Understanding the bioaccessibility, α-amylase and α-glucosidase enzyme inhibition kinetics of Allmania nodiflora (L.) R.Br. ex Wight polyphenols during in vitro simulated digestion

Phytochemical composition, simulated digestive bioaccessibility and cytotoxicity of Ficus auriculata Lour. fruits: In vitro and in silico insights

Ficus auriculata Lour. (Moraceae) is an underutilized wild edible fruit widely consumed for its nutritional properties. The present study aimed to determine the phytochemical composition and in vitro antioxidant, enzyme inhibitory, anti-inflammatory and anti-cancerous properties of the F. auriculata fruit extracts through in vitro digestion (oral, gastric and intestinal phases). The extracts were obtained by hot extraction and cold maceration methods using aqueous and methanolic solvents. Major phytoconstituents identified through LC-MS was subjected to molecular docking against the target proteins. The elemental analysis shows the presence of major elements; high levels of total phenolics (124.61 ± 0.82 mg gallic acid equivalent/g), flavonoids (76.38 ± 0.82 mg quercetin equivalent/g), vitamin E (32.48 ± 0.09 mg alpha-tocopherol equivalent/g), and carbohydrate (34.59 ± 0.45 mg glucose equivalent/g) in hot extracted methanolic undigested extract (HEM UD) and high level of total protein (124.71 ± 0.34 mg bovine serum albumin equivalent/g) in cold extracted methanolic undigested fruit extract were found. HEM UD showed high antioxidant activity in 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picryl-hydrazyl, and superoxide radical scavenging assays with IC50 of 53.30 ± 0.57, 80.69 ± 0.12, and 65.47 ± 1.13 μg/mL, respectively. The HEM UD extract also potentially inhibited the enzyme activity of α-amylase, α-glucosidase, tyrosinase, and protein denaturation (IC50 of 67.76 ± 1.22, 83.18 ± 1.23, 87.24 ± 1.15, and 65.76 ± 0.60 μg/mL). The most potent extract (HEM UD) was studied for its anticancer effects by MTT assay against the MCF-7 and HeLa cell lines and showed the IC50 of 89.80 ± 0.56 and 60.76 ± 0.04 μg/mL, respectively. The LC-MS analysis elucidated ten phytoconstituents. Based on the molecular docking study, querciturone could potentially be an effective constituent in treating diabetes and inflammation-related issues. The findings indicated the ability of F. auriculata fruits as a promising functional food.

Natural α-glucosidase inhibitors from Aquilaria sinensis leaf-tea: Targeted bio-affinity screening, identification, and inhibition mechanism

Aquilaria sinensis leaves have long been consumed as a popular replacement tea for lowering postprandial blood glucose levels, but their specific functional components remain unclear. In this study, Aquilaria sinensis leaf-tea 70 % ethanol extract (ALTE) exhibited excellent anti-α-glucosidase activity (IC50 = 6.93 ± 1.91 μg/mL) and promoted glucose consumption ability in 3 T3-L1 preadipocyte cells. Subsequently phenolic compositions of ALTE were identified for the first time. After that, five potential α-glucosidase inhibitors (α-GIs) including cynaroside-3,5-diglucose, malvidin 3-glucose, epicatechin, epigallocatechin gallate, and dihydromyricetin in ALTE were screened using a targeted bio-affinity ultrafiltration-HPLC/MS method. Moreover, these five α-GIs all showed good anti-α-glucosidase effects and glucose consumption-promoting ability. Furthermore, the binding properties and inhibition mechanisms of five α-GIs to α-glucosidase were further analyzed via enzyme inhibition kinetics, molecular docking, and molecular dynamics simulation. This study confirms that Aquilaria sinensis leaf-tea is effective in preventing post-hyperglycemia in vitro models, suggesting potential for future research in human trials.

