Lipase-catalyzed highly regioselective synthesis of acylated chlorogenic acid

Enzyme-esterified grape seed proanthocyanidin derivatives as novel lipid-lowering agents

Grape seed proanthocyanidin (GSP), as a natural antioxidant, has great potential to be developed into a lipid-lowering agent, but its low lipophilicity and stability greatly limit its application. In this study, an enzymatic esterification strategy was developed to introduce fatty acid chains into GSP, resulting in the successful synthesis of a series of new GSP derivatives. The results showed that up to 85% conversion of GSP and 35% TAG inhibition rate of GSP derivatives were achieved. The structures of GSP derivatives were identified by UPLC-MS/MS, and seven derivatives were confirmed as catechin-3'-O-laurate, epicatechin-3'-O-laurate, epicatechin gallate-3″,5″-di-O-laurate, epicatechin gallate-3',3″,5″-tri-O-laurate, procyanidin B1-3',3″-di-O-laurate, procyanidin B2-3',3″-di-O-laurate and procyanidin C1-3',3″,3‴-tri-O-laurate by NMR. GSP derivatives exhibited higher inhibitory effects on lipid accumulation, intracellular TAG and TC than parent GSP. These results indicate that GSP derivatives have potential as lipid-lowering agents for utilization in the food industry.

Effect of structural stability of lipase in acetonitrile on its catalytic activity in EGCG esterification reaction: FTIR and MD simulation

In this study, (-)-Epigallocatechin-3-O-gallate (EGCG) esterification reaction was catalyzed by Novozym 435, Lipozyme RM, Lipozyme TLIM, and lipase Amano 30SD in acetonitrile. Fourier transform infrared spectroscopy (FTIR) and molecular dynamic (MD) simulations were used to analyze the structural stability of different lipases in acetonitrile and their effect on EGCG esterification reaction. The results showed that conversion rate of EGCG catalyzed by Lipozyme RM was the highest, followed by Lipozyme TLIM. FTIR indicated that the secondary structure of Lipozyme RM was the most stable. MD simulations suggested that whole structural stability of Lipozyme RM in acetonitrile was superior to Novozym 435 and lipase Amano 30SD and similar to Lipozyme TLIM due to their similar conformation, while the active site of Lipozyme RM is more flexible than that of Lipozyme TLIM, which indicated that lipase with stable whole structure and flexible active site may be more conducive to the esterification of EGCG in acetonitrile. This study provided a direction for rapidly screening lipase to synthetize EGCG or other polyphenols esterified derivatives.

Enzymatic molecular modification of water-soluble polyphenols: Synthesis, structure, bioactivity and application

The poor lipophilicity and instability of water-soluble polyphenols limit their bioavailability and application in food. However, increasing attention has been given to water-soluble polyphenols due to their multiple biological activities, which prompts the modification of the structure of water-soluble polyphenols to improve their lipophilicity and stability and enable more efficient application. This review presents the enzymatic biosynthesis of lipophilic derivatives of water-soluble polyphenols, which will change the molecular structure of water-soluble polyphenols based on the loss of hydroxyl or carboxyl groups. Therefore, the effects of reaction factors on the structure of polyphenol derivatives and the change in their bioactivities will be further analyzed. Previous studies have shown that lipases, solvent systems, and hydrophobic groups are major factors influencing the synthesis and lipophilicity of polyphenol derivatives. Moreover, the biological activities of polyphenol derivatives were changed to a certain extent, such as through the enhancement or weakening of antioxidant activity in different systems and the increase in anti-influenza virus activity and antibacterial activity. The improvement of lipophilicity also expands polyphenol application in food. This review may contribute to the efficient synthesis of lipophilic derivatives of water-soluble polyphenols to extend the utilization and application range of polyphenols.

