Quercetagetin complex as well as preparation method and application thereof

Abstract

The invention discloses a quercetagetin complex, quercetagetin is used as a ligand material, the unique space structure of the quercetagetin is easy to form a stable complex with metal elements, and the quercetagetin complex has the biological activity of the quercetagetin and also has the effects of metal trace elements. The quercetin and marigold microelement complex is applied as a feed additive, and compared with the mode that microelements are directly used as the feed additive, the quercetin and marigold microelement complex can reduce oxidative damage to vitamins in feed, so that the antioxidant index of animal blood is improved, the health condition of animals is improved, in addition, the utilization rate of the microelements can be increased, and the feed utilization rate is increased. The apparent digestibility of animals to copper, zinc, iron and manganese can be remarkably improved, and the method has huge application potential in the field of animal feed.

Description

Technical Field

[0001] The invention belongs to the technical field of complexes, and particularly relates to a method for preparing a quercetin complex. Background Art

[0002] Trace elements in animal nutrition refer to metal elements such as copper, zinc, iron, and manganese, which directly affect certain biochemical reactions in animals and are very important for animal metabolism and growth and development. Inorganic trace elements are commonly used in feeds, because their metal elements exist in the form of ions, which will accelerate the oxidation of nutrients such as oils and vitamins in feeds and reduce the nutritional value of feeds. In addition, the digestibility and utilization rate of inorganic trace elements is low, and most of the inorganic trace elements added to feeds are excreted with feces, causing great pollution to the environment. The formation of organic trace elements by complexing metal ions with organic compounds can reduce the negative effects of metal ions and improve the utilization rate of trace elements. At present, the complex of amino acids and metal ion salts is more widely used in feed additives, but different amino acids have different metal ion chelation rates, and the chelation of mixed amino acids may also reduce the chelation ability of metal ions, so that trace element amino acid complexes have low chelation strength and poor stability, thereby affecting the digestibility and utilization rate of trace elements. Therefore, it is necessary to develop a new type of metal ion complex with low oxidizability and high stability for use in feed. Summary of the invention

[0003] In order to overcome the problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide a quercetin complex. The second purpose of the present invention is to provide a method for preparing the above-mentioned quercetin complex. The third purpose of the present invention is to provide a vitamin composition. The fourth purpose of the present invention is to provide the application of the above-mentioned quercetin complex. The fifth purpose of the present invention is to provide a feed.

[0004] Quercetagetin (QG), also known as quercetagetin, has antioxidant and immune-regulating effects in animal nutrition. Its molecular structure is a polyhydroxyflavonoid compound, and its unique spatial structure makes it easy to form stable complexes with metal elements. The present invention uses quercetagetin as a ligand, and the obtained quercetagetin trace element complex has the biological activity of quercetagetin and the efficacy of metal trace elements, which can not only reduce the oxidative damage to vitamins in feed, but also has a high utilization rate of trace elements.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a quercetin complex, the structural formula of the quercetin complex is shown in formula (I):

[0007]

[0008] Wherein, M is a metal ion selected from Cu 2+ 、Zn 2+ , Fe 3+ , Mn 2+ One of the .

[0009] The second aspect of the present invention provides a method for preparing the quercetin complex described in the first aspect, comprising the following steps:

[0010] S1, propionic anhydride and quercetin react A to obtain 3',4',6,7-propionic anhydride protected quercetin, the structural formula of which is shown in formula (II):

[0011]

[0012] S2, the 3',4',6,7-propionic anhydride protected quercetin is reacted with metal M salt in a reaction B to obtain a 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex, the structural formula of which is shown in formula (III):

[0013]

[0014] S3. The 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex is subjected to hydroxyl deprotection treatment to obtain the quercetin complex.

[0015] The direct reaction of quercetin with metal salts will react with 3', 4 and other strong antioxidant hydroxyl groups, which may affect the antioxidant activity of quercetin. The acrylic acid protection preparation method of the present invention can better prepare the target product, thereby avoiding the above problem.