Roasted yerba mate (Ilex paraguariensis) infusions in bovine milk model before and after in vitro digestion: Bioaccessibility of phenolic compounds, antioxidant activity, protein-polyphenol interactions and bioactive peptides

Yerba mate is increasingly acknowledged for its bioactive properties and is currently being incorporated into various food and pharmaceutical products. When roasted, yerba mate transforms into mate tea, consumed as a hot aqueous infusion, and has gained popularity. This study investigated the bioaccessibility of phenolic compounds, protein-polyphenol interactions, antioxidant activity, and bioactive peptides in roasted yerba mate infusions, utilizing whole, semi-skimmed, and skimmed bovine milk models. The phytochemical profile of roasted yerba mate was analyzed in infusions with water and milk (whole, semi-skimmed, and skimmed), before and after in vitro digestion, identifying 18 compounds that exhibited variations in composition and presence among the samples. Bioavailability varied across different milk matrices, with milk being four times more efficient as a solvent for extraction. Gastric digestion significantly impacted (p < 0.05) the release of phenolic compounds, such as chlorogenic acid and rutin, with only chlorogenic acid remaining 100 % bioavailable in the infusion prepared with skimmed milk. Protein-polyphenol interaction did not influence protein digestion in different infusions, as there was a similarity in the hydrolysis pattern during the digestive process. Changes in antioxidant activity during digestion phases, especially after intestinal digestion in milk infusions, were related to alterations in protein structures and digestive interactions. The evaluation of total phenolic compounds highlighted that skimmed milk infusion notably preserved these compounds during digestion. Peptidomic analysis identified 253, 221, and 191 potentially bioactive peptides for whole, semi-skimmed, and skimmed milk-digested infusions, respectively, with a focus on anti-inflammatory and anticancer activities, presenting a synergistic approach to promote health benefits. The selection of milk type is crucial for comprehending the effects of digestion and interactions in bioactive compound-rich foods, highlighting the advantages of consuming plant infusions prepared with milk.

Hypoglycemic Effects of Gynura divaricata (L.) DC Polysaccharide and Action Mechanisms via Modulation of Gut Microbiota in Diabetic Mice

Aiming to provide a basis for the application of Gynura divaricata (L.) DC polysaccharide (GDP) in functional foods, the hypoglycemic effects of GDP, and action mechanisms, were investigated. Results showed that GDP effectively inhibited α-glucosidase and remarkably increased the glucose absorption, glycogen content, and pyruvate kinase and hexokinase activities of insulin-resistant HepG2 cells, indicating its potent in vitro hypoglycemic effect. In streptozotocin-induced type 2 diabetes mice, GDP significantly improved various glycolipid metabolism-related indices in serum and liver, e.g., fasting blood glucose, oral glucose tolerance, glycosylated serum protein content, serum insulin level, antioxidant enzyme activities, TG, TC, LDL-C, and HDL-C levels, and hepatic glycogen content, and recovered the structure of gut microbiota to the normal level. It was also found that GDP significantly affected the expression of related genes in the PI3K/Akt, AMPK, and GS/GSK-3β signaling pathways. Therefore, GDP regulates blood glucose possibly by directly inhibiting α-glucosidase, exerting antioxidant activity, and regulating intestinal microbiota.

In Vitro Gastrointestinal Digestion of Various Sweet Potato Leaves: Polyphenol Profiles, Bioaccessibility and Bioavailability Elucidation

The chemical composition discrepancies of five sweet potato leaves (SPLs) and their phenolic profile variations during in vitro digestion were investigated. The results indicated that Ecaishu No. 10 (EC10) provided better retention capacity for phenolic compounds after drying. Furthermore, polyphenols were progressively released from the matrix as the digestion process proceeded. The highest bioaccessibility of polyphenols was found in EC10 intestinal chyme at 48.47%. For its phenolic profile, 3-, 4-, and 5-monosubstituted caffeoyl quinic acids were 9.75%, 57.39%, and 79.37%, respectively, while 3,4-, 3,5-, and 4,5-disubstituted caffeoyl quinic acids were 6.55, 0.27 and 13.18%, respectively. In contrast, the 3,4-, 3,5-, 4,5-disubstituted caffeoylquinic acid in the intestinal fluid after dialysis bag treatment was 62.12%, 79.12%, and 62.98%, respectively, which resulted in relatively enhanced bioactivities (DPPH, 10.51 μmol Trolox/g; FRAP, 8.89 μmol Trolox/g; ORAC, 7.32 μmol Trolox/g; IC50 for α-amylase, 19.36 mg/g; IC50 for α-glucosidase, 25.21 mg/g). In summary, desirable phenolic acid release characteristics and bioactivity of EC10 were observed in this study, indicating that it has potential as a functional food ingredient, which is conducive to the exploitation of the sweet potato processing industry from a long-term perspective.

