned as a platform for rapid screening of drug molecules based on their inhibition potency. Therefore, the protocol is useful for facilitating the advancement of therapeutics and diagnostics targeting this important class of enzymes.

Suppression of the postprandial hyperglycemia in patients with type 2 diabetes by a raw medicinal herb powder is weakened when consumed in ordinary hard gelatin capsules: A randomized crossover clinical trial.

Contradictory claims about the efficacy of several medicinal plants to promote glycemic control in patients with type 2 diabetes mellitus (T2DM) have been explained by divergences in the administration form and by extrapolation of data obtained from healthy individuals. It is not known whether the antidiabetic effects of traditional herbal medicines are influenced by gelatin capsules. This randomized crossover trial aimed to evaluate the acute effect of a single dose of raw cinnamon consumed orally either dissolved in water as a beverage or as ordinary hard gelatin capsules on postprandial hyperglycemia (>140 mg/dL; >7.8 mmol/L) in T2DM patients elicited by a nutritionally-balanced meal providing 50 g of complex carbohydrates. Fasting T2DM patients (n = 19) randomly ingested a standardized meal in five experimental sessions, one alone (Control) and the other after prior intake of 3 or 6 g of crude cinnamon in the form of hard gelatin capsules or powder dissolved in water. Blood glucose was measured at fasting and at 0.25, 0.5, 0.75, 1, 1.5 and 2 hours postprandially. After each breakfast, its palatability scores for visual appeal, smell and pleasantness of taste were assessed, as well as the taste intensity sweetness, saltiness, bitterness, sourness and creaminess. The intake of raw cinnamon dissolved in water, independently of the dose, decreased the meal-induced large glucose spike (peak-rise of +87 mg/dL and Δ1-hour glycemia of +79 mg/dL) and the hyperglycemic blood glucose peak. When cinnamon was taken as capsules, these anti-hyperglycemic effects were lost or significantly diminished. Raw cinnamon intake did not change time-to-peak or the 2-h post-meal glycaemia, but flattened the glycemic curve (lower iAUC) without changing the shape that is typical of T2DM patients. This cinnamon's antihyperglycemic action confirms its acarbose-like property to inhibit the activities of the carbohydrate-digesting enzymes α-amylases/α-glucosidases, which is in accordance with its exceptionally high content of raw insoluble fiber. The efficacy of using raw cinnamon as a diabetes treatment strategy seems to require its intake at a specific time before/concomitantly the main hyperglycemic daily meals. Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC), number RBR-98tx28b.

Ethiopian coffee (Coffea arabica) improves glucose uptake and modulates metabolic enzyme activities linked to hyperglycemia-induced infertility in isolated rats’ testes

The present study evaluated the inhibitory effect of Ethiopian coffee (Coffea arabica) on carbohydrate digestive enzymes and its protective effect against glucose-induced testicular dysfunction using in vitro and in silico study models. Testicular oxidative stress was initiated by co-incubating testocular tissue collected from male Sprague-Dawley rats in glucose solution with different concentrations of Ethiopian coffee aqueous extracts (hot and cold) for 2 h at 37ºC. Glucose-mediated oxidative stress significantly (p < 0.05) depleted reduced glutathione and total glycogen levels while it lowered catalase and superoxide dismutase (SOD) activities in the testicular tissue. Concomitantly, this led to elevated malondialdehyde and nitric oxide levels while it also increased glycogen phosphorylase, fructose-1,6-bisphosphatase, ATPase, and acetylcholinesterase activities. Treatment with different concentrations of coffee aqueous extracts restored the enzymes’ and markers’ levels and activities. Although both the cold and hot coffee extracts strongly inhibited α-glucosidase and α-amylase enzymes, the former showed better activities. The subjection of the coffee extracts to LC-MS analysis indicated the presence of several compounds, including chlorogenic acid, caffeic acid, cafestol, kahweol, caffeine, quinic acid, ferulic acid, and catechol which were further docked with the carbohydrate digestive enzymes. The in silico results displayed that among the various metabolites, chlorogenic acid strongly interacted and had the best binding affinity with α-glucosidase and α-amylase. Our findings implied that Ethiopian coffee may have a preventive effect against glucose-induced testicular damage. These are evidenced by the capacity of the plant product to decrease oxidative stress and protect against testicular dysfunction.Graphical

Phenolic Compositions of Different Fractions from Coffee Silver Skin and Their Antioxidant Activities and Inhibition towards Carbohydrate-Digesting Enzymes.

