Water-soluble gallic acid derivatives, methods of preparation and use in the antioxidant treatment of aquatic products

Abstract

The application belongs to the technical field of antioxidant synthesis, and particularly relates to a water-soluble gallic acid derivative, a preparation method thereof and application thereof in water product antioxidant treatment. The structural formula of the water-soluble gallic acid derivative is shown as formula I. The water-soluble gallic acid derivative has good normal-temperature and low-temperature water solubility, and is particularly suitable for antioxidant treatment of water-based system water products. The water-soluble gallic acid derivative significantly inhibits the pi-pi stacking phenomenon between the aromatic benzene rings of gallic acid, effectively exposes the active phenolic hydroxyl group, improves the water-based antioxidant activity, and can be applied to the field of antioxidant treatment of water products in a water-based environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antioxidant synthesis, and particularly relates to a water-soluble gallic acid derivative, a preparation method thereof and application thereof in water product antioxidant treatment. BACKGROUND

[0002] Gallic acid and its ester derivatives antioxidants, such as a representative propyl gallate, are currently widely used in the field of food antioxidants. However, such antioxidants are generally oil-soluble molecules, which aggregate and precipitate due to π-π stacking in a water-based environment, have poor water solubility, and result in poor antioxidant effect of water-based environment antioxidant treatment or hydrophilic components of water products.

[0003] The methods for improving the bioavailability, water solubility or antioxidant activity of gallic acid or its ester derivatives usually use nanomaterials, liposomes, plant proteins and other materials for coating and compounding, but such methods do not completely solve the problem of antioxidant activity reduction caused by π-π stacking in a water-based environment from the molecular level.

[0004] For molecular water solubility modification, the water-soluble groups such as amino (-NH2), carboxyl (-COOH), sulfonic acid group (-SO3H) or amide group (-CONH2 or -CONH-) that can form hydrogen bonds with water molecules are modified in the structure, which can enhance the binding energy with water molecules and play a solubilizing effect. SUMMARY

[0005] In view of the problems in the prior art, the purpose of the present application is to design a water-soluble gallic acid derivative, a preparation method thereof and application thereof in water product antioxidant treatment. The present application completely solves the problem of poor water solubility of gallic acid from the molecular level. After modification of the -COOH and -SO3H groups of the gallic acid derivative, the water solubility is significantly improved, and the water-based antioxidant activity is greatly improved.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] On the one hand, the present application provides a water-soluble gallic acid derivative antioxidant, and the structure of the water-soluble gallic acid derivative is as follows:

[0008]

[0009] In formula I, R is selected from SO3H, COOH or NH2.

[0010] On the other hand, the present application provides a preparation method of the water-soluble gallic acid derivative antioxidant, and the preparation method comprises the following steps:

[0011] (1) Weigh gallic acid, 1-ethyl-3-(3'-dimethylaminopropyl) carbonyldiimidazole hydrochloride, 1-hydroxybenzotriazole, and dissolve them in anhydrous N,N-dimethylformamide, and stir in an ice bath;

[0012] (2) Add 2-aminoethanesulfonic acid, continue to stir in an ice bath, and then restore to room temperature and continue to stir;

[0013] (3) Add ultrapure water to quench the reaction, add ethyl acetate to precipitate the product, and then perform suction filtration, column chromatography purification, rotary evaporation, and vacuum drying to obtain the water-soluble gallic acid derivative.

[0014] Alternatively, (1) weigh gallic acid and N,N'-carbonyldiimidazole, and dissolve them in anhydrous N,N-dimethylformamide, and stir in an ice bath;

[0015] (2) Add 2-aminopropionic acid and triethylamine, continue to stir in an ice bath, and then restore to room temperature and continue to stir;

[0016] (3) Add ultrapure water to quench the reaction, add ethyl acetate to precipitate the product, and then perform suction filtration, column chromatography purification, rotary evaporation, and vacuum drying to obtain the water-soluble gallic acid derivative.

[0017] In the preparation method, the molar ratio of gallic acid, 1-ethyl-3-(3'-dimethylaminopropyl) carbonyldiimidazole hydrochloride, and 1-hydroxybenzotriazole is 1:1.0-1.5:1.0-1.5; and the molar ratio of gallic acid and 2-aminoethanesulfonic acid is 1:1.0-1.5.

