Borneolum and preparation method thereof

Abstract

The invention provides kapur and a preparation method thereof, and belongs to the technical field of daily chemical industry. According to the method, an enzymolysis extraction technology is adopted, and cell walls of branches and leaves of cinnamomum camphora are selectively degraded under mild reaction conditions through the catalytic action of specific enzyme, so that the extraction rate of the cinnamomum camphora is increased. By means of selective degradation, the impurity content is effectively reduced, and the purity of kapur is remarkably improved. In addition, water or a buffer solution used in the enzymolysis extraction process is environment-friendly and conforms to the concept of green chemistry. Meanwhile, the modified silicon dioxide is used for adsorbing the kapur, so that the extraction efficiency is improved, the extraction time is shortened, and the cost of the whole extraction process is further reduced through the characteristic that the modified silicon dioxide can be repeatedly used, so that the whole extraction process is more economical and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of daily chemical industry and relates to borneol and a preparation method thereof. Background Art

[0002] Camphor is a natural organic compound with a special aroma. Its chemical formula is C 10 H 18 O, belongs to the class of monoterpene alcohol compounds. Usually, camphor exists in crystalline or solid form, with a white or colorless appearance, and is widely welcomed for its unique aroma.

[0003] Camphor is not only loved for its aroma, but also for its remarkable biological activity. Studies have shown that camphor has significant antibacterial, antioxidant and anti-inflammatory properties. These properties make camphor play an important role in traditional medicine and are often used to treat a variety of ailments, such as headaches, colds, muscle pain, and indigestion. In addition, camphor is believed to improve blood circulation and relieve stress, so it is also widely used in aromatherapy.

[0004] In terms of modern applications, borneol also shows great market potential. Due to its refreshing aroma and multiple biological activities, borneol is widely used in cosmetics and skin care products. It not only enhances the fragrance of the product, but also provides health benefits for the skin, helps soothe and calm the skin, reduces inflammation, and even has certain anti-aging effects. In addition, borneol is also used in the manufacture of products such as perfumes, soaps and spices, further enriching its application in daily life.

[0005] With the increase in consumer demand for natural and organic products, the market prospects of borneol are becoming more and more broad. Its natural source and versatility will continue to play an important role in the future health and beauty industry. There are various extraction methods for borneol, including steam distillation, solvent extraction and enzymatic extraction. For example, in the Chinese patent application with publication number CN105837405A, borneol is extracted from camphor camphor branches and leaves by steam distillation: the borneol camphor branches and leaves are cut off and the steam condensation gas is collected by distillation, and then impurities are removed by an oil-water separator, and centrifugal separation is performed after cooling and crystallization to obtain borneol. This method has convenient production efficiency, but the extraction efficiency is not high, and the purity of the borneol obtained is impure, which limits the application of borneol; the Chinese patent with authorization announcement number CN108503510B adopts solvent extraction, assisted by ultrasound-microwave assisted method: the crude extract of borneol is obtained by extraction with ethanol-water mixed solvent, and then purified by supramolecular solvent to obtain refined borneol. This method may leave residual solvents, affecting the safety and purity of the product. At the same time, some of the solvents used may be harmful to the environment and health, and improper use may cause pollution and safety hazards. Summary of the invention

[0006] In view of the above problems, the present invention provides a borneol and a preparation method thereof. The present invention adopts an enzymatic extraction method: under mild reaction conditions, the catalytic action of a specific enzyme is used to selectively decompose the cell walls of borneol branches and leaves, thereby improving the extraction rate of borneol. This selectivity helps to reduce the content of impurities and improve the purity of borneol. In addition, the water or buffer used in the enzymatic extraction is good for the environment and conforms to the concept of green chemistry. At the same time, the use of modified silica to adsorb borneol can improve the extraction efficiency of borneol and reduce the extraction time. At the same time, the reusable nature of the modified silica makes the overall extraction process more economical.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing borneol, the method comprising:

[0009] S1: Ammonia water, ethanol and deionized water are mixed to obtain a mixed solution A, and a mixed solution B is reacted at a constant temperature. After adding tetraethyl orthosilicate, the mixture is reacted at a constant temperature, and the mixture is centrifuged and dried to obtain nano-silica. A chitosan / acetic acid solution is prepared, and the nano-silica is added to the chitosan / acetic acid solution. The mixture is stirred for reaction and allowed to stand overnight, and then filtered and washed to obtain pre-dried modified silica, and dried to obtain modified silica.

