An amorphous curcumin nanoparticle, a preparation method thereof, and an application thereof

Abstract

The present invention discloses an amorphous curcumin nanoparticle and its preparation method and application. In the present invention, an absolute ethanol solution of curcumin and apple polyphenol is dropped into water under stirring, and then left standing for treatment to remove ethanol and adjust the pH to obtain amorphous curcumin nanoparticles. Through the bottom-up antisolvent precipitation method and the interaction between curcumin and polyphenol, and by optimizing the important conditions in the preparation process, the present invention effectively reduces the particle size of curcumin and transforms its crystal structure into an amorphous structure. At the same time, the amorphous curcumin nanoparticles can be used as an emulsifier for Pickering emulsions to prepare curcumin emulsions. Compared with curcumin nanoparticles, the curcumin emulsions have higher stability. The present invention has low energy consumption, reduced particle size, can improve solubility, enhance its bioavailability, improve its emulsifying properties, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano-particle technology for drugs and functional health foods, and particularly relates to an amorphous curcumin nano-particle, a preparation method thereof and an application thereof. Background Art

[0002] Curcumin is a diketone compound, which can be extracted from the rhizomes of plants of the Zingiberaceae family and Araceae family. Its powder is orange-yellow crystals, slightly bitter in taste, insoluble in water, but easily soluble in organic solvents and alkaline solutions. Curcumin is reddish-brown in alkaline condition, yellow in neutral and acidic conditions, and has different stabilities. Curcumin has pharmacological activities such as antioxidant, anti-inflammatory, anti-diabetic, anti-tumor, antibacterial, etc., but there are many limitations in its practical application, such as low water solubility, sensitivity to light, heat and oxidants.

[0003] Conventional commercial curcumin powder has large particle size, irregular shape and poor water solubility, thus it is difficult to be absorbed by the human body and exert its own health benefits. At the same time, it limits its application in the food industry, such as water dispersibility and Pickering particle emulsification. It can be known from the relevant reports of Stohs that the water dispersibility of curcumin is only 11 ng / ml. Therefore, reducing the particle size of curcumin and improving its water dispersibility are potential ways to increase its bioavailability and efficacy. Nanonization is a process of converting particles into nano-size to change their particle properties (such as size, polymorphism, shape, etc.). Nanonization can be obtained by bottom-up methods or top-down methods. Commonly used top-down methods include wet media grinding method and high-pressure homogenization method, which break and refine large particle crystals to the nano-level through high-energy shearing, with high energy consumption and poor crystal stability. The bottom-up method obtains nano-size particles by controlling the crystallization and nucleation process of molecules. Commonly used methods are anti-solvent precipitation method and combination method, with low energy consumption and strong particle stability.

[0004] Bottom-up is an ideal method for preparing nano-curcumin, and the key is how to control the growth of crystals in solution. The present invention modifies the anti-solvent method and uses water-soluble polyphenols to change the crystallization behavior of curcumin in solution, thereby generating amorphous curcumin and preparing nano-level curcumin co-crystal powder. This method effectively reduces the particle size of curcumin, improves its solubility, bioavailability and functional properties, and is of great significance for expanding the commercial application of curcumin. Summary of the Invention

[0005] The primary object of the present invention is to overcome the above deficiencies in the prior art and provide a preparation method for amorphous curcumin nano-particles. The preparation method first adopts a modified anti-solvent method and combines with the co-crystal interaction of water-soluble polyphenols to prepare an amorphous curcumin particle structure, thereby obtaining the curcumin nano-particles.

[0006] Another object of the present invention is to provide an amorphous curcumin nanoparticle.

[0007] Another object of the present invention is to provide an application of the amorphous curcumin nanoparticle.

[0008] The above object of the present invention is achieved by the following technical solutions:

[0009] A preparation method of an amorphous curcumin nanoparticle, comprising the following steps:

[0010] Drop an ethanol solution of curcumin and apple polyphenol into water under stirring (during the dropping process, curcumin and apple polyphenol interact with each other), then stand for treatment, remove ethanol, and adjust the pH to obtain an amorphous curcumin nanoparticle.

