Interaction mechanism of phenolic acids and zein: A spectrofluorometric and molecular dynamics investigation

Exploring novel lead scaffolds for SGLT2 inhibitors: Insights from machine learning and molecular dynamics simulations

Sodium-glucose cotransporter 2 (SGLT2) plays a pivotal role in mediating glucose reabsorption within the renal filtrate, representing a well-known target in type 2 diabetes and heart failure. Recent emphasis has been directed toward designing SGLT2 inhibitors, with C-glycoside inhibitors emerging as front-runners. The architecture of SGLT2 has been successfully resolved using cryo-electron microscopy. However, comprehension of the pharmacophores within the binding site of SGLT2 remains unclear. Here, we use machine learning and molecular dynamics simulations on SGLT2 bound with its inhibitors in preclinical or clinical development to shed light on this issue. Our dataset comprises 1240 SGLT2 inhibitors amalgamated from diverse sources, forming the basis for constructing machine learning models. SHapley Additive exPlanation (SHAP) elucidates the crucial fragments that contribute to inhibitor activity, specifically Morgan_3, 162, 310, 325, 366, 470, 597, 714, 926, and 975. Furthermore, the computed binding free energies and per-residue contributions for SGLT2-inhibitor complexes unveil crucial fragments of inhibitors that interact with residues Asn-75, His-80, Val-95, Phe-98, Val-157, Leu-274, and Phe-453 in the binding site of SGLT2. This comprehensive investigation enhances understanding of the binding mechanism for SGLT2 inhibitors, providing a robust framework for evaluating and discovering novel lead scaffolds within this domain.

Ultrasound and enzyme assisted preparation of novel lactoferrin-cereal phenolic acid conjugates: structural, physicochemical and functional properties

The effects of covalent binding of protocatechuic acid (PA) and gallic acid (GA) to lactoferrin (LF) on the structure, functional, and antioxidant properties of the protein conjugate were investigated. These protein-phenolic conjugates were produced by laccase cross-linking and ultrasound-assisted free radical grafting, which were characterized using turbidity, particle size, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses. Structural changes in conjugates were monitored by endogenous fluorescence spectroscopy, fourier transform infrared spectroscopy (FTIR), and circular dichroism (CD). The antioxidant capacities and pH stability were determined using DPPH, ABTS, FRAP, and potentiometric analysis. The enzymatic cross-linking and free radical grafting yielded LF-PA/GA conjugates with altered hydrodynamic diameter and zeta-potential. Spectroscopic and chromatographic analyses revealed that binding to PA/GA altered the molecular structure of LF, with a decrease in LF isoelectric point post binding to PA/GA, without affecting antioxidant activities. In conclusion, LF-PA/GA conjugates present potential applications in the food industry.

Insight into the Interaction Mechanism of Vitamin D against Metabolic Syndrome: A Meta-Analysis and In Silico Study

As a dietary supplement or functional food additive, vitamin D (VD) deficiency may impact extra-skeletal functions associated with metabolic syndrome (MetS) risk factors. However, the precise effects and mechanisms of VD supplementation on dyslipidemia and insulin resistance in MetS subjects remain controversial. Here, we investigate potential therapeutic targets, pathways and mechanisms of VD against MetS through a comprehensive strategy including meta-analysis, network pharmacology analysis, molecular docking, dynamics simulations, and quantum chemical calculations. Our results reveal that VD supplementation significantly reduces triglyceride levels, fasting glucose, and insulin concentrations in subjects, thereby improving insulin homeostasis to some extent. We theoretically identify 14 core MetS-associated targets. Notably, VD exhibits substantial interactions with three targets (PPARγ, FABP4, and HMGCR) in the PPAR signaling pathway, indicating that VD can modulate this pathway. Van der Waals forces predominantly stabilize the complexes formed between VD and the three targets. Nonetheless, to provide valuable insights for personalized MetS management, further research is necessary to confirm our findings, emphasizing the importance of exploring genetic variability in VD response. In conclusion, our study contributes insights into the mechanisms of VD in preventing and treating MetS through dietary supplementation, promoting the development of VD-based functional foods or nutritious diets.

Investigation of bovine β-lactoglobulin-procyanidin complexes interactions and its utilization in O/W emulsion

Procyanidins are bioactive polyphenols that have a strong affinity to proteins. Beta-lactoglobulin (BLG) is widely used as an emulsifier in the food and other industries. This study evaluated the interaction between BLG and A-type procyanidin dimer (PA2) using the spectroscopic, thermodynamic, and molecular simulation. PA2 decreased the transmissivity and quenched the intrinsic fluorescence of BLG, suggesting that the two molecules formed a complex. The binding of PA2 reduced the surface hydrophobicity and altered the conformation of BLG with increasing the random coil regions. Thermodynamic and isothermal titration calorimetry analyses suggested that the main driving force of PA2-BLG interaction was hydrophobic attraction. Molecular docking simulations were used to identify the main interaction sites and forces in the BLG-PA2 complexes, which again indicated that hydrophobic interactions dominated. In addition, the influence of PA2 on the ability of BLG to form and stabilize O/W emulsions was analyzed. Emulsions formulated using BLG-PA2 complexes contained relatively small droplets (D_4,3 ≈ 0.7 μm) and high surface potentials (absolute value >50 mV). Compared to BLG alone, BLG-PA2 complexes improved the storage stability of the emulsions. This study provides valuable new insights into the formation, properties, and application of protein-polyphenol complexes as functional ingredients in foods.

