Chitosan quaternary ammonium salt derivative containing selenium cyano group as well as preparation method and application of chitosan quaternary ammonium salt derivative

Abstract

The invention belongs to the technical field of marine chemical engineering, and particularly relates to a chitosan quaternary ammonium salt derivative containing selenium cyano groups as well as a preparation method and application of the chitosan quaternary ammonium salt derivative. The structure of the chitosan quaternary ammonium salt derivative containing the selenium cyano group is as shown in a formula I in the specification. The method has the advantages that selenium cyano groups are efficiently grafted to a chitosan skeleton through a chemical method, the preparation process is simple and convenient, side reactions are few, and the raw material cost is low. Researches prove that the derivative has excellent antioxidant activity, and shows wide application prospects in the fields of medicines, cosmetics, especially functional food and health care products. And the # imgabs0 # is shown in the formula 1.

Description

Technical Field

[0001] The invention belongs to the technical field of marine chemical engineering, and particularly relates to a chitosan quaternary ammonium salt derivative containing a selenium cyanide group, and a preparation method and application thereof. Background Art

[0002] Chitosan (CTS) is a natural polymer compound with a chitin deacetylation degree exceeding 50%. Its basic structural units are glucosamine and a small amount of residual N-acetylglucosamine. Chitosan molecules contain important functional groups such as free amino groups (-NH2) and hydroxyl groups (-OH). These functional groups provide effective reaction sites for the introduction of various external functional groups through chemical modification, significantly improving functional properties and further expanding its application areas.

[0003] Selenium is an essential trace element for the human body. It participates in the synthesis of the antioxidant enzyme glutathione peroxidase, thereby protecting cells. Selenium cyanide compounds play an important role in medicine and other fields and are widely used in drug design and synthesis. Selenium cyanide and its derivatives have various biological activities, including antioxidant, anticancer, and anti-inflammatory activities.

[0004] However, weak biological activity and low water solubility limit the commercial application of chitosan and selenocyanate compounds. Therefore, based on the principle of activity superposition, chitosan is modified to find target derivatives that exhibit higher water solubility and comprehensive biological activity. Summary of the Invention

[0005] The purpose of the present invention is to provide a chitosan quaternary ammonium salt derivative containing a selenocyanate group, a preparation method and an application thereof, so as to solve the problems of low biological activity and water solubility of chitosan and selenocyanate compounds.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A chitosan quaternary ammonium salt derivative containing a selenocyanate group, the structure of the chitosan quaternary ammonium salt derivative containing a selenocyanate group is shown in Formula 1: Formula 1, where R= 、 、 、 、 ; The average value range of n is 20-3000.

[0007] A method for preparing a chitosan quaternary ammonium salt derivative containing a selenium cyanide group comprises first dispersing chitosan in N -methyl pyrrolidone (NMP) swelling, followed by the addition of anhydrous sodium iodide, sodium hydroxide solution and methyl iodide, reflux reaction for 3 hours, and then ethanol precipitation to obtain chitosan quaternary ammonium salt; then the chitosan quaternary ammonium salt is dissolved in N, N -dimethylformamide (DMF), add chloroacetyl chloride, react at 45°C for 24 hours, and then precipitate with acetone to obtain chloroacetylated chitosan quaternary ammonium salt; finally, the chloroacetylated chitosan quaternary ammonium salt is dissolved in dimethyl sulfoxide (DMSO), and selenocyanide compound is added, react at 60°C for 24 hours, and then precipitate with acetone to obtain the final product.

[0008] The chloroacetylated chitosan quaternary ammonium salt is prepared by dispersing chitosan in NMP, subjecting it to swelling reaction at room temperature for 1 hour, sequentially adding anhydrous sodium iodide, sodium hydroxide solution, and methyl iodide, and reacting it under reflux at 60° C. for 3 hours; then precipitating it with anhydrous ethanol, washing it with ethanol, and filtering it to obtain a filter cake, which is then freeze-dried in vacuum to a constant weight to obtain the chitosan quaternary ammonium salt; and dissolving the obtained chitosan quaternary ammonium salt in N , N -dimethylformamide, add chloroacetyl chloride dropwise at room temperature, then react at 45°C for 24 hours. After the reaction is completed, precipitate with acetone, wash with ethanol, filter to obtain a filter cake, and freeze-dry to constant weight.