A new α-amylase inhibitory peptide from Gynura medica extract

In this study, we discovered a novel peptide, Gymepeptide A, with α-amylase inhibitory activity in the water extract of Gynura medica. The structure of Gymepeptide A was determined as CGDREETR using HR-MS, 1H NMR, 13C NMR, and 2D-NMR techniques. Notably, Gymepeptide A possesses a rare double arginine residue structure and exhibits strong α-amylase inhibitory activity. Enzyme dynamic assays, molecular docking experiments, and isothermal titration calorimetry indicated that the double arginine residue structure of Gymepeptide A interacts with amino acid residues in the nearby active site region of α-amylase through hydrogen bonds and van der Waals forces. This interaction effectively inhibits the hydrolysis activity of α-amylase. Furthermore, in vitro starch digestion tests revealed that Gymepeptide A significantly reduced the digestion rate of starch and the concentration of glucose produced after starch digestion. These findings highlight the great potential of Gymepeptide A in decreasing postprandial blood glucose levels.

Effect of Porphyra haitanensis polyphenols from different harvest periods on hypoglycaemic activity based on in vitro digestion and widely targeted metabolomic analysis

The hypoglycemic effect of Porphyra is well known. Based on in vitro digestion and metabolomics, the bioaccessibility, antidiabetic activity and phenolic conversion of P. haitanensis were investigated at different harvests. Total polyphenol content (TPC), α-glucosidase inhibition and oxygen radical absorbance capacity (ORAC) increased with harvesting and digestion stages, reaching maximum at the fourth harvest. TPC and α-glucosidase inhibition after digestion reached 130-150 mg/g and 50-90 %, ORAC was 8.7-13.5 times higher than the undigestion. However, bioaccessibility in the first and second harvests was 10-80 % higher than other harvests. The phenolic content in the fourth harvest was up-regulated to 2-30 times than the first and mostly were citrus flavonoids. Redundancy analysis indicated significant correlation between phenolic metabolites and bioactivities in different harvests of P. haitanensis during digestion, with the strongest correlation coefficients were apigenin and genistein. This study provides reference for the application of P. haitanensis in treating type 2 diabetes.

Exploring the hypoglycaemic efficacy of bio-accessed antioxidative polyphenolics in thermally processed Cucumis dipsaceus fruits - An in vitro and in silico study

Inhibition of breakdown of dietary carbohydrates, by controlling the postprandial activity of diabetic enzymes through fruit polyphenolics can help downregulate the effects of Type 2 Diabetes Mellitus (T2DM). The study focuses on deciphering the induction of hyperglycaemic control by bio-accessed anti-oxidative polyphenols of Cucumic dipsaceus fruits. Chiefly, we examined the antioxidant activity of bio-accessed polyphenols of C. dipsaceus fruits (DPPH: ME (GDE)-66.26 %; ABTS: FE (IDE)-1963.83 µM TEAC/mg extract; Phosphomolybdenum reduction: FE (IDE)- 64.95 mg AAEAC/g extract). To add more significance, the anti-diabetic activity was predetermined by in silico docking analyses (Pseudojervine - -5.43; Squalene- -10.41) and was concurrently confirmed by in vitro studies (α amylase inhibition: ME (GDE) - 69.58 %; α glucosidase inhibition: FE (UDE)- 88.67 %). A higher bio-accessibility of rutin (37.92 mg/g ODE) and gallic acid (8.36 mg/g ODE) was observed after quantification by HPLC, which confirmed the correlation between anti-diabetic activity and C. dipsaceus fruit phenolic compounds.