[0018] In the preparation method, the molar ratio of gallic acid and N,N'-carbonyldiimidazole is 1:1.0-1.5; and the molar ratio of gallic acid, 2-aminopropionic acid, and triethylamine is 1:1.5-2.5:2-6.

[0019] In the preparation method, the ice bath stirring in step (1) is performed at a temperature of 0℃ for 1h.

[0020] In the preparation method, the ice bath stirring in step (2) is performed for 30min; and the stirring is continued for 24h.

[0021] In a third aspect, the present application provides the use of the water-soluble gallic acid derivative antioxidant in the treatment of aquatic products.

[0022] In the use, the aquatic products include one or more of shrimp, fish, and shellfish.

[0023] In a fourth aspect, the present application provides a method for using the water-soluble gallic acid derivative antioxidant, which comprises soaking aquatic products in an aqueous solution of the water-soluble gallic acid derivative, and then draining the surface moisture of the aquatic products in the dark.

[0024] In the method, the temperature of the aqueous solution of the water-soluble gallic acid derivative is 4°C, the concentration of the aqueous solution of the gallic acid derivative is 0.1%, and the soaking time is 30 min.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The present application significantly improves the water solubility and photothermal stability of the traditional antioxidant gallic acid by optimizing the molecular structure and improving the water solubility of the gallic acid. The water-soluble gallic acid derivative has good water solubility at room temperature and low temperature, and is particularly suitable for the antioxidant treatment of aquatic products in a water-based system.

[0027] In addition, due to the introduction of the water-soluble group, the π-π stacking phenomenon between the aromatic benzene rings of the gallic acid is significantly inhibited, so that the active phenolic hydroxyl group is effectively exposed, and the water-based antioxidant activity is significantly improved. The water-soluble gallic acid derivative can be applied to the field of antioxidant treatment of aquatic products in a water-based environment. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The molecular structure of the water-soluble gallic acid derivative GA-(CH2)2-R (R = SO3H, COOH or NH2);

[0029] Figure 2 High-resolution mass spectrometric analysis of the water-soluble gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH;

[0030] Figure 3 UV light stability experimental data curve of GA-(CH2)2-SO3H and GA-(CH2)2-COOH (with gallic acid GA and propyl gallate PG as control groups);

[0031] Figure 4 Antioxidant activity data curve of GA-(CH2)2-SO3H and GA-(CH2)2-COOH (including DPPH · , ·OH and ABTS +· radical scavenging capacity comparison, and with gallic acid GA and propyl gallate PG as control groups);

[0032] Figure 5 Method for using the water-soluble gallic acid derivative antioxidant for antioxidant treatment of aquatic products. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the accompanying drawings and examples.

[0034] The application provides a water-soluble gallic acid derivative antioxidant GA-(CH2)2-R, R is a sulfonic acid group (-SO3H), a carboxyl group (-COOH) or an amino group (-NH2), and the molecular structure is as shown in Figure 1 .

[0035] Example 1: Preparation of water-soluble gallic acid derivative antioxidant GA-(CH2)2-SO3H

[0036] (1) 0.300 g of gallic acid, 0.439 g of 1-ethyl-3-(3'-dimethylaminopropyl) carbonyldiimidazole hydrochloride (EDCI) and 0.310 g of 1-hydroxybenzotriazole (HOBT) were dissolved in 5 mL of N,N-dimethylformamide (DMF) (the molar ratio of the raw materials can be in the range of gallic acid: EDCI: HOBT = 1: 1: 0 ~ 1.5: 1: 0 ~ 1.5), and stirred in an ice bath at 0°C for 1 h;

[0037] (2) 0.287 g of 2-aminoethanesulfonic acid was added (the molar ratio of the raw materials can be in the range of gallic acid: 2-aminoethanesulfonic acid = 1: 1.0 ~ 1.5), and the reaction was continued for 30 min with ice bath stirring;

[0038] (3) After stirring in an ice bath for 30 min, the reaction was continued for 24 h at room temperature;

[0039] (4) After the reaction was completed, 5 mL of ultrapure water was added to quench the reaction, 10 mL of ethyl acetate was added to precipitate the product, and after filtration, column chromatography, rotary evaporation and vacuum drying, the target product, water-soluble gallic acid derivative GA-(CH2)2-SO3H, was obtained.