[0009] Each 1-2g of chitosan is used N -Methylpyrrolidone 20-100mL, anhydrous sodium iodide 2-10g, sodium hydroxide 2-9g, iodomethane 20-50mL, chloroacetyl chloride 0.5-6mL, N , N -Dimethylformamide 20-100 mL.

[0010] The obtained chloroacetylated chitosan quaternary ammonium salt is dissolved in dimethyl sulfoxide, a selenocyanate compound is added at room temperature, and then the mixture is reacted at 60° C. for 24 hours. After the reaction is completed, the mixture is precipitated with acetone and washed three times, and then filtered to obtain a filter cake, which is freeze-dried to a constant weight to obtain a chitosan quaternary ammonium salt containing a selenocyanate group as shown in Formula 1.

[0011] The selenocyanide compound is N-(3-selenocyanopropyl)nicotinamide, N-(3-selenocyanopropyl)isonicotinamide, 2-methoxy-N-(3-selenocyanopropyl)nicotinamide, 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide or 2-mercapto-N-(3-selenocyanopropyl)nicotinamide.

[0012] For every 1-2 g of the chloroacetylated chitosan quaternary ammonium salt, 3-6 g of the selenocyanide compound and 45-150 mL of dimethyl sulfoxide are used.

[0013] An application of the chitosan quaternary ammonium salt derivative containing a selenium cyanide group, and an application of the compound represented by formula 1 in the preparation of an antioxidant.

[0014] The compound represented by formula 1 is used in the preparation of antioxidants in the fields of medicine, functional food health care, and cosmetics.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows: (1) The derivatives obtained by the present invention have good antioxidant activity. Studies have shown that the antioxidant activity of chitosan quaternary ammonium salt derivatives containing selenium cyanide groups is significantly higher than that of chitosan and chloroacetylated chitosan quaternary ammonium salt.

[0016] (2) The derivatives obtained by the present invention have good water solubility and excellent antioxidant activity, and can be used in medicine, functional food and health care, especially in the cosmetics industry and selenium-rich food additive industry, and have broad application value.

[0017] (3) The derivatives of the present invention have a simple preparation process, few side reactions, and low material costs. They also have good antioxidant activity and are technically and economically feasible for large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the infrared spectrum of chitosan; Figure 2 Provide an infrared spectrum of chloroacetylated chitosan quaternary ammonium salt for Example 1 of the present invention; Figure 3 Provided is an infrared spectrum of chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl) nicotinamide for Example 1 of the present invention; Figure 4 Provided is an infrared spectrum of chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl)isonicotinamide for Example 2 of the present invention; Figure 5 Provided is an infrared spectrum of chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl) nicotinamide for Example 3 of the present invention; Figure 6 Provided is an infrared spectrum of chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide for Example 4 of the present invention; Figure 7 Provided is an infrared spectrum of chitosan quaternary ammonium salt containing 2-mercapto-N-(3-selenocyanopropyl) nicotinamide for Example 5 of the present invention; Figure 8 is the H NMR spectrum of chitosan; Figure 9 Provided is a hydrogen nuclear magnetic resonance spectrum of chloroacetylated chitosan quaternary ammonium salt for Example 1 of the present invention; Figure 10 Provided is a hydrogen nuclear magnetic resonance spectrum of a chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl) nicotinamide for Example 1 of the present invention; Figure 11 for Figure 10 A partial enlarged view of Figure 12Provided is a hydrogen nuclear magnetic resonance spectrum of a chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl)isonicotinamide for Example 2 of the present invention; Figure 13 for Figure 12 A partial enlarged view of Figure 14 Provided is a hydrogen nuclear magnetic resonance spectrum of a chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl) nicotinamide for Example 3 of the present invention; Figure 15 for Figure 14 A partial enlarged view of Figure 16 Provided is a hydrogen nuclear magnetic resonance spectrum of a chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide for Example 4 of the present invention; Figure 17 for Figure 16 A partial enlarged view of Figure 18 Provided is a hydrogen nuclear magnetic resonance spectrum of a chitosan quaternary ammonium salt containing 2-mercapto-N-(3-selenocyanopropyl) nicotinamide for Example 5 of the present invention; Figure 19 for Figure 18 A partial enlarged view of . DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention are further described below with reference to examples. It should be noted that the specific embodiments described here are only for illustrating and explaining the present invention, and are not intended to limit the present invention.

[0020] The molecular weight of chitosan used in the following examples is 5000-10000.

