Phenolic Hydroxyl Research Articles

Pd-Catalyzed Migratory 1,1-Cycloannulation Reaction of Alkenes.

Here, we report a novel strategy for the preparation of diverse heterocycles via a Pd-catalyzed migratory 1,1-cycloannulation reaction (MCAR) of alkenes. Starting from readily available alkenyl amines and alkenyl alcohols, this approach allows the formation of a wide range of five- to seven-membered azaheterocycles and oxaheterocycles with high efficiency and good functional group tolerance. The key to the realization of this reaction is the use of 4-iodophenol or 2-iodophenol derivatives where the phenolic hydroxyl group plays a critical role in controlling the direction of migration and the ring-size of the heterocycles through the formation of a quinone methide intermediate.

High-Performance Triple-Network Hydrogels Derived from Chrome Leather Scraps: Ultrahigh Compressive Strength, Adhesion, and Self-Recovery.

The development of engineered hydrogels with high strength, self-recovery, and adhesion is essential for applications requiring resistance to large deformations and cyclic loading. Herein, a triple-network (TN) hydrogel with ultrahigh compressive strength, strong adhesion, and good self-recovery was constructed by using tannic acid-modified chrome leather scrap hydrolysate as the first network, polyacrylamide as the second network, and poly-2-propenamide-2-methylpropanesulfonic acid as the third network. The ultrahigh (70 MPa compressive strength and 95% compression deformation) TN hydrogels were effectively created, which is attributed to the synergy of the three networks. The TN hydrogels display adhesion (adhesion strength > 20 kPa) ascribed to the introduction of phenolic hydroxyl groups in tannic acid. Intriguingly, the TN hydrogels exhibit excellent self-recovery performance (93.6% dissipated energy recovery at 70 °C) and shape memory performance (restored to the original shape in 20 s). These properties are essential for the development of high-performance hydrogels and promote the resource utilization of leather waste.

Design, Synthesis, and Evaluation of Benzoxazine Copolymers for Anti‐Corrosion Coating Applications Based on Improved High Crosslinking Density and Hydrophobicity

ABSTRACTThe main‐chain benzoxazine (BA‐ddm) and diamine‐type benzoxazine (Ph‐hda) were prepared by solution method, and a series of copolymers were prepared by mixing them at various mass ratios. Second, copolymer coatings (P(PB)) were prepared on the surface of the tinplate by dip coating and heat curing. The results of FTIR and 1HNMR showed that the benzoxazine copolymer coating was successfully prepared. DSC test results showed that the copolymerization of two benzoxazine oligomers was promoted by the introduction of BA‐ddm containing phenolic hydroxyl groups. The introduction of Ph‐hda containing a long aliphatic chain provided the copolymer coatings with good hydrophobicity, as verified by the hydrophilicity and hydrophobicity tests. When the mass ratio of BA‐ddm to Ph‐hda was 1:19, the water contact angle and water absorption of P(PB5) were 100.10% and 0.56%, respectively. The results of dynamic polarization curves and electrochemical impedance spectroscopy (EIS) indicated that different copolymer coatings had good corrosion resistance. Among them, the P(PB5) coating exhibited the best anti‐corrosion performance, with a corrosion current of 5.15 × 10−8 A cm−2, a protection efficiency of 99.23%, and an impedance modulus of 1.78 × 107 Ω cm2 at 0.01 Hz, which was nearly 5 orders of magnitude higher than the impedance modulus of the blank tinplate.

Enhancing stability and physiological activity of Aronia melanocarpa L. anthocyanin by polysaccharides.