Seeking food-derived antioxidants and inhibitors of α-glucosidase and α-amylase has been recognized as an effective way for managing diabetes. Coffee silver skin (CSS) is rich in phenolic compounds, which may be potential agents as antioxidants and for α-glucosidase and α-amylase inhibition. But whether phenolics in different forms show similar bioactivity remains unknown. In this study, phenolic compounds in CSS were extracted as free phenolics (FPs), esterified phenolics (EPs), and bound phenolics (BPs). The phenolic profiles and antioxidant activities of them were investigated. Their inhibitory effects on α-glucosidase and α-amylase were analyzed, and the inhibitory mechanisms were elucidated by molecular docking and molecular dynamic simulation. Results showed that FPs exhibited the best antioxidant ability and inhibitory effects on α-glucosidase and α-amylase. A total of 17 compounds were identified in FPs with 3-caffeoylquinic acid, 4-feruloylquinic acid, and dicaffeoylquinic acids as the dominant ones. Typical phenolics in FPs could bind to α-glucosidase and α-amylase through hydrogen bonds and form hydrophobic interaction with several key amino acid residues. In addition, 3,4-dicaffeoylquinic acid and 3-caffeoylquinic acid might be the principal components that account for the inhibitory effect of FPs on α-glucosidase. The results of this study may provide some scientific support for CSS utilization as a health-beneficial component in functional food development for type 2 diabetes mellitus management.

An in vitro and in silico study of the antioxidant and antidiabetic activities of Nauclea latifolia fruit

The current study assessed the antioxidant and antidiabetic properties of Nauclea latifolia fruit in vitro and in silico. The aqueous infusion of the fruit was analysed for its in vitro antioxidant capacity using ferric-reducing antioxidant power (FRAP), nitric oxide (NO), and 2,2'-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging activities. Its inhibitory effects on carbohydrate digestive enzymes was also determined. The phytoconstituents of the fruit were docked with carbohydrate digestive enzymes (α-amylase and α-glucosidase), and the compounds were further evaluated for ADME parameters. The total phenolic content of N. Latifolia was 44.56 ± 0.78 mg g-1 GAE. N. latifolia aqueous extract exhibited remarkable ferric reducing power (IC50 value of 5.58 µg/mL) when compared to the control Trolox (IC50 value of 6.42 μg/mL). The extract displayed definite capability in inhibiting nitric oxide production than its radical scavenging effect on DPPH with IC50 values of 5.04 and 9.10 μg/mL, respectively. Aqueous extract further exhibited comparable inhibitory activity of the carbohydrate digestive enzymes compared to the standard drug, Acarbose. Moreover, the extract significantly increased glucose uptake in yeast in a dose-dependent manner. N. latifolia fruit aqueous extact's compound profiling with GCMS revealed several phenolic compounds with 2-mercaptophenol, exhibiting the highest in abundance. In silico study revealed that compounds 7,8-dihydroxy-4-methylcoumarin and 4‑methoxy-2‑pent-3-en-2-ylphenol, showed higher binding affinity against α-amylase (-28.8651 kcal/mol), and α-glycosidase (-31.0689 kcal/mol), respectively. Furthermore, the ADME properties of the compounds revealed oral bioavailability, pharmacokinetics, and toxicity properties. These results suggest the possible antioxidant and antidiabetic potential N. Latifolia.

The screening of α-glucosidase inhibitory peptides from β-conglycinin and hypoglycemic mechanism in HepG2 cells and zebrafish larvae

Inhibition of carbohydrate digestive enzymes is a key focus across diverse fields, given the prominence of α-glucosidase inhibitors as preferred oral hypoglycaemic drugs for diabetes treatment. β-conglycinin is the most abundant functional protein in soy; however, it is unclear whether the peptides produced after its gastrointestinal digestion exhibit α-glucosidase inhibitory properties. Therefore, we examined the α-glucosidase inhibitory potential of soy peptides. Specifically, β-conglycinin was subjected to simulated gastrointestinal digestion by enzymatically cleaving it into 95 peptides with gastric, pancreatic and chymotrypsin enzymes. Eight soybean peptides were selected based on their predicted activity; absorption, distribution, metabolism, excretion and toxicity score; and molecular docking analysis. The results indicated that hydrogen bonding and electrostatic interactions play important roles in inhibiting α-glucosidase, with the tripeptide SGR exhibiting the greatest inhibitory effect (IC50 = 10.57 μg/mL). In vitro studies revealed that SGR markedly improved glucose metabolism disorders in insulin-resistant HepG2 cells without affecting cell viability. Animal experiments revealed that SGR significantly improved blood glucose and decreased maltase activity in type 2 diabetic zebrafish larvae, but it did not result in the death of zebrafish larvae. Transcriptomic analysis revealed that SGR exerts its anti-diabetic and hypoglycaemic effects by attenuating the expression of several genes, including Slc2a1, Hsp70, Cpt2, Serpinf1, Sfrp2 and Ggt1a. These results suggest that SGR is a potential food-borne bioactive peptide for managing diabetes.