[0016] Preferably, in step S1, the molar ratio of quercetin to propionic anhydride is 1:(4-6).

[0017] Preferably, in step S1, the reaction A is carried out in a solvent, and the solvent is selected from one or more of dimethylformamide, dimethyl sulfoxide, acetonitrile and acetone.

[0018] Preferably, in step S1, the reaction temperature of reaction A is 50-70° C., and the reaction time is 4-6 h.

[0019] More preferably, in step S1, the reaction temperature of reaction A is 55-65°C, and the reaction time is 4-5h.

[0020] Preferably, step S1 further comprises the following steps: adjusting the pH of the mixed solution after reaction A to neutral, and obtaining 3',4',6,7-propionic anhydride-protected quercetin through extraction, concentration and drying.

[0021] Preferably, in step S2, the molar ratio of quercetin to M in the metal M salt is 1:(1-2).

[0022] More preferably, in step S2, the molar ratio of quercetin to M in the metal M salt is 1:(1.3-1.6).

[0023] Preferably, the metal M salt is selected from one of copper acetate, copper sulfate, copper chloride, zinc nitrate, zinc chloride, ferric chloride and manganese acetate.

[0024] Preferably, in step S2, the reaction temperature of reaction B is 50-70°C, and the reaction time is 3-5h.

[0025] Preferably, in step S2, the reaction B is carried out in a solvent, and the solvent is selected from one or more of dichloroethane, dichloropropane and trichloroethane.

[0026] Preferably, step S2 further comprises the following steps: adjusting the pH of the mixed solution after reaction B to neutral, extracting, concentrating and drying to obtain the 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex.

[0027] Preferably, in step S3, the hydroxyl deprotection treatment comprises the following steps: adding the 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex to an acid solution for reaction to obtain the quercetin complex.

[0028] More preferably, the reaction temperature of the reaction is 25-40°C, and the reaction time is 1-3h.

[0029] More preferably, the acid solution comprises a halogenated hydrocarbon solvent and hydrochloric acid, and the halogenated hydrocarbon solvent is selected from one or more of dichloroethane, dichloropropane and trichloroethane.

[0030] The third aspect of the present invention provides a vitamin composition, comprising vitamins and the quercetin complex described in the first aspect.

[0031] Preferably, the vitamins include one or more of vitamin A, vitamin D, vitamin E, vitamin B1, vitamin B2, vitamin B6, vitamin B12, folic acid, D-pantothenic acid, and choline chloride.

[0032] The fourth aspect of the present invention provides the use of the quercetin complex described in the first aspect or the vitamin composition described in the third aspect in feed.

[0033] The fifth aspect of the present invention provides a feed, which uses the quercetin complex described in the first aspect as an active additive.

[0034] Preferably, the feed is pig feed.

[0035] The beneficial effects of the present invention are:

[0036] The present invention provides a quercetin complex, which uses quercetin as a ligand material, and its unique spatial structure is easy to form a stable complex with a metal element. The quercetin complex has the biological activity of quercetin and also has the efficacy of metal trace elements. The quercetin trace element complex of the present invention is used as a feed additive. Compared with directly using trace elements as feed additives, it can reduce the oxidative damage to vitamins in feed, thereby improving animal blood antioxidant indicators and animal health. In addition, it can also improve the utilization rate of trace elements, and can significantly improve the apparent digestibility of copper, zinc, iron and manganese in animals, and has great application potential in the field of animal feed. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0038] Example 1

[0039] This embodiment provides a quercetin copper complex, the structural formula of the quercetin copper complex is The synthesis steps are as follows:

[0040] S1. Add propionic anhydride to the DMF solution containing quercetin, the molar ratio of quercetin to propionic anhydride is 1:4.5, stir at 60°C for 5 hours, adjust to neutral with sodium bicarbonate aqueous solution, add ethyl acetate for extraction, and concentrate and dry to obtain the compound, namely 3',4',6,7-propionic anhydride-protected quercetin.

