An amorphous curcumin with a high loading capacity, its preparation method and applications

Abstract

The present invention discloses a high-loading amorphous curcumin and a preparation method thereof: hydroxypropyl methylcellulose and galactomannan are dissolved in water to prepare a cellulose mixed solution; curcumin powder is dissolved in absolute ethanol to prepare a curcumin ethanol solution; the curcumin ethanol solution is added to the cellulose mixed solution under uniform stirring, and after stirring and mixing evenly, ethanol is removed by rotary evaporation to obtain a high-loading amorphous curcumin solution, which is freeze-dried to obtain a high-loading amorphous curcumin solid preparation. The present invention uses the compounding of hydroxypropyl methylcellulose and galactomannan to significantly improve the solubility of curcumin while achieving a maximum loading of 60% amorphous curcumin, improving the water solubility, thermal stability, bioaccessibility and biocompatibility of curcumin, enabling the targeted sustained release of curcumin, and improving the site-specific release performance of curcumin in the colon region.

Description

Technical Field

[0001] The present invention relates to a high-loading amorphous curcumin, a preparation method thereof and an application thereof. Background Art

[0002] Curcumin is a natural plant flavonoid, mainly extracted from the rhizomes of turmeric. Curcumin powder is an orange-yellow crystal, insoluble in water, and easily soluble in organic solvents such as ethanol and alkaline solutions with a pH greater than 12. Curcumin has pharmacological activities such as antioxidant, anti-inflammatory, anti-tumor, and antibacterial, but there are many limitations in its practical applications, such as low water solubility (less than 0.01%) and easy degradation under the action of light and heat. These factors have hindered the application of curcumin in the fields of food and medicine. There are patents and literature reports on using stabilizing aids to prevent the crystallization of curcumin, improve the solubility of curcumin in solution and storage stability, but there is an upper limit to the concentration of curcumin that can be dissolved in liquid preparations, and as raw materials, transportation and storage are not as convenient as solid preparations, and there are also great limitations in formula and process applicability. Amorphous curcumin solid preparations are more suitable for industrial production.

[0003] Using the polymer embedding technology to transform curcumin solid preparations from crystal form to amorphous form is a common method to improve the water solubility and bioavailability of curcumin. Currently, the polymer materials mainly used for curcumin embedding and delivery include polyethylene glycol 6000 (PEG), polyvinylpyrrolidone K30 (PVP), polyacrylic acid resin EPO (EPO), etc. Although the above synthetic polymer materials can load up to 25-30% curcumin, they cannot be used in food due to safety reasons. In the prior art, the loading amount of amorphous curcumin prepared from food-derived materials is only 10-20%, and the loading amount is too low, so it is necessary to further improve it.

[0004] Hydroxypropyl methylcellulose is a non-ionic cellulose mixed ether, which is often used as an emulsifier and stabilizer in the food industry. Hydrogen bonds can be formed between hydroxypropyl methylcellulose and curcumin, which can effectively inhibit the crystallization of curcumin, and improve the cell membrane permeability by reducing the order level of the phospholipid bilayer to improve the bioaccessibility of curcumin. However, the loading amount of curcumin embedded with hydroxypropyl methylcellulose alone is below 10%. It is still necessary to compound suitable edible materials with hydroxypropyl methylcellulose to achieve a higher curcumin loading amount. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-loading amorphous curcumin, a preparation method thereof and an application thereof. The present invention uses the compound of hydroxypropyl methylcellulose and galactomannan to significantly improve the solubility of curcumin while achieving a maximum loading amount of 60% of amorphous curcumin.

[0006] The technical solution adopted by the present invention is:

[0007] A preparation method of high-loading amorphous curcumin, the method comprising the following steps:

[0008] (1) Hydroxypropyl methylcellulose and galactomannan are dissolved in water to prepare a cellulose mixture, wherein the mass fraction of hydroxypropyl methylcellulose is 0.05-0.2% and the mass fraction of galactomannan is 0.05-0.2%;

[0009] The galactomannan is one or more of fenugreek gum, guar gum or locust bean gum; preferably locust bean gum.

[0010] (2) Curcumin powder is dissolved in absolute ethanol to prepare a curcumin ethanol solution with a mass fraction of 0.05-0.2%;

[0011] (3) The curcumin ethanol solution is added to the cellulose mixture under uniform stirring. After stirring and mixing evenly, ethanol is removed by rotary evaporation to obtain a high-loading amorphous curcumin solution, which is freeze-dried to obtain a high-loading amorphous curcumin solid preparation.