Croton gratissimus Burch Herbal Tea Exhibits Anti-Hyperglycemic and Anti-Lipidemic Properties via Inhibition of Glycation and Digestive Enzyme Activities.

Over the years, the world has continued to be plagued by type 2 diabetes (T2D). As a lifestyle disease, obese individuals are at higher risk of developing the disease. Medicinal plants have increasingly been utilized as remedial agents for managing metabolic syndrome. The aim of the present study was to investigate the in vitro anti-hyperglycemic and anti-lipidemic potential of Croton gratissimus herbal tea infusion. The inhibitory activities of C. gratissimus on carbohydrate (α-glucosidase and α-amylase) and lipid (pancreatic lipase) hydrolyzing enzymes were determined, and the mode of inhibition of the carbohydrate digestive enzymes was analyzed and calculated via Lineweaver-Burk plots and Michaelis Menten's equation. Its effect on Advanced Glycation End Product (AGE) formation, glucose adsorption, and yeast glucose utilization were also determined. High-performance liquid chromatography (HPLC) was used to quantify the possible phenolic compounds present in the herbal tea infusion, and the compounds were docked with the digestive enzymes. C. gratissimus significantly (p < 0.05) inhibited α-glucosidase (IC50 = 60.56 ± 2.78 μg/mL), α-amylase (IC50 = 35.67 ± 0.07 μg/mL), as well as pancreatic lipase (IC50 = 50.27 ± 1.51 μg/mL) in a dose-dependent (15-240 µg/mL) trend. The infusion also inhibited the non-enzymatic glycation process, adsorbed glucose effectively, and enhanced glucose uptake in yeast cell solutions at increasing concentrations. Molecular docking analysis showed strong binding affinity between HPLC-quantified compounds (quercetin, caffeic acid, gallic acid, and catechin) of C. gratissimus herbal tea and the studied digestive enzymes. Moreover, the herbal tea product did not present cytotoxicity on 3T3-L1 cell lines. Results from this study suggest that C. gratissimus herbal tea could improve glucose homeostasis and support its local usage as a potential anti-hyperglycemic and anti-obesogenic agent. Further in vivo and molecular studies are required to bolster the results from this study.

Exploring anti-diabetic potential of compounds from roots of Dendrobium polyanthum Wall. ex Lindl. through inhibition of carbohydrate-digesting enzymes and glycation inhibitory activity

Eight compounds, including one anthraquinone, two bibenzyls, one phenanthrene, three dihydrophenanthrenes, and one flavonoid, were isolated from the roots of Dendrobium polyanthum Wall. ex Lindl. Among these, six compounds were investigated for inhibitory activities against alpha-glucosidase, alpha-amylase, and advanced glycation end products (AGEs) production. Additionally, molecular docking was conducted to analyze the interactions of the test compounds with alpha-glucosidase. Moscatin, the only isolated phenanthrene, displayed the strongest anti–alpha-glucosidase activity with an IC50 of 32.45 ± 1.04 μM, approximately 10-fold smaller than that of acarbose. Furthermore, moscatilin most strongly inhibited alpha-amylase and AGEs production with IC50 values of 256.94 ± 9.87 and 67.89 ± 9.42 μM, respectively. Molecular docking analysis revealed the effective binding of all substances to alpha-glucosidase with smaller lowest binding energy values than acarbose. Moscatin was selected for kinetics studies, and it was identified as a non-competitive inhibitor with approximately 9-fold greater inhibitory capability than acarbose. This study represents the first report on the phytochemical constituents and antidiabetic potential of compounds derived from the roots of D. polyanthum Wall. ex Lindl.