[0010] S2: washing, drying and chopping borneol camphor branches and leaves to obtain borneol camphor branch and leaf powder; soaking the borneol camphor branch and leaf powder in a buffer solution, adding cellulase to obtain a mixture, and performing enzymolysis at a constant temperature to obtain a reaction solution;

[0011] S3: adding modified silica to the reaction solution, stirring to obtain an extract, and centrifuging the extract to retain the modified silica that adsorbs borneol;

[0012] S4: using n-hexane to preliminarily wash the modified silica adsorbing borneol, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring and separating the upper liquid with a separating funnel, and rotary evaporating the upper liquid to obtain borneol.

[0013] As a preferred technical solution of the present invention, in step S1, the molar ratio of aqueous ammonia to anhydrous ethanol in the mixed solution A is (1-2):100, for example, it can be 1.0:100, 1.1:100, 1.2:100, 1.3:100, 1.4:100, 1.5:100, 1.6:100, 1.7:100, 1.8:100, 1.9:100 or 2.0:100, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] In some optional embodiments, the molar ratio of anhydrous ethanol to deionized water in the mixed solution A is (0.5-1):1, for example, it can be 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1 or 1:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] In some optional embodiments, the temperature of the isothermal reaction of the mixed solution A is 80-90°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] In some optional embodiments, the isothermal reaction time of the mixed solution A is 15-30 min, for example, it can be 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min or 30 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In some optional embodiments, the molar ratio of tetraethyl orthosilicate to aqueous ammonia is (1-2):1, for example, it can be 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] In some optional embodiments, the time for the mixed solution B to continue the constant temperature reaction after adding tetraethyl orthosilicate is 20-24 hours, for example, it can be 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h or 6h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In some optional embodiments, the mass fraction of chitosan in the chitosan / acetic acid solution is 1-3%, for example, it can be 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8% or 3.0%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In some optional embodiments, the mass ratio of nano-silicon dioxide to chitosan is 1:(1-2), for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In some optional embodiments, the drying temperature of the pre-dried modified silica is 50-60°C, for example, it can be 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C or 60°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] In some optional embodiments, the drying time of the pre-dried modified silica is 12-20 hours, for example, it can be 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours or 20 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] As a preferred technical solution of the present invention, in step S2, based on the borneol camphor tree leaf powder, the added amount of cellulase is 50-150U / g, for example, it can be 50U / g, 60U / g, 70U / g, 80U / g, 90U / g, 100U / g, 110U / g, 120U / g, 130U / g, 140U / g or 150U / g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0024] In some optional examples, the pH of the mixture is 5.0-6.0, for example, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 or 6.0, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In some optional examples, the temperature of the isothermal enzymatic hydrolysis is 35-40°C, for example, it can be 35.0°C, 35.5°C, 36.0°C, 36.5°C, 37.0°C, 37.5°C, 38.0°C, 38.5°C, 39.0°C, 39.5°C or 40.0°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In some optional examples, the stirring speed during the constant temperature enzymolysis is 200-300 rpm, for example, it can be 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm or 300 rpm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] In some optional examples, the isothermal enzymatic hydrolysis time is 4-5h, for example, it can be 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h or 5.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] As a preferred technical solution of the present invention, in step S3, the mass ratio of the modified silica to the reaction liquid is 1:(10-20), for example, it can be 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In some optional examples, the centrifugal treatment speed is 5000-6000rpm, for example, it can be 5000rpm, 5100rpm, 5200rpm, 5300rpm, 5400rpm, 5500rpm, 5600rpm, 5700rpm, 5800rpm, 5900rpm or 6000rpm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In some optional examples, the centrifugal treatment time is 5-10 min, for example, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] In a second aspect, the present invention provides a borneol obtained according to the above-mentioned preparation method.

