Improved Productivity of Naringin Oleate with Flavonoid and Fatty Acid by Efficient Enzymatic Esterification

Abstract

Naringin is a flavonoid found in citrus fruits. It exhibits biological activities, such as anticancer and antioxidant effects, but it suffers from low solubility and low stability in lipophilic systems. These drawbacks lead to difficulties in the commercial application of naringin, but they can be overcome through esterification. In this study, naringin oleate was synthesized by enzymatic esterification and optimal conditions for the reaction were investigated. Experiments were conducted focusing on the following parameters: enzyme type, enzyme concentration, molar ratio of naringin to oleic acid, reaction temperature, and reaction solvent. We further confirmed the degree of esterification based on the difference in the initial and the final naringin concentrations. A conversion of 93.10% was obtained under optimized conditions (Lipozyme TL IM 10 g/L, molar ratio 1:20, reaction temperature 40 °C, acetonitrile as solvent, and 48 h reaction time). Thus, naringin oleate, a high value-added material that overcomes the low hydrophobicity of naringin and enhances its performance, was obtained through esterification of naringin using oleic acid. This study presented a method for the efficient enzymatic synthesis that could ensure high conversion within a shorter reaction time compared with that required in previously reported methods.

Efficient Production of Naringin Acetate with Different Acyl Donors via Enzymatic Transesterification by Lipases

“…In addition, protection and deprotection steps are required to perform the regioselective acylation of flavonoids like polyol [ 13 ]. Considering that these processes often generate toxic by-products and require harsh reaction conditions, including high temperatures [ 14 ], the application of chemical methods in food has remained limited owing to the adverse effects on the environment and overall safety concerns. In contrast, enzymatic methods use mild conditions and one-step synthesis reactions, without the need for protection and deprotection steps.…”

“…In contrast, enzymatic methods use mild conditions and one-step synthesis reactions, without the need for protection and deprotection steps. Moreover, it is an eco-friendly synthesis method, as it generates less by-products due to its excellent regioselectivity [ 14 , 15 , 16 ].…”

“…Esters, such as triacylglyceride (TAG), phospholipid derivatives of phenolic acids, and flavonoid esters, can be produced by enzymatic methods [ 17 , 18 ]. The enzymatic acylation of flavonoids has been studied using proteases, esterases, acyltransferases, and lipases [ 14 , 19 ]. Currently, lipases are used in most flavonoid ester synthesis studies.…”

“…When an immobilized enzyme is used, it can be readily separated and reused, thus reducing the overall consumption of the enzyme. Further, the stability against heat and organic solvents is increased [ 14 , 15 , 24 ], as a result of which many recent studies on the synthesis of flavonoid esters have been conducted using immobilized lipases [ 20 , 21 ]. Existing studies on flavonoid ester, including those on naringin acetate, focus on synthesis using enzymatic methods ( Table 1 ).…”

“…Many reports have suggested that acylated flavonoids have improved physical and chemical properties, such as thermal stability, light resistance, and lipophilic solubility [ 14 , 30 , 31 , 32 , 33 , 34 , 35 ]. The improved function of acylated flavonoids increases its applicability in various industries, including food, pharmaceutical, and cosmetics.…”