[0012] In the high-loading amorphous curcumin solid preparation prepared by the present invention, the loading amount of amorphous curcumin is 40-60%.

[0013] The loading amount is the ratio of the mass of curcumin to the total mass of curcumin, hydroxypropyl methylcellulose and galactomannan.

[0014] The ratio of the mass of curcumin to the total mass of curcumin, hydroxypropyl methylcellulose and galactomannan is 0.4-0.6:1.

[0015] Preferably, in the cellulose mixture, the mass fraction of hydroxypropyl methylcellulose is 0.1% and the mass fraction of galactomannan is 0.1%.

[0016] Preferably, the mass fraction of the curcumin ethanol solution is 0.1%.

[0017] The volume ratio of the curcumin ethanol solution to the cellulose mixture is 0.17-3.75:1,

[0018] In the step (1), generally, it is stirred at 300-600 r / min at room temperature for 20-30 h to obtain a completely dissolved cellulose mixture.

[0019] In the step (2), generally, it is stirred at 300-600 r / min at room temperature for 0.3-1 h to obtain a completely dissolved curcumin ethanol solution.

[0020] In the step (3), the stirring and mixing are generally carried out at 300-600 r / min at room temperature for 2-5 h.

[0021] In the present invention, the galactomannan used is a heteropolysaccharide composed of a β-(1-4)-D-mannan main chain and individual D-galactose branches linked by α-(1-6). The ratios of the hydrophobic main chain (mannose) to the hydrophilic side chain (galactose) in galactomannans from different sources are different, and they are divided into fenugreek gum (1:1), guar gum (2:1), and locust bean gum (4:1). The present invention discovers that hydroxypropyl methylcellulose can crosslink with galactomannan through hydrogen bonds and hydrophobic interactions to form more hydrophobic domains, and the loading amount of curcumin can reach 60%. In addition, galactomannan is not digested in the stomach and small intestine and can only be slowly degraded by the mannanase secreted by colonic flora, having good colon-targeted delivery and sustained-release effects.

[0022] The high-loading amorphous curcumin solution and the high-loading amorphous curcumin solid preparation provided by the present invention have the characteristic of high loading amount, and can be used as a food additive when the galactomannan does not contain fenugreek gum. And it has enteric-targeting and sustained-release properties, and can be used to prepare an enteric-targeting and sustained-release curcumin oral preparation, and the oral preparation can be various pharmaceutical forms commonly used, such as drinking solution, capsule, etc.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) For the first time, a food-grade natural polymer polysaccharide is used to achieve a high loading amount of amorphous curcumin by a synthetic polymer. All are pure food-grade natural polymer polysaccharides as delivery excipients, which are non-toxic, safe and environmentally friendly. The product does not contain alcohol, and all raw materials meet the standards of food additives.

[0025] (2) It is reported for the first time that hydroxypropyl methylcellulose and galactomannan have a synergistic effect, which improves the loading amount of curcumin in the amorphous curcumin solid preparation. In the solution state, the polysaccharide molecules stretch in water. After the main chains and side chains of the two polysaccharide molecules, galactomannan and hydroxypropyl methylcellulose, interact with each other, they jointly form intermolecular hydrogen bonds to form a large number of hydrophobic cavities. These hydrophobic cavities can adsorb curcumin molecules, which are also hydrophobic, and prevent curcumin from crystallizing. And during the drying process of preparing the solid preparation, the formation of the ordered crystal structure of curcumin is effectively destroyed, so that amorphous curcumin is generated in the solid preparation, and the loading amount of amorphous curcumin in the solid preparation is increased to 40 - 60%.

[0026] (3) Utilizing the characteristic that galactomannan can be slowly fermented and decomposed by the mannanase secreted by colonic flora in the colon, the targeted sustained release of curcumin is realized, and the localization release performance of curcumin in the colon part is improved.

[0027] (4)The amorphous curcumin prepared by the present invention overcomes the disadvantages of low water solubility and poor stability of curcumin, improves the water solubility, thermal stability, bioaccessibility and biocompatibility of curcumin, and has a higher protein inhibition rate.