[0041] S2. The above compound was dissolved in dichloromethane, copper acetate was added (the molar ratio of copper acetate to quercetin was 1.4:1), the pH value was adjusted to 7.0, the reaction temperature was 60° C., and the reaction was carried out for 4 hours. The resulting compound was 3,4-Cu-3',4',6,7-propionic anhydride protected quercetin complex.

[0042] S3. Dissolve 3 g of the above complex in 30 mL of dichloromethane and 30 mL of hydrochloric acid for hydroxyl deprotection treatment, stir and react at 30°C for 2 hours, wash with saturated sodium carbonate solution after the reaction, extract with ethyl acetate 3 times, add anhydrous sodium sulfate for drying, concentrate under reduced pressure, and separate the compound by column chromatography purification (petroleum ether: ethyl acetate = 16:3), which is the quercetin copper complex.

[0043] Example 2

[0044] This embodiment provides a quercetin zinc complex, the structural formula of the quercetin zinc complex is The synthesis steps are as follows:

[0045] S1. Add propionic anhydride to the DMF solution containing quercetin, the molar ratio of quercetin to propionic anhydride is 1:4.5, stir at 60°C for 5 hours, adjust to neutral with sodium bicarbonate aqueous solution, add ethyl acetate for extraction, and concentrate and dry to obtain the compound, namely 3',4',6,7-propionic anhydride-protected quercetin.

[0046] S2. The above compound was dissolved in dichloromethane, zinc nitrate (molar ratio to quercetin was 1.4:1) was added, pH was adjusted to 7.0, reaction temperature was 60°C, reaction was carried out for 4 hours, and the obtained compound was 3,4-Zn-3',4',6,7-propionic anhydride protected quercetin complex.

[0047] S3. Dissolve 3 g of the above complex in 30 mL of dichloromethane and 30 mL of hydrochloric acid for hydroxyl deprotection treatment, stir and react at 30°C for 2 hours, wash with saturated sodium carbonate solution after the reaction, extract with ethyl acetate 3 times, add anhydrous sodium sulfate for drying, concentrate under reduced pressure, and separate the compound by column chromatography purification (petroleum ether: ethyl acetate = 16:3), which is the quercetin zinc complex.

[0048] Example 3

[0049] This embodiment provides a quercetin iron complex, the structural formula of the quercetin iron complex is The synthesis steps are as follows:

[0050] S1. Add propionic anhydride to the DMF solution containing quercetin, the molar ratio of quercetin to propionic anhydride is 1:4.5, stir at 60°C for 5 hours, adjust to neutral with sodium bicarbonate aqueous solution, add ethyl acetate for extraction, and concentrate and dry to obtain the compound, namely 3',4',6,7-propionic anhydride-protected quercetin.

[0051] S2. The above compound was dissolved in dichloromethane, and ferric chloride (with a molar ratio of 1.4:1 to quercetin) was added, and the pH value was adjusted to 7.0, the reaction temperature was 60° C., and the reaction was carried out for 4 hours. The obtained compound was 3,4-Fe-3',4',6,7-propionic anhydride protected quercetin complex.

[0052] S3. Dissolve 3 g of the above complex in 30 mL of dichloromethane and 30 mL of hydrochloric acid for hydroxyl deprotection treatment, stir and react at 30°C for 2 hours, wash with saturated sodium carbonate solution after the reaction, extract with ethyl acetate 3 times, add anhydrous sodium sulfate for drying, concentrate under reduced pressure, and separate the compound by column chromatography purification (petroleum ether: ethyl acetate = 16:3), which is the quercetin iron complex.

[0053] Example 4

[0054] This embodiment provides a method for preparing a quercetin manganese complex, wherein the structural formula of the quercetin manganese complex is The synthesis steps are as follows:

[0055] S1. Add propionic anhydride to the DMF solution containing quercetin, the molar ratio of quercetin to propionic anhydride is 1:4.5, stir at 60°C for 5 hours, adjust to neutral with sodium bicarbonate aqueous solution, add ethyl acetate for extraction, and concentrate and dry to obtain the compound, namely 3',4',6,7-propionic anhydride-protected quercetin.

