A kind of borneol and preparation method thereof

Abstract

The present invention provides a borneol and a preparation method thereof, and belongs to the technical field of daily chemical industry. The present invention adopts enzymatic hydrolysis and extraction technology, and selectively degrades the cell walls of borneol camphor branches and leaves through the catalytic action of specific enzymes under mild reaction conditions, thereby improving the extraction rate of borneol. This selective degradation not only effectively reduces the impurity content, but also significantly improves the purity of borneol. In addition, the water or buffer used in the enzymatic hydrolysis and extraction process is environmentally friendly and conforms to the concept of green chemistry. At the same time, the use of modified silica to adsorb borneol not only improves the extraction efficiency and shortens the extraction time, but also further reduces the cost of the overall extraction process through its reusable characteristics, making the entire extraction process 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 monoterpene alcohol class of compounds. Usually, camphor exists in crystalline or solid form, has a white or colorless appearance, and is widely popular for its unique aroma.

[0003] Camphor is not only beloved for its aroma but also for its remarkable biological activity. Research has shown that camphor possesses significant antibacterial, antioxidant, and anti-inflammatory properties. These properties have made it a key component of traditional medicine, where it is often used to treat a variety of ailments, such as headaches, colds, muscle pain, and indigestion. Furthermore, camphor is believed to improve circulation and relieve stress, leading to its widespread use in aromatherapy.

[0004] In modern applications, borneol also demonstrates significant market potential. Due to its refreshing aroma and diverse bioactivities, borneol is widely used in cosmetics and skincare products. It not only enhances the fragrance of products but also provides skin health benefits, helping to soothe and calm the skin, reduce inflammation, and even possess certain anti-aging properties. Furthermore, borneol is used in the manufacture of perfumes, soaps, and fragrances, further enriching its applications in daily life.

[0005] With the increasing demand of consumers for natural and organic products, the market prospect of borneol is becoming more and more broad. Its natural origin and versatility make borneol continue to play an important role in the future health and beauty industry. There are various methods for extracting borneol, including steam distillation, solvent extraction and enzymatic extraction. For example, in the Chinese patent application with publication number CN105837405A, borneol is extracted from the branches and leaves of camphor tree by steam distillation: the branches and leaves of camphor tree are cut and the steam condensate is collected by distillation, then impurities are removed by oil-water separator, and the borneol is obtained by centrifugation after cooling and crystallization. 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 borneol extract is obtained by extraction with ethanol-water mixed solvent, and then purified using 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 response to 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 camphor 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, comprising:

[0009] S1: Ammonia water, ethanol and deionized water are mixed to obtain a mixed solution A, and the mixed solution B is reacted at a constant temperature. After adding tetraethyl orthosilicate, the reaction is continued at a constant temperature. 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. The mixture is then filtered and washed to obtain pre-dried modified silica, and dried to obtain modified silica.

[0010] S2: Clean, dry, and chop borneol camphor leaves to obtain borneol camphor leaf powder; soak the borneol camphor leaf powder in a buffer solution, add cellulase to obtain a mixture, and perform 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 has adsorbed 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, separating the upper liquid with a separatory 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 values ​​not listed 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 this 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 this numerical range are also applicable.

[0016] In some optional embodiments, the constant temperature 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 the ethyl 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 this 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 ethyl orthosilicate is 20-24 hours, for example, it can be 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours or 6 hours, 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 this numerical range are also applicable.

[0020] In some optional embodiments, the mass ratio of the nano-silica 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 this 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 amount of cellulase added 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 constant temperature 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 this 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 this 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 5000-6000 rpm, for example, it can be 5000 rpm, 5100 rpm, 5200 rpm, 5300 rpm, 5400 rpm, 5500 rpm, 5600 rpm, 5700 rpm, 5800 rpm, 5900 rpm or 6000 rpm, 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, it can be 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 preparation method.

[0032] Plant cell walls are composed of complex polysaccharides, primarily cellulose, hemicellulose, and lignin. These components not only provide essential support and protection for the plant, maintaining its structure and morphology, but also form a natural barrier to the extraction of active ingredients, restricting their release and making the extraction process more difficult and time-consuming. The robustness and complexity of the cell wall mean that traditional extraction methods often require a long time and large amounts of organic solvents, resulting in wasted resources and a significant environmental burden.

[0033] To overcome this challenge, enzymatic extraction has emerged as an advanced method. It utilizes the catalytic action of specific enzymes to precisely cleave these polysaccharide chains, selectively disrupting the integrity of the cell wall. This process not only significantly reduces the cell wall's barrier to active ingredients but also maximizes the release of the borneol components within, thereby improving extraction efficiency.