[0032] Plant cell walls are composed of complex polysaccharides, mainly including cellulose, hemicellulose and lignin. These components not only provide the necessary support and protection for plants and maintain their structure and morphology, but also form a natural barrier to the extraction of active ingredients, limiting the release of internal active ingredients and making the extraction process more difficult and time-consuming. The firmness and complexity of the cell wall means that traditional extraction methods often require a long time and a large amount of organic solvents, resulting in waste of resources and environmental burden.

[0033] To overcome this challenge, enzymatic extraction has emerged as an advanced method. It uses the catalytic action of specific enzymes to accurately cut these polysaccharide chains and selectively destroy the integrity of the cell wall. This process can not only significantly reduce the barrier effect of the cell wall on the effective ingredients, but also maximize the release of the internal borneol components, thereby improving the extraction efficiency.

[0034] The selectivity of enzymatic extraction is a significant advantage. These specific enzymes are highly specific and can specifically decompose specific components in plant cell walls, such as cellulose, hemicellulose, and lignin. This precise action allows the enzyme to effectively release the desired active ingredients without interfering with other non-target components. This efficient selectivity can not only significantly increase the extraction rate of the target component, but also reduce the content of impurities in the extraction process, thereby improving the purity of the extract.

[0035] High-purity extracts are crucial in many subsequent applications, especially in the fields of drug development and cosmetic production. High-purity products not only ensure the safety of users, but also improve the effectiveness of products and ensure their efficacy in treatment or health care. This is particularly critical for the efficacy of drugs and the performance of cosmetics, because the safety and effectiveness of products directly affect consumer trust and market acceptance.

[0036] In addition, by precisely targeting the cell wall structure, enzymatic extraction not only maximizes the release of target components, but also provides a reliable guarantee for improving product quality. The effectiveness of this method is not only reflected in the acquisition of high-purity extracts, but also makes the extraction process more economical and sustainable. At the same time, the selective action of the enzyme can reduce the amount of organic solvent required, thereby reducing production costs and environmental impact. In this way, enzymatic extraction not only provides strong technical support for the development of modern natural products, but also promotes the application of green chemistry and sustainable development concepts in actual production.

[0037] Reducing the use of organic solvents not only reduces the burden on the environment, but also significantly improves product safety. This advantage becomes particularly important in the context of today's consumers' increasing concern for product safety and environmental protection. The demand for residue-free products is increasing, and enzymatic extraction can meet this demand, making consumers feel more at ease when using products. By reducing the residue of organic solvents, enzymatic extraction provides a new solution for the development of safe and effective natural products.

[0038] In addition, reducing dependence on organic solvents can also help reduce potential health risks in the production process, which not only protects the health of operators, but also reduces environmental risks in the factory. As the concept of sustainable development becomes more popular, the use of enzymatic extraction will help enhance the image of corporate social responsibility and enhance market competitiveness. In summary, the environmental advantages and high efficiency of enzymatic extraction make it an important choice in modern extraction technology, opening up new prospects for the development and application of natural ingredients.

[0039] In addition, enzymatic extraction is usually carried out under relatively mild conditions, which greatly protects heat-sensitive components and prevents them from degradation or denaturation during the extraction process. Such mild operating conditions are essential for maintaining the chemical structure and biological activity of borneol, ensuring that the final extract can maintain its original physiological function and efficacy, so as to play the best effect in medicinal and health products.

[0040] By effectively destroying the plant cell walls, enzymatic extraction significantly increases the release rate of the target ingredients. This unique advantage makes enzymatic extraction generally superior to traditional physical or chemical extraction methods in terms of efficiency, especially when dealing with complex plant matrices. Traditional extraction methods, such as soaking, boiling or organic solvent extraction, often require a long time and higher energy consumption. This not only increases production costs, but may also lead to the loss or denaturation of the target ingredients, thereby affecting the quality of the final extract.

[0041] In contrast, enzymatic extraction can complete the extraction in a shorter time by optimizing the reaction conditions, which makes it a more efficient option. Under the catalysis of the enzyme, the polysaccharide chains in the cell wall are precisely cut, thereby accelerating the release of the target components. This rapid release mechanism not only significantly saves time and resources, but also improves the extraction efficiency, making the production process more flexible and economical.

