Preparation method of clausena lansium leaf essential oil Pickering oral antibacterial emulsion stabilized by modified nano attapulgite clay

Abstract

The invention belongs to the technical field of oral cavity bacteriostasis, and particularly relates to a preparation method of a clausena lansium leaf essential oil Pickering oral cavity antibacterial emulsion stabilized by modified nano attapulgite clay, which comprises the following specific steps: taking a proper amount of nano attapulgite clay and water, and uniformly mixing by using a magnetic stirrer to obtain a suspension; then, adjusting the pH value of the suspension to 4.0 by using a 1mol / L hydrochloric acid solution, carrying out a reaction at a set temperature, after the reaction, slowly adding sodium oleate, carrying out a stirring reaction to obtain a reaction product, filtering the reaction product, and after filtering, washing with warm water for three times to remove unreacted sodium oleate. According to the invention, the anionic surface activity of sodium oleate is utilized to modify the nano-attapulgite clay, the hydrophilic-hydrophobic property of the surface of the nano-attapulgite clay is adjusted in the process, and the defects of stable emulsion of the nano-attapulgite clay are overcome.

Description

Technical Field

[0001] The invention relates to the technical field of oral antibacterial, and in particular to a method for preparing a Pickering oral antibacterial emulsion of pangidifolia leaf essential oil stabilized by modified nano-attapulgite clay. Background Art

[0002] Dental caries, as a common global oral health problem, has long had a significant impact on the quality of human life. It not only affects the beauty and function of teeth, but may also cause pain, infection, and even lead to systemic health problems. According to estimates by the World Health Organization (WHO), the prevalence of dental caries is extremely high worldwide, especially among children and adolescents. In China, with the development of the economy and changes in lifestyle, the incidence of dental caries has shown an upward trend, especially among children and middle-aged people. The fourth national oral health epidemiological survey showed that the prevalence of dental caries in deciduous teeth of 5-year-old children in China was as high as 70.9%, while the prevalence of dental caries in permanent teeth of adults aged 35-44 was as high as 89.0%. These data not only reveal the severe oral health challenges facing China, but also reflect the urgent need for dental caries prevention and treatment measures. At present, chemical synthetic drugs such as fluoride and chlorhexidine are commonly used in clinical practice to prevent and treat dental caries. However, these chemical preparations have defects such as poor stability, drug resistance problems, and potential toxic side effects.

[0003] Based on the above, the specific problems of traditional emulsions are as follows:

[0004] Traditional emulsions usually rely on surfactants to reduce the oil-water interfacial tension and achieve stable dispersion of the oil-water phase. However, the ecotoxicity and biodegradability problems that surfactants may bring limit their application. In contrast, Pickering emulsions stand out for their unique stability and environmental protection characteristics. This emulsion uses solid particles instead of traditional surfactants to stabilize the emulsion by forming a physical barrier at the oil-water interface. In view of this, a Pickering emulsion based on modified attapulgite clay, chitosan and phellodendron chinense essential oil will be innovated to provide a safer, more efficient and environmentally friendly solution for the prevention and treatment of dental caries, specifically a method for preparing a phellodendron chinense essential oil Pickering oral antibacterial emulsion stabilized by modified nano-attapulgite clay. Summary of the invention

[0005] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0006] A method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, comprising the following specific steps:

[0007] S1, nano-attapulgite clay modification:

[0008] S11: Take appropriate amounts of nano-attapulgite clay and water, and mix them evenly using a magnetic stirrer to obtain a suspension;

[0009] S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature;

[0010] S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product;

[0011] S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate;

[0012] S15: drying the sample, grinding it after drying, and storing it in a 4°C environment after grinding;

[0013] S2, Pickering antibacterial emulsion preparation:

[0014] S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution;

[0015] S22: stirring the chitosan solution by magnetic force for 50-70 min;

[0016] S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside;

[0017] S24: weighing a certain amount of modified nano-attapulgite clay, and then preparing a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stirring and mixing;

[0018] S25: measuring a certain volume of Phellodendron chinense leaf essential oil, and adding the essential oil to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture;

[0019] S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a Pickering emulsion of pampas grass leaf essential oil synergistically stabilized by modified nano-attapulgite clay / chitosan.

[0020] As a preferred embodiment of the method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay described in the present invention, the ratio of the nano-attapulgite clay to water in S11 is 1:15.

[0021] As a preferred embodiment of the method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay described in the present invention, the temperature set in S12 is 50-70° C. and the reaction time is 50-70 min.