[0040] Example 2: Preparation of water-soluble gallic acid derivative antioxidant GA-(CH2)2-COOH

[0041] (1) 0.600 g of gallic acid and 0.629 g of N,N'-carbonyldiimidazole (CDI) were dissolved in 5 mL of N,N-dimethylformamide (DMF) (the molar ratio of the raw materials can be in the range of gallic acid: CDI = 1: 1: 0 ~ 1.5), and stirred in an ice bath at 0°C for 1 h;

[0042] (2) 0.628 g of 2-aminoethanesulfonic acid and 1.428 g of triethylamine were added (the molar ratio of the raw materials can be in the range of gallic acid: 2-aminoethanesulfonic acid: triethylamine = 1: 1.5 ~ 2.5: 2 ~ 6), and the reaction was continued for 30 min with ice bath stirring;

[0043] (3) After stirring in an ice bath for 30 min, the reaction was continued for 24 h at room temperature;

[0044] (4) After the reaction is completed, 5 mL of ultrapure water is added to quench the reaction, 10 mL of ethyl acetate is added to precipitate the product, and the product is purified by column chromatography, rotary evaporation, and vacuum drying to obtain the target product, water-soluble gallic acid derivative GA-(CH2)2-COOH. As shown in FIG. 2, the structure of the target product is verified by1H-NMR. Figure 2 High-resolution mass spectrometry analysis of water-soluble gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH.

[0045] Example 3: Low-temperature and room-temperature water solubility test of water-soluble gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH

[0046] An excess amount of gallic acid derivative is accurately weighed and dissolved in 1 mL of ultrapure water at room temperature (or 4°C) to prepare a saturated solution at room temperature (or 4°C). The saturated solution is separated by rapid filtration, and the solvent water is removed by rotary evaporation under reduced pressure. The mass of the solid solute m1 is accurately weighed, and the solubility of the gallic acid derivative in water at room temperature (or 4°C) is calculated as m1 / 1 mg / L (g / L). As shown in Table 1, the water solubility of gallic acid (GA) and propyl gallate (PG) is low at room temperature, while the water solubility of the water-soluble gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH is greatly improved. In addition, the water solubility of the water-soluble gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH is much higher than that of GA and PG in low-temperature water (4°C). Therefore, the water solubility of the gallic acid derivatives is significantly improved after modification with the water-soluble groups -COOH and -SO3H.

[0047] Table 1: Low-temperature and room-temperature water solubility measurement data of water-soluble gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH (with gallic acid GA and propyl gallate PG as control groups)

[0048]

[0049] Example 4: UV light stability test of GA-(CH2)2-SO3H and GA-(CH2)2-COOH

[0050] The ultraviolet light stability of gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH normal temperature solution was evaluated by ultraviolet light source irradiation method. That is, 0.1 g / L GA-(CH2)2-SO3H and GA-(CH2)2-COOH aqueous solution was placed in a cuvette, and the aqueous solution of gallic acid derivatives was irradiated by a handheld ultraviolet lamp (power 12 W). The ultraviolet absorption spectrum was measured after a certain time interval (0, 10, 20, 30, 40, 50, 60 min), the ultraviolet light stability was evaluated by drawing the normalized maximum absorbance value decay curve, and GA and PG were used as control groups.

[0051] The ultraviolet light stability of gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH normal temperature solution was evaluated by ultraviolet light source irradiation method. That is, 0.1 g / L GA-(CH2)2-SO3H and GA-(CH2)2-COOH aqueous solution was placed in a cuvette, and the aqueous solution of gallic acid derivatives was irradiated by a handheld ultraviolet lamp (power 12 W). The ultraviolet absorption spectrum was measured after a certain time interval (0, 10, 20, 30, 40, 50, 60 min), the ultraviolet light stability was evaluated by drawing the normalized maximum absorbance value decay curve, and GA and PG were used as control groups. Figure 3 The ultraviolet light stability evaluation results of gallic acid derivatives of formula (I) and (II) show that: after water-soluble modification, the ultraviolet light stability of gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH is significantly higher than that of GA and PG control group, which is because the water solubility is improved to avoid a large amount of aggregation in water, and the molecular light stability is improved.

[0052] Example 5: Antioxidant activity test of GA-(CH2)2-SO3H and GA-(CH2)2-COOH

[0053] The antioxidant activity test (DPPH·, ·OH, ABTS+·) was carried out by using free radical scavenging rate detection kit according to the standard operation, and GA and PG were used as control groups (the equivalent concentration of their aqueous solution was consistent with that of gallic acid derivatives).

