Conversion of Beech Wood into Antiviral Lignin–Carbohydrate Complexes by Microwave Acidolysis

Abstract

Virus pandemics pose a threat to human life. In this study, we developed a simple method for the conversion of woody biomass into antiviral substances. Beech wood was decomposed by microwave acidolysis in 0.5% aq H2SO4 and fractionated by silica gel chromatography. The obtained fractions exhibited strong antiviral activity against encephalomyocarditis virus (EMCV) without cytotoxicity. Structural analyses revealed that the separated antiviral substances were lignin–carbohydrate complexes with molecular weight in the range of 2600–3900, containing 86.8–90.4% lignin and 3.1–6.1% carbohydrates. Moreover, the native β-O-4 linkages were considerably cleaved by microwave acidolysis, whereas the β–β and β-1 interlinkages remained partially unchanged. A signal corresponding to the α-ether linkage between the lignin and carbohydrates was observed in the heteronuclear single-quantum coherence nuclear magnetic resonance spectra. The cleavage of the carbohydrate chains by hemicellulase significantly reduced the antiviral activity, suggesting that the carbohydrate moiety played a critical role in the inactivation of EMCV. This research provides a green strategy for the production of huge amounts of antiviral substances from a sustainable bio-resource.

A Review: Depolymerization of Lignin to Generate High-Value Bio-Products: Opportunities, Challenges, and Prospects

“…LCC isolated from beech wood through microwave acidolysis is effective against encephalomyocarditis virus. Decoupling of carbohydrate moieties from these LCC significantly suppresses the antiviral activity, emphasizing the importance of carbohydrate moieties on LCC for biological activities (Li et al, 2021).…”

Sulfonic Acid-Functionalized Inorganic Materials as Efficient Catalysts in Various Applications: A Minireview

“…A powerful tool for the characterization of functionalized silica is 13 C and 29 Si NMR which permits analysis of the evolution of the chemical environment around silicon atoms introduced by addition of active components. The 29 Si NMR of bare silica presents features to be attributed to silicon without hydroxy groups Si-(O-Si) 4 , silicon atoms bearing one hydroxy group (Si-O) 3 -Si-OH and silicon atoms bearing two hydroxy groups (Si-O) 2 -Si-(OH) 2 called germinal silanols. The first species, whose peak is named Q 4 , is largely present in the bulk whereas the second and the third (respectively called Q 3 and Q 2 ) are present at the silica surface.…”

“…The 29 Si NMR of bare silica presents features to be attributed to silicon without hydroxy groups Si-(O-Si) 4 , silicon atoms bearing one hydroxy group (Si-O) 3 -Si-OH and silicon atoms bearing two hydroxy groups (Si-O) 2 -Si-(OH) 2 called germinal silanols. The first species, whose peak is named Q 4 , is largely present in the bulk whereas the second and the third (respectively called Q 3 and Q 2 ) are present at the silica surface. In addition to the changes in proportion between these peaks, when functionalized, a new set of peaks in the range {−45;−80} ppm appears giving evidence for the covalent incorporation of the functional groups.…”

“…Moreover, they are applied in several organic reactions involved in heterocyclic chemistry catalyzing multi-component reactions (MCR) or condensation reactions [3]. Due to their versatile use, they are involved in pharmaceutical chemistry for the synthesis of new molecules as potential drugs [4], in environmental chemistry for the abatement of pollutants [5], in biomass conversion for the production of sustainable added value products or for the achievement of new eco-friendly biofuels [1,2].…”

Adsorptive Inhibition of Enveloped Viruses and Nonenveloped Cardioviruses by Antiviral Lignin Produced from Sugarcane Bagasse via Microwave Glycerolysis

“…Recently, we reported that the anti-EMCV lignin− carbohydrate complex was produced from beech wood by microwave acidolysis. 22 We also reported that anti-EMCV lignin was produced via microwave glycerolysis of sugarcane bagasse, an agro-industrial lignocellulosic residue. 23 We separated lignin from sugarcane bagasse through acidic microwave glycerolysis at 140, 160, 180, and 200 °C.…”