[0011] Preferably, the mass ratio of curcumin to apple polyphenol is 1:6 - 8;

[0012] Preferably, the concentration range of curcumin in absolute ethanol is 2 - 3 mg / mL.

[0013] Preferably, the water is distilled water;

[0014] Preferably, the standing time for treatment is 5 - 10 minutes;

[0015] Preferably, the ethanol removal is by rotary evaporation; more preferably, during the rotary evaporation process, the temperature of the solution before rotary evaporation is 20 - 25 °C, and the rotary evaporation condition temperature is 25 - 30 °C.

[0016] Preferably, a lyoprotectant is added to the solution after pH adjustment for freeze-drying;

[0017] More preferably, the lyoprotectant is maltodextrin (abbreviation M); the mass ratio of curcumin to the lyoprotectant is 1:8 - 10.

[0018] More preferably, the freeze-drying time is 48 - 72 h.

[0019] Preferably, the volume ratio of the ethanol solution of curcumin and apple polyphenol to water is 1:10 - 25;

[0020] More preferably, the volume ratio of the ethanol solution of curcumin and apple polyphenol to water is 1:25;

[0021] Preferably, the stirring is magnetic stirring; the stirring speed is 100 - 1500 rpm.

[0022] More preferably, the stirring speed is 1500 rpm.

[0023] Preferably, the temperature of the water is 5 - 45 °C;

[0024] More preferably, the temperature of the water is 5 °C;

[0025] Preferably, the pH adjustment is to adjust the pH to 2.5 - 6.5.

[0026] More preferably, the pH adjustment is to adjust the pH to 5.5.

[0027] The amorphous curcumin nanoparticles prepared by the above preparation method. The amorphous curcumin nanoparticles of the present invention are nanoscale and have good water solubility.

[0028] The application of the above amorphous curcumin nanoparticles in the preparation of drugs and foods.

[0029] In the preparation method of the present invention, by controlling the solvent ratio, rotation speed, distilled water temperature and pH adjustment range after rotary evaporation during the dropping process, the purpose of controlling the particle size of the relevant nanoparticles is achieved.

[0030] The present invention has the following advantages and effects compared with the prior art:

[0031] 1) Based on the antisolvent precipitation method and the co-crystallization interaction with polyphenols, and optimizing conditions such as solvent ratio, temperature, rotation speed and pH, the curcumin particles prepared by the present invention have a minimum size of about 120 nm after being dispersed in water;

[0032] 2) Compared with the conventional curcumin nano-colloidal dispersion, this method does not add traditional surfactants and colloid stabilizers, and at the same time, the added water-soluble polyphenols have health benefits for the human body;

[0033] 3) The curcumin nanoparticles prepared by the present invention are amorphous, the powder particles are smaller in size, closer to spherical, and the addition of water-soluble polyphenols enhances the hydrophilicity of the particles, thereby improving the emulsifying performance of curcumin particles as Pickering particles;

[0034] 4) The present invention is a novel method for preparing amorphous curcumin nanoparticles. The instruments required in the preparation process are conventional, the operation is simple, the energy consumption is low, the obtained particles have a small size and good water dispersibility, which is beneficial to improving their bioavailability and emulsifying performance, and has good application prospects. Description of the Drawings

[0035] Figure 1 It is a diagram showing the influence of different solvent ratios on the particle size and dispersion degree of curcumin particles in Example 1.

[0036] Figure 2 It is a diagram showing the influence of different rotation speeds on the particle size and dispersion degree of curcumin particles in Example 2.

[0037] Figure 3 It is a graph showing the influence of different temperatures on the particle size and dispersity of curcumin granules in Example 3.

[0038] Figure 4 It is a graph showing the influence of different pH values on the particle size and dispersity of curcumin granules in Example 4.

[0039] Figure 5 It is a storage appearance graph of the control pure curcumin prepared by the anti-solvent method and the sample curcumin granules in Comparative Example 1.

[0040] Figure 6 It is an SEM graph of the curcumin solid and the curcumin solid sample prepared by the anti-solvent method in Example 5.