Nutritional Composition, Simulated Digestion and Biological Activities of Campomanesia xanthocarpa Fruit

Gabirobeira fruits are known for their rich nutrient content and bioactive phytochemical compounds that contribute to significant biological activities. Despite these attributes, the antioxidant potential and stability of phenolic compounds in gabiroba by-products after digestion have yet to be studied. The objective of this work was to evaluate the physical-chemical composition, antibacterial activity, α-amylase, and α-glucosidase inhibitory effects, as well as the in vitro digestibility of total phenolic compounds, total flavonoids, and antioxidant activity of powder and extract from gabiroba to valorize these byproducts. The gabiroba powder had low moisture, high carbohydrate and fiber content. The extraction using 80% ethanol demonstrated higher antioxidant, antibacterial, α-amylase, and α-glucosidase inhibition activities compared to the 12% ethanol and water extracts. Catechin and ferulic acid were the major phenolic compounds identified by HPLC-DAD. After digestion, both the powder and the gabiroba extract exhibited a bioaccessibility of more than 30% for total phenolic compounds and antioxidant activity during the gastric phase. However, the dry ethanol extract displayed higher total phenolic compounds after both the gastric and intestinal phases compared to the flour. Processing gabiroba into powder and extract is a promising approach to fully utilize this seasonal fruit, minimize waste, concentrate health-beneficial compounds, and valorize a by-product for use as a functional ingredient and raw material within the food and pharmaceutical industries.

In vitro digestibility and hepato-protective potential of Lophatherum gracile Brongn. leave extract

Lophatherum gracile Brongn. (L. gracile) is a traditional herb for both medicine and food use, but its digestibility and hepato-protective activity is unknown. Herein we investigated the digestibility and hepato-protective potential of L. gracile leave extract (LGE) using in vitro digestion and alcohol-induced oxidative damage models. Compared to the undigested group, the content of phenolics/flavonoids and the antioxidant activity in LGE generally decreased by 9.30-19.97% in the oral and small intestine phase after digestion, while that increased by 9.96-10.17% in the gastric phase. The main phenolics/flavonoids showed promising stability during digestion and their bio-accessiblity ranged from 67.64% to 84.47%. By reducing cellular reactive oxidative species and malonaldehyde levels, LGE (0.23-0.45 mg/mL) pretreatment significantly ameliorated alcohol-induced oxidative damage in HepG2 cells (P < 0.05), and their survival rate increased from 59.23% to 67.76%. These findings suggested that L. gracile could be used for the development of hepato-protective foods.

Screening and Characterization of an α-Amylase Inhibitor from Carya cathayensis Sarg. Peel

Inhibiting α-amylase can lower postprandial blood glucose levels and delay glucose absorption, offering an effective approach for the development of antidiabetic diets. In this study, an active constituent with inhibitory activity against α-amylase was isolated and purified by bioassay-guided fractionation from Carya cathayensis Sarg. peel (CCSP). The active constituent was identified by NMR and Q-Exactive Orbitrap Mass Spectrometry as 5-O-p-coumaroylquinic acid (5-CQA). 5-CQA possessed strong inhibitory activity against α-amylase, with an IC50 value of 69.39 µM. In addition, the results of the kinetic study indicated that 5-CQA was a potent, reversible, noncompetitive inhibitor against α-amylase. The findings indicate that 5-CQA derived from CCSP has potential as a novel inhibitor against α-amylase, which can help mitigate postprandial blood sugar spikes, making it suitable for inclusion in antidiabetic diets.

HPLC-DAD-MS Characterization, Antioxidant Activity, α-amylase Inhibition, Molecular Docking, and ADMET of Flavonoids from Fenugreek Seeds