[0042] The present invention uses silicon dioxide as an adsorbent to adsorb borneol in the reaction solution. Silicon dioxide has a high specific surface area and good adsorption performance, and can quickly adsorb and capture borneol components in the reaction solution. This rapid adsorption mechanism can not only improve the extraction efficiency of borneol, shorten the extraction time, but also ensure that a higher extraction rate is obtained in a shorter time.

[0043] At the same time, the use of silica also makes it easier to separate borneol from the extract: pure borneol extract can be obtained through simple centrifugation, washing and desorption steps, thus simplifying the entire extraction process. This simplification not only improves the experimental operating efficiency, but also reduces dependence on complex equipment and technology, making operations in laboratories or production environments more flexible.

[0044] More importantly, the use of silica as an adsorbent also effectively reduces the demand for organic solvents during the extraction process. This change not only helps reduce environmental pollution and conforms to the concept of green chemistry, but also significantly reduces production costs. In today's context of increasing demands for sustainability and environmental protection, reducing the use of organic solvents is particularly important; in addition, the reusability of silica makes the entire extraction process more economical. Through reasonable washing and regeneration steps, silica can be used multiple times, reducing material costs and improving economic benefits. This recycling not only helps reduce resource waste, but also further promotes the realization of sustainable development goals.

[0045] Modification of silica with chitosan has shown multiple advantages. As a natural polysaccharide, chitosan not only has good biocompatibility, but also has excellent adsorption properties. This makes it popular in many biomedical and environmental engineering applications. By combining chitosan with silica, the modified silica obtained not only retains the high specific surface area characteristics of silica, but also introduces the hydrophilicity of chitosan, thereby significantly improving its adsorption capacity for active ingredients such as borneol.

[0046] The microstructure design of this composite material is particularly important, as it provides more adsorption sites, thereby increasing the adsorption of borneol. This means that during the extraction process, more borneol molecules can be effectively captured, thereby improving the efficiency of the extraction and the quality of the final product. In addition, the hydrophilicity of chitosan helps to improve the molecular interaction in the solvent environment, making the target components easier to adsorb.

[0047] The application of modified silica also optimizes the desorption process, allowing it to be carried out under relatively mild conditions. Such mild desorption conditions not only reduce the risk of degradation or denaturation of borneol caused by high temperature or strong solvents, but also effectively maintain its chemical structure and biological activity. This is crucial to ensure the functionality of the final extract, especially in the field of medicine and health care, where the stability of active ingredients directly affects their efficacy and safety.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) Compared with steam distillation, enzymatic extraction of borneol has higher extraction efficiency and lower energy consumption, thereby reducing production costs;

[0050] (2) Compared with the solvent extraction method, it reduces the dependence on organic solvents and avoids the impact of solvent residues on product safety and purity;

[0051] (3) The use of modified silica as an adsorbent can shorten the extraction time and make the separation of borneol from the extract easier. Its reusable nature makes the entire extraction process more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The present invention provides a flow chart of the method for preparing borneol provided in Examples 1-4. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

[0054] The chemical reagents used in the examples and comparative examples of the present invention are all commercially available products, and their brands, specifications, manufacturers and other information are as follows:

[0055] Ammonia water: purity 25%, purchased from Shandong Zhongyuan Chemical Co., Ltd.

[0056] Anhydrous ethanol: purity ≥99%, purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0057] Tetraethyl orthosilicate: purity ≥99%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0058] Chitosan: purity ≥99%, purchased from Xi'an Kangnuo Chemical Co., Ltd.;

[0059] Acetic acid: purity ≥99%, purchased from Shanghai Denuo Chemical Co., Ltd.;

[0060] Phosphate buffer: purity ≥99%, purchased from Shanghai Zeye Biotechnology Co., Ltd.;

[0061] Acetic acid-sodium acetate buffer: pH = 6.0, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0062] Cellulase: pH = 7.4, purchased from Shanghai Dingfen Chemical Technology Co., Ltd.;

[0063] n-Hexane: purity ≥99%, purchased from Jinan Chuangshi Chemical Co., Ltd.;

[0064] Ethyl acetate: purity ≥99%, purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0065] Example 1