The existence of multiple phenolic hydroxyl groups in anthocyanins makes their structure unstable and leads to the degradation of anthocyanins. At present, there are few studies on the stability and physiological activity of Aronia melanocarpa L. anthocyanins by different polysaccharides. The present study investigated the effects of carboxymethyl cellulose (CMC), pectin and xanthan gum (XG) on the stability and biological activities of A. melanocarpa L. anthocyanins. The anthocyanins of A. melanocarpa L. (AAM) were successfully extracted from A. melanocarpa L. with an extraction rate of 3.07 mg g-1 by single factor and response surface experiments. The results of scanning electron microscopy and a multispectral technique showed that AAM-polysaccharides complex was combined by hydrogen bond, cation-π interaction and electrostatic interaction. The AAM-polysaccharides complex improved the retention rate of anthocyanins after treatment with light, heating, oxidant reducing agent, metal ions and preservatives compared to the results for AAM alone. Determination of DPPH· scavenging capacity, ABTS+ scavenging capacity and total reducing capacity indicated that the presence of polysaccharide could improve the antioxidant activity of AAM in vitro. The three polysaccharides combined with AAM showed higher binding ability to taurocholate and glycocholate compared to the AAM group, with the AAM-XG binding rate being the highest at 27.61% and 20.61%, respectively. The tyrosinase inhibition rate significantly increased with the incorporation of XG, reaching 72.22%. The stability and physiological activity of AAM were improved after the addition of CMC, pectin and XG in the simulated system, and the presence of XG showed greater advantages. The present study strongly suggests that anthocyanins driven by polysaccharides have a positive effect on the stability and physiological activity of anthocyanins and may also provide a research basis for the development of processing technology for anthocyanins in food. © 2024 Society of Chemical Industry.

Bleached rice straw lignin: Thermal-chemical properties and its application in polyurethane-based paper coatings

Rice straw lignin (LRS) tends to be dark in color, which makes it less appealing for material applications. Therefore, a bleaching process involving lignin oxidation is of interest. This study aimed to investigate the mechanical and chemical properties of bleached LRS and explore its potential application in PU-based paper coatings. LRS and commercial lignin (LC) were subjected to bleaching using 29% H2O2 through oxidation treatment. The bleached lignin was then used to prepare PU-based paper coatings. The effects of bleaching treatment on the functional groups, structural, and thermal properties of lignin, as well as the water resistance of the PU composites were assessed. The oxidation treatment resulted in a reduction in the phenolic hydroxyl content, methoxy content, antioxidant activity, and equivalent weight of lignin. However, LRS exhibited greater thermal resistance than did LC. The bleached LRS was successfully integrated with toluene di-isocyanate (TDI) to produce transparent polyurethane. This polyurethane was then applied as a coating for paper containers, which successfully held cold water for over 4 h without leaking, indicating its outstanding water repellency.

A novel chitosan/quercetin-based film enables non-enzymatic detection of glucose: Electrochemical and fluorescent behavior

In this study, a novel functional hydrogel film was synthesized using natural polymer chitosan and quercetin as raw materials. Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS) analysis indicate that phenylboronic acid modified carbon nanodots (PBA-CDs) were successfully prepared via a simple microwave-assisted hydrothermal method. The experimental results demonstrate that a dual electrochemical and fluorescence detection of glucose can be realized based on the boronate ester bonding between chitosan/quercetin (Chit0/Quer) films and PBA-CDs. The addition of PBA-CDs hinders the electron transfer between the phenolic hydroxyl groups of quercetin and the redox mediators, and inhibits the intramolecular rotation of quercetin, which leads to a decreased electrical signal and enhanced fluorescence intensity. After the addition of glucose, the peak redox current of the Chit0/Quer hydrogel film is restored due to the competitive binding of glucose to the boronate ester, resulting in a dual-input logic circuit for the qualitative detection of glucose. In addition, the fluorescence intensity of the hydrogel decreases with increasing glucose concentration, and the concentration of glucose can be quantitatively detected by detecting the change in fluorescence intensity. Besides, the sensor has better stability and selectivity for biomarkers. Finally, we demonstrate that the electrochemical and fluorescence sensing strategies can be used for the detection of glucose in real beverage samples. In conclusion, based on the redox activity of quercetin and the competitive binding of boronate ester bonds, we explored a new strategy for enzyme-free electrochemical and fluorescence sensing for the detection of glucose, which is expected to be applied in biomedicine, food industry and other fields.