In vitro and in silico assessment of antidiabetic and antioxidant potencies of secondary metabolites from Gymnema sylvestre

This study investigated the chemical constituents, antioxidant potential, and in vitro and in silico antidiabetic activity of Gymnema sylvestre. Column chromatography and spectroscopic techniques identified twelve compounds from the methanol extract, including 4 sterols (1–4), 5 triterpenoids (5–9), and 3 flavonoids (10–12). The chemophenetic significance of all compounds was also investigated. The antioxidant capacity of the extract and compounds (1–4) was evaluated using FRAP and DPPH assays. The extract exhibited strong free radical scavenging activity (IC50 = 48.34 µg/mL), while compounds (1–4) displayed varying degrees of efficacy (IC50 = 98.30–286.13 µg/mL). The FRAP assay indicated significant reducing power for both extract and compounds (58.54, 47.61, 56.61, and 49.11 mg Eq.VitC/g for extract and compounds 1 &2, 3, and 4, respectively). The antidiabetic potential was assessed through α-amylase and α-glucosidase enzyme inhibition assays. The crude extract demonstrated the most potent inhibition (IC50 = 218.46 and 57.42 µg/mL for α-glucosidase and α-amylase respectively) suggesting its potential for managing postprandial hyperglycaemia. In silico studies employed molecular docking and dynamics simulations to elucidate the interactions between identified compounds and α-amylase/α-glucosidase enzymes. The results revealed promising binding affinities between the compounds and target enzymes, with compound 6 demonstrating the highest predicted inhibitory activity with −10 kcal/mol and −9.1 kcal/mol for α-amylase and α-glucosidase, respectively. This study highlights the presence of diverse bioactive compounds in Gymnema sylvestre. The extract exhibits antioxidant properties and inhibits carbohydrate-digesting enzymes, suggesting its potential as a complementary therapeutic approach for managing hyperglycaemia associated with type 2 diabetes.

The antioxidant, anti-obesogenic, and anti-diabetic potential of selected South African marine algal species

South African marine algae are a prevalent traditional medicine utilized by indigenous populations. There has been recent attention on the health advantages of South African marine algae and its bioactive compounds, which have been associated with favourable health outcomes such as diabetes and obesity. This study investigated the antioxidant, anti-obesogenic and anti-diabetic potentials of three South African marine algal species or seaweeds, namely Codium fragile, Radicilingua thysanorhizans and Mazzaella capensis using a variety of in vitro and in silico experiments. The crude extracts, obtained using different solvents (aqueous and ethanol), were examined to assess their total phenolic and total flavonoid content as well as their antioxidant properties by means of 2,2-diphenyl-β-picrylhydrazyl (DPPH), non-site-specific hydroxyl radical (OH•), and nitric oxide (NO) radical scavenging assays. Thereafter, the extracts were subjected to carbohydrate digestive enzyme inhibitory assays, including α-glucosidase and α-amylase, and a lipid digestive enzyme inhibitory assay, such as pancreatic lipase. The glucose uptake by yeast cells was also evaluated in vitro. The subjection of the marine algal extracts to LC-MS analysis revealed several beneficial compounds. These compounds were further docked against α-glucosidase and α-amylase, and a lipid digestive enzyme, pancreatic lipase. The results of this study indicate that the selected South African marine algae possess potent antioxidant capacity while also exhibiting anti-obesogenic and anti-diabetic activities by inhibiting carbohydrate and lipid digesting enzyme activity as well as by increasing glucose uptake in yeast cells. Evaluated ADME profiles revealed that the compounds of these plants have excellent bioavailability and are considered safe for consumption. Overall, the results of this study suggest that all studied seaweeds have potential antioxidant, anti-diabetic, and anti-obesogenic potentials with Codium fragile found to be the most promising among them. The current work serves as a validation of the data currently available regarding the antioxidant, anti-obesogenic and anti-diabetic potential of C. fragile. The study will also serve as a first-report of the aforementioned activities for R. thysanorhizans and M. capensis.

Review on the Anti-Hyperglycemic Potential of Psidium guajava and Seriphium plumosum L.