[0034] A significant advantage of enzymatic extraction is its selectivity. These specialized enzymes are highly specific, capable of breaking down specific components of plant cell walls, such as cellulose, hemicellulose, and lignin. This precise action enables the enzymes to effectively release the desired active ingredient without interfering with other non-target components. This high selectivity not only significantly increases the extraction yield of the target ingredient but also reduces the level of impurities during the extraction process, thereby enhancing the purity of the extract.

[0035] High-purity extracts are crucial in many subsequent applications, particularly in areas such as drug development and cosmetics production. High-purity products not only ensure user safety but also enhance product effectiveness, ensuring its therapeutic or health-enhancing properties. This is particularly crucial for the efficacy of pharmaceuticals and cosmetics, as product safety and effectiveness directly impact consumer trust and market acceptance.

[0036] Furthermore, 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 production of high-purity extracts, but also makes the extraction process more economical and sustainable. Furthermore, 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 is particularly important given today's consumers' increasing focus on product safety and environmental protection. Enzymatic extraction methods meet the growing demand for residue-free products, providing consumers with greater peace of mind when using these products. By reducing organic solvent residues, enzymatic extraction offers a new solution for developing safe and effective natural products.

[0038] Furthermore, reducing reliance on organic solvents also helps mitigate potential health risks during the production process, protecting not only the health of operators but also the environmental risks of the factory. As the concept of sustainable development becomes more and more popular, the adoption of enzymatic extraction methods will help enhance a company's social responsibility image and strengthen its market competitiveness. In summary, the environmental advantages and high efficiency of enzymatic extraction make it a valuable option in modern extraction technology, opening up new prospects for the development and application of natural ingredients.

[0039] Furthermore, enzymatic extraction is typically performed under relatively mild conditions, which significantly protects heat-sensitive components from degradation or denaturation during the extraction process. These mild operating conditions are crucial for maintaining the chemical structure and biological activity of borneol, ensuring that the final extract retains its original physiological functions and therapeutic efficacy, thus achieving optimal results in medicinal and health supplements.

[0040] By effectively disrupting plant cell walls, enzymatic extraction significantly increases the release rate of target ingredients. This unique advantage makes enzymatic extraction generally more efficient than traditional physical or chemical extraction methods, particularly when working with complex plant matrices. Traditional extraction methods, such as soaking, boiling, or organic solvent extraction, often require a long time and high energy consumption. This not only increases production costs but can also lead to loss or denaturation of target ingredients, compromising the quality of the final extract.

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

[0042] The present invention uses silicon dioxide as an adsorbent to absorb borneol from the reaction solution. Silicon dioxide has a high specific surface area and excellent adsorption properties, allowing it to rapidly absorb and capture borneol components in the reaction solution. This rapid adsorption mechanism not only improves borneol extraction efficiency and shortens extraction time, but also ensures a high extraction rate in a relatively short period of 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, thereby simplifying the entire extraction process. This simplification not only improves the experimental operation efficiency, but also reduces the dependence on complex equipment and technology, making the operation more flexible in the laboratory or production environment.

[0044] More importantly, using silica as an adsorbent effectively reduces the need for organic solvents during the extraction process. This change not only helps reduce environmental pollution and aligns with the principles of green chemistry, but also significantly reduces production costs. Reducing the use of organic solvents is particularly important in today's increasingly demanding environment for sustainability and environmental protection. Furthermore, silica's reusability makes the entire extraction process more economical. Through appropriate washing and regeneration steps, silica can be used multiple times, reducing material costs and improving economic efficiency. This recycling not only helps reduce resource waste but also furthers the achievement of sustainable development goals.

[0045] Modifying silica with chitosan offers multiple advantages. Chitosan, a natural polysaccharide, not only possesses excellent biocompatibility but also possesses exceptional adsorption properties, making it popular in many biomedical and environmental engineering applications. By combining chitosan with silica, the resulting modified silica retains the high surface area of ​​silica while also incorporating chitosan's hydrophilicity, significantly enhancing its adsorption capacity for active ingredients such as borneol.

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

[0047] The use of modified silica also optimizes the desorption process, enabling it to be carried out under relatively mild conditions. These mild conditions not only reduce the risk of degradation or denaturation of borneol caused by high temperatures or strong solvents, but also effectively preserve its chemical structure and biological activity. This is crucial for ensuring the functionality of the final extract, especially in the pharmaceutical and healthcare fields, 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, thus reducing production costs;

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

[0051] (3) Using modified silica as an adsorbent can shorten the extraction time and make the separation of borneol in 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 preparation method of borneol provided in Examples 1-4. DETAILED DESCRIPTION