Understanding the role of sodium lignosulphonate on obstructing the aggregation of fine serpentine particles on to the hydrophobized pyrite surface

The slime coatings of serpentine via its hydrophobic Si-O layers significantly weaken the floatability of the hydrophobized sulfide minerals. In this paper, sodium lignosulphonate (SLS) was adopted to avoid the aggregation of fine serpentine particles on to the hydrophobized pyrite surface. The micro-flotation findings indicated that for the artificial mixture of pyrite and serpentine (2:1 mass ratio), 1.0 × 10-4 mol/L sodium isobutyl xanthate (SIBX) only floated out ∼22% pyrite at pH ∼9.0, while, after extra addition of 70 mg/L SLS, the floatability of pyrite was restored and its recovery reached ∼90%. In situ AFM (Atomic Force Microscope), contact angle, zeta potential, fourier transform infrared spectrometer (FTIR) and optical microscope deduced that the strong affinity of SIBX to pyrite rendered it replace the most part of the pre-aggregated SLS from pyrite surface, thus to restore the hydrophobicity of pyrite and further decrease the zeta potential. In addition, SLS attached on the positively-charged Mg sites of serpentine through its carboxyl and phenolic hydroxyl groups reduce the hydrophobicity and zeta potential of serpentine. While, the hard base O atom/anion exhibited much stronger affinity to hard acid Mg cation than that of the soft base S atom/anion, SIBX hardly replaced the adsorbed SLS from serpentine surface. Therefore, the increased electrostatic repulsion and weakened hydrophobic attraction between the SLS-adsorbed serpentine and SIBX-hydrophobized pyrite avoided their aggregation. The combination of SLS and SIBX realized the selective flotation separation of pyrite from serpentine.

Synthetic lignin derived from ferulic acid for UV-blocking sunscreen.

Conventional lignin, a dehydrogenated polymer derived primarily from hydroxycinnamic alcohol monomers, exhibits relatively low antioxidant and ultraviolet (UV)-blocking activities due to its structural imperfection. Herein, we demonstrated that the dehydrogenated polymer of ferulic acid (an unconventional lignin precursor) (FAL) had excellent antioxidant and UV-blocking properties. Structural characterization showed that FAL contains abundant dihydrobenzofuran and butyrolactone structures, free phenolic hydroxyl groups, and cinnamic acid end groups. Such structural characteristics endow FAL with much higher antioxidant activity and broader and stronger UV absorptivity (especially UVA) than conventional lignins. Our investigation showed that FAL could significantly improve the UV-blocking property of commercial SPF30 and SPF50 and render a relatively light color. These versatile properties make the FAL a potential ingredient for application in sunscreen products. This work is enlightening not only for exploring better antioxidant and UV-blocking polymers from the dehydrogenated polymers of phenolic compounds but also for biosynthesizing more advantageous lignin in plants.

Catalytic pyrolysis mechanism of tetrabromobisphenol A by calcium oxide: A density functional theory study

In this paper, the mechanisms of catalytic pyrolysis of tetrabromobisphenol A (TBBPA) by calcium oxide (CaO) were studied through density functional theory methods. The results indicate that the phenolic hydroxyl group of TBBPA is the preferred site for CaO to extract protons, and the generated anion further transforms into 2,6-dibromophenol via demethylation and hydrogen transfer reactions. The reaction activity of CaO with hydrogen bromide is relatively high, with an energy barrier of 133.2 kJ/mol. CaO produces calcium ions, which combine with bromine ions to form calcium bromide to achieve the purpose of fixing bromine. In addition, the participation of calcium ions results in the OH bond being easier to crack, which further lowers the reaction energy barrier of keto-enol tautomerism reactions H2O produced during catalytic pyrolysis also has an obvious catalytic effect, and the energy barrier of the keto-enol tautomerism reaction decreased from 309.1 kJ/mol to 150.6 kJ/mol with the participation of H2O.