[0021] Example 1 ,R= Formula (1) The structural formula of the chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl) nicotinamide is shown in formula (1), wherein the average value range of n is 20-3000.

[0022] 1.61 g of chitosan was dispersed in 40 mL of NMP and allowed to swell at room temperature for 1 hour. 5 g of anhydrous sodium iodide, 15 mL of 15% sodium hydroxide solution, and 20 mL of methyl iodide were then added sequentially. The mixture was refluxed at 60°C for 3 hours. An appropriate amount of anhydrous ethanol was then added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. This was then freeze-dried to a constant weight to obtain chitosan quaternary ammonium salt. 1 g of chitosan quaternary ammonium salt was dissolved in 30 mL of DMF, and 1 mL of chloroacetyl chloride was added. The mixture was allowed to react at 45°C for 12 hours. After the reaction was complete, an appropriate amount of acetone was added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. This was freeze-dried to a constant weight to obtain chloroacetylated chitosan quaternary ammonium salt.

[0023] 1 g of the above-mentioned chloroacetylated chitosan quaternary ammonium salt was dissolved in 50 mL of dimethyl sulfoxide, and 5 g of N-(3-selenocyanopropyl)nicotinamide was added. The mixture was reacted at 60°C for 24 hours. After the reaction was completed, an appropriate amount of acetone was used for precipitation, and the mixture was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain the chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl)nicotinamide as shown in formula (1).

[0024] from Figure 2 It can be seen that compared with chitosan raw materials (see Figure 1 ) compared to the chlorinated chitosan quaternary ammonium salt at 1473 cm -1 The vibration absorption peak of quaternary ammonium salt appeared at 1752 cm -1 The vibration absorption peak of the ester group appeared at 788 cm -1 The absorption vibration peak of carbon-chlorine bond appeared. The above analytical data proved the synthesis of chloroacetylated chitosan quaternary ammonium salt.

[0025] And further from Figure 3 Chu Zhi, 1475cm -1 and 1745cm -1 The vibration absorption peak at 2065cm -1 The vibration absorption peak of the selenocyanate group appeared, which proved that the chitosan quaternary ammonium salt derivative containing N-(3-selenocyanopropyl) nicotinamide was successfully synthesized.

[0026] from Figure 9 It can be seen that the chitosan raw material (see Figure 8 ), the quaternary ammonium salt of chloroacetylated chitosan showed new proton peaks at chemical shifts of 2.9 ppm and 4.2 ppm, which were the proton peaks of the methyl group in the quaternary ammonium salt group and the proton peaks of the methylene group in the chloroacetyl group, respectively.

[0027] Further from Figure 11 It can be seen that the proton peak of the pyridine ring appears at 7.5-9.2 ppm, and the proton peak of the methylene group in the selenocyanide group appears at around 2.2 ppm. This further proves that the quaternary ammonium salt derivative of chitosan containing N-(3-selenocyanopropyl) nicotinamide was successfully synthesized.

[0028] Example 2 ,R= Formula (2) The structural formula of the chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl)isonicotinamide is shown in Formula (2), wherein the average value of n ranges from 20 to 3000.

[0029] The difference from Example 1 is that: 1g of chitosan was dispersed in 20mL of NMP and allowed to swell at room temperature for 0.5 hours. 2.5g of anhydrous sodium iodide, 10mL of 15% sodium hydroxide solution, and 10mL of methyl iodide were then added sequentially. The mixture was refluxed at 60°C for 2 hours. An appropriate amount of anhydrous ethanol was then added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. This was then freeze-dried to a constant weight to obtain chitosan quaternary ammonium salt. 1.5g of the obtained chitosan quaternary ammonium salt was dissolved in 20mL of DMF, and 1.2mL of chloroacetyl chloride was added. The mixture was allowed to react at 30°C for 12 hours. After the reaction was complete, an appropriate amount of acetone was added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. This was freeze-dried to a constant weight to obtain chloroacetylated chitosan quaternary ammonium salt.

[0030] 1.6 g of the above-mentioned chloroacetylated chitosan quaternary ammonium salt was dissolved in 50 mL of dimethyl sulfoxide, and 5.5 g of N-(3-selenocyanopropyl)isonicotinamide was added. The mixture was reacted at 60° C. for 24 hours. After the reaction was completed, an appropriate amount of acetone was used for precipitation, and the mixture was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain the chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl)isonicotinamide as shown in formula (2).