[0066] This embodiment provides a borneol and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0067] S1: Mix ammonia water, anhydrous ethanol and deionized water to obtain a mixed solution A, wherein the molar ratio of ammonia water to anhydrous ethanol is 1:100; the molar ratio of anhydrous ethanol to deionized water is 0.5:1, and react at 80°C for 30 minutes to obtain a mixed solution B, add tetraethyl orthosilicate and continue the constant temperature reaction, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 1:1, and the constant temperature reaction time is 6 hours, centrifuge and dry to obtain nano-silica; prepare a chitosan / acetic acid solution with a mass fraction of 2%, add nano-silica to the chitosan / acetic acid solution, wherein the mass ratio of nano-silica to chitosan is 1:1, stir the reaction and let it stand overnight, then filter and wash to obtain pre-dried modified silica, and dry at 60°C for 12 hours to obtain modified silica;

[0068] S2: Wash, dry and chop the borneol camphor leaves to obtain borneol camphor leaf powder; soak the borneol camphor leaf powder in phosphate buffer, add cellulase to obtain a mixture, wherein the borneol camphor leaf powder is used as a reference, and the amount of cellulase added is 150 U / g; the pH of the mixture is maintained at 5.0, and isothermal enzymolysis is performed to obtain a reaction solution, wherein the temperature of the isothermal enzymolysis is 35° C., the stirring speed is 200 rpm, and the time is 4 hours;

[0069] S3: adding modified silica to the reaction solution, wherein the mass ratio of modified silica to the reaction solution is 1:10, stirring to obtain an extract, and centrifuging the extract at a speed of 5000 rpm for 10 min to retain the modified silica that adsorbs borneol;

[0070] S4: using n-hexane to preliminarily wash the modified silica adsorbing borneol, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring and separating the upper liquid with a separating funnel, and rotary evaporating the upper liquid to obtain borneol.

[0071] Example 2

[0072] S1: Ammonia water, anhydrous ethanol and deionized water are mixed to obtain a mixed solution A, wherein the molar ratio of ammonia water to anhydrous ethanol is 1.5:100; the molar ratio of anhydrous ethanol to deionized water is 0.7:1, 0.85:1 and 1:1, and the mixed solution B is reacted at a constant temperature of 85°C for 20 minutes, and the mixture is reacted at a constant temperature for 5 hours after adding tetraethyl orthosilicate, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 2:1; the reaction is continued at a constant temperature for 5 hours, and the mixture is centrifuged and dried to obtain nano-silica; a chitosan / acetic acid solution with a mass fraction of 3% is prepared, and the nano-silica is added to the chitosan / acetic acid solution, wherein the mass ratio of the nano-silica to the chitosan is 1:1.5, and the mixture is stirred for reaction and allowed to stand overnight, and then filtered and washed to obtain pre-dried modified silica, and dried at 58°C for 15 hours to obtain modified silica;

[0073] S2: Wash, dry and chop the borneol camphor leaves to obtain borneol camphor leaf powder; soak the borneol camphor leaf powder in an acetic acid buffer, add cellulase to obtain a mixture, wherein the borneol camphor leaf powder is used as a reference, and the amount of cellulase added is 100 U / g; the pH of the mixture is maintained at 5.5, and isothermal enzymolysis is performed to obtain a reaction solution, wherein the temperature of the isothermal enzymolysis is 36° C., the stirring speed is 300 rpm, and the time is 4.5 h;

[0074] S3: adding modified silica to the reaction solution, wherein the mass ratio of modified silica to the reaction solution is 1:18, stirring to obtain an extract, and centrifuging the extract at a speed of 5500 rpm for 8 min to retain the modified silica that adsorbs borneol;

[0075] S4: using n-hexane to preliminarily wash the modified silica adsorbing borneol, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring and separating the upper liquid with a separating funnel, and rotary evaporating the upper liquid to obtain borneol.