Selective adsorption and synchronous reduction of Au from water with difunctional cellulose aerogel: Performance and mechanism

Here, valonia tannin and sulfhydryl functional groups were added to the cellulose aerogel from waste textiles to form a thiol-modified tannin-immobilized cellulose-based aerogel (TVTCA) with selective adsorption and outstanding reducing properties. This aerogel was then utilized to recycle Au(III) in the water. The resulting 3D TVTCA contained abundant -SH groups and phenolic hydroxyl groups and exhibited stable crystal structure and good thermal properties. TVTCA showed excellent Au (Ⅲ) adsorption performance (598.3 mg/g of maximum adsorption capacity) and strong reductivity (78 %). The adsorption process was conducted using both the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. In addition, TVTCA displayed excellent anti-interference ability. Even though the coexisting ions concentration was as high as 100 mmol/L, TVTCA still owned a high Au adsorption capacity (178.91–224.14 mg/g) and selectivity factor (29.16–2629.34), which was much higher than valonia tannin-immobilized cellulose-based aerogel (VTCA). Furthermore, the recycling of Au with TVTCA mainly included adsorption and in-situ reduction processes. The mechanisms involved the electrostatic interaction and chelation effects, which were ascribed to the introduced sulfhydryl groups. Meanwhile, the in-situ Au reduction was mainly caused by the studies showing that the high adsorption capacity of TVTCA was owing to the phenolic hydroxyl groups on the introduced valonia tannin. All the findings would provide a new way to achieve the recycling of precious metals from wastewater by using valuable cotton waste.

Toxicokinetics of benzotriazole UV stabilizer UV-P in humans after single oral administration.

UV-P (2-(2H-Benzotriazol-2-yl)-p-cresol) is used as an ultraviolet (UV) light absorber in coating products, paints, adhesives, and sealants. Due to its widespread industrial and consumer uses, human exposure to UV-P is conceivable. In the study presented herein, initial data on its human invivo metabolism were obtained for three study participants after single oral administration of 0.3mg of UV-P/kg body weight. Urine and blood samples of two volunteers were collected up to 48h after exposure. The third study participant donated urine and blood samples up to 72h. Maximum levels of UV-P in blood of 184 ± 36µg/l (85 ± 3% as conjugates) were reached 2.4 ± 1.2h post-exposure. Maximum excretion rates of UV-P in urine of 2896 ± 884µg/h (completely conjugated) were reached 3.5 ± 1.1h post-exposure. 37.2 ± 5.4% of the orally administered dose of UV-P was recovered in urine within 48h post-exposure. The present study provides insight into the complex absorption, distribution, metabolism, and elimination (ADME) processes of benzotriazole UV stabilizers (BUVS). The study also demonstrates differences in the ADME between sterically hindered BUVS, such as UV-327 and UV-328, and sterically unhindered BUVS, such as UV-P, in which the phenolic hydroxyl group is readily accessible for conjugation with glucuronic acid or sulfate.

Enhancing Tannic Acid-Arginine Complex Loading in Ultraporous PA6 Nanofibers through NH3 Foaming for Efficient Heavy Metal Removal from Textile Wastewater.

Metal-containing dyes in the textile industry release heavy metal ions into wastewater, posing significant environmental risks and complicating treatment processes. Among various removal methods, chemical adsorption through functional groups that form stable complexes is one of the most effective. Tannic acid (TA), renowned for its strong chelation of metal ions via phenolic hydroxyl groups, faces challenges in operation and recycling in its powdered form. Electrospun polyamide 6 (PA6) nanofiber membranes, characterized by high surface area and structural stability, offer a promising platform. However, achieving an optimal TA loading remains a technical hurdle for industrial applications. To address this, we developed an arginine (l-Arg) bridging strategy to enhance the TA loading on PA6 nanofibers. Additionally, we implemented an NH3 escape foaming technique to increase membrane porosity by 20% and quadruple pore size, enhancing surface roughness and resulting in a 70% increase in TA loading. The optimized adsorbent demonstrated the effective removal of various heavy metal ions, achieving over 95% removal efficiency for five different metals. Even after five adsorption-desorption cycles, the membrane retained over 92% efficiency, translating to a treatment capacity of 12.5 tons of wastewater per kilogram of foaming fiber, underscoring its potential for practical wastewater treatment applications.