[0053] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments described 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 described 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, and manufacturers 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: 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 1:100; the molar ratio of anhydrous ethanol to deionized water is 0.5:1, and the mixture is isothermal reacted at 80°C for 30 minutes to obtain a mixed solution B, and after adding tetraethyl orthosilicate, the isothermal reaction is continued, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 1:1, and the isothermal reaction time is continued for 6 hours, centrifuged and dried to obtain nano-silica; a chitosan / acetic acid solution with a mass fraction of 2% is prepared, and nano-silica is added to the chitosan / acetic acid solution, wherein the mass ratio of nano-silica to chitosan is 1:1, the reaction is stirred and allowed to stand overnight, and then filtered and washed to obtain pre-dried modified silica, which is dried at 60°C for 12 hours to obtain modified silica;

[0068] S2: cleaning, drying, and chopping borneol camphor leaves to obtain borneol camphor leaf powder; soaking the borneol camphor leaf powder in phosphate buffer, adding cellulase to obtain a mixture, wherein the amount of cellulase added is 150 U / g based on the borneol camphor leaf powder; maintaining the pH of the mixture at 5.0, and performing isothermal enzymolysis to obtain a reaction solution, wherein the isothermal enzymolysis temperature is 35° C., the stirring speed is 200 rpm, and the time is 4 h;

[0069] S3: adding modified silica to the reaction solution at a mass ratio of modified silica to reaction solution of 1:10, stirring to obtain an extract, and centrifuging the extract at a speed of 5000 rpm for 10 minutes to retain the modified silica that has adsorbed 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, separating the upper liquid with a separatory 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 mixture is isothermal reacted at 85°C for 20 minutes to obtain a mixed solution B, and tetraethyl orthosilicate is added and the isothermal reaction is continued, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 2:1; the isothermal reaction is continued 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 nano-silica to 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, which is dried at 58°C for 15 hours to obtain modified silica;

[0073] S2: cleaning, drying, and chopping borneol camphor leaves to obtain borneol camphor leaf powder; soaking the borneol camphor leaf powder in acetic acid buffer, adding cellulase to obtain a mixture, wherein the amount of cellulase added is 100 U / g based on the borneol camphor leaf powder; maintaining the pH of the mixture at 5.5, and performing isothermal enzymolysis to obtain a reaction solution, wherein the isothermal enzymolysis temperature is 36° C., the stirring speed is 300 rpm, and the time is 4.5 hours;

[0074] S3: adding modified silica to the reaction solution at a mass ratio of modified silica to reaction solution of 1:18, stirring to obtain an extract, and centrifuging the extract at a speed of 5500 rpm for 8 minutes to retain the modified silica that has adsorbed 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, separating the upper liquid with a separatory funnel, and rotary evaporating the upper liquid to obtain borneol.

[0076] Example 3

[0077] 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 1.8:100; the molar ratio of anhydrous ethanol to deionized water is 0.7:1, 0.85:1 and 1:1, and the mixture is isothermal reacted at 90°C for 15 minutes to obtain a mixed solution B, and tetraethyl orthosilicate is added and the isothermal reaction is continued, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 1.8:1; the isothermal reaction is continued for 4 hours, and the mixture is centrifuged and dried to obtain nano-silica; a chitosan / acetic acid solution with a mass fraction of 1% is prepared, and nano-silica is added to the chitosan / acetic acid solution, wherein the mass ratio of nano-silica to chitosan is 1:1.9, and the mixture is stirred for reaction and allowed to stand overnight, and then filtered and washed to obtain pre-dried modified silica, which is dried at 55°C for 18 hours to obtain modified silica;

[0078] S2: Cleaning, drying, and chopping borneol camphor leaves to obtain borneol camphor leaf powder; soaking the borneol camphor leaf powder in phosphate buffer, adding cellulase to obtain a mixture, wherein the amount of cellulase added is 50 U / g based on the borneol camphor leaf powder; maintaining the pH of the mixture at 5.8, and performing isothermal enzymolysis to obtain a reaction solution, wherein the isothermal enzymolysis temperature 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 at a mass ratio of modified silica to reaction solution of 1:20, stirring to obtain an extract, and centrifuging the extract at a speed of 5800 rpm for 6 minutes to retain the modified silica that has adsorbed 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, separating the upper liquid with a separatory 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 mixture is reacted at a constant temperature of 88°C for 25 minutes to obtain a mixed solution B, and tetraethyl orthosilicate is added and the constant temperature reaction is continued, wherein the molar ratio of tetraethyl orthosilicate to ammonia water is 1.5:1; the constant temperature reaction time is continued 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 nano-silica is added to the chitosan / acetic acid solution, wherein the mass ratio of nano-silica to 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, which is dried at 50°C for 20 hours to obtain modified silica;

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

[0084] S3: adding modified silica to the reaction solution at a mass ratio of modified silica to reaction solution of 1:15, stirring to obtain an extract, and centrifuging the extract at a speed of 6000 rpm for 5 minutes to retain the modified silica that has adsorbed 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, separating the upper liquid with a separatