Continuous production of eugenol esters using enzymatic packed‐bed microreactors and an evaluation of the products as antifungal agents

Abstract

The enzymatic synthesis of biologically active compounds is receiving increasing interest from academic and industrial researchers. Herein, we report on the continuous‐flow enzymatic production of eugenol esters with packed‐bed microreactors prepared with the Novozym 435 and Lipozyme RM IM lipases. After optimization of the independent process variables, namely temperature (68 °C), flow rate (8 μL min−1), and eugenol/isobutyric anhydride molar ratio (1 : 5) by means of experimental design methodologies, the unprecedented continuous‐flow production of eugenyl isobutyrate has been achieved with steady‐state conversions of 77 and 70%, using packed‐bed microreactors prepared with Novozym 435 and Lipozyme RM IM, respectively. With acetic anhydride as the acylating agent, the same reactors, under the same conditions, afforded eugenyl acetate with steady‐state conversions of 82% (Novozym 435) and 90% (Lipozyme RM IM). The two ester products have been tested against phytopathogenic and dermatophytic fungi, demonstrating interesting action against dermatophytic fungi. The reported results demonstrated the suitability of the enzymatic packed‐bed microreactors as a sustainable and scalable technology for the solvent‐free continuous‐flow production of biologically active esters of eugenol.

Acetylation of Eugenol over 12-Molybdophosphoric Acid Anchored in Mesoporous Silicate Support Synthesized from Flint Kaolin

“…However, in high concentrations, it has an adverse effect of provoking inflammatory and allergic reactions, possibly due to its low instability, which favors the formation of phenoxyl radicals via its pro-oxidant activity [2,9]. Despite the fact that its structure is polyfunctional and readily accessible, eugenol is considered as a useful starting material for producing valuable derivatives through chemical synthesis [2,10,11,12,13,14,15] or biochemistry [1,4,9,16,17,18].…”

“…Eugenol derivatives can be obtained by reactions on the hydroxyl group of its structure via acetylation [4,15,19] or benzoylation [2,9,20]. Investigations have shown that this modification also improves antioxidant and larvicidal activities 2 or 5 times, respectively, moreover to the reduced level of cytotoxicity compared to its precursor, eugenol [4,7].…”

Enzymatic Esterification as Potential Strategy to Enhance the Sorbic Acid Behavior as Food and Beverage Preservative

“…Effective esterification of eugenol in solventless systems has been reported, with augmented antimicrobial activity against several bacteria compared to pure eugenol [23]. Encouraging results were also obtained considering the antifungal activity of the eugenol isobutyryl and acetyl esters that inhibit dermatophytes M. gypseum and T. mentagrophytes growth [24]. The scientific literature reports several works where C. antarctica lipase B performed efficiently as a biocatalyst of esterification reactions [25].…”

The Effect of Cream and Gel Vehicles on the Percutaneous Absorption and Skin Retention of a New Eugenol Derivative With Antioxidant Activity

“…The use of waste water from the clove bud steam distillation process is environmentally friendly and allows us to apply the waste, containing valuable biologically active compounds. These compounds, due to their mechanism of action, can have a beneficial effect on the balance between oxidants and antioxidants in the body, minimizing the effects of oxidative stress (Ivy and Payne, 1991;Dahham et al, 2015;Sarpietro et al, 2015;Giovannini et al, 2019;Razafindrakoto et al, 2020). The use of cream and gel vehicles for this type of research is, therefore, justified; moreover, the pH value of the acceptor phase in permeation in vitro tests was set at 7.4 for simulation of the skin surface (Ossowicz et al, 2020;Nowak et al, 2021).…”