[0031] from Figure 4 It can be seen that 1463cm -1 and 1744cm -1 The vibration absorption peak at 2064cm -1 The vibration absorption peak of the selenocyanide group appeared, which proved that the chitosan quaternary ammonium salt derivative containing N-(3-selenocyanopropyl)isonicotinamide was successfully synthesized.

[0032] In addition, from Figure 13 It can be seen that the proton peak of the pyridine ring appears at 7.5-9.0 ppm, and the proton peak of the methylene group in the selenocyanide group appears at 2.0 ppm. This further proves that the quaternary ammonium salt derivative of chitosan containing N-(3-selenocyanopropyl)isonicotinamide was successfully synthesized.

[0033] Example 3 ,R= Formula (3) The structural formula of the chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl) nicotinamide is shown in Formula (3), wherein the average value of n ranges from 20 to 3000.

[0034] The difference from Example 1 is that: 1.35g of chitosan was dispersed in 25mL of NMP and allowed to swell at room temperature for 0.5h. 3.2g of anhydrous sodium iodide, 13mL of 15% sodium hydroxide solution, and 13mL of methyl iodide were then added sequentially. The mixture was refluxed at 60°C for 2h. An appropriate amount of anhydrous ethanol was then added for precipitation. The mixture was washed with ethanol and filtered to obtain a filter cake. The mixture was freeze-dried to a constant weight to obtain chitosan quaternary ammonium salt. 1.6g of chitosan quaternary ammonium salt was dissolved in 20mL of DMF and 1.35mL of chloroacetyl chloride was added. The mixture was allowed to react at 30°C for 12h. After the reaction, an appropriate amount of acetone was added for precipitation. The mixture was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain chloroacetylated chitosan quaternary ammonium salt.

[0035] 1.2 g of the above-mentioned chloroacetylated chitosan quaternary ammonium salt was dissolved in 70 mL of dimethyl sulfoxide, and 6.5 g of 2-methoxy-N-(3-selenocyanopropyl)nicotinamide was added. The mixture was reacted at 60°C for 24 hours. After the reaction was completed, an appropriate amount of acetone was used for precipitation, and the mixture was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain the chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl)nicotinamide as shown in formula (3).

[0036] from Figure 5 It can be seen that 1467cm -1 and 1748cm -1 The vibration absorption peak at 2064cm -1 The vibration absorption peak of the selenocyanate group appeared, which proved that the chitosan quaternary ammonium salt derivative containing 2-methoxy-N-(3-selenocyanopropyl) nicotinamide was successfully synthesized.

[0037] In addition, from Figure 15 The proton peak of the pyridine ring appears at 7.0-8.5 ppm, the proton peak of the methyl group in the methoxy group appears at 2.9 ppm, and the proton peak of the methylene group in the selenocyanide group appears at 2.0 ppm. This further proves that the chitosan quaternary ammonium salt derivative containing 2-methoxy-N-(3-selenocyanopropyl) nicotinamide was successfully synthesized.

[0038] Example 4 ,R= Formula (4) The structural formula of the chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide is shown in Formula (4), wherein the average value of n ranges from 20 to 3000.

[0039] The difference from Example 1 is that: 1.7 g of chitosan was dispersed in 35 mL of NMP and allowed to swell at room temperature for 0.5 hours. 4.75 g of anhydrous sodium iodide, 17 mL of 15% sodium hydroxide solution, and 17 mL of methyl iodide were then added sequentially. The mixture was refluxed at 60-70°C for 2 hours. An appropriate amount of anhydrous ethanol was then added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. The mixture was then freeze-dried to a constant weight to obtain chitosan quaternary ammonium salt. 1.37 g of chitosan quaternary ammonium salt was dissolved in 18 mL of DMF, and 1.24 mL of chloroacetyl chloride was added. The mixture was allowed to react at 30°C for 12 hours. After the reaction was complete, an appropriate amount of acetone was added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain chloroacetylated chitosan quaternary ammonium salt.

[0040] 2.1 g of the above-mentioned chloroacetylated chitosan quaternary ammonium salt was dissolved in 75 mL of dimethyl sulfoxide, and 6.55 g of 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide was added. The mixture was reacted at 60°C for 24 hours. After the reaction was completed, an appropriate amount of acetone was used for precipitation, and the mixture was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain the chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide as shown in formula (4).

[0041] from Figure 6 It can be seen that 1475cm -1 and 1744cm -1 The vibration absorption peak at 2062cm -1 The vibration absorption peak of the selenocyanide group appeared, which proved that the chitosan quaternary ammonium salt derivative containing 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide was successfully synthesized.

[0042] In addition, from Figure 17 It can be seen that the proton peak of the pyridine ring appears at 6.9-8.3 ppm, the proton peak of the methyl group in the methoxy group appears at 2.9 ppm, and the proton peak of the methylene group in the selenocyanide group appears at 2.0 ppm. This further proves that the quaternary ammonium salt derivative of chitosan containing 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide was successfully synthesized.

[0043] Example 5 ,R= Formula (5) The structural formula of the chitosan quaternary ammonium salt containing 2-mercapto-N-(3-selenocyanopropyl) nicotinamide is shown in Formula (5), wherein the average value of n ranges from 20 to 3000.

[0044] The difference from Example 1 is that: 2.75 g of chitosan was dispersed in 45 mL of NMP and allowed to swell at room temperature for 0.5 hours. 6 g of anhydrous sodium iodide, 22 mL of 15% sodium hydroxide solution, and 22 mL of methyl iodide were then added sequentially. The mixture was refluxed at 60°C for 2 hours. An appropriate amount of anhydrous ethanol was then added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. This was then freeze-dried to a constant weight to obtain chitosan quaternary ammonium salt. 2.2 g of chitosan quaternary ammonium salt was dissolved in 45 mL of DMF, and 1.85 mL of chloroacetyl chloride was added. The mixture was allowed to react at 30°C for 12 hours. After the reaction was complete, an appropriate amount of acetone was added for precipitation, which was washed with ethanol and filtered to obtain a filter cake. This was freeze-dried to a constant weight to obtain chloroacetylated chitosan quaternary ammonium salt.

[0045] 2.1 g of the above-mentioned chloroacetylated chitosan quaternary ammonium salt was dissolved in 85 mL of dimethyl sulfoxide, and 7.3 g of 2-mercapto-N-(3-selenocyanopropyl)nicotinamide was added. The mixture was reacted at 60°C for 24 hours. After the reaction was completed, an appropriate amount of acetone was used for precipitation, and the mixture was washed with ethanol and filtered to obtain a filter cake. The filter cake was freeze-dried to a constant weight to obtain the chitosan quaternary ammonium salt containing 2-mercapto-N-(3-selenocyanopropyl)nicotinamide as shown in formula (5).

[0046] from Figure 7 It can be seen that 1454cm -1 and 1738cm -1 The vibration absorption peak at 2064cm -1 The vibration absorption peak of the selenocyanide group appeared, thereby proving that the chitosan quaternary ammonium salt derivative containing 2-mercapto-N-(3-selenocyanopropyl) nicotinamide was successfully synthesized.

[0047] In addition, from Figure 19 It can be seen that the proton peak of the pyridine ring appears at 7.2-8.6 ppm, and the proton peak of the methylene group in the selenocyanide group appears at 2.0 ppm. This further proves that the chitosan quaternary ammonium salt derivative containing 2-mercapto-N-(3-selenocyanopropyl) nicotinamide is successfully synthesized.

[0048] Application Example 1 Antioxidant activity assay (1) Determination of antioxidant capacity for scavenging superoxide anions: The superoxide anion scavenging capacity of the chitosan used in the experiment in Example 1 and the chloroacetylated chitosan quaternary ammonium salt in Example 1, the chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl) nicotinamide, the chitosan quaternary ammonium salt containing N-(3-selenocyanopropyl) isonicotinamide, the chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl) nicotinamide, the chitosan quaternary ammonium salt containing 2-methoxy-N-(3-selenocyanopropyl) isonicotinamide and the chitosan quaternary ammonium salt containing 2-mercapto-N-(3-selenocyanopropyl) nicotinamide were determined respectively (Table 1): Specifically, the experimental chitosan in Example 1 and the chloroacetylated chitosan quaternary ammonium salt in Example 1, the following compounds obtained in each example: N-(3-selenocyanopropyl)nicotinamide chitosan quaternary ammonium salt, N-(3-selenocyanopropyl)isonicotinamide chitosan quaternary ammonium salt, 2-methoxy-N-(3-selenocyanopropyl)nicotinamide chitosan quaternary ammonium salt, 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide chitosan quaternary ammonium salt and 2-mercapto-N-(3-selenocyanopropyl)nicotinamide chitosan quaternary ammonium salt were vacuum freeze-dried to constant weight as test samples, and each test sample was washed with Tris-HCl buffer solution (1.9382 g Prepare sample solutions of 0.2, 0.4, 0.8, 1.6, and 3.2 mg / mL by adding Tris and 0.8 mL concentrated HCl to 1000 mL (pH 8.2). Add 1.5 mL of each sample solution to 0.5 mL of NADH (468 μM). Then, add 0.5 mL of NBT (144 μM) and 0.5 mL of PMS (60 μM). Mix thoroughly in a test tube to achieve final sample concentrations of 0.1, 0.2, 0.4, 0.8, and 1.6 mg / mL. Incubate at room temperature for 5 minutes, then measure absorbance at 560 nm. A control group consists of 1.5 mL of each sample solution, 0.5 mL of Tris-HCl buffer, 0.5 mL of NBT, and 0.5 mL of PMS. The blank group consisted of 1.5 mL of deionized water, 0.5 mL of NADH, 0.5 mL of NBT, and 0.5 mL of PMS (Note: All tested samples were tested three times and the average value was taken).