[0076] Example 3

[0077] S1: Mix ammonia water, anhydrous ethanol and deionized water to obtain a mixed solution A, wherein the molar ratio of ammonia water to anhydrous ethanol is 1.8:100; the molar ratio of anhydrous ethanol to deionized water is 0.7:1, 0.85:1, and 1:1, and react at a constant temperature of 90°C for 15 minutes to obtain a mixed solution B, add tetraethyl orthosilicate and continue the constant temperature reaction, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 1.8:1; continue the constant temperature reaction for 4 hours, centrifuge and dry to obtain nano-silica; prepare a chitosan / acetic acid solution with a mass fraction of 1%, add nano-silica to the chitosan / acetic acid solution, wherein the mass ratio of nano-silica to chitosan is 1:1.9, stir the reaction and let it stand overnight, then filter and wash to obtain pre-dried modified silica, and dry at 55°C for 18 hours to obtain modified silica;

[0078] S2: Wash, dry and chop the borneol camphor leaves to obtain borneol camphor leaf powder; soak the borneol camphor leaf powder in phosphate buffer, add cellulase to obtain a mixture, wherein the borneol camphor leaf powder is used as a reference, and the amount of cellulase added is 50 U / g; the pH of the mixture is maintained at 5.8, and isothermal enzymolysis is performed to obtain a reaction solution, wherein the temperature of the isothermal enzymolysis is 38° C., the stirring speed is 250 rpm, and the time is 4.7 h;

[0079] S3: adding modified silica to the reaction solution, wherein the mass ratio of modified silica to the reaction solution is 1:20, stirring to obtain an extract, and centrifuging the extract at a speed of 5800 rpm for 6 min to retain the modified silica that adsorbs borneol;

[0080] S4: using n-hexane to preliminarily wash the modified silica adsorbing borneol, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring and separating the upper liquid with a separating funnel, and rotary evaporating the upper liquid to obtain borneol.

[0081] Example 4

[0082] S1: Ammonia water, anhydrous ethanol and deionized water are mixed to obtain a mixed solution A, wherein the molar ratio of ammonia water to anhydrous ethanol is 2:100; the molar ratio of anhydrous ethanol to deionized water is 0.7:1, 0.85:1 and 1:1, and the mixed solution B is reacted at a constant temperature for 25 minutes at 88°C, and the mixture is reacted at a constant temperature for 5.2 hours after adding tetraethyl orthosilicate, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 1.5:1; the reaction is continued at a constant temperature for 5.2 hours, and the mixture is centrifuged and dried to obtain nano-silica; a chitosan / acetic acid solution with a mass fraction of 2.4% is prepared, and the nano-silica is added to the chitosan / acetic acid solution, wherein the mass ratio of the nano-silica to the chitosan is 1:2, and the mixture is stirred for reaction and allowed to stand overnight, and then filtered and washed to obtain pre-dried modified silica, and dried at 50°C for 20 hours to obtain modified silica;

[0083] S2: Wash, dry and chop the borneol camphor leaves to obtain borneol camphor leaf powder; soak the borneol camphor leaf powder in an acetic acid buffer, add cellulase to obtain a mixture, wherein the borneol camphor leaf powder is used as a reference, and the amount of cellulase added is 120 U / g; the pH of the mixture is maintained at 6.0, and isothermal enzymolysis is performed to obtain a reaction solution, wherein the temperature of the isothermal enzymolysis is 40° C., the stirring speed is 280 rpm, and the time is 5 h;

[0084] S3: adding modified silica to the reaction solution, wherein the mass ratio of modified silica to the reaction solution is 1:15, stirring to obtain an extract, and centrifuging the extract at a speed of 6000 rpm for 5 min to retain the modified silica that adsorbs borneol;

[0085] S4: using n-hexane to preliminarily wash the modified silica adsorbing borneol, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring and separating the upper liquid with a separating funnel, and rotary evaporating the upper liquid to obtain borneol.

[0086] Comparative Example 1

[0087] The borneol was extracted by referring to the method of Chinese patent with publication number CN105837405A.

[0088] Comparative Example 2

[0089] The borneol was extracted by referring to the method of Chinese patent with authorization announcement number CN108503510B.

[0090] The borneol of the above-mentioned embodiments 1-4 and comparative examples 1-2 were detected, and the specific process was as follows: DB-5 chromatographic column (30m×250m×0.25μm), hydrogen flame ionization detector (FID) 300°C, carrier gas N2, injection port temperature 250°C, injection volume 0.5μl, programmed temperature, column temperature 80°C, insulation for 2min, and then heating to 150°C at 3°C / min.