[0028] (5)The present invention discovers that the compounding of hydroxypropyl methylcellulose and galactomannan can significantly improve the solubility of curcumin while achieving a curcumin loading of up to 60%, which significantly exceeds the curcumin loading levels of food-derived materials and synthetic polymers in the prior art. Moreover, both hydroxypropyl methylcellulose and galactomannan are food additives that can be used in various foods in appropriate amounts as required by production in GB-2760, and have great application prospects in the food field. Description of the Drawings

[0029] Figure 1 It is a graph showing the solubility and contact angle results of pure curcumin and the complex of hydroxypropyl methylcellulose and its combination with three galactomannans (fenugreek gum, guar gum, and locust bean gum) and xanthan gum loaded with 40% amorphous curcumin.

[0030] Figure 2 It is a graph showing the maximum loading results of hydroxypropyl methylcellulose and its combination with three galactomannans (fenugreek gum, guar gum, and locust bean gum) and xanthan gum on amorphous curcumin.

[0031] Figure 3 It is a picture of the appearance of the solid preparation of amorphous curcumin prepared by the present invention (Figure A) and the picture of the sample after redissolution (Figure B).

[0032] Figure 4 It is an X-ray diffraction pattern of pure curcumin, the curcumin solid preparation prepared by the present invention, and the curcumin solid preparation prepared using hydroxypropyl methylcellulose and xanthan gum in Comparative Example 1.

[0033] Figure 5 It is an SEM image of curcumin crystals and the curcumin solid preparation prepared by the present invention, where Figure A is the curcumin crystal and Figure B is the amorphous curcumin solid preparation.

[0034] Figure 6 It is a functional characteristic diagram of curcumin crystals and the curcumin solid preparation prepared by the present invention, where Figure A is the diagram of inhibiting ovalbumin denaturation and colon cancer cell toxicity, Figure B is the diagram of thermal stability and in vitro antioxidant stability, Figure C is the in vitro dissolution curve diagram of in vitro simulated gastric juice (pH 1.2); Figure D is the in vitro dissolution curve diagram of in vitro simulated intestinal juice (pH 7.6). Detailed Embodiments

[0035] The following further elaborates on the technical solutions of the present invention in conjunction with the drawings, but the protection scope of the present invention is not limited thereto.

[0036] Example 1 High-loading amorphous curcumin solid preparation is used to prepare curcumin oral beverage, and the steps are as follows:

[0037] (1) Weigh 1 g of hydroxypropyl methylcellulose and 1 g of fenugreek gum precisely and place them in the same beaker containing 1 L of water. Stir at a constant speed of 450 r / min at room temperature for 24 h to obtain a completely dissolved cellulose mixture solution.

[0038] (2) Weigh 1.5 g of curcumin powder precisely and add it to 1.5 L of absolute ethanol. Stir at a constant speed of 450 r / min at room temperature for 0.5 h to obtain a completely dissolved curcumin ethanol solution.

[0039] (3) Add 1.5 L of curcumin ethanol solution to the 1 L of cellulose mixture solution stirred at a constant speed. Stir at a constant speed of 450 r / min at room temperature for 3 h, and then remove ethanol by rotary evaporation to obtain a high-loading amorphous curcumin solution.

[0040] (4) Freeze the high-loading amorphous curcumin solution overnight at -20 °C, and then perform freeze-drying to obtain a high-loading amorphous curcumin solid preparation, denoted as HPMC-FG.

[0041] (5) Weigh 1 g of curcumin oral preparation precisely and dissolve it in 100 mL of water, and stir evenly to obtain curcumin oral beverage.

[0042] Replace fenugreek gum with guar gum and locust bean gum, and operate according to steps (1) to (4) to obtain amorphous curcumin solid preparations, denoted as HPMC-GG and HPMC-LBG respectively.

[0043] The loading amount is calculated by the following method:

[0044]

[0045] m c is the mass (g) of curcumin in the amorphous solid preparation, and m a is the total mass (g) of the amorphous solid preparation.

[0046] Perform physical and chemical properties, in vitro dissolution and colon cancer cell toxicity tests, and the results are as Figures 3 to 6 shown. The solubility and contact angle results of pure curcumin, hydroxypropyl methylcellulose and their complexes with three galactomannans, namely fenugreek gum, guar gum and locust bean gum, loaded with 40% amorphous curcumin solid preparations (HPMC-FG, HPMC-GG and HPMC-LBG respectively) are as Figure 1 shown. Figure 1The results showed that the solubility and hydrophilic properties of HPMC-FG, HPMC-GG, and HPMC-LBG prepared by the technical solution of the present invention were significantly improved (p < 0.05). Among them, the solubility of the amorphous curcumin prepared by compounding hydroxypropyl methylcellulose and locust bean gum was more than 400 times that of pure curcumin. Figure 1 In A, B, C, D, and E in Figure 1 , it represents the significance analysis of data differences. Different letters represent significant differences between values.