Versatile laccase-mimicking enzyme for dye decolorization and tetracyclines identification upon a colorimetric array sensor

In this study, the laccase-mimicking enzyme MnO2/Cu-BDC-His was synthesized by a facile procedure, and was applied in tetracycline antibiotics (TCs) identification and dye degradation. The MnO2/Cu-BDC-His nanozymes effectively recognized phenolic hydroxyl groups in TCs and catalyzed the generation of colored oxidation products with different characteristic absorbance peaks at 350 nm, 525 nm and 600 nm. Different TCs mixtures produced different absorbance intensities at the above wavelengths and exhibited cross-color responses. Consequently, a colorimetric array sensor for the simultaneous identification and detection of TCs with wavelength as the sensing element was established. Unlike the traditional "lock-and-key" detection mode, the array sensor enabled simultaneous multi-analyte detection and identification, which achieved the identification and quantification of mixed TCs in the range of 5–200 µM, providing a premise for its application in lake and soil water. Additionally, the MnO2/Cu-BDC-His nanozymes were also applied in colored dyes decolorization. Therefore, MnO2/Cu-BDC-His nanozymes provided a promising application in environmental monitoring.

Spectral fingerprints of DOM-tungsten interactions: Linking molecular binding to conformational changes

Tungsten (W), a widely used yet understudied emerging contaminant, forms oxyanions in aqueous environments, distinguishing it from conventional heavy metals. While dissolved organic matter (DOM) demonstrates considerable potential for W binding, DOM-W interactions remain largely unexplored. Of particular significance, yet frequently overlooked, are the conformational changes in DOM during W binding processes. This study proposes a novel theoretical framework integrating superposition and charge transfer models to elucidate the complexity of these interactions. By combining spectroscopic techniques and photophysical models, we revealed that aromatic compounds containing 1–3 rings, especially monocyclic aromatic protein-like components, exhibit high affinity for W (logK=3.74–4.00). Phenolic hydroxyls served as primary binding sites for W, with aromatic rings facilitating binding through π interactions. Importantly, W binding to aromatic compounds induced conformational changes in DOM, transitioning from a loosely aggregated state to a more compact configuration. These changes facilitated W encapsulation within DOM through the synergistic effects of hydrophobic interactions, hydrogen/π-hydrogen bonding and π-stacking, potentially leading to stable trapping of W. Two-dimensional correlation spectroscopy analysis elucidated the sequential encapsulation process, involving phenolic, aromatic carboxylic/aliphatic carboxylic, polysaccharides, and aliphatics. The intricate behavior of DOM-W binding profoundly reshapes DOM's conformation, subtly yet significantly orchestrating W's binding affinity, environmental transport, and bioavailability in aquatic ecosystems.

Structure-performance relationship and molecular structure optimization design of acid phosphate ester extractants

