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The prevention of enzymatic browning through the application of tyrosinase inhibitors has become a research focus in food industry. In this article, multi-spectroscopic and computational simulation was used to study the binding behavior and inhibition mechanism of aloin to tyrosinase. It found that aloin was an effective inhibitor of tyrosinase activity with a mixed type inhibition. Aloin bound to tyrosinase through hydrophobic forces, causing a conformational change in the enzyme and resulting in its inherent fluorescence being quenched. There was a binding site for aloin with tyrosinase and the binding constant was approximately 104 L mol−1. Molecular simulations showed that hydrophobic and hydrogen-bonding forces were the main factors in the binding of aloin to tyrosinase. Aloin introduced into the active site of tyrosinase interacted with amino acid residues Gly281, His244, Val283, Ala286 and His263, occupying the catalytic center of the tyrosinase and blocking substrate entry, resulting in tyrosinase inhibition. Molecular dynamics simulation further indicated that the binding of aloin changed the secondary structure of tyrosinase with little effect on the microenvironment of tyrosinase amino acid residues. This study offers new understanding of the mechanisms of activity of aloin as a tyrosinase inhibitor. [ABSTRACT FROM AUTHOR]

Curcumin (Cur) is an acidic polyphenol with some effects on α‐glucosidase (α‐Glu), but Cur has disadvantages such as being a weak target, lacking passing the blood–brain barrier and having low bioavailability. To enhance the curative effect of Cur, the hybrid composed of ZnO nanoparticles decorated on rGO was used to load Cur (ZnO@rGO‐Cur). The use of the multispectral method and enzyme inhibition kinetics analysis certify the inhibitory effect and interaction mechanism of ZnO@rGO‐Cur with α‐Glu. The static quenching of α‐Glu with both Cur and ZnO@rGO‐Cur is primarily driven by hydrogen bond and van der Waals interactions. The conformation‐changing ability by binding to the neighbouring phenolic hydroxyl group of Cur increased their ability to alter the secondary structure of α‐Glu, resulting in the inhibition of enzyme activity. The inhibition constant (Ki, Cur > Kis,ZnO@rGO‐Cur) showed that the inhibition effect of ZnO@rGO‐Cur on α‐Glu was larger than that of Cur. The CCK‐8 experiments proved that ZnO@rGO nanocomposites have good biocompatibility. These results suggest that the therapeutic potential of ZnO@rGO‐Cur composite is an emerging nanocarrier platform for drug delivery systems for the potential treatment of diabetes mellitus. [ABSTRACT FROM AUTHOR]

A novel NiMoO4@NiMoS4/NF nanocomposite is facilely grown on nickel foam (NF) via hydrothermal reaction and high-temperature calcination methods. The NiMoO4@NiMoS4/NF possesses a specific nanorods@nanosheets core–shell structure, greatly facilitating the transfer of electrons and ions. So, the NiMoO4@NiMoS4/NF shows excellent electrochemical performance. When a current density is 1 A g−1, the specific capacity (Cp) of NiMoO4@NiMoS4/NF reaches 1996 C g−1, which is 7 times that of single NiMoO4/NF, and its Cp is higher than the Cp of other Ni-Mo-based electrode materials reported in the literatures. Moreover, the NiMoO4@NiMoS4/NF has a long cycling life, and its capacity retention rate reaches 83.1% after 5000 cycles at 20 A g−1. The hybrid supercapacitor—NiMoO4@NiMoS4/NF-2//AC with NiMoO4@NiMoS4/NF as the positive electrode and AC as the negative electrode has an energy density of 32.75 Wh kg−1 and a power density of 725.09 W kg−1. So the NiMoO4@NiMoS4/NF is a promising high-performance electrode material for battery-type hybrid supercapacitors. [ABSTRACT FROM AUTHOR]