Exploration of molecular interaction between different plant proteins and 2-pentylfuran: based on multiple spectroscopy and molecular docking

BACKGROUND

Soy protein, peanut protein and wheat protein are commonly applied in plant-based products, but specific off-odor makes it difficult for consumers to accept, with 2-pentylfuran being one of the most representative flavors. In this study, 2-pentylfuran was employed as an example to explore the behavior and mechanism of the three proteins in absorbing off-odors.

RESULTS

Gas chromatographic-mass spectrometric analysis indicated that different plant proteins were able to adsorb 2-pentylfuran. Circular dichroism proved 2-pentylfuran could drive the α-helix to β-sheet transition of soy protein, which was not obvious in peanut protein or wheat protein. Ultraviolet spectroscopy tentatively determined that 2-pentylfuran caused changes in the tyrosine and tryptophan microenvironments of different plant proteins, which were further evidenced by synchronous fluorescence at fixed wavelength intervals of 15 nm and 60 nm. Static quenching of protein intrinsic fluorescence indicated that they formed a stable complex with 2-pentylfuran, except for wheat protein (dynamic quenching).

CONCLUSION

The various conformations of the three proteins are the main reason for the difference in flavor retention of protein. Soy protein, peanut protein and wheat protein adsorbing 2-pentylfuran relies on non-covalent forces, especially hydrophobic interactions, maintained between the protein and 2-pentylfuran. © 2023 Society of Chemical Industry.

Application of Molecular Simulation Methods in Food Science: Status and Prospects

Molecular simulation methods, such as molecular docking, molecular dynamic (MD) simulation, and quantum chemical (QC) calculation, have become popular as characterization and/or virtual screening tools because they can visually display interaction details that in vitro experiments can not capture and quickly screen bioactive compounds from large databases with millions of molecules. Currently, interdisciplinary research has expanded molecular simulation technology from computer aided drug design (CADD) to food science. More food scientists are supporting their hypotheses/results with this technology. To understand better the use of molecular simulation methods, it is necessary to systematically summarize the latest applications and usage trends of molecular simulation methods in the research field of food science. However, this type of review article is rare. To bridge this gap, we have comprehensively summarized the principle, combination usage, and application of molecular simulation methods in food science. We also analyzed the limitations and future trends and offered valuable strategies with the latest technologies to help food scientists use molecular simulation methods.

Covalent modification of zein with polyphenols: A feasible strategy to improve antioxidant activity and solubility

Covalent modification of protein with polyphenols is an attractive research topic, since it is an effective way to improve the properties and broaden the applications of protein. However, the majority of prolamin-polyphenol reactions were carried out in alcohol aqueous solution, and this study aimed to investigate the covalent interaction of zein and polyphenols in water. Chlorogenic acid (CGA), gallic acid (GA), and caffeic acid (CA) were used as polyphenol models. The grafting ratio revealed that zein interacted more strongly with CGA and CA than with GA, which was probably due to the larger molecular weight of CGA and the hydroxycinnamic acid structure of CA. Afterward, the differences in structural and functional properties between control zein and zein-polyphenol complexes were compared. Covalent interaction with polyphenols induced great changes in the morphology and secondary structure of zein. Compared with control zein and non-covalent complexes, covalent zein-polyphenol complexes exhibited better solubility, antioxidant activity, and thermal stability. PRACTICAL APPLICATION: Covalent modification of zein with polyphenols in water is a simple and efficient method, which can ameliorate the antioxidant activity as well as the hydrophilicity of zein and improve its application value. The findings of this research carry important implications for using zein-polyphenol complexes as novel food additives, or to design more efficient delivery systems.

Increasing the Efficacy of Seproxetine as an Antidepressant Using Charge-Transfer Complexes

The charge transfer interactions between the seproxetine (SRX) donor and π-electron acceptors [picric acid (PA), dinitrobenzene (DNB), p-nitrobenzoic acid (p-NBA), 2,6-dichloroquinone-4-chloroimide (DCQ), 2,6-dibromoquinone-4-chloroimide (DBQ), and 7,7′,8,8′-tetracyanoquinodi methane (TCNQ)] were studied in a liquid medium, and the solid form was isolated and characterized. The spectrophotometric analysis confirmed that the charge–transfer interactions between the electrons of the donor and acceptors were 1:1 (SRX: π-acceptor). To study the comparative interactions between SRX and the other π-electron acceptors, molecular docking calculations were performed between SRX and the charge transfer (CT) complexes against three receptors (serotonin, dopamine, and TrkB kinase receptor). According to molecular docking, the CT complex [(SRX)(TCNQ)] binds with all three receptors more efficiently than SRX alone, and [(SRX)(TCNQ)]-dopamine (CTcD) has the highest binding energy value. The results of AutoDock Vina revealed that the molecular dynamics simulation of the 100 ns run revealed that both the SRX-dopamine and CTcD complexes had a stable conformation; however, the CTcD complex was more stable. The optimized structure of the CT complexes was obtained using density functional theory (B-3LYP/6-311G++) and was compared.