[0022] As a preferred embodiment of the method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay described in the present invention, the amount of sodium oleate in S13 is 16% of the nano-attapulgite clay, and the stirring reaction time is 50-70 min.

[0023] As a preferred embodiment of the method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay described in the present invention, the temperature of the warm water in S14 is 40-60°C, and the drying temperature in S15 is 60-80°C.

[0024] As a preferred solution of the method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay described in the present invention, wherein: the ultrasonic power in S24 is 80% and the ultrasonic time is 10-20 min.

[0025] As a preferred solution of the method for preparing the Pickering oral antibacterial emulsion using modified nano-attapulgite clay stabilized with phellodendron chinense essential oil, the amount of phellodendron chinense essential oil in S25 is 20% of the total volume of the emulsion.

[0026] As a preferred embodiment of the method for preparing the Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay described in the present invention, the rotation speed of the S26 medium-high shear homogenizer is 7000-9000r / min, and the running time is 1-3min.

[0027] Compared with existing technologies:

[0028] 1. The present invention utilizes the anionic surfactant of sodium oleate to modify attapulgite clay, thereby adjusting the hydrophilicity and hydrophobicity of the attapulgite clay surface and overcoming the defect of attapulgite clay in stabilizing emulsions;

[0029] 2. The present invention uses modified attapulgite clay as an emulsifier, stabilizer and viscosity enhancer for preparing Pickering emulsion, uses chitosan aqueous solution and plant essential oil as continuous phase and dispersed phase respectively, optimizes the emulsion preparation conditions (such as concentration of each component, stirring rate, etc.), and finally successfully prepares a highly stable Pickering antibacterial emulsion, effectively solving the practical application problems of the essential oil in the antibacterial products of the yellow peel leaf essential oil, such as easy volatility and easy oxidation, and can be used as an antibacterial agent, daily chemical product and animal feed additive, which is helpful to realize the high-value application of attapulgite clay and yellow peel resources in the field of antibacterial materials;

[0030] 3. The raw materials used in the preparation process of the Huangpi leaf essential oil Pickering emulsion and its antibacterial product of the present invention are mainly chitosan, attapulgite clay, Huangpi leaf essential oil, etc., most of which are natural clay minerals and plant extracts, and have the characteristics of wide sources, non-toxicity, easy degradation and good biocompatibility, and the preparation, application and waste of the emulsion product will not cause pollution to the environment and ecology; the whole preparation process is reasonably designed, the reaction conditions are mild, the process is easy to control and is green and environmentally friendly, which is convenient for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the particle size diagram of attapulgite clay (APT);

[0032] Figure 2 Fourier transform infrared spectra of sodium oleate, attapulgite clay (APT) and modified attapulgite clay (M-APT);

[0033] Figure 3 The three-phase contact angle diagram of attapulgite clay (APT) and modified attapulgite clay (M-APT);

[0034] Figure 4 The zeta potential diagrams of attapulgite clay (APT) and modified attapulgite clay (M-APT);

[0035] Figure 5 This is the Pickering emulsion static diagram with different volume fractions of Phellodendron chinense essential oil;

[0036] Figure 6 The inhibition zone diagrams of different samples;

[0037] Figure 7 This is a diagram showing the sustained-release effect of the Pickering lotion of Phellodendron chinense essential oil. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0039] Embodiment 1:

[0040] The present invention provides a method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, comprising the following specific steps:

[0041] S1, nano-attapulgite clay modification:

[0042] S11: taking appropriate amounts of nano-attapulgite clay and water, and mixing them evenly using a magnetic stirrer to obtain a suspension, wherein the ratio of the nano-attapulgite clay to water is 1:15;

[0043] S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature, wherein the set temperature is 50° C. and the reaction time is 50 min;

[0044] S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product, wherein the amount of sodium oleate is 16% of the nano-attapulgite clay, and the stirring reaction time is 50 minutes;

[0045] S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate, wherein the temperature of the warm water is 40° C.;

[0046] S15: drying the sample, grinding and crushing the sample, and storing the sample in a 4°C environment at a drying temperature of 60°C.