[0056] S2. The above compound was dissolved in dichloromethane, manganese acetate (with a molar ratio of 1.4:1 to quercetin) was added, the pH value was adjusted to 7.0, the reaction temperature was 60° C., and the reaction was carried out for 4 hours. The obtained compound was 3,4-Mn-3',4',6,7-propionic anhydride protected quercetin complex.

[0057] S3. Dissolve 3 g of the above complex in 30 mL of dichloromethane and 30 mL of hydrochloric acid for hydroxyl deprotection treatment, stir and react at 30°C for 2 hours, wash with saturated sodium carbonate solution after the reaction, extract with ethyl acetate 3 times, add anhydrous sodium sulfate for drying, concentrate under reduced pressure, and separate the compound by column chromatography purification (petroleum ether: ethyl acetate = 16:3), which is the quercetin manganese complex.

[0058] Complex structure characterization

[0059] Structural identification: The products prepared in Examples 1-4 were characterized by infrared spectroscopy using the KBr tableting method, and compared with the infrared spectrum of quercetin, it was determined that the quercetin trace element complex was prepared. The identified structure is shown in Table 1.

[0060] Table 1 Main infrared spectral data and attribution of quercetin-copper (ν / cm -1 )

[0061]

[0062]

[0063] From the infrared spectrum data in Table 1, we can see that the hydroxyl group ν (OH) is at 3200-3500 cm -1 The characteristic peaks of phenolic hydroxyl group ν (C-OH) are at 1300-1380cm -1 The characteristic peak at 1662 cm-1 is present in QG and its several trace element complexes, indicating that phenolic hydroxyl groups exist in the structures of QG and its trace element complexes. -1 After the complex is formed, the vibration frequency of the 4-carbonyl group moves to the low wave number direction, indicating that the complex forms a coordination bond at the carbonyl group. The bending vibration absorption peak of ν(C-OH) in quercetin is at 1330cm -1 The hydroxyl group at position 3 in the complex red-shifted by 14-18 cm -1 , indicating that a coordination bond is formed at the 3-hydroxyl group. The position of quercetin in the complex does not change much compared to ν(COC), indicating that the oxygen atom in the pyran ring does not participate in the coordination. And the complex has a peak at 600cm -1 The absorption in the following low-frequency fingerprint region can be considered as the stretching and bending vibration absorption of the coordinated atom-metal, indicating that the metal ions have participated in the coordination.

[0064] Experimental characterization

[0065] 1. Vitamin oxidation experiment

[0066] (1) The experiment adopted a single-factor variance design and was divided into three treatments, each with three replicates. Treatment 1 was a vitamin group (no trace elements added), treatment 2 was a vitamin plus inorganic trace element group, and treatment 3 was a vitamin plus organic trace element group. The specific formula is shown in Table 2. Premixes were prepared separately and stored for 120 days. The vitamin content of the three groups of premixes was consistent, and the same amount of antioxidant (ethoxyquin) was added to all of them. The organic carrier (wheat bran) and inorganic carrier (medical stone) were used to prepare the premixes of each group to the same ratio.

[0067] Table 2 Composition of vitamins and trace elements in premix (g / kg)

[0068]

[0069]

[0070] Note: The copper, zinc, iron and manganese in the inorganic trace group are feed-grade sulfates, CuSO4·5H2O, ZnSO4·H2O, FeSO4·H2O and MnSO4·H2O, with the contents of each element being 25.00%, 72.50%, 30.00% and 27.00% respectively; the copper, zinc, iron and manganese in the organic trace group are quercetin metal complexes, with the contents of each element being 15.82%, 16.75%, 14.30% and 14.15% respectively.

[0071] (2) Premix storage

[0072] Each group of premixes weighs 15 kg, which is then divided into 3 bags (5 kg / bag) in light-proof sealed self-sealing bags as one replicate and stored in a room at 30°C.