The treatment and management of diabetes mellitus (DM) with conventional therapies, such as insulin injections and oral hypoglycemic agents, present significant challenges due to their side effects and burdensome administration. Therapies often manage symptoms rather than addressing insulin regulation, akin to medications like thiazolidinediones and glinides, which resemble many medicinal plants. Medicinal plants offer potential alternative treatments due to bioactive compounds targeting diabetes causes. We aimed to explore the antidiabetic potential of two medicinal plants, Psidium guajava and Seriphium plumosum L., by investigating their phytochemical constituents, medicinal uses, pharmacological actions, and mechanisms. This review followed specific guidelines and searched databases including PubMed, Scopus, ScienceDirect, and Web of Science for studies on medicinal plants and DM. Eligible studies underwent quality assessment and were categorized based on their design and interventions for data synthesis. This review identified the phytochemical constituents in Psidium guajava and Seriphium plumosum L., including tannins, flavonoids, phenols, and steroids, exerting antidiabetic effects through various mechanisms like antioxidant activity, anti-inflammatory effects, stimulation of insulin secretion, glucose regulation, and inhibition of carbohydrate-digesting enzymes. Psidium guajava and Seriphium plumosum L. exhibit promising antidiabetic potential, offering alternative approaches to diabetes management. Polyherbalism, combining multiple plant extracts, may enhance therapeutic efficacy in diabetes treatment. Comprehensive research is needed to explore the combined therapeutic effects of these plants and develop more effective antidiabetic treatments. This review highlights the importance of harnessing natural resources to combat the global burden of DM. Further research is warranted to fully explore the combined therapeutic effects of these plants and develop novel treatments.

New Insights into the Potential Inhibitory Effects of Native Plants from Cyprus on Pathogenic Bacteria and Diabetes-Related Enzymes

Plants possess endless structural and chemical diversity, which is peerless with any synthetic library of small biomolecules, inspiring novel drug discovery. Plants are widely applied to encounter global health challenges such as antimicrobial resistance and diabetes. The objective of this work was to evaluate the antibacterial and antidiabetic potency of native plants grown in Cyprus. All plants were sequentially extracted with solvents of increasing polarity, namely hexane, acetone, methanol, and water. First, the phenolic and flavonoid contents of the extracts were assessed. Afterwards, the bacteriostatic and bactericidal potency of plant extracts were tested against a panel of six bacteria using the broth microdilution method, whereas the inhibitory effects on alpha-glucosidase and alpha-amylase enzymes were also determined with the employment of microplate assays. The results highlighted the superiority of Sarcopoterium spinosum as a potential enzyme inhibitor, while a knowledge base was also acquired for the inhibitory potential of all plants. Daucus carota, Ferula communis, and Tordylium.aegyptiacum displayed additionally outstanding bacteriostatic and bactericidal effects on Gram-positive bacteria at concentrations of 250 µg mL−1 and 500 µg mL−1. Overall, the present study describes the antibacterial and inhibitory activity against carbohydrate digestive enzymes of native plants grown in Cyprus delivering the first reports for many plant species.

Pichia pastoris Mediated Digestion of Water-Soluble Polysaccharides from Cress Seed Mucilage Produces Potent Antidiabetic Oligosaccharides.

Diabetes mellitus is a heterogeneous metabolic disorder that poses significant health and economic challenges across the globe. Polysaccharides, found abundantly in edible plants, hold promise for managing diabetes by reducing blood glucose levels (BGL) and insulin resistance. However, most of these polysaccharides cannot be digested or absorbed directly by the human body. Here we report the production of antidiabetic oligosaccharides from cress seed mucilage polysaccharides using yeast fermentation. The water-soluble polysaccharides extracted from cress seed mucilage were precipitated using 75% ethanol and fermented with Pichia pastoris for different time intervals. The digested saccharides were fractionated through gel permeation chromatography using a Bio Gel P-10 column. Structural analysis of the oligosaccharide fractions revealed the presence of galacturonic acid, rhamnose, glucuronic acid, glucose and arabinose. Oligosaccharide fractions exhibited the potential to inhibit α-amylase and α-glucosidase enzymes in a dose-dependent manner in vitro. The fraction DF73 exhibited strong inhibitory activity against α-amylase with IC50 values of 38.2 ± 1.12 µg/mL, compared to the positive control, acarbose, having an IC50 value of 29.18 ± 1.76 µg/mL. Similarly, DF72 and DF73 showed the highest inhibition of α-glucosidase, with IC50 values of 9.26 ± 2.68 and 50.47 ± 5.18 µg/mL, respectively. In in vivo assays in streptozotocin (STZ)-induced diabetic mice, these oligosaccharides significantly reduced BGL and improved lipid profiles compared to the reference drug metformin. Histopathological observations of mouse livers indicated the cytoprotective effects of these sugars. Taken together, our results suggest that oligosaccharides produced through microbial digestion of polysaccharides extracted from cress seed mucilage have the potential to reduce blood glucose levels, possibly through inhibition of carbohydrate-digesting enzymes and regulation of the various signaling pathways.