Antioxidant Activities of Dihydromyricetin Derivatives with Different Acyl Donor Chain Lengths Synthetized by Lipozyme TL IM

Dihydromyricetin (DHM) is a phytochemical with multiple bioactivities. However, its poor liposolubility limits its application in the field. In this study, DHM was acylated with different fatty acid vinyl esters to improve its lipophilicity, and five DHM acylated derivatives with different carbon chain lengths (C2-DHM, C4-DHM, C6-DHM, C8-DHM, and C12-DHM) and different lipophilicity were synthesized. The relationship between the lipophilicity and antioxidant activities of DHM and its derivatives was evaluated with oil and emulsion models using chemical and cellular antioxidant activity (CAA) tests. The capacity of DHM derivatives to scavenge 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS+•) was similar to that of DHM, except for C12-DHM. The antioxidant activity of DHM derivatives was lower than that of DHM in sunflower oil, while C4-DHM exhibited better antioxidant capacity in oil-in-water emulsion. In CAA tests, C8-DHM (median effective dose (EC₅₀) 35.14 μmol/L) exhibited better antioxidant activity than that of DHM (EC₅₀: 226.26 μmol/L). The results showed that in different antioxidant models, DHM derivatives with different lipophilicity had various antioxidant activities, which has guiding significance for the use of DHM and its derivatives.

A Green Lipophilization Reaction of a Natural Antioxidant

A natural antioxidant, widely spread in plants, chlorogenic acid (CGA), can be lipophilized through a heterogeneous, non-enzymatic, catalytic process. Thus, sulfonic resins under no solvent conditions allow to obtain a series of esters in up to 93% yield through reaction of CGA with fatty alcohols of different chain length. The reaction takes place in one single step under mild conditions with conversions up to 96% and selectivity up to 99%. Product recovery in high purity was very easy and the esters obtained were fully characterized with spectroscopic techniques and through the DPPH test to verify the preservation of antioxidant activity. According to this test, all of them showed increased activity with respect to the parent acid and anyway higher than butylated hydroxyanisole. An in-silico method also suggested their very low toxicity. The increased lipophilicity of the esters allows their formulation in cosmetic and nutraceutic lipid-based products.

Highly Efficient Regioselective Acylation of Dihydromyricetin Catalyzed by Lipase in Nonaqueous Solvents

This study aimed to explore the enzymatic acylation of dihydromyricetin (DHM) to synthesized DHM derivatives with a different substituted carbon chain to improve its liposolubility. In the presence of Lipozyme TL IM, DHM was butyrylated in a 96.28% conversion in methyl tert-butyl ether under the optimized conditions (molar ratio of DHM to vinyl butyrate, 1:20; lipase dosage, 0.4 U/mg DHM; temperature, 50 °C; stirrer speed, 200 rpm; reaction time, 72 h). Liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy revealed that two acylation products were formed; these were 7-O-acyl-DHM and 3-O-acyl-DHM. In addition, the liposolubility of the DHM derivatives increased with the increase in the substituted carbon chain length; their antioxidant activities were higher than that of DHM in the lecithin peroxidation system, and C8-DHM had a better effect. Therefore, enzymatic acylation broadens the application of DHM in a lipid system in the food field.

Antioxidant activities of chlorogenic acid derivatives with different acyl donor chain lengths and their stabilities during in vitro simulated gastrointestinal digestion

In this study, chlorogenic acid (CA) was acylated with vinyl esters of different carbon chain lengths under the action of the lipase Lipozyme RM. Five CA derivatives (C2-CA, C4-CA, C6-CA, C8-CA, and C12-CA) with different lipophilicities were obtained, and their digestive stabilities and antioxidant activities were evaluated. The lipophilicities were positively correlated with the digestive stabilities of CA derivatives. The antioxidant activities of CA derivatives did not change with the reduction of phenolic hydroxyl groups, and their capacity to scavenge 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) were similar to those of CA. In cellular antioxidant activity (CAA) tests, it was found that the capacity of these derivates to cross cell membranes were enhanced upon enhancing lipophilicity, and their antioxidant activities were improved. C12-CA showed the best antioxidant activity with a median effective dose (EC50) of 9.40 μg/mL, which was significantly lower than that of CA (i.e., 29.08 μg/mL).