[0073] (3) Index measurement and statistical analysis

[0074] Liquid chromatography was used to determine the vitamin content in each premix. The vitamin loss rate was equal to the difference between the set value and the measured value divided by the set value. The differences between the groups were evaluated using Tukey's method, with α = 0.05 as the significance level, P > 0.05 indicating no significant difference, P < 0.05 indicating significant difference, and 0.05 < P < 0.1 indicating a trend of significant difference.

[0075] (4) Results and analysis

[0076] Compared with the inorganic trace element group, the organic trace element group using quercetin trace element complex significantly reduced the loss rate of vitamin A, vitamin B1, vitamin B6, vitamin B12, folic acid, vitamin B6 and choline chloride in the premix (P < 0.05). The results are shown in Table 3.

[0077] Table 3 Vitamin loss rate of premixes in different groups on day 60 (%)

[0078]

[0079]

[0080] Note: Different letters in the same row indicate significant differences, P < 0.05; the same letters or no letters in the same row indicate no significant differences, P > 0.05. The same applies to the letter annotations in the following tables.

[0081] 2. Animal experiments

[0082] (1) Experimental diet

[0083] The experimental diet was a corn-soybean meal-based feed, and its nutritional indicators met the nutritional needs of weaned piglets. The diet composition and nutritional levels are shown in Table 4.

[0084] Table 4 Basic diet and nutrient level (air-dried)

[0085] raw material content / % Nutritional Levels content / % corn 60 Crude protein 17.60 Soybean meal 19 Digestible energy / (MJ / kg) 14.43 Expanded soybeans 8 Lysine 1.42 Whey Powder 6 Methionine 0.33 Premix 5 Threonine 0.85 Fishmeal 1 Tryptophan 0.25 Calcium Hydrogen Phosphate 1 Total Phosphorus 0.62 total 100 calcium 0.80

[0086] 1) Premix provides VA12000IU, VD 6000IU, VE 800IU, VB1 35mg, VB220mg, VB6 35mg, VB 12 0.1mg, folic acid 1.5mg, D-pantothenic acid 50mg, choline chloride 1g, Fe 90mg, Cu 20mg, Zn80mg, Mn 40mg, Se 0.3mg, I 0.4mg.

[0087] 2) Digestible energy was calculated according to NRC (2012), and other nutrient levels were measured values.

[0088] (2) Experimental animals

[0089] Three hundred healthy weaned piglets [Du×(Large×Long)] weighing about 10 kg were selected and randomly divided into 9 treatments. Each treatment was divided into 5 replicates, with 20 piglets (half male and half female) in each replicate.

[0090] (3) Experimental groups

[0091] The three treatments were control group, experimental group 1 and experimental group 2. The premix types of each group are shown in Table 5. Other basic diets were the same.

[0092] Table 5 Grouping and premix type (g / kg)

[0093]

[0094]

[0095] Note: The copper, zinc, iron and manganese in the inorganic trace group are feed-grade sulfates, CuSO4·5H2O, ZnSO4·H2O, FeSO4·H2O and MnSO4·H2O, with the contents of each element being 25.00%, 72.50%, 30.00% and 27.00% respectively; the copper, zinc, iron and manganese in the organic trace group are quercetin metal complexes, with the contents of each element being 15.82%, 16.75%, 14.30% and 14.15% respectively.

[0096] (5) Feeding and management

[0097] The experiment lasted for a total of 31 days (3 days for the pre-experiment and 28 days for the formal experiment). During the experiment, the piglets had free access to water and food, the pig house was kept ventilated and clean, the animals' feeding and health conditions were observed, and daily management was carried out in accordance with conventional feeding management.

[0098] (6) Detection indicators

[0099] 1) Growth performance

[0100] On the first and 28th day of the formal experiment, the weight of each group of fasting piglets was weighed and recorded, and the average daily weight gain of each group of piglets was calculated accordingly. The amount of addition and the remaining amount of the basal diet of each group of piglets during the experiment was weighed and recorded, and the average daily feed intake of each group of piglets was calculated accordingly. The feed-to-weight ratio of each group of piglets was calculated based on the average daily weight gain and average daily feed intake of each group of piglets. The calculation formula is as follows:

[0101] Average daily weight gain = (piglet final weight - piglet initial weight) / 28

[0102] Average daily feed intake = (basic diet addition amount - basic diet remaining amount) / 28

[0103] Feed to weight ratio = average daily feed intake / average daily weight gain

[0104] Diarrhea rate = [number of piglets with diarrhea in each replicate / (number of test days × number of piglets in each replicate)] × 100

[0105] 2) Serum antioxidant index

[0106] The catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) and malondialdehyde (MDA) in serum were determined according to the kit instructions.