[0047] S2, Pickering antibacterial emulsion preparation:

[0048] S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution;

[0049] S22: stirring the chitosan solution using magnetic force for 50 min;

[0050] S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside;

[0051] S24: Weigh a certain amount of modified nano-attapulgite clay, and then prepare a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stir and mix, wherein the ultrasonic power is 80% and the ultrasonic time is 10 minutes;

[0052] S25: measuring a certain volume of Phellodendron chinense essential oil, and adding it to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture, wherein the amount of Phellodendron chinense essential oil is 20% of the total volume of the emulsion;

[0053] S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a modified nano-attapulgite clay / chitosan synergistically stabilized Phellodendron chinense essential oil Pickering emulsion, wherein the rotation speed of the high shear homogenizer is 7000 r / min and the operation time is 1 min.

[0054] Embodiment 2:

[0055] The present invention provides a method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, comprising the following specific steps:

[0056] S1, nano-attapulgite clay modification:

[0057] S11: taking appropriate amounts of nano-attapulgite clay and water, and mixing them evenly using a magnetic stirrer to obtain a suspension, wherein the ratio of the nano-attapulgite clay to water is 1:15;

[0058] S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature, wherein the set temperature is 55° C. and the reaction time is 55 min;

[0059] S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product, wherein the amount of sodium oleate is 16% of the nano-attapulgite clay, and the stirring reaction time is 55 minutes;

[0060] S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate, wherein the temperature of the warm water is 45° C.;

[0061] S15: drying the sample, grinding and crushing the sample, and storing the sample in a 4°C environment, wherein the drying temperature is 65°C;

[0062] S2, Pickering antibacterial emulsion preparation:

[0063] S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution;

[0064] S22: stirring the chitosan solution using magnetic force for 55 min;

[0065] S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside;

[0066] S24: Weigh a certain amount of modified nano-attapulgite clay, and then prepare a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stir and mix, wherein the ultrasonic power is 80% and the ultrasonic time is 12.5 min;

[0067] S25: measuring a certain volume of Phellodendron chinense essential oil, and adding it to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture, wherein the amount of Phellodendron chinense essential oil is 20% of the total volume of the emulsion;

[0068] S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a modified nano-attapulgite clay / chitosan synergistically stabilized Phellodendron chinense essential oil Pickering emulsion, wherein the rotation speed of the high shear homogenizer is 7500 r / min and the operation time is 1.5 min.

[0069] Embodiment 3:

[0070] The present invention provides a method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, comprising the following specific steps:

[0071] S1, nano-attapulgite clay modification:

[0072] S11: taking appropriate amounts of nano-attapulgite clay and water, and mixing them evenly using a magnetic stirrer to obtain a suspension, wherein the ratio of the nano-attapulgite clay to water is 1:15;

[0073] S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature, wherein the set temperature is 60° C. and the reaction time is 60 min;

[0074] S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product, wherein the amount of sodium oleate is 16% of the nano-attapulgite clay, and the stirring reaction time is 60 minutes;

[0075] S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate, wherein the temperature of the warm water is 50° C.;

[0076] S15: drying the sample, grinding and crushing the sample, and storing the sample in a 4°C environment at a drying temperature of 70°C.

[0077] S2, Pickering antibacterial emulsion preparation:

[0078] S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution;

[0079] S22: stirring the chitosan solution using magnetic force for 60 min;

[0080] S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside;

[0081] S24: Weigh a certain amount of modified nano-attapulgite clay, and then prepare a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stir and mix, wherein the ultrasonic power is 80% and the ultrasonic time is 15 minutes;

[0082] S25: measuring a certain volume of Phellodendron chinense essential oil, and adding it to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture, wherein the amount of Phellodendron chinense essential oil is 20% of the total volume of the emulsion;

[0083] S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a modified nano-attapulgite clay / chitosan synergistically stabilized Phellodendron chinense essential oil Pickering emulsion, wherein the rotation speed of the high shear homogenizer is 8000 r / min and the operation time is 2 min.

[0084] Embodiment 4:

[0085] The present invention provides a method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, comprising the following specific steps:

[0086] S1, nano-attapulgite clay modification:

[0087] S11: taking appropriate amounts of nano-attapulgite clay and water, and mixing them evenly using a magnetic stirrer to obtain a suspension, wherein the ratio of the nano-attapulgite clay to water is 1:15;

[0088] S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature, wherein the set temperature is 65° C. and the reaction time is 65 min;

[0089] S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product, wherein the amount of sodium oleate is 16% of the nano-attapulgite clay, and the stirring reaction time is 65 minutes;

[0090] S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate, wherein the temperature of the warm water is 55° C.;

[0091] S15: drying the sample, grinding and crushing the sample, and storing the sample in a 4°C environment, wherein the drying temperature is 75°C;