[0049] Superoxide anion scavenging ability (%) = [1-(A 样品 -A 对照 ) / A 空白 ]×100% Among them, A 样品 : Absorbance of sample group, A 对照 : Absorbance of control group, A 空白 : Blank group absorbance The results of the determination of the antioxidant capacity for scavenging superoxide anions are shown in Table (1): Table 1 Superoxide anion scavenging ability of chitosan, chloroacetylated chitosan quaternary ammonium salt, and chitosan quaternary ammonium salt derivatives containing selenocyanate groups (%)

[0050] (2) Determination of DPPH free radical scavenging ability Deionized water was used to prepare test sample solutions with concentrations of 0.3 mg / mL, 0.6 mg / mL, 1.2 mg / mL, 2.4 mg / mL, and 4.8 mg / mL, respectively.

[0051] Sample group: Take 1 mL of the sample solution to be tested, add 2 mL of 0.036 mg / mL DPPH ethanol solution, and mix in a test tube. The final concentrations of the sample to be tested in the system are 0.1 mg / mL, 0.2 mg / mL, 0.4 mg / mL, 0.8 mg / mL, and 1.6 mg / mL. Incubate in the dark at room temperature for 20 min, and then measure the absorbance at 517 nm.

[0052] Control group: no DPPH was added. Specifically, 1 mL of the sample solution to be tested was added with 2 mL of anhydrous ethanol and mixed in a test tube. The final concentrations of the sample to be tested were 0.1 mg / mL, 0.2 mg / mL, 0.4 mg / mL, 0.8 mg / mL, and 1.6 mg / mL. The solution was allowed to stand in the dark at room temperature for 20 min, and then the absorbance was measured at 517 nm.

[0053] Blank group: No sample was added. Specifically, 1 mL of deionized water was added to 2 mL of 0.036 mg / mL DPPH ethanol solution, mixed in a test tube, and allowed to stand at room temperature in the dark for 20 min. The absorbance was then measured at 517 nm.

[0054] The absorbance of each sample was measured three times and the average value was taken.

[0055] The calculation formula of the sample's scavenging DPPH free radical ability is as follows: DPPH free radical scavenging ability (%) = [1-(A 样品 -A 对照 ) / A 空白 ]×100% Among them, A 样品 is the absorbance of the sample group, A 对照 is the absorbance of the control group, A 空白 is the absorbance of the blank group.

[0056] The results of the DPPH free radical scavenging ability (%) of each sample are shown in Table 2.

[0057] Table 2 Determination results of DPPH free radical scavenging ability (%) of each sample

[0058] The results show that the superoxide anion radical scavenging abilities of the chitosan quaternary ammonium salt derivatives containing selenocyanate groups synthesized by the present invention, chitosan, and chloroacetylated chitosan quaternary ammonium salts are shown in Table 1, and the DPPH radical scavenging antioxidant activities are shown in Table 2. The present invention introduces selenocyanate groups into chitosan quaternary ammonium salts through chemical modification to obtain chitosan quaternary ammonium salt derivatives containing selenocyanate groups with strong antioxidant activity. The experimental results show that the free radical scavenging antioxidant activity of the selenocyanate chitosan quaternary ammonium salt derivatives containing selenocyanate groups is significantly enhanced compared to that of chitosan, and the derivatives have good water solubility, and have broad application value in medicine, cosmetics, and particularly in the functional food and health care industries.

