Crude peroxidase from onion solid waste as a tool for organic synthesis. Part II: oxidative dimerization–cyclization of methyl p-coumarate, methyl caffeate and methyl ferulate

Antioxidant, antibacterial, and molecular docking of methyl ferulate and oleic acid produced by Aspergillus pseudodeflectus AUMC 15761 utilizing wheat bran

Secondary metabolites (SMs) are the primary source of therapeutics and lead chemicals in medicine. They have been especially important in the creation of effective cures for conditions such as cancer, malaria, bacterial and fungal infections, neurological and cardiovascular problems, and autoimmune illnesses. In the present study, Aspergillus pseudodeflectus AUMC 15761 was demonstrated to use wheat bran in solid state fermentation (SSF) at optimum conditions (pH 7.0 at 30 °C after 10 days of incubation and using sodium nitrate as a nitrogen source) to produce methyl ferulate and oleic acid with significant antioxidant and antibacterial properties. Gas chromatography-mass spectrometry (GC-MS) analysis of the crude methanol extract revealed eleven peaks that indicated the most common chemical components. Purification of methyl ferulate and oleic acid was carried out by column chromatography, and both compounds were identified by in-depth spectroscopic analysis, including 1D and 2D NMR and HR-ESI-MS. DPPH activity increased as the sample concentration increased. IC50 values of both compounds obtained were 73.213 ± 11.20 and 104.178 ± 9.53 µM, respectively. Also, the MIC value for methyl ferulate against Bacillus subtilis and Staphylococcus aureus was 0.31 mg/mL, while the corresponding MIC values for oleic acid were 1.25 mg/mL and 0.62 mg/mL for both bacterial strains, respectively. Molecular modeling calculations were carried out to reveal the binding mode of methyl ferulate and oleic acid within the binding site of the crucial proteins of Staphylococcus aureus. The docking results were found to be well correlated with the experimental data.

Antibacterial Properties of Coaxial Spinning Membrane of Methyl ferulate/zein and Its Preservation Effect on Sea Bass

Methyl ferulate is a new natural antibacterial agent with strong activity and low toxicity. It has good application prospects in food preservation. In this paper, the antibacterial activity of methyl ferulate against Shigella putrefaciens was verified, and it was embedded into zein by electrospinning technology to prepare fiber membranes. The addition of methyl ferulate could improve the tensile strength of zein fiber membrane and decrease the crystallinity of the membrane, which was mainly a physical combination. The fiber membrane improved the thermal stability of methyl ferulate. The water contact angle (WCA) decreased to 54.85°. The results showed that methyl ferulate in fiber membrane could be released slowly, gradually exerting its antibacterial activity. After coating perch with methyl ferulate/zein fiber membrane, the growth of microorganisms in perch meat was inhibited, and the pH value and total volatile basic nitrogen (TVB-N)content were effectively increased. In a word, methyl ferulate had antibacterial activity in the fiber film, which was able to achieve a sustained release effect in the process of fish packaging, prolonging its antibacterial activity, and having preservation effect on sea bass; thus, it could be used in food packaging.

Oxidative dehydrogenative couplings of alkenyl phenols

Alkenyl phenols are utilized by nature in the construction of one of the most important biopolymers, lignin. Using similar building blocks, an array of distinct structures can be formed by selective dimerization of the starting phenols to form lignans, neolignans, oxyneolignans, and norlignans. Given the multitude of possible outcomes, many methods have been reported to affect the desired bond formations and access these biologically relevant scaffolds. The most biomimetic of these methods, discussed here, involve the unprotected phenols undergoing oxidative bond formation that proceeds via dehydrogenative coupling. This review aims to place the known literature in context, highlight the progress made toward the synthesis of these important molecules, and recognize the gaps and limitations that still exist.

Antioxidant Properties of Agri-food Byproducts |and Specific Boosting Effects of Hydrolytic Treatments

Largely produced agri-food byproducts represent a sustainable and easily available source of phenolic compounds, such as lignins and tannins, endowed with potent antioxidant properties. We report herein the characterization of the antioxidant properties of nine plant-derived byproducts. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated the superior activity of pomegranate peels and seeds, grape pomace and pecan nut shell. An increase in the antioxidant potency was observed for most of the waste materials following a hydrolytic treatment, with the exception of the condensed tannin-rich pecan nut shell and grape pomace. UV-Vis and HPLC investigation of the soluble fractions coupled with the results from IR analysis and chemical degradation approaches on the whole materials allowed to conclude that the improvement of the antioxidant properties was due not only to removal of non-active components (mainly carbohydrates), but also to structural modifications of the phenolic compounds. Parallel experiments run on natural and bioinspired model phenolic polymers suggested that these structural modifications positively impacted on the antioxidant properties of lignins and hydrolyzable tannins, whereas significant degradation of condensed tannin moieties occurred, likely responsible for the lowering of the reducing power observed for grape pomace and pecan nut shell. These results open new perspectives toward the exploitation and manipulation of agri-food byproducts for application as antioxidant additives in functional materials.

Synthetic approaches to natural products containing 2,3-dihydrobenzofuran skeleton

This review describes the synthetic approaches to natural products containing the 2,3-dihydrobenzofuran (2,3-DHB) skeleton.

An antioxidant bioinspired phenolic polymer for efficient stabilization of polyethylene

The synthesis, structural characterization and properties of a new bioinspired phenolic polymer (polyCAME) produced by oxidative polymerization of caffeic acid methyl ester (CAME) with horseradish peroxidase (HRP)-H2O2 is reported as a new sustainable stabilizer toward polyethylene (PE) thermal and photo-oxidative degradation. PolyCAME exhibits high stability toward decarboxylation and oxidative degradation during the thermal processes associated with PE film preparation. Characterization of PE films by thermal methods, photo-oxidative treatments combined with chemiluminescence, and FTIR spectroscopy and mechanical tests indicate a significant effect of polyCAME on PE durability. Data from antioxidant capacity tests suggest that the protective effects of polyCAME are due to the potent scavenging activity on aggressive OH radicals, the efficient H-atom donor properties inducing free radical quenching, and the ferric ion reducing ability. PolyCAME is thus proposed as a novel easily accessible, eco-friendly, and biocompatible biomaterial for a sustainable approach to the stabilization of PE films in packaging and other applications.

Strategies for the Synthesis of 2,3-Dihydrobenzofurans

This article gives an overview of synthetic approaches to the 2,3-dihydrobenzofuran ring system with an emphasis on recently developed methods. The synthetic approaches are classified according to the key bond(s) formed during the construction of the dihydrobenzofuran skeleton, and approaches of relevance to the synthesis of natural products are highlighted.