Evaluation of Mediterranean Tree Leaves as Valuable Biomass of Digestive Enzymes and Bacterial Inhibitors in the Concept of Circular Bioeconomy

This study aspires to evaluate the antibacterial and inhibitory effects of carbohydrate digestive enzymes in tree leaves that are widely distributed in the Mediterranean region. Leaves were sequentially extracted with solvents of increasing polarity. The results demonstrated a wide range of phenolic (3.5–770.7 mg gallic acid equivalent g−1) and flavonoid (0.2–321.3 mg catechin equivalent g−1) contents in leaf extracts. The minimum inhibitory and bactericidal concentration of leaf extracts was determined for six bacteria using the broth microdilution method. The polar extracts of carob, lentisk, and white mulberry leaves exerted strong antibacterial potency against Gram-positive bacteria, while the susceptibility of Escherichia coli on relative apolar extracts of carob, fig, and olive leaves was also observed. In parallel, the inhibitory effects of leaf extracts on carbohydrate digestive enzymes were evaluated. A robust inhibition of α-glucosidase was found for carob and lentisk leaf extracts, followed by extracts produced by white mulberry and olive leaves. Carob and lentisk leaves also act as a-amylase inhibitors at high concentrations. Overall, this study provides valuable data for the nutraceutical value of the “forgotten” treasure of Mediterranean tree leaves and assesses these plants as potential sources of antibacterial and carbohydrate digestive enzyme inhibitory agents for drug discovery.

Genomic insights into Streptomyces hygroscopicus subsp. hygroscopicus SRF1: a potential biocontrol agent against fusarium wilt with plant growth-promoting abilities in tomatoes

ABSTRACT Streptomyces sp. isolate SRF1 has previously demonstrated promising results in controlling various plant fungi under in vitro conditions. However, further exploration of its genome and its efficacy in disease control and plant growth promotion under in vivo conditions is warranted. This study aimed to utilise whole genome sequencing (WGS) to classify Streptomyces sp. isolate SRF1 at the species level and predict genes associated with antagonistic ability and plant growth promotion, thereby assessing its potential as a biocontrol agent against fusarium wilt and a promoter of plant growth. WGS was employed to elucidate the taxonomic classification of isolate SRF1 and predict genes involved in disease suppression and plant growth promotion. In vitro assays were conducted to evaluate its antagonistic activity against Fusarium oxysporum f. sp. lycopersici (Fol) and its production of cellulase, amylase, indole-3-acetic acid (IAA), and siderophores. Pot experiments were carried out using SRF1 cell suspension and culture filtrate to assess its efficacy against Fol and its impact on tomato growth. Real-time PCR analysis was performed to correlate gene expression levels with observed activities. The results showed that isolate SRF1 was classified as S. hygroscopicus subsp. hygroscopicus and demonstrated antagonism against Fol. Furthermore, WGS revealed genes or gene clusters associated with disease control, including those encoding antifungal agents such as butyrolactol A, nigericin, and hygromycin A. Additionally, genes responsible for auxin biosynthesis, siderophore production, and carbohydrate-digesting enzymes such as chitinase, cellulase, and amylase were identified, suggesting potential roles in disease suppression and plant growth promotion.

Investigating the effect of polyphenols from nuts on human carbohydrate digestion in vitro

