Hops are a common ingredient in beer production, and a considerable quantity of hops is usually discarded as a waste material once the brewing process is completed. Transforming this waste material into valuable nanomaterials offers a sustainable approach that has the potential to significantly mitigate environmental impact. Herein, a facile and green protocol for the production of zinc oxide nanozymes (ZnO NZs) using wasted hop extract (WHE) as a natural precursor was demonstrated. The process involved a hydrothermal synthesis method followed by a calcination step to form the final ZnO NZs. The results revealed that lupulon, the main β-acid in hops, particularly the phenolic hydroxy group, is primarily responsible for the biosynthesis of ZnO NZs. The WHE-ZnO NZs exhibited exceptional peroxidase-like (POD-like) activity and served as effective catalysts for the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H₂O₂). Analysis of the catalytic mechanism revealed that the POD-like activity of these WHE-ZnO NZs originated from their ability to expedite the transfer of electrons between TMB and H₂O₂, resulting in the enzymatic kinetics following the standard Michaelis–Menten mechanism. Furthermore, we developed a straightforward and user-friendly colorimetric technique for detecting both H₂O₂ and glucose. By utilizing the WHE-ZnO NZs as POD-like catalysts, we achieved a linear detection range of 1–1000 μM and a limit of detection of 0.24 μM (S/N = 3) for H₂O₂ detection and a linear range of 0–100 mM and a detection limit of 16.73 μM (S/N = 3) for glucose detection. These results highlighted the potential applications of our waste-to-resource approach for nanozyme synthesis in the field of analytical chemistry.

We investigated whether Ca2+/calmodulin-dependent kinase II (CaMKII) and calcineurin (CaN) are involved in myocardial hypertrophy induced by tumor necrosis factor α (TNF-α). The cardiomyocytes of neonatal Wistar rats (1-2 days old) were cultured and stimulated by TNF-α (100 μg/L), and Ca2+ signal transduction was blocked by several antagonists, including BAPTA (4 µM), KN-93 (0.2 µM) and cyclosporin A (CsA, 0.2 µM). Protein content, protein synthesis, cardiomyocyte volumes, [Ca2+]i transients, CaMKIIδB and CaN were evaluated by the Lowry method, [³H]-leucine incorporation, a computerized image analysis system, a Till imaging system, and Western blot analysis, respectively. TNF-α induced a significant increase in protein content in a dose-dependent manner from 10 µg/L (53.56 µg protein/well) to 100 μg/L (72.18 µg protein/well), and in a time-dependent manner from 12 h (37.42 µg protein/well) to 72 h (42.81 µg protein/well). TNF-α (100 μg/L) significantly increased the amplitude of spontaneous [Ca2+]i transients, the total protein content, cell size, and [³H]-leucine incorporation in cultured cardiomyocytes, which was abolished by 4 µM BAPTA, an intracellular Ca2+ chelator. The increases in protein content, cell size and [³H]-leucine incorporation were abolished by 0.2 µM KN-93 or 0.2 µM CsA. TNF-α increased the expression of CaMKIIδB by 35.21% and that of CaN by 22.22% compared to control. These effects were abolished by 4 µM BAPTA, which itself had no effect. These results suggest that TNF-α induces increases in [Ca2+]i, CaMKIIδB and CaN and promotes cardiac hypertrophy. Therefore, we hypothesize that the Ca2+/CaMKII- and CaN-dependent signaling pathways are involved in myocardial hypertrophy induced by TNF-α.

To improve the quality of palm kernel meal (PKM), the effect of solid-state fermentation (SSF) with Bacillus velezensis, Saccharomyces cerevisiae and Lactobacillus paracasei on nutritional components, anti-nutritional factor and antioxidant activity were investigated. The results show that inoculation ratio of three strains 4:2:1, inoculation amount 21%, moisture content 52%, fermentation temperature 34 °C and fermentation time 60 h were the optimal SSF conditions. After 60 h of fermentation, the content of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose and hemicellulose in PKM were significantly decreased by 22.5%, 18.2%, 20.2%, 17.6% and 32.4%, respectively. Meanwhile, the content of crude protein, soluble protein, peptides, amino acids and reducing sugar were increased significantly by 27.3%, 193%, 134%, 16.3% and 228%, respectively. SSF significantly improved the total phenolic content, DPPH radical scavenging activity, hydroxyl radical scavenging activity and reducing power. In addition, in vitro dry matter digestibility (IVDMD) and in vitro crude protein digestibility (IVCPD) were increased. Scanning electron microscopy (SEM) analysis revealed microstructural alterations in PKM. The results indicate that SSF with B. velezensis, S. cerevisiae and L. paracasei is an effective and promising method to enhance the nutritional value and antioxidant activity of PKM, providing a feasible solution for increasing the utilization of PKM in animal feed.