Fenugreek (Trigonella foenum-graecum) has a great beneficial health effect; it has been used in traditional medicine by many cultures. Likewise, the α-amylase inhibitors are potential compounds in the development of drugs for the treatment of diabetes. The beneficial health effects of fenugreek lead us to explore the chemical composition of the seeds and their antioxidant and α-amylase inhibition activities. The flavonoid extraction from fenugreek seeds was achieved with methanol through a Soxhlet apparatus. Then, the flavonoid glycosides were characterized using HPLC-DAD-ESI-MS analysis. The antioxidant capacity of fenugreek seed was measured using DPPH, FRAP, ABTS, and CUPRAC assays. Finally, the α-amylase inhibition activity was carried out using in vitro and in silico methods. The methanolic extract was found to contain high amounts of total phenolics (154.68 ± 1.50 μg GAE/mg E), flavonoids (37.69 ± 0.73 μg QE/mg E). The highest radical-scavenging ability was recorded for the methanolic extract against DPPH (IC50 = 556.6 ± 9.87 μg/mL), ABTS (IC50 = 593.62 ± 9.35 μg/mL). The ME had the best reducing power according to the CUPRAC (A 0.5 = 451.90 ± 9.07 μg/mL). The results indicate that the methanolic extracts of fenugreek seed best α-amylase inhibition activities IC50 = 653.52 ± 3.24 μg/mL. Twenty-seven flavonoids were detected, and all studied flavonoids selected have good affinity and stabilize very well in the pocket of α-amylase. The interactions between the studied flavonoids with α-amylase were investigated. The flavonoids from fenugreek seed present a good inhibitory effect against α-amylase, which is beneficial for the prevention of diabetes and its complications.

In Vitro Anti-Tumor and Hypoglycemic Effects of Total Flavonoids from Willow Buds

Salix babylonica L. is a species of willow tree that is widely cultivated worldwide as an ornamental plant, but its medicinal resources have not yet been reasonably developed or utilized. Herein, we extracted and purified the total flavonoids from willow buds (PTFW) for component analysis in order to evaluate their in vitro anti-tumor and hypoglycemic activities. Through Q-Orbitrap LC-MS/MS analysis, a total of 10 flavonoid compounds were identified (including flavones, flavan-3-ols, and flavonols). The inhibitory effects of PTFW on the proliferation of cervical cancer HeLa cells, colon cancer HT-29 cells, and breast cancer MCF7 cells were evaluated using an MTT assay. Moreover, the hypoglycemic activity of PTFW was determined by investigating the inhibitory effects of PTFW on α-amylase and α-glucosidase. The results indicated that PTFW significantly suppressed the proliferation of HeLa cells, HT-29 cells, and MCF7 cells, with IC50 values of 1.432, 0.3476, and 2.297 mg/mL, respectively. PTFW, at different concentrations, had certain inhibitory effects on α-amylase and α-glucosidase, with IC50 values of 2.94 mg/mL and 1.87 mg/mL, respectively. In conclusion, PTFW at different doses exhibits anti-proliferation effects on all three types of cancer cells, particularly on HT-29 cells, and also shows significant hypoglycemic effects. Willow buds have the potential to be used in functional food and pharmaceutical industries.

Natural deep eutectic ready to use extract of astilbin: Super high in vitro bioaccessibility, α-amylase and α-glucosidase enzyme inhibition kinetics

Astilbin, a natural flavonoid, possesses multiple functionalities, while the poor bioavailability seriously restricts its application in functional food and medicine. Therefore, in this study, a natural deep eutectic solvent (NaDES) with choline chloride: lactic acid (CHCL-LAC) is selected to deliver astilbin by evaluating the bioaccessibility and antioxidant capacity during in vitro gastrointestinal digestion, and the inhibitory effect with underlying mechanism of astilbin-CHCL-LAC against α-amylase/α-glucosidase were investigated. The CHCL-LAC showed significant high astilbin bioaccessibility (84.1% bioaccessible) and DPPH and ORAC antioxidant capacity with 75.7% and 57.7% respectively after 3 h in vitro digestion, which may be attributed by hydrogen bond based supramolecule formed between astilbin and CHCL-LAC. Moreover, significant inhibitions of astilbin-CHCL-LAC on α-amylase (IC50 of 0.67 g/L) and α-glucosidase (IC50 of 0.64 g/L) were observed in mixed competitive and non-competitive manners. The dominant binding force between enzymes and astilbin were the hydrogen and hydrophobic interaction. This is the first time that the underlying mechanisms for astilbin delivered by NaDESs were revealed, suggesting that CHCL-LAC-based NaDESs are promising ready-to-use vehicles of natural inhibitors for carbohydrate-hydrolyzing enzymes.