[0092] S2, Pickering antibacterial emulsion preparation:

[0093] S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution;

[0094] S22: stirring the chitosan solution using magnetic force for 65 min;

[0095] S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside;

[0096] S24: Weigh a certain amount of modified nano-attapulgite clay, and then prepare a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stir and mix, wherein the ultrasonic power is 80% and the ultrasonic time is 17.5 min;

[0097] S25: measuring a certain volume of Phellodendron chinense essential oil, and adding it to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture, wherein the amount of Phellodendron chinense essential oil is 20% of the total volume of the emulsion;

[0098] S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a modified nano-attapulgite clay / chitosan synergistically stabilized Phellodendron chinense essential oil Pickering emulsion, wherein the rotation speed of the high shear homogenizer is 8500 r / min and the operation time is 2.5 min.

[0099] Embodiment 5:

[0100] The present invention provides a method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, comprising the following specific steps:

[0101] S1, nano-attapulgite clay modification:

[0102] S11: taking appropriate amounts of nano-attapulgite clay and water, and mixing them evenly using a magnetic stirrer to obtain a suspension, wherein the ratio of the nano-attapulgite clay to water is 1:15;

[0103] S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature, wherein the set temperature is 70° C. and the reaction time is 70 min;

[0104] S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product, wherein the amount of sodium oleate is 16% of the nano-attapulgite clay, and the stirring reaction time is 70 minutes;

[0105] S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate, wherein the temperature of the warm water is 60° C.;

[0106] S15: drying the sample, grinding and crushing the sample, and storing the sample in a 4°C environment at a drying temperature of 80°C.

[0107] S2, Pickering antibacterial emulsion preparation:

[0108] S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution;

[0109] S22: stirring the chitosan solution using magnetic force for 70 min;

[0110] S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside;

[0111] S24: Weigh a certain amount of modified nano-attapulgite clay, and then prepare a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stir and mix, wherein the ultrasonic power is 80% and the ultrasonic time is 20 minutes;

[0112] S25: measuring a certain volume of Phellodendron chinense essential oil, and adding it to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture, wherein the amount of Phellodendron chinense essential oil is 20% of the total volume of the emulsion;

[0113] S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a modified nano-attapulgite clay / chitosan synergistically stabilized Phellodendron chinense essential oil Pickering emulsion, wherein the rotation speed of the high shear homogenizer is 9000 r / min and the operation time is 3 min.

[0114] The Pickering antibacterial emulsions prepared in the above Examples 1-5 were compared to obtain the following data:

[0115]

[0116] It can be seen from the above table that the Pickering antibacterial emulsions prepared in Examples 1-3 have good performance in terms of stability and preparation time. After use, Example 3 has the best effect.

[0117] Among them, in the present invention, Figure 1-Figure 7 The specific analysis is as follows:

[0118] Figure 1 The particle size diagram of attapulgite clay (APT) is shown in Figure 1. A certain amount of APT is weighed, and the particle size of APT is measured using a nano-laser particle size analyzer at a solid-liquid ratio of 1:2000 and ultrapure water as the dispersion medium.

[0119] Figure 2The Fourier transform infrared spectra of sodium oleate, nano-attapulgite (APT) and modified attapulgite (M-APT) were obtained by KBr tablet method at 4000-400 cm -1 Scan within the wavelength range and set the resolution to 4cm -1 ; 2921cm in spectral line a -1 and 2850cm -1 The -CH2 antisymmetric and symmetric absorption peaks are at 1560cm -1 and 1456cm -1 The symmetric and antisymmetric stretching vibration peaks of -COO- are characteristic peaks of sodium oleate; 3551cm in the spectrum b -1 and 1655cm -1 The stretching and bending vibration absorption peaks of OH on the APT surface are at 1197 cm -1 and 984cm -1 It is the characteristic peak of Si-O-Si in the APT crystal structure;

[0120] Figure 3 The three-phase contact angle diagram of attapulgite clay (APT) and modified attapulgite clay (M-APT). The APT sample was pressed into a 13mm×2mm cylindrical tablet using a hydraulic press. 2uL of ultrapure water was dropped on the sample surface and captured in real time. The θ value was measured using the photo angle measurement method. The three-phase contact angle of unmodified APT is 16°, and the three-phase contact angle of modified APT is 43.5°.