[0047] The appearance diagram of the curcumin solid preparation HPMC-FG prepared by the present invention and the sample diagram of it dissolved in water are as Figure 3 shown. Figure 3 It shows that the appearance of the curcumin solid preparation HPMC-FG prepared by the present invention is yellow powder, and it becomes a yellow homogeneous solution after being dissolved.

[0048] The X-ray diffraction diagrams of curcumin and the curcumin solid preparation HPMC-FG prepared in Example 1 are as Figure 4 shown. Figure 4 The results showed that there were no characteristic crystal diffraction peaks of curcumin in the curcumin solid preparation, which was a typical amorphous form, indicating that the polysaccharide composite system in this method successfully and efficiently carried curcumin.

[0049] The SEM diagrams of curcumin and the curcumin solid preparation HPMC-FG prepared in Example 1 are as Figure 5 shown, where Figure A is the curcumin crystal and Figure B is the curcumin solid preparation. Figure 5 The results showed that curcumin was successfully dispersed into the polysaccharide complex of hydroxypropyl methylcellulose and fenugreek gum in an amorphous form.

[0050] The functional properties of curcumin and the curcumin solid preparation HPMC-FG prepared in Example 1 are as Figure 6 shown, where Figure A is the diagram of inhibiting ovalbumin denaturation and colon cancer cell toxicity, Figure B is the diagram of thermal stability and in vitro antioxidant stability, Figure C is the in vitro dissolution curve diagram of in vitro simulated gastric juice (pH 1.2); Figure D is the in vitro dissolution curve diagram of in vitro simulated intestinal juice (pH 7.6).

[0051] Figure 6The results showed that, compared with pure curcumin, the solid preparation of curcumin was in an amorphous state, its thermal stability was nearly doubled, its in vitro antioxidant activity was increased to more than 80%, and both showed significant improvements. The activity of inhibiting ovalbumin denaturation was increased, and the activity of inhibiting cancer cell proliferation was increased to more than 50%, and the bioactive effect was significantly improved. The dissolution rate of the solid preparation of curcumin was less than 10% within 3 hours in the simulated gastric juice (pH 1.2) environment, which was a trace dissolution. The dissolution rate was as high as 70 - 80% in the simulated intestinal juice (pH 7.6) environment, far higher than that of pure curcumin and significantly higher than that in gastric juice. Therefore, the solid preparation of curcumin can be defined as having an intestinal targeting and sustained release function.

[0052] Example 2

[0053] Gradually increase the feeding amount of curcumin powder in step (2), and keep other method steps unchanged to prepare the solid preparation of flavin, and obtain products with different loadings. Perform X-ray diffraction analysis on the product powder. No characteristic crystal peaks of curcumin are detected, indicating that all curcumin in the sample has been successfully transformed into an amorphous state. Increase the feeding amount of curcumin until characteristic crystal peaks of curcumin are detected in the product, indicating the appearance of crystalline curcumin. The loading amount at this time is the highest loading amount.

[0054] The highest loading amounts of hydroxypropyl methylcellulose and its complex embedding of amorphous curcumin with three galactomannans, namely fenugreek gum, guar gum and locust bean gum, are as Figure 2 shown. Figure 2 The results showed that the loading amount of amorphous curcumin with hydroxypropyl methylcellulose alone was less than 10 wt%. The loading amount of the complex embedding of hydroxypropyl methylcellulose and galactomannan with amorphous curcumin increased significantly (p < 0.05). Among them, the loading amount of the complex embedding of hydroxypropyl methylcellulose and locust bean gum with amorphous curcumin was the highest, which was 60 wt%.

[0055] Example 3 The preparation steps of the high-loading amorphous curcumin solid preparation for preparing curcumin oral capsules are as follows:

[0056] (1) Weigh 1 g of hydroxypropyl methylcellulose and 1 g of guar gum precisely and place them in the same beaker containing 1 L of water. Stir at a constant speed of 450 r / min at room temperature for 24 h to obtain a completely dissolved cellulose mixture.