[0041] Figure 7 It is an XRD graph of the curcumin solid, curcumin - apple polyphenol mixture, and solid curcumin sample solid prepared by the anti-solvent method in Example 5.

[0042] Figure 8 It is the appearance graph (a) and the content change graph (b) of the stability of curcumin in the Pickering emulsion prepared from the sample curcumin granules at different pH values in Example 6.

[0043] Figure 9 It is the content change graph of the stability of curcumin in the control curcumin granules at different pH values in Example 6. Detailed implementation manners

[0044] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0045] The apple polyphenols used in the examples and comparative examples were purchased from Xi'an Huilin Biotechnology Co., Ltd., Shaanxi.

[0046] Example 1:

[0047] Dissolve 75 mg of curcumin and 450 mg of apple polyphenols (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, suck 0.6 mL of the curcumin - apple polyphenol ethanol solution, and gradually add it dropwise to 6 mL, 9 mL, 12 mL, and 15 mL of distilled water at different solvent ratios (1:10 - 25). Control the rotation speed of the stirrer at 1500 rpm during the dropwise addition, and the temperature of the distilled water is 5°C; let it stand for 10 minutes and then the solution is heated to 20°C, and perform rotary evaporation at 30°C. Finally, adjust the pH of the solution after rotary evaporation to 5.5 with 0.1 mol HCl or NaOH solution, and finally measure the average particle size and dispersibility PDI of the particles in the solution (as Figure 1 and Table 1).

[0048] Table 1 Influence of solvent ratio on the particle size and dispersity of curcumin granules

[0049]

[0050] Example 2:

[0051] Dissolve 75 mg of curcumin and 450 mg of apple polyphenol (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, draw 0.6 mL of the curcumin - apple polyphenol ethanol solution, and drop - add it into 15 mL of distilled water. Control the rotation speed of the stirrer during dropping, which are 200 rpm, 500 rpm, 1000 rpm, and 1500 rpm respectively, and the temperature of the distilled water is 5°C; let it stand for 10 minutes, the solution temperature rises to 20°C, perform rotary evaporation at 30°C, and finally adjust the pH of the solution after rotary evaporation to 5.5 with 0.1 mol HCl or NaOH solution. Finally, measure the average particle size and dispersibility PDI of the particles in the solution (as Figure 2 and Table 2).

[0052] Table 2 Influence of rotation speed on the particle size and dispersity of curcumin particles

[0053]

[0054] Example 3:

[0055] Dissolve 75 mg of curcumin and 450 mg of apple polyphenol (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, draw 0.6 mL of the curcumin - apple polyphenol ethanol solution, and drop - add it into 15 mL of distilled water. Control the rotation speed of the stirrer during dropping to be 1500 rpm, and control the temperature of the distilled water to be 5°C, 25°C, and 45°C respectively; let it stand for 10 minutes, adjust the solution temperature to 20°C, perform rotary evaporation at 30°C, and finally adjust the pH of the solution after rotary evaporation to 5.5 with 0.1 mol HCl or NaOH solution. Finally, measure the average particle size and dispersibility PDI of the particles in the solution (as Figure 3 and Table 3).

[0056] Table 3 Influence of temperature on the particle size and dispersity of curcumin particles

[0057]

[0058] Example 4:

[0059] Dissolve 75 mg of curcumin and 450 mg of apple polyphenols (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, suck 0.6 mL of the curcumin - apple polyphenol ethanol solution, and drop it into 15 mL of distilled water. Control the rotation speed of the stirrer at 1500 rpm during dropping, and the temperature of the distilled water is 5 °C; let it stand for 10 minutes until the solution temperature rises to 20 °C, perform rotary evaporation at 30 °C, and finally adjust the pH of the solution after rotary evaporation with 0.1 mol HCl or NaOH solution, and its pH values are 2.5, 3.5, 4.5, 5.5, 6.5 respectively. Finally, measure the average particle size and dispersibility PDI of the particles in the solution (as Figure 4 and Table 4).