Simulated Gastrointestinal Digestion of Chestnut (Castanea sativa Mill.) Shell Extract Prepared by Subcritical Water Extraction: Bioaccessibility, Bioactivity, and Intestinal Permeability by In Vitro Assays

Chestnut shells (CSs) are an appealing source of bioactive molecules, and constitute a popular research topic. This study explores the effects of in vitro gastrointestinal digestion and intestinal permeability on the bioaccessibility and bioactivity of polyphenols from CS extract prepared by subcritical water extraction (SWE). The results unveiled higher phenolic concentrations retained after gastric and intestinal digestion. The bioaccessibility and antioxidant/antiradical properties were enhanced in the following order: oral < gastric ≤ intestinal digests, attaining 40% of the maximum bioaccessibility. Ellagic acid was the main polyphenol in the digested and undigested extract, while pyrogallol-protocatechuic acid derivative was only quantified in the digests. The CS extract revealed potential mild hypoglycemic (<25%) and neuroprotective (<75%) properties before and after in vitro digestion, along with upmodulating the antioxidant enzymes' activities and downregulating the lipid peroxidation. The intestinal permeation of ellagic acid achieved 22.89% after 240 min. This study highlighted the efficacy of the CS extract on the delivery of polyphenols, sustaining its promising use as nutraceutical ingredient.

Microwave-Induced Behavior and Digestive Properties of the Lotus Seed Starch-Chlorogenic Acid Complex

The effect of chlorogenic acid (CA) on the dielectric response of lotus seed starch (LS) after microwave treatment, the behavior and digestive characteristics of the resulting starch/chlorogenic acid complex (LS-CA) at different degrees of gelatinization and the inhibition of α-amylase by chlorogenic acid were investigated. The variation in dielectric loss factor, ε″, and dielectric loss tangent, tanδε, of the microwave thermal conversion indicated that LS-CA had a more efficient microwave-energy-to-thermal-energy conversion efficiency than LS. This gelatinized LS-CA to a greater extent at any given temperature between 65 and 85 °C than LS, and it accelerated the degradation of the starch crystalline structure. The greater disruption of the crystal structure decreased the bound water content and increased the thermal stability of LS-CA compared to LS. The simulated in vitro digestion found that the presence of the LS-CA complex improved the slow-digestion property of lotus seed starch by increasing its content of resistant and slowly digested starch. In addition, the release of chlorogenic acid during α-amylase hydrolysis further slowed starch digestion by inhibiting α-amylase activity. These findings provide a foundation for understanding the correlation between the complex behavior and digestive properties of naturally polyphenol-rich, starch-based foods, such as LS, under microwave treatment, which will facilitate the development of starch-based foods with tailored digestion rates, lower final degrees of hydrolysis and glycemic indices.

Physicochemical property changes of Dendrobium officinale leaf polysaccharide LDOP-A and it promotes GLP-1 secretion in NCI-H716 cells by simulated saliva-gastrointestinal digestion

A polysaccharide LDOP-A with a molecular weight of 9.9 kDa was isolated and purified from Dendrobium officinale leaves by membrane separation, cellulose column, and dextran gel column. The Smith degradable products, methylation products, and nuclear magnetic resonance analysis showed that LDOP-A may be composed of →4)-Glc-(1→, →3,6)-Man-(1→, and →6)-Glc-(1→sugar residues. In vitro, simulated digestion assays showed that LDOP-A could be partially digested in the stomach and small intestine, and produced a large amount of acetic acid and butyric acid during colonic fermentation. Further cell experiment results illustrated that LDOP-A-I (LDOP-A digested by gastrointestinal tract) could induce glucagon-like peptide-1 (GLP-1) secretion in NCI-H716 cells without showing any cytotoxicity.