[0057] (2) Weigh 1.5 g of curcumin powder precisely and add it to 1.5 L of absolute ethanol. Stir at a constant speed of 450 r / min at room temperature for 0.5 h to obtain a completely dissolved curcumin ethanol solution.

[0058] (3) Add 1.5 L of curcumin ethanol solution to 1 L of cellulose mixture under uniform stirring. After stirring at a constant speed of 450 r / min for 3 h at room temperature, rotary evaporate to remove ethanol to obtain a high-loading amorphous curcumin solution.

[0059] (4) Freeze-dry the high-loading amorphous curcumin solution to obtain an oral preparation of high-loading amorphous curcumin.

[0060] (5) Place 0.25 g of the amorphous curcumin oral preparation into an enteric capsule to obtain a curcumin oral capsule.

[0061] Comparative Example 1

[0062] Change the fenugreek gum in step (1) of Example 1 to xanthan gum, and prepare the curcumin solid preparation HPMC-XG in the same method. When the loading amount is 40%, the solubility and contact angle results are as Figure 1 shown, and the X-ray diffraction pattern is as Figure 4 shown. Figure 1 It can be seen that the solubility of HPMC-XG is comparable to that of the curcumin solid preparation prepared by using hydroxypropyl methylcellulose alone. There is no synergistic effect between hydroxypropyl methylcellulose and xanthan gum to form a hydrophobic cavity. The contact angle is also large. There are characteristic crystal diffraction peaks of curcumin in the XRD pattern of the HPMC-XG product. It can be seen that when the loading amount is 40%, it contains curcumin crystals and is not all amorphous curcumin.

[0063] According to the method of Example 2, gradually reduce the amount of xanthan gum, and detect that when the polysaccharide is hydroxypropyl methylcellulose and xanthan gum, for the amorphous curcumin solid preparation, the highest loading amount is 15%, as Figure 2 shown.

[0064] In the present invention, the synergistic effect between hydroxypropyl methylcellulose and galactomannan is the key. Galactomannan and hydroxypropyl methylcellulose jointly generate intermolecular hydrogen bonds to form local hydrophobic cavities. These hydrophobic cavities capture a large number of hydrophobic curcumin molecules and prevent curcumin crystallization. During the subsequent drying process, curcumin precipitates from the alcohol solution, and these polysaccharide segments will disrupt the orderly formation of curcumin crystals to generate amorphous curcumin. While ordinary high-molecular polysaccharides cannot disrupt the formation of curcumin crystals under high loading, so curcumin crystals will appear in the product. The loading amount of the amorphous curcumin solid preparation that can be prepared by conventional high-molecular polysaccharides (non-the technical solution of the present invention) is very low.

Claims

1. A method for preparing a high-load amorphous curcumin, characterized in that The method comprises the following steps: (1) Hydroxypropyl methylcellulose and galactomannan are dissolved in water to prepare a cellulose mixed solution, wherein the mass fraction of hydroxypropyl methylcellulose is 0.05-0.2% and the mass fraction of galactomannan is 0.05-0.2%; (2) curcumin powder is dissolved in anhydrous ethanol to prepare a curcumin ethanol solution with a mass fraction of 0.05-0.2%; (3) adding the curcumin ethanol solution to the uniformly stirred cellulose mixture, stirring and mixing, and then removing the ethanol by rotary evaporation to obtain a high-load amorphous curcumin solution, and freeze-drying to obtain a high-load amorphous curcumin solid preparation; the galactomannan is one or more of fenugreek gum, guar gum or locust bean gum; The ratio of the mass of the curcumin to the total mass of the curcumin, hydroxypropyl methylcellulose and galactomannan is 0.4-0.6:1; In the cellulose mixed solution, the mass fraction of hydroxypropyl methylcellulose is 0.1%, the mass fraction of galactomannan is 0.1%, and the mass fraction of curcumin ethanol solution is 0.1%.

2. The high-load amorphous curcumin solid preparation prepared according to the method of claim 1, wherein the loading capacity of the amorphous curcumin is 40-60%.

3. Use of the high-load amorphous curcumin solid preparation as claimed in claim 2 in the preparation of an enteric-coated targeted sustained-release curcumin oral preparation.

4. The use of the high-load amorphous curcumin solid preparation as claimed in claim 2 as a food additive, wherein the galactomannan is one or both of guar gum and locust bean gum.

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