The extraction performance of acid phosphate ester extractants (PEEs) decreases significantly as the acidity of the aqueous phase increases. Therefore, finding PEEs suitable for high-acid environments has become critical to addressing their performance attenuation. However, the unclear structure-performance relationship of PEEs has led to a lack of guidance in experimental synthesis, significantly impeding the emergence of new acid-resistant PEEs. To tackle these issues, ten novel phenyl phosphate ester extractants were designed based on the molecular formula of phosphodiester (R1R2P(=O)OH) and the conjugation effect of the benzene ring. The relationship between the intrinsic extraction performance of acid PEEs and substituent groups (phenoxy, alkoxy, and alkyl) was quantitatively established by calculating the Gibbs free energy changes of three primary reactions (dimer dissociation, monomer acid ionization, and metal coordination) during divalent cobalt ion extraction. Additionally, the impact of different substitution sites (para, meta, and ortho) of the benzene ring on the extraction performance of acid PEEs was studied. The results indicated that introducing phenoxy groups into traditional acid PEEs (P204 and P507) can effectively enhance the extractants’ acid ionization ability and thermodynamic driving force. The extraction performance of acid PEEs is positively correlated with the number of phenoxy groups, and carbon chain substitution at the meta-position of the benzene ring is the most advantageous. By screening five low-toxicity and low-cost phenolic hydroxyl reagents currently available on the market, design a phenyl phosphate ester extractant ([(CH3)3CCH2C(CH3)2C6H4O]2P(=O)OH, P-4TO) that combines cost and performance advantages. Furthermore, the transition state theory was used to confirm the feasibility of preparing P-4TO, which provided a comprehensive theoretical research method for the future design and synthesis of efficient PEEs.

Tannic acid and trivalent iron modified Fe3O4 nanoparticles as a new adsorbent to remove uranium from wastewater

This study reports the preparation and application of Fe3O4 nanoparticles modified by tannic acid and trivalent iron for U(Ⅵ) removal. The phenolic hydroxyl group on the tannic acid molecule can be complexed with U(Ⅵ), so as to achieve the goal of adsorping uranium from wastewater, and the maximum adsorption capacity of TA-FeIII@Fe3O4 can reach 98.2 mg/g. Through the research on pH, dosage, adsorption kinetics and adsorption thermodynamics indicted that it were excepting as a new green adsorbent for removing U(Ⅵ) from wastewater.

Nitric acid modified powdered activated carbon for simultaneous adsorption of lead and phenol in aqueous solution

Powdered activated carbon (PAC) was modified with various concentrations of nitric acid (HNO3) to adsorb lead and phenol. The modification was carried out with HNO3 concentrations of 1 M (PAC-1), 3 M (PAC-3), and 5 M (PAC-5), respectively, and sodium hydroxide treatment was performed for neutralization. Oxygen functional groups such as phenolic hydroxyl, carboxy and lactone were produced after the HNO3 modification, and the surface area was decreased compared to unmodified PAC (PAC-W). A negative charge appeared in modified PACs due to the increased carboxyl groups, and PAC-5 exhibited the highest negative value as −34.56 mV. Batch adsorption was performed on both lead and phenol. Lead adsorption increased from 17.83 mg/g (PAC-W) to 28.70 mg/g (PAC-5) as HNO3 concentration increased. More lead was adsorbed in PAC-5 because of enhanced electrostatic attractions with increased oxygen functional groups. Conversely, phenol exhibited lower adsorption in PAC-5 (102.79 mg/g) than PAC-W (111.67 mg/g). Phenol adsorbed to PAC through π-π interactions, but reduced surface area and hydrophilic surface functional groups in modified PACs limited the adsorption of hydrophobic phenol molecules. In simultaneous adsorption, the lead and phenol concentration were fixed as 30 mg/L and 20 mg/L. The modified PACs exhibited a similar trend to single adsorption. However, the simultaneous lead and phenol adsorption on PAC-5 decreased to 26.74 mg/g and 84.13 mg/g, respectively. Lead ion reacted to oxygen functional groups while phenol occupied a less active site in PAC-5. The PAC-5 can be suitable for application in environmental decontamination due to the abundant functional groups.