[0107] 3) Trace element determination and apparent digestibility calculation

[0108] The contents of copper, zinc, iron, manganese and titanium in feed, feces and urine were determined by atomic flame absorption spectrometry. The apparent digestibility (ATTD) of trace elements was calculated as follows:

[0109] ATTD(%)=100*(1-Ir*Nf / (If*Nr))

[0110] Ir: indicator titanium content in feed (%); If: indicator titanium content in feces (%); Nr: trace element content in feed (%); Nf: trace element content in feces (%)

[0111] (7) Experimental results

[0112] 1) Growth performance

[0113] As shown in Table 6, compared with the control group, the use of inorganic trace elements-quercetin in experimental group 1 had no significant effect on the average daily feed intake, feed-to-weight ratio and diarrhea rate of piglets (P>0.05); the use of quercetin trace element complex in experimental group 2 was able to significantly increase the average daily feed intake of piglets (P<0.05); significantly reduce the trend of feed-to-weight ratio (P<0.05); and significantly improve the diarrhea rate of piglets (P<0.05).

[0114] Table 6 Growth performance of weaned piglets

[0115] Group Control group Experimental Group 1 Experimental Group 2 Starting weight(kg) 10.00±0.39 10.01±0.35 10.00±0.27 Final weight(kg) 20.73±0.87 20.79±0.76 21.82±0.72 Average daily feed intake (g / d) <![CDATA[662.58±13.65 b ]]> <![CDATA[663.20±11.41 b ]]> <![CDATA[658.94±11.41 a ]]> Average daily weight gain (g / d) 383.20±13.65 385.58±11.41 422.43±15.27 Feed weight ratio (F / G) <![CDATA[1.73±0.06 a ]]> <![CDATA[1.72±0.03 a ]]> <![CDATA[1.56±0.02 b <!-- 10 -->]]> Diarrhea rate (%) <![CDATA[9.45±0.90 a ]]> <![CDATA[9.00±0.72 a ]]> <![CDATA[8.42±0.86 b ]]>

[0116] 2) Serum antioxidant index

[0117] As shown in Table 7, compared with the control group, the use of inorganic trace elements-quercetin in experimental group 1 can significantly increase the glutathione peroxidase (GSH-Px) content and total antioxidant capacity (T-AOC) in piglet serum (P < 0.05), and significantly reduce the MDA content in serum (P < 0.05), and there is no significant difference in superoxide dismutase (SOD) content (P > 0.05); the use of organic trace elements-quercetin trace element complex in experimental group 2 can significantly increase the glutathione peroxidase (GSH-Px) content, superoxide dismutase (SOD) content and total antioxidant capacity (T-AOC) in piglet serum (P < 0.05), and significantly reduce the MDA content in serum (P < 0.05), and the effect is better than that of experimental group 1.

[0118] Table 7 Antioxidant indexes in serum of weaned piglets

[0119] Group Control group Experimental Group 1 Experimental Group 2 Glutathione peroxidase (GSH-Px, U / mL) <![CDATA[55.28±8.90 c ]]> <![CDATA[57.71±5.79 b ]]> <![CDATA[72.35±5.56 a ]]> Superoxide dismutase (SOD, U / mL) <![CDATA[90.58±7.35 b ]]> <![CDATA[100.37±8.69 ab ]]> <![CDATA[105.87±10.35 a ]]> Total antioxidant capacity (T-AOC, U / mL) <![CDATA[4.45±0.38 c ]]> <![CDATA[5.08±0.57 b ]]> <![CDATA[7.23±0.76 a ]]> Malondialdehyde (MDA, nmol / mL) <![CDATA[6.48±0.71 a ]]> <![CDATA[5.11±0.64 b ]]> <![CDATA[4.82±0.21 b ]]>