Recent studies have documented the importance of postprandial hyperglycaemia in the incidence of chronic diseases, including type 2 diabetes. Inhibition of digestive enzymes, including membrane-bound brush-border α-glucosidases, leads to slowed carbohydrate digestion and absorption, and reduced postprandial glycemia. Nuts are widely eaten around the world and have the potential to inhibit α-glucosidases through their content of polyphenols and other bioactive compounds. According to our recent systematic review(1), no study has investigated the inhibitory effects of nut extracts on human α-glucosidase activities. Almost all studies in this area have been conducted on yeast α-glucosidase, with only a few using rat α-glucosidase. While there is no sequence homology between yeast and human α-glucosidase, there is 74% to 78% sequence homology between rat and human α-glucosidases(1). The lack of studies on the effect of bioactive compounds from nuts on human α-glucosidases, along with the growing attention to nuts as an important component of a healthy diet with the potential to reduce the risk of chronic diseases(2), highlights the need for research to evaluate the inhibitory effect of nut extracts on human α-glucosidases. The aim of the current study is to explore the inhibitory effect of extracts from nuts on human carbohydrate digestive enzymes. Walnuts and almonds were ground and defatted with hexane, extracted in 80% (v/v) acetone, and further purified using solid-phase extraction to obtain phenolic-rich extracts. The Folin–Ciocalteu assay was used to approximate the polyphenol content of the samples. Following our recently published detailed protocol(3), cell-free extracts from human intestinal Caco-2/TC7 cells were used as a source of α-glucosidase in enzyme inhibition assays, with sucrose, maltose and isomaltose as substrates and appropriate controls. The assay products were quantified using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Glucose production in the presence of various concentrations of phenol-rich nut extracts was compared using a one-way ANOVA and half-maximal inhibitory concentration (IC50) values were calculated. The Folin–Ciocalteu data demonstrate that walnut extracts comprise a relatively high polyphenol content, with 18.1 ± 0.23 mg (epigallocatechin gallate [EGCG] equivalent) per gram of fresh weight, while almond extracts contain 0.87 ± 0.03 mg EGCG equivalent/g of fresh weight. The walnut phenolic-rich extract dose-dependently inhibited human intestinal sucrase and maltase activities (both p&lt;0.01), with IC50 values of 1.67 mg/mL and 2.84 mg/mL, respectively. We demonstrate that phenolic-rich walnut extracts can inhibit human α-glucosidases in vitro and therefore walnuts may contribute to slowing carbohydrate digestion in humans. As such, we plan to assess the effects of walnuts on postprandial glycaemia in vivo.

Biochemical properties and hydrolytic activity in the nutria (Myocastor coypus) digestive tract

Current understanding of site-specific digestion of carbohydrates in mammals is that whereas starch can be degraded by mammalian enzymes, other complex carbohydrates (e.g. pectin, inulin, xylan or cellulose) are typically digested by the enzymes of symbiotic microbes. To test whether the previously reported presence of complex carbohydrate-digesting enzymes in the small intestine of sheep represent actual small intestinal enzyme activity or just outflux of microbial enzymes from the forestomach, we applied the same methodology of isolating enzymes from gastrointestinal contents and applying them in vitro to test substrates in nutria (Myocastor coypus), a hindgut-fermenting rodent without a forestomach. No enzymatic activity against carbohydrates was detected in the stomach, excluding an effect of coprophagy on the presence of the investigated enzymes. While – as expected – starch digestion was highest in the small intestine, and that of the other carbohydrates was highest in the caecum, there was nevertheless detectable enzymatic activity against pectin, inulin, xylan and cellulose in the small intestine. Further investigations notwithstanding, we suggest that these results indicate a certain degree of unspecific carbohydrase activity by small intestinal enzymes that plays no relevant role in vivo due to the short residence time of digesta in the small intestine.

Understanding Antidiabetic Potential of Oligosaccharides from Red Alga Dulse Devaleraea inkyuleei Xylan by Investigating α-Amylase and α-Glucosidase Inhibition.

In this study, the α-glucosidase (maltase-glucoamylase: MGAM) and α-amylase inhibitory properties elicited by xylooligosaccharides (XOSs) prepared from dulse xylan were analysed as a potential mechanism to control postprandial hyperglycaemia for type-2 diabetes prevention and treatment. Xylan was purified from red alga dulse powder and used for enzymatic hydrolysis using Sucrase X to produce XOSs. Fractionation of XOSs produced xylobiose (X2), β-(1→3)-xylosyl xylobiose (DX3), xylotriose (X3), β-(1→3)-xylosyl-xylotriose (DX4), and a dulse XOS mixture with n ≥ 4 xylose units (DXM). The different fractions exhibited moderate MGAM (IC50 = 11.41-23.44 mg/mL) and α-amylase (IC50 = 18.07-53.04 mg/mL) inhibitory activity, which was lower than that of acarbose. Kinetics studies revealed that XOSs bound to the active site of carbohydrate digestive enzymes, limiting access to the substrate by competitive inhibition. A molecular docking analysis of XOSs with MGAM and α-amylase clearly showed moderate strength of interactions, both hydrogen bonds and non-bonded contacts, at the active site of the enzymes. Overall, XOSs from dulse could prevent postprandial hyperglycaemia as functional food by a usual and continuous consumption.