Comparative study on the physicochemical characteristics of lignin via sequential solvent fractionation of ethanol and Kraft lignin derived from poplar and their applications

The challenges in high value-added utilization of lignin own to its wide molecular weight distribution and complex physicochemical properties associated with it. How to narrow the molecular weight of lignin and elucidate the differences in physiochemical properties related to molecular weight of lignins is of crucial importance for lignin conversion processing. In this study, lab-made Kraft and ethanol lignins were fractionated into several narrower molecular weight distribution components through a designed solvent system. The yield, molecular weight distribution, structural characterization and their physicochemical properties of each fractionated lignin were analyzed comparatively. The results indicated that the yield of ethanol lignin is higher (8.44 %) than that of Kraft lignin (5.26 %). Kraft lignin shows lower molecular weight (Mw=2480 g/mol), higher hydroxyl content (4.29 mmol/g), and lower content of β-O-4 and β-5 bonds compared to ethanol lignin (Mw=3682 g/mol, 2.10 mmol/g). Meanwhile, the phenolic hydroxyl content in both ethanol and Kraft lignins increased with the decrease of molecular weight. Furthermore, ethanol lignin demonstrated higher antioxidant activity and much higher (65times) tensile strength of lignin-based polyurethane elastomer than that of Kraft lignin-based polyurethane elastomer.

Investigation of the hypoglycemic bioactive components of Phyllanthi Fructus through biological assessment combined with ultrafiltration affinity mass spectrometry.

Phyllanthi Fructus (PF) is a tropical fruit with the potential to effectively reduce postprandial blood glucose. However, the lack of quantitative evaluation methods and comprehensive understanding of hypoglycemic active compounds has hindered the development and application of functional foods and dietary supplements derived from PF. In this study, based on the "mass reaction parallel line method", with acarbose as the control and PF extract as the test material, a biological evaluation method for PF hypoglycemic activity based on α-glucosidase inhibition was established for the first time. The in vitro and in vivo validation experiments showed that the coefficient (r) of correlation between the biological evaluation results and the AUC of rat postprandial blood glucose concentration was as high as 0.866, which confirmed the reliability of the evaluation method. The analysis of 20 batches of PF samples showed that the hypoglycemia potency of PF ranged from 2.66 to 8.39 U mg-1, with an average value of 4.00 U mg-1, and the standard deviation was 1.5. UF-LC-MS was used to identify 36 components of PF capable of binding to α-glucosidase. Molecular docking results showed that the binding energy was between -3.5 and -14.3 kJ mol-1. The hypoglycemic activity of 17 available control products was tested, and 8 inhibitors were found, including hyperoside, gallic acid, and corilagin. Dose-effect analysis suggested that flavonoids and polyphenols with a phenolic hydroxyl structure could inhibit α-glucosidase. In short, this study provides a basis for the development of PF hypoglycemic functional foods.

Coupled Effect of Nutritional Food Molecules and Lactobacillus reuteri Surface Protein Interaction on the Bacterial Gastrointestinal Tolerance.

Lactobacillus reuteri, which is present in fermented foods, can produce LPxTG motif proteins (LMPs) to help the strain resist gastrointestinal fluid environmental stress and enhance the adherence and colonizing properties. Intestinal nutrient small molecules can interact with LMPs and cooperate with Lactobacillus to exert probiotic effects in the host intestine. However, the mechanism of their correlation with gastrointestinal tolerance needs to be further studied. In this study, different kinds of nutritional food molecules, such as intestinal phenols, sugars, and acids, were screened and the interaction between the LPxTG proteins and small molecules was explored via the molecular docking approach. The docking results showed that phenols and oligosaccharides were more likely to bind to the LPxTG protein (B3XKV5), with the benzene ring, phenolic hydroxyl group, and glycosidic bond in the small molecule more easily binding to the active site of B3XKV5. Furthermore, the gastrointestinal tolerance was enhanced under the rutin, myricetin, quercetin phenols, and stachyose-treated L. reuteri strain groups, especially the phenol group, which revealed the relationship between the molecular interaction of the strain with the small molecules and strain tolerance mechanism. All the findings illustrated the gastrointestinal tolerance escape effect of the Lactobacillus strain under enriched intestinal nutrient small molecular conditions, and they also provide insight regarding the small molecules for the Lactobacillus strain under abnormal growth environments.