[0054] The antioxidant activity test (DPPH·, ·OH, ABTS+·) was carried out by using free radical scavenging rate detection kit according to the standard operation, and GA and PG were used as control groups (the equivalent concentration of their aqueous solution was consistent with that of gallic acid derivatives). Figure 4 The free radical scavenging ability evaluation results of gallic acid derivatives of formula (I) and (II) show that: after water-soluble modification, the antioxidant activity of gallic acid derivatives GA-(CH2)2-SO3H and GA-(CH2)2-COOH is greatly improved, and the modification of -SO3H is particularly significant. It can be seen that the water-soluble modification strategy can improve the antioxidant activity of gallic acid.

[0055] Example 6: Application of water-soluble gallic acid derivative antioxidant in water product antioxidant treatment

[0056] The water-soluble gallic acid derivative was used as an antioxidant, and the water product was soaked in the prepared antioxidant aqueous solution, and the strong water-based antioxidant activity was used to provide antioxidant protection for the water product. The specific steps are as follows, as shown in Figure 5

[0057] (1) Prepare a water-soluble gallic acid derivative aqueous solution with a certain temperature and concentration in a light-proof water tank. The temperature is 4℃, and the concentration of the gallic acid derivative aqueous solution is 0.1%; ​

[0058] (2) After the aquatic products are cleaned, they are put into the light-proof water tank prepared in step 1) to start the antioxidant soaking treatment for 30 min;

[0059] (3) After the soaking is completed, the aquatic products are light-proofed and drained of surface moisture.

Claims

1. The application of a class of water-soluble gallic acid derivatives in the preparation of antioxidants, characterized in that, The structural formula of the water-soluble gallic acid derivative is as follows: Formula I: In Formula I: R is selected from SO3H, COOH or NH2.

2. The application as described in claim 1, characterized in that, The method for preparing the water-soluble gallic acid derivative includes the following steps: (1) Weigh out gallic acid, 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide hydrochloride and 1-hydroxybenzotriazole, dissolve them in anhydrous N,N-dimethylformamide, and stir in an ice bath; (2) Add 2-aminoethanesulfonic acid, continue stirring in an ice bath, then return to room temperature and continue stirring. (3) The reaction was terminated by adding ultrapure water to quench the reaction, ethyl acetate was added to precipitate the precipitate, and after filtration, column chromatography purification, rotary evaporation and vacuum drying, a water-soluble gallic acid derivative was obtained. Alternatively, (1) weigh gallic acid and N,N'-carbonyldiimidazole, dissolve them in anhydrous N,N-dimethylformamide, and stir under ice bath conditions; (2) Add 2-aminopropionic acid and triethylamine, continue stirring in an ice bath, then return to room temperature and continue stirring. (3) The reaction was terminated by adding ultrapure water, ethyl acetate was added, precipitate was formed, and after filtration, column chromatography purification, rotary evaporation and vacuum drying, a water-soluble gallic acid derivative was obtained.

3. The application as described in claim 2, characterized in that, The molar ratio of gallic acid, 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide hydrochloride, and 1-hydroxybenzotriazole is 1:1.0-1.5:1.0-1.5; the molar ratio of gallic acid to 2-aminoethanesulfonic acid is 1:1.0-1.

5.

4. The application as described in claim 2, characterized in that, The molar ratio of gallic acid to N,N'-carbonyldiimidazole is 1:1.0 to 1.5; the molar ratio of gallic acid, 2-aminopropionic acid, and triethylamine is 1:1.5 to 2.5:2 to 6.

5. The application as described in claim 2, characterized in that, The conditions for ice bath stirring in step (1) are: temperature 0℃, time 1h.

6. The application as described in claim 2, characterized in that, The time for continuing the ice bath stirring reaction in step (2) is 30 min; the time for continuing the stirring reaction is 24 h.

7. The application as described in claim 1, characterized in that, Application in the treatment of aquatic products for antioxidant purposes.

8. The application as described in claim 7, characterized in that, The aquatic products include one or more of shrimp, fish, and shellfish.

9. The application as described in claim 1, characterized in that, This involves soaking aquatic products in an aqueous solution of water-soluble gallic acid derivatives, and then draining the surface moisture of the aquatic products in the dark.

10. The application as described in claim 9, characterized in that, The temperature of the aqueous solution of the water-soluble gallic acid derivative is 4°C; the concentration of the aqueous solution of the gallic acid derivative is 0.1%; and the soaking time is 30 min.

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