[0120] 3) Trace element determination and apparent digestibility calculation

[0121] As shown in Table 8, compared with the control group, the use of inorganic trace elements-quercetin in Experiment 1 had no significant effect on the apparent digestibility of each metal element (P>0.05); the use of organic trace elements-quercetin trace element complex in Experiment 2 could significantly improve the apparent digestibility of copper, zinc, iron and manganese in piglets (P<0.05);

[0122] Table 8 Apparent digestibility of trace elements in piglets from 0 to 28 days

[0123] Group Control group Experimental Group 1 Experimental Group 2 copper(%) <![CDATA[27.46±2.15 b ]]> <![CDATA[27.58±1.65 b ]]> <![CDATA[34.88±1.97 a ]]> Zinc (%) <![CDATA[50.34±4.26 b ]]> <![CDATA[50.32±3.86 b ]]> <![CDATA[59.25±2.41 a ]]> iron(%) <![CDATA[30.38±2.68 b ]]> <![CDATA[29.98±2.14 b ]]> <![CDATA[44.32±3.02 a ]]> manganese(%) <![CDATA[27.66±1.25 b ]]> <![CDATA[27.32±1.84 b ]]> <![CDATA[37.11±2.93 a ]]>

[0124] In summary, the application of the quercetin marigold trace element complex of the present invention as a feed additive can reduce the oxidative damage to vitamins in feed, thereby improving the antioxidant index of animal blood and the health of animals, compared with directly using trace elements as feed additives. In addition, it can also improve the utilization rate of trace elements and significantly improve the apparent digestibility of copper, zinc, iron and manganese in animals, and has great application potential in the field of animal feed.

[0125] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A quercetin complex, characterized in that: The structural formula of the quercetin complex is shown in formula (I): Wherein, M is a metal ion selected from Cu 2+ 、Zn 2+ , Fe 3+ , Mn 2+ One of the .

2. The method for preparing the quercetin complex according to claim 1, characterized in that: The steps include: S1, propionic anhydride and quercetin react A to obtain 3',4',6,7-propionic anhydride protected quercetin, the structural formula of which is shown in formula (II): S2, the 3',4',6,7-propionic anhydride protected quercetin is reacted with metal M salt in a reaction B to obtain a 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex, the structural formula of which is shown in formula (III): S3. The 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex is subjected to hydroxyl deprotection treatment to obtain a quercetin complex as shown in formula (I).

3. The method for preparing the quercetin complex according to claim 2, characterized in that: In step S1, the molar ratio of quercetin to propionic anhydride is 1:(4-6).

4. The method for preparing the quercetin complex according to claim 2, characterized in that: In step S1, the reaction temperature of reaction A is 50-70°C, and the reaction time is 4-6h.

5. The method for preparing the quercetin complex according to claim 2, characterized in that: In step S2, the molar ratio of the quercetin to the M in the metal M salt is 1:(1-2); The metal M salt is selected from one of copper acetate, copper sulfate, copper chloride, zinc nitrate, zinc chloride, ferric chloride and manganese acetate.

6. The method for preparing the quercetin complex according to claim 2, characterized in that: In step S2, the reaction temperature of reaction B is 50-70°C, and the reaction time is 3-5h.

7. The method for preparing the quercetin complex according to claim 2, characterized in that: In step S3, the hydroxyl deprotection treatment comprises the following steps: adding the 3,4-M-3',4',6,7-propionic anhydride protected quercetin complex into an acid solution for reaction to obtain the quercetin complex.

8. A vitamin composition, characterized in that The invention comprises vitamins and the quercetin complex according to claim 1.

9. Use of the quercetin complex according to claim 1 or the vitamin composition according to claim 8 in feed.

10. A feed, characterized in that: The quercetin complex described in claim 1 is used as an active additive.

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