Claims

1. A chitosan quaternary ammonium salt derivative containing a selenium cyanide group, characterized in that: The structure of the chitosan quaternary ammonium salt derivative containing a selenium cyanide group is shown in Formula 1: Formula 1, where R= 、 、 、 、 ; The average value range of n is 20-3000.

2. A method for preparing the chitosan quaternary ammonium salt derivative containing a selenium cyanide group according to claim 1, characterized in that: First, chitosan was dispersed in N -methyl pyrrolidone, and then anhydrous sodium iodide, sodium hydroxide solution and methyl iodide were added in sequence, and the mixture was refluxed for 3 hours, and then ethanol was precipitated to obtain chitosan quaternary ammonium salt; the chitosan quaternary ammonium salt was then dissolved in N , N -dimethylformamide, add chloroacetyl chloride, react at 45°C for 24 hours, and then precipitate with acetone to obtain chloroacetylated chitosan quaternary ammonium salt; finally, dissolve the chloroacetylated chitosan quaternary ammonium salt in dimethyl sulfoxide, add selenocyanide compound, react at 60°C for 24 hours, and then precipitate with acetone to obtain the final product.

3. The method for preparing a chitosan quaternary ammonium salt derivative containing a selenium cyanide group according to claim 2, wherein: The chloroacetylated chitosan quaternary ammonium salt is prepared by dispersing chitosan in NMP, subjecting it to swelling reaction at room temperature for 1 hour, sequentially adding anhydrous sodium iodide, sodium hydroxide solution, and methyl iodide, and reacting it under reflux at 60° C. for 3 hours; then precipitating it with anhydrous ethanol, washing it with ethanol, and filtering it to obtain a filter cake, which is then freeze-dried in vacuum to a constant weight to obtain the chitosan quaternary ammonium salt; and dissolving the obtained chitosan quaternary ammonium salt in N , N -dimethylformamide, add chloroacetyl chloride dropwise at room temperature, then react at 45°C for 24 hours. After the reaction is completed, precipitate with acetone, wash with ethanol, filter and obtain a filter cake, which is freeze-dried to constant weight.

4. The method for preparing a chitosan quaternary ammonium salt derivative containing a selenium cyanide group according to claim 3, wherein: Each 1-2g of chitosan is used N -Methylpyrrolidone 20-100mL, anhydrous sodium iodide 2-10g, sodium hydroxide 2-9g, iodomethane 20-50mL, chloroacetyl chloride 0.5-6mL, N , N -Dimethylformamide 20-100 mL.

5. The method for preparing the chitosan quaternary ammonium salt derivative containing selenium cyanide group according to claim 2 or 3, characterized in that: The obtained chloroacetylated chitosan quaternary ammonium salt is dissolved in dimethyl sulfoxide, a selenocyanate compound is added at room temperature, and then the mixture is reacted at 60° C. for 24 hours. After the reaction is completed, the mixture is precipitated with acetone and washed three times, and then filtered to obtain a filter cake, which is freeze-dried to a constant weight to obtain a chitosan quaternary ammonium salt containing a selenocyanate group as shown in Formula 1.

6. The method for preparing the chitosan quaternary ammonium salt derivative containing a selenium cyanide group according to claim 5, wherein: The selenocyanide compound is N-(3-selenocyanopropyl)nicotinamide, N-(3-selenocyanopropyl)isonicotinamide, 2-methoxy-N-(3-selenocyanopropyl)nicotinamide, 2-methoxy-N-(3-selenocyanopropyl)isonicotinamide or 2-mercapto-N-(3-selenocyanopropyl)nicotinamide.

7. The method for preparing the chitosan quaternary ammonium salt containing selenium cyanide groups according to claim 5, wherein: For every 1-2 g of the chloroacetylated chitosan quaternary ammonium salt, 3-6 g of the selenocyanide compound and 45-150 mL of dimethyl sulfoxide are used.

8. Use of the chitosan quaternary ammonium salt derivative containing selenium cyanide groups according to claim 1, characterized in that: The use of the compound represented by formula 1 in the preparation of antioxidants.

9. The use of the chitosan quaternary ammonium salt derivative containing a selenium cyanide group according to claim 8, characterized in that: The compound represented by formula 1 is used in the preparation of antioxidants in the fields of medicine, functional food health care, and cosmetics.

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