Enzymatic modification of 2,6-dimethoxyphenol for the synthesis of dimers with high antioxidant capacity

Abstract

Abstract2,6-Dimethoxyphenol is a phenolic compound that is extensively used for the measurement of laccase activity, but is often not exploited for its potential as an antioxidant compound. Since laccase can be used to modify phenolic antioxidants as a way of improving their activities, the present study investigated the laccase-mediated oxidation of 2,6-dimethoxyphenol in biphasic or homogenous aqueous-organic media for the production of compounds with higher antioxidant capacity than the starting substrate. The main product was a dimer (m/z 305.0672), which was further characterized as a symmetrical C-C linked 3,3',5,5'-tetramethoxy biphenyl-4,4'-diol. In the monophasic system, the dimer was preferentially formed when acetone was used as cosolvent, while in the biphasic system, formation of the dimer increased as the concentration of ethyl acetate was increased from 50 to 90 %. The dimer showed higher antioxidant capacity than the substrate (≈ 2×) as demonstrated by standard antioxidant assays (DPPH and FRAP). These results demonstrate that a product of the laccase-catalysed oxidation of 2,6-dimethoxyphenol can find useful application as a bioactive compound.

Selective laccase-catalyzed dimerization of phenolic compounds derived from lignin: Towards original symmetrical bio-based (bis) aromatic monomers

“…Furthermore, the coupling of 2,6-dimethoxyphenol was also investigated at the aforementioned conditions. The reaction led selectively to the formation of dimer 8 in 80% yield, contrary to a previously reported study, where four demethylated products were also observed employing laccase from Trametes pubescens [49]. During the oxidative coupling of 2,6-dimethoxyphenol, Q1 is produced by recombination of two para radical species.…”

“…Further reaction of this compound with laccase can lead either to its re-aromatization into compound 8 or to the formation of the very stable quinone 7 (Scheme 3) which show different molar masses. In the literature, depending on the study, the formation of 8 or 7 was reported [49], [50]. In this experiment, mass spectroscopy resulted in a molar mass of 304 g/mol attributed to the quinone 7.…”

Enabling microbial syringol conversion through structure-guided protein engineering

“…To date, there are no reports describing syringol O -demethylation or, more broadly, even its catabolism by microbes. Rather, the best-studied biological reaction of syringol is its 4–4 dimerization to form cerulignone (30–33).…”

Aplicação De Lacases Em Síntese Orgânica Para Obtenção De Bioativos Com Atividade Antioxidante: Uma Revisão

“…Os compostos fenólicos naturais com atividade antioxidante estão presentes em baixas concentrações em relação a um substrato oxidável e recebem atenção pela capacidade de retardar ou inibir a oxidação desse substrato (ADELAKUN et al, 2012b). Muitos dos compostos fenólicos naturais são sensíveis à temperatura, pH e à luz devido à presença de duplas ligações alternadas (NEMADZIVA et.…”

“…O apelo ambiental é o grande impulsionador desta abordagem, pois possibilita a modificação dos substratos sem o uso de substâncias químicas e em condições brandas, com baixo impacto ambiental. Os radicais formados pela ação dos biocatalisadores resultam, geralmente, na formação de novas moléculas com propriedades biológicas de interesse (ADELAKUN et al, 2012b;MUNIZ-MOURO et al, 2017).…”