[0060] Table 4 Effect of pH on the particle size and dispersity of curcumin particles

[0061]

[0062]

[0063] Comparative Example 1:

[0064] Dissolve 75 mg of curcumin in 30 mL of absolute ethanol, stir for 12 h, suck 0.6 mL of the curcumin ethanol solution, and drop it into 15 mL of distilled water. Control the rotation speed of the stirrer at 1500 rpm during dropping, and the temperature of the distilled water is 5 °C; let it stand for 10 minutes until the solution temperature rises to 20 °C, perform rotary evaporation at 30 °C, and finally adjust the pH of the solution after rotary evaporation with 0.1 mol HCl or NaOH solution to 5.5 (control sample).

[0065] Dissolve 75 mg of curcumin and 450 mg of apple polyphenols (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, suck 0.6 mL of the curcumin - apple polyphenol ethanol solution, and drop it into 15 mL of distilled water. Control the rotation speed of the stirrer at 1500 rpm during dropping, and the temperature of the distilled water is 5 °C; let it stand for 10 minutes until the solution temperature rises to 20 °C, perform rotary evaporation at 30 °C, and finally adjust the pH of the solution after rotary evaporation with 0.1 mol HCl or NaOH solution to 5.5 (sample).

[0066] Take pictures of the prepared control sample and sample, and take pictures again after 5 h.

[0067] It can be seen from Figure 5 that when the control sample (abbreviated as Cur) was prepared, larger particles precipitated, while this phenomenon did not occur in the sample. After 5 h, large particles precipitated in the control sample, while the sample (abbreviated as C - A - MYP) did not change and remained relatively stable. It shows that apple polyphenols play an important role in maintaining the stability of curcumin during rotary evaporation, and the amorphous curcumin in this state exhibits strong stability.

[0068] Example 5:

[0069] Dissolve 75 mg of curcumin and 450 mg of apple polyphenols (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, draw 0.6 mL of the curcumin - apple polyphenol ethanol solution, and drop it into 15 mL of distilled water. Control the rotation speed of the stirrer at 1500 rpm during dropping, and the temperature of the distilled water at 5 °C; let it stand for 10 minutes until the solution temperature rises to 20 °C, perform rotary evaporation at 30 °C, and finally adjust the pH of the solution after rotary evaporation to 5.5 with 0.1 mol HCl or NaOH solution. Add maltodextrin (abbreviation M, the mass ratio of curcumin to maltodextrin is 1:8) as a freeze - drying protectant and then freeze - dry for 72 h and then perform XRD( Figure 7 ) and SEM detection( Figure 6 ). (The product prepared without adding apple polyphenols is used as a control sample, and the curcumin - apple polyphenol mixture is used as a control sample)

[0070] It can be seen from the SEM images that the curcumin particles (abbreviation Cur) prepared by the anti - solvent method change from large - sized block - shaped crystal particles to small - sized spherical amorphous curcumin particles (abbreviation C - A - M YP). The morphology of the solid crystal changes, indicating that this preparation method can significantly change the morphology of curcumin crystal particles and affect the curcumin structure. When using XRD to test the particles, if the particles have a crystal structure, peaks will be generated. If there are no peaks, it means that the particles do not produce crystals and are in an amorphous state. It can be seen from the XRD detection that the curcumin particles (abbreviation Cur) prepared by the simple anti - solvent method are in a multi - peak crystal shape, while the curcumin particles prepared by the anti - solvent method after adding polyphenols are in an amorphous state without peaks (abbreviation C - A - M YP), and there are also crystal peaks in the curcumin - apple polyphenol mixture (abbreviation C - A H). This shows that simple mixing cannot play a role in crystal transformation, and apple polyphenols play an important role in the crystal transformation of curcumin during the preparation process.