[0121] Figure 4 The Zeta potential diagram of attapulgite (APT) and modified attapulgite (M-APT) is shown in Figure 1. A certain amount of M-APT is taken, and the solid-liquid ratio is 1:2000. Ultrapure water is used as the dispersion medium. The Zeta potential of APT before and after sodium oleate modification is measured using a nano-laser particle size analyzer. The refractive index of the dispersion medium is 1.330, and the test temperature is 25°C. The average Zeta potential of APT before modification is 0mV, and the average Zeta potential of APT after modification is -23.3mV.

[0122] Figure 5 This is the static graph of emulsions with different volume fractions of Phellodendron chinense essential oil. The mass fraction of M-APT is fixed at 5%, and the mass fraction of chitosan is 2%. The stability of emulsions with different volume fractions of Phellodendron chinense essential oil was investigated after 60 days of storage.

[0123] Figure 6Table 1 is the inhibition zone diagram of penicillin / streptomycin (P / S), yellow peel leaf essential oil (WEO), yellow peel leaf essential oil Pickering emulsion, chlorhexidine (CHX) and sterile water. Table 2 is the inhibition zone diameter of different samples against Streptococcus mutans. Aseptic operation was used to evenly pour BHI culture medium into the culture dish in advance, wait for it to cool and solidify, absorb 100uL of bacterial suspension, and evenly spread it on the surface of the culture medium. Then, a sterile filter paper with a diameter of 6mm soaked overnight with 50μL of various reagents (1x P / S, WEO, yellow peel leaf essential oil Pickering emulsion, 0.6mg / mLCHX and sterile pure water) was placed on the surface of the culture medium, and the culture was placed in an incubator at 37°C for 24h to observe and measure the size of the inhibition zone to evaluate the antibacterial effect of the emulsion. Three parallel experiments were performed and the average value was taken. The inhibition zone diameters of different samples are shown in Table 1:

[0124] Table 1 Diameters of inhibition zones of different samples

[0125]

[0126] Note: “—” indicates no inhibition zone is produced;

[0127] Figure 7 The figure is a sustained-release effect diagram of the Pickering emulsion of the pomelo leaf essential oil. A certain mass of the pomelo leaf essential oil and the emulsion were accurately weighed, placed in an oven at 75°C for volatilization for a certain period of time, and taken out and weighed at 6, 12, and 24 hours, respectively. The loss rate of the pomelo leaf essential oil and the emulsion was calculated according to the following formula:

[0128]

[0129] Where: m J is the initial mass of Phellodendron chinense essential oil, g; m Jt is the mass of Phellodendron chinense essential oil at time t, g; m R is the initial mass of the Pickering emulsion of Phellodendron chinense essential oil, g; m Rt is the mass of the Pickering emulsion of Phellodendron chinense essential oil at time t, g; n is the mass fraction of Phellodendron chinense essential oil in the emulsion.

[0130] In addition, the analysis of Pickering emulsion, attapulgite clay, chitosan and yellow peel in the present invention is specifically as follows:

[0131] Pickering emulsion is a new type of emulsion that uses solid particles to replace traditional surfactants to stabilize the emulsion system. Compared with traditional emulsions, Pickering emulsions have the advantages of being environmentally friendly, excellent performance, good stability, and anti-Ostwald aging. It can encapsulate, control the release, and deliver a variety of active ingredients. The solid particles in the Pickering emulsion are closely arranged at the oil-water interface through adsorption, forming a solid mechanical barrier. The emulsification stability is achieved by regulating the steric hindrance effect between solid particles. Its stability mechanism is thermodynamic irreversibility. At present, there are three main stabilization mechanisms for Pickering emulsions. First, the particles form a dense film around the oil droplets, mainly preventing them from agglomerating through spatial repulsion; second, the particles are connected to each other to form a three-dimensional network of aggregated particles in the continuous phase, the system viscosity increases, and the emulsion agglomeration is reduced; third, the depletion interaction may increase the attraction between particles, resulting in the formation of a three-dimensional particle network that inhibits the movement of droplets.

[0132] Attapulgite clay, referred to as attapulgite (APT), is rich in magnesium, silicon, salt and other elements. It has a layered chain transition structure, and has the characteristics of being slippery, light, highly absorbent, non-swelling when exposed to water, and viscoplastic when wet. Due to its unique structure, it has been widely used in many fields and is known as the "soil with a thousand faces". Attapulgite clay has significant advantages in stabilizing Pickering emulsions due to its unique nanorod structure, excellent dispersion characteristics, inherent negative charge properties and abundant surface active groups. Natural attapulgite clay has strong hydrophilicity and is difficult to stably exist at the oil-water interface to form a strong solid particle film. Therefore, it cannot directly stabilize Pickering emulsions, but can be used as a stabilizer to form a charged interface layer or form a complex with other biopolymers to synergistically stabilize the emulsion.