[0091] The test results are shown in Table 1:

[0092] Table 1: Extraction rate and purity of borneol in Examples 1-4 and Comparative Examples 1-2

[0093] Extraction rate (%) purity(%) Example 1 91 99.0 Example 2 88 98.4 Example 3 89 99.1 Example 4 90 98.9 Comparative Example 1 78 92.5 Comparative Example 2 88 99.0

[0094] As can be seen from Table 1, the borneol obtained by the preparation methods of Examples 1-4 provided by the present invention has a higher extraction rate and purity.

[0095] It can be seen from the test results of Examples 1-4 and Comparative Example 1 that, compared with the steam distillation method, the enzymatic extraction of borneol has higher extraction efficiency and purity.

[0096] From the test results of Examples 1-4 and Comparative Example 2, it can be seen that although the solvent extraction method has high extraction efficiency and purity, it relies heavily on organic solvents during the extraction process, which is harmful to the environment and health, and improper use may cause pollution and safety hazards.

[0097] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing borneol, characterized in that: The preparation method comprises: S1: Ammonia water, anhydrous ethanol and deionized water are mixed to obtain a mixed solution A, and a mixed solution B is reacted at a constant temperature. After adding tetraethyl orthosilicate, the mixture is reacted at a constant temperature, and the mixture is centrifuged and dried to obtain nano-silica. A chitosan / acetic acid solution is prepared, and the nano-silica is added to the chitosan / acetic acid solution. The mixture is stirred for reaction and allowed to stand overnight, and then filtered and washed to obtain pre-dried modified silica, and dried to obtain modified silica. S2: washing, drying and chopping borneol camphor branches and leaves to obtain borneol camphor branch and leaf powder; soaking the borneol camphor branch and leaf powder in a buffer solution, adding cellulase to obtain a mixture, and performing enzymolysis at a constant temperature to obtain a reaction solution; S3: adding modified silica to the reaction solution, stirring to obtain an extract, and centrifuging the extract to retain the modified silica that adsorbs borneol; S4: using n-hexane to preliminarily wash the modified silica adsorbing borneol, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring and separating the upper liquid with a separating funnel, and rotary evaporating the upper liquid to obtain borneol.

2. The method for preparing borneol according to claim 1, characterized in that: In S1, The molar ratio of aqueous ammonia to anhydrous ethanol in the mixed solution A is (1-2): 100; The molar ratio of anhydrous ethanol to deionized water in the mixed solution A is (0.5-1):1; The temperature of the isothermal reaction of the mixed solution A is 80-90°C; The time for the isothermal reaction of the mixed solution A is 15-30 minutes.

3. The method for preparing borneol according to claim 1, characterized in that: In S1, The molar ratio of tetraethyl orthosilicate to ammonia water is (1-2):1; After adding ethyl orthosilicate to the mixed solution B, the reaction is continued at a constant temperature for 4-6 hours.

4. The method for preparing borneol according to claim 1, characterized in that: In S1, The mass fraction of chitosan in the chitosan / acetic acid solution is 1-3%; The mass ratio of the nano silicon dioxide to chitosan is 1:(1-2).

5. The method for preparing borneol according to claim 1, characterized in that: In S1, the pre-dried modified silica is dried at a temperature of 50-60°C; The pre-dried modified silicon dioxide is dried for 12-20 hours.

6. The method for preparing borneol according to claim 1, characterized in that: In S2, the buffer is a phosphate buffer or an acetate buffer; Based on the borneol camphor leaf powder, the added amount of cellulase is 50-150U / g.

7. The method for preparing borneol according to claim 1, characterized in that: In S2, the pH of the mixture is 5.0-6.0; The temperature of the isothermal enzymolysis is 35-40°C; The stirring speed during the isothermal enzymolysis is 200-300 rpm; The time of the isothermal enzymolysis is 4-5h.

8. The method for preparing borneol according to claim 1, characterized in that: In S3, the mass ratio of the modified silicon dioxide to the reaction liquid is 1:(10-20); The rotation speed of the centrifugal treatment is 5000-6000rpm; The centrifugal treatment time is 5-10 minutes.

9. A borneol prepared according to the preparation method according to any one of claims 1 to 8.

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