[0071] Example 6:

[0072] Preparation of Pickering emulsions from curcumin particles at different pH values and their stability:

[0073] Dissolve 75 mg of curcumin and 450 mg of apple polyphenols (ratio 1:6) in 30 mL of absolute ethanol, stir for 12 h, suck 0.6 mL of the curcumin - apple polyphenol ethanol solution, and drop it into 15 mL of distilled water. Control the stirrer speed at 1500 rpm and the distilled water temperature at 5 °C during dropping; let it stand for 10 minutes until the solution temperature rises to 20 °C, and perform rotary evaporation at 30 °C. Finally, adjust the pH of the solution after rotary evaporation to 2.5, 3.5, 4.5, 5.5, 6.5 with 0.1 mol HCl or NaOH solution, dilute the solution through the standard curve to a curcumin concentration of 50 μg / mL, and prepare an emulsion with 10% oil phase. (The product prepared without adding apple polyphenols is used as a control sample)

[0074] Take pictures of the prepared control sample and the sample, and measure the change in the curcumin content in the emulsions prepared from the control sample and the sample before and after three days.

[0075] It can be seen from Figure 5 that the amorphous curcumin nanoparticles prepared by the anti-solvent method have higher water solubility and stability than the curcumin prepared by the anti-solvent method of the control sample, but there is instability in itself. However, as can be seen from a in Figure 8 , the stability of the emulsion prepared using amorphous curcumin nanoparticles will be further improved. It can be seen from b in Figure 8 and Figure 9 that the retention rate of the emulsion of the amorphous curcumin nanoparticle sample after 3 days is much greater than the retention rate of the crystalline curcumin nanoparticles of the control sample at this pH, indicating that the emulsion of the amorphous curcumin nanoparticle sample has higher stability compared to the crystalline curcumin nanoparticles of the control sample, and it still remains in a good state at the oil-water interface after 72 h. Thus, it can be known that while the amorphous curcumin nanoparticles are stabilized at the oil-water interface, it also prevents their crystal form transformation and crystallization behavior, making the retention amount of curcumin more than 80%. However, this is also affected by the pH. At 3.5 and 6.5, the retention amount of curcumin in the emulsion is less, probably because some amorphous curcumin undergoes crystal form changes and crystallization behavior and other unstable precipitation behaviors.

[0076] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing amorphous curcumin nanoparticles, characterized in that, it comprises the following steps: Drop the anhydrous ethanol solution of curcumin and apple polyphenols into water under stirring, then let it stand for treatment, remove ethanol, adjust the pH to obtain amorphous curcumin nanoparticles; the pH adjustment is to adjust the pH to 2.5 - 6.

5.

2. The preparation method according to claim 1, characterized in that, the mass ratio of curcumin to apple polyphenols is 1:6 - 8; the concentration range of curcumin in anhydrous ethanol is 2 - 3 mg / mL.

3. The preparation method according to claim 1, characterized in that, the water is distilled water; the time of the standing treatment is 5 - 10 minutes; the removal of ethanol is to remove ethanol by rotary evaporation; add a freeze-drying protectant to the solution after pH adjustment and perform freeze-drying.

4. The preparation method according to claim 3, characterized in that, during the rotary evaporation process, the temperature of the solution before evaporation is 20 - 25 °C, and the temperature of the rotary evaporation condition is 25 - 30 °C; the freeze-drying protectant is maltodextrin; the mass ratio of curcumin to the freeze-drying protectant is 1:8 - 10; the time of freeze-drying is 48 - 72 h.

5. The preparation method according to claim 1, characterized in that, the volume ratio of the anhydrous ethanol solution of curcumin and apple polyphenols to water is 1:10 - 25; the stirring is magnetic stirring; the rotation speed of the stirring is 100 - 1500 rpm.

6. The preparation method according to claim 5, characterized in that, the volume ratio of the anhydrous ethanol solution of curcumin and apple polyphenols to water is 1:25; the rotation speed of the stirring is 1500 rpm.

7. The preparation method according to claim 1, characterized in that, the temperature of the water is 5 - 45 °C.

8. The preparation method according to claim 7, characterized in that, the temperature of the water is 5 °C; the pH adjustment is to adjust the pH to 5.

5.

9. Amorphous curcumin nanoparticles prepared by the preparation method according to any one of claims 1 - 8.

10. Use of the amorphous curcumin nanoparticles according to claim 9 in the preparation of drugs.

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