Hesperetin-Cu(II) complex as potential α-amylase and α-glucosidase inhibitor: Inhibition mechanism and molecular docking

Inhibition of α-amylase and α-glucosidase activity is an effective way for controlling postprandial blood glucose-related diabetes. The study found that hesperetin-Cu(II) complex (Hsp-Cu(II)) exhibited a stronger inhibitory ability on α-amylase and α-glucosidase compared to hesperetin (Hsp), with smaller IC₅₀ values of Hsp-Cu(II) (60.3 ± 0.9 µM for α-amylase; 1.25 ± 0.03 µM for α-glucosidase) than Hsp (115.6 ± 1.1 µM for α-amylase; 55.2 ± 0.1 µM for α-glucosidase). Interestingly, Hsp-Cu(II) and acarbose exerted a synergistic effect on inhibition of α-glucosidase. The binding affinities of Hsp-Cu(II) to α-amylase and α-glucosidase were strong with the Ka values (binding constant) in the magnitude order of 10⁵, which was 9 times larger than Hsp. After interacting, Hsp-Cu(II) reduced α-helix contents of α-amylase and α-glucosidase, resulting in a looser conformation of these two enzymes. Molecular simulations manifested that Hsp-Cu(II) bound to the active center of enzymes driven by hydrogen bonds and interacted with the key catalytic amino acids (α-amylase: Gln63, Asp300 and His305; α-glucosidase: Tyr158, Asp215, Glu277 and Glu411), altering the conformation of enzymes, blocking the entrance of substrates, ultimately reducing the activities of α-glucosidase and α-amylase. This study has demonstrated that Hsp-Cu(II) may be a promising candidate of functional nutritional additive and medicine for the prevention of diabetes.

Improved performance of metal-organic frameworks loaded cellulose acetate based film for packaging application

Bio-nanocomposite-based packaging materials have gained significance due to their possible applications in food packaging. Cellulose acetate is a biopolymer obtained by acetylation of cellulose and has characteristics such as biocompatibility, biodegradability and high transparency. Introducing iron-based metal-organic frameworks offer good mechanical strength, unique surface area and both chemical and thermally stability, making them favourable as supporting materials in fabricating polymer-based packaging materials. Among them, Fe- (Material Institute Lavoisier) MIL-88A is an iron-based nontoxic metal-organic framework, integrated with cellulose acetate and spinach extract was added to the prepared material in different compositions and cast as film. The Spinach loaded, Fe- (Material Institute Lavoisier) MIL-88A integrated cellulose acetate film significantly enhanced the tensile strength, water vapour permeability, and anti-microbial activity. The prepared film is then characterized using a scanning electron microscope (SEM), Fourier transforms infrared spectrometer (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Further, studies on mechanical properties as well as degradation tests and real-time applications of the prepared films were carried out.

Structure-activity relationships and the underlying mechanism of α-amylase inhibition by hyperoside and quercetin: Multi-spectroscopy and molecular docking analyses

Inhibiting the activity of α-amylase has been considered an effective strategy to manage hyperglycemia. Hyperoside and quercetin are the main natural flavonoids in various plants, and the inhibition mechanism on α-amylase remains unclear. In this study, the structure-activity relationships between hyperoside/quercetin and α-amylase were evaluated by enzyme kinetic analysis, multi-spectroscopic techniques, and molecular docking analysis. Results showed that hyperoside and quercetin exhibited significant α-amylase inhibitory activities with IC₅₀ values of 0.491 and 0.325 mg/mL, respectively. The α-amylase activity decreased in the presence of hyperoside and quercetin in a competitive and noncompetitive manner, respectively. UV-vis spectra suggested that the aromatic amino acid residues (Trp and Tyr) microenvironment of α-amylase changed in the presence of these two flavonoids. FTIR and CD spectra showed the vibrations of the amide bands and the secondary structure content changes. The fluorescence quenching mechanism of α-amylase by hyperoside and quercetin belonged to the static quenching type. Finally, molecular docking intuitively showed that hyperoside/quercetin formed hydrogen bonds with the key active site residues (Asp197, Glu233, and Asp300) in α-amylase. MD simulation indicated hyperoside/quercetin-α-amylase docked complexes had good stability. Taken together, this research provides new sights to developing potent drugs or functional foods with hyperoside and quercetin, offering new avenues for hyperglycemia treatment.