[0133] Chitosan (CS) is a unique cationic alkaline polysaccharide in nature. It has a wide range of sources and contains amino groups, which give it many unique physical and chemical properties, such as biocompatibility, biodegradability, low toxicity and immunogenicity. It can be designed as "green" micro / nanoparticles to stabilize Pickering emulsions, so it has broad application prospects. However, the emulsification ability of natural chitosan is weak, and the active functional groups in its molecules can combine with other solid particles through covalent or non-covalent interactions to form binary or ternary structures, thereby enhancing the stability of the emulsion.

[0134] Wampee (Clausena lansium, commonly known as wampee) is a subtropical fruit of the Rutaceae family, which is characterized by high nutritional content and abundant bioactive substances. Many bioactive ingredients in wampee have health-promoting effects, such as anti-inflammatory, antibacterial and antioxidant activities. Wampee fruits are often eaten directly or processed into products such as juice, preserves and jams. In contrast, wampee leaves are often discarded, which not only leads to a waste of resources, but also may pollute the environment. In recent years, some scholars have confirmed that the essential oil extracted from wampee leaves has antibacterial activity.

[0135] In the oral microbiome, streptococci account for 60-80% of all major colonizing species. This species plays an important role in the formation and maintenance of oral biofilms, especially Streptococcus mutans. Streptococcus mutans is the main pathogen causing dental caries in humans and has a strong ability to form biofilms. This is mainly due to the following abilities of Streptococcus mutans: (a) producing glycosyltransferases, which can produce insoluble and soluble glucans, thereby promoting the formation of oral biofilms on tooth surfaces; (b) metabolizing a variety of carbohydrates into organic acids, lowering the pH of the oral environment; and (c) being able to grow in an environment with a pH value below 5.5, which is the threshold pH value at which teeth begin to dissolve and demineralize.

[0136] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay, characterized in that: The specific steps are as follows: S1, nano-attapulgite clay modification: S11: Take appropriate amounts of nano-attapulgite clay and water, and mix them evenly using a magnetic stirrer to obtain a suspension; S12: adjusting the pH value of the suspension to 4.0 using 1 mol / L hydrochloric acid solution, and reacting at a set temperature; S13: slowly adding sodium oleate to carry out stirring reaction to obtain a reaction product; S14: filtering the reaction product, and washing it with warm water three times to remove unreacted sodium oleate; S15: drying the sample, grinding it after drying, and storing it in a 4°C environment after grinding; S2, Pickering antibacterial emulsion preparation: S21: weigh a certain amount of chitosan, and prepare a chitosan solution with a mass fraction of 2.0% using 1% glacial acetic acid solution; S22: stirring the chitosan solution by magnetic force for 50-70 min; S23: After stirring, the mixture is allowed to stand until bubbles are completely eliminated and the mixture is set aside; S24: weighing a certain amount of modified nano-attapulgite clay, and then preparing a modified nano-attapulgite clay suspension with a mass fraction of 5% by ultrasonic dispersion, and stirring and mixing; S25: measuring a certain volume of Phellodendron chinense leaf essential oil, and adding the essential oil to the modified nano-attapulgite clay suspension and the chitosan solution to obtain a mixture; S26: homogenizing the mixture using a high shear homogenizer under ice bath conditions to obtain a Pickering emulsion of pampas grass leaf essential oil synergistically stabilized by modified nano-attapulgite clay / chitosan.

2. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: The ratio of nano-attapulgite clay to water in the S11 is 1:

15.

3. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: The temperature set in S12 is 50-70° C., and the reaction time is 50-70 min.

4. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: The amount of sodium oleate in S13 is 16% of the nano-attapulgite clay, and the stirring reaction time is 50-70 minutes.

5. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: The warm water temperature in S14 is 40-60°C, and the drying temperature in S15 is 60-80°C.

6. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: In the S24, the ultrasonic power is 80% and the ultrasonic time is 10-20 minutes.

7. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: The amount of the phellodendron chinense essential oil in the S25 is 20% of the total volume of the emulsion.

8. The method for preparing a Pickering oral antibacterial emulsion of phellodendron chinense essential oil stabilized by modified nano-attapulgite clay according to claim 1, characterized in that: The speed of the S26 medium-high shear homogenizer is 7000-9000 r / min, and the running time is 1-3 min.

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