Mechanistic insights into C-C coupling in electrochemical CO reduction using gold superlattices.

Developing in situ/operando spectroscopic techniques with high sensitivity and reproducibility is of great importance for mechanistic investigations of surface-mediated electrochemical reactions. Herein, we report the fabrication of highly ordered rhombic gold nanocube superlattices (GNSs) as substrates for surface-enhanced infrared absorption spectroscopy (SEIRAS) with significantly enhanced SEIRA effect, which can be controlled by manipulating the randomness of GNSs. Finite difference time domain simulations reveal that the electromagnetic effect accounts for the significantly improved spectroscopic vibrations on the GNSs. In situ SEIRAS results show that the vibrations of CO on the Cu2O surfaces have been enhanced by 2.4 ± 0.5 and 18.0 ± 1.3 times using GNSs as substrates compared to those on traditional chemically deposited gold films in acidic and neutral electrolytes, respectively. Combined with isotopic labeling experiments, the reaction mechanisms for C-C coupling of CO electroreduction on Cu-based catalysts are revealed using the GNSs substrates.

Metabolic regulation and antihyperglycemic properties of diet-derived PGG through transcriptomic and metabolomic profiling.

Diabetes has become a significant disease threatening human health and social development. Food intervention is considered an essential strategy to prevent early diabetes development sustainably. The natural product, 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG), commonly found in fruits and diets, has many potential antihypoglycemic, antibacterial, and antitumor activities. We found that PGG can promote glucose uptake in whole-organism zebrafish screening, which help in downregulating the glucose levels. We investigated the metabolome and transcriptome changes in zebrafish exposed to high glucose and PGG intervention. The differential genes and metabolites were screened out based on the comparisons of blank, hyperglycemic, and the PGG-exposed groups of zebrafish larvae. Combined with RT-qPCR validation, we found that PGG mainly restored four genes (fthl27, LOC110438965, plat, and aacs) and six metabolites abnormally invoked by high glucose. These validated genes are related with the key metabolites sphingosine and (R)-3-hydroxybutanoate involving the pathways of apelin, apoptosis, necroptosis, and butanoate metabolism. Our findings provided a new mechanistic basis for understanding the hypoglycaemic function of the commonly present dietary molecule (PGG) and offered a new perspective for the rational utilization of PGG to regulate metabolic disorders.

Enhancing Mechanical Performance of a Polymer Material by Incorporating Pillar[5]arene-Based Host-Guest Interactions.

Polymer gels have been widely used in the field for tissue engineering, sensing, and drug delivery due to their excellent biocompatibility, hydrophilicity, and degradability. However, common polymer gels are easily deformed on account of their relatively weak mechanical properties, thereby hindering their application fields, as well as shortening their service life. The incorporation of reversible non-covalent bonds is capable of improving the mechanical properties of polymer gels. Thus, here, a poly(methyl methacrylate) polymer network was prepared by introducing host-guest interactions between pillar[5]arene and pyridine cation. Owing to the incorporated host-guest interactions, the modified polymer gels exhibited extraordinary mechanical properties according to the results of the tensile tests. In addition, the influence of the host-guest interaction on the mechanical properties of the gels was also proved by rheological experiments and swelling experiments.

Insight into the α-glucosidase-inhibiting mechanism of ß-PGG, a commonly occurring polyphenol in diets.

1,2,3,4,6-Penta-O-galloyl-ß-D-glucopyranose (ß-PGG) is a compound commonly available in vegetables and fruits. It exhibited potential inhibition of α-glucosidase and hypoglycemic effect in vivo. This study explored its dynamics properties inhibiting α-glucosidase by Lineweaver - Burk plots, spectral analysis, docking analysis, and molecular dynamics simulations. ß-PGG showed a mix-type inhibition when it was interacting with α-glucosidase. The fluorescence quenching indicated that the PGG-glucosidase complex formed in a spontaneous exothermic process and was driven by enthalpy. The synchronous fluorescence and ECD spectra indicate that ß-PGG induced and changed the enzyme conformation in the complex formation. Docking results revealed multiple hydrogen bonds between the phenols and the amino acid residues. Further dynamic simulations indicated that the residues Asp345, Phe153, Arg435, Glu300, Pro305, and Phe296 played a more critical role in the interactions between ß-PGG and α-glucosidase.

Meroterpene-Like α-Glucosidase Inhibitors Based on Biomimetic Reactions Starting from ß-Caryophyllene.

BACKGROUND: Natural meroterpenes derived from phloroglucinols and ß-caryophyllene have shown high inhibitory activity against α-glucosidase or cancer cells, however, the chemical diversity of this type of skeletons in Nature is limited. METHODS: To expand the chemical space and explore their inhibitory activities against α-glucosidase (EC 3.2.1.20), we employed ß-caryophyllene and some natural moieties (4-hydroxycoumarins, lawsone or syncarpic acid) to synthesize new types of meroterpene-like skeletons. All the products (including side products) were isolated and characterized by NMR, HR-MS, and ECD. RESULTS: In total, 17 products (representing seven scaffolds) were generated through a one-pot procedure. Most products (12 compounds) showed more potential activity (IC50 < 25 µM) than the positive controls (acarbose and genistein, IC50 58.19, and 54.74 µM, respectively). Compound 7 exhibited the most potent inhibition of α-glucosidase (IC50 3.56 µM) in a mixed-type manner. The CD analysis indicated that compound 7 could bind to α-glucosidase and influence the enzyme's secondary structure. CONCLUSIONS: Compound 7 could serve as a new type of template compound to develop α-glucosidase inhibitors. Full investigation of a biomimic reaction can be used as a concise strategy to explore diverse natural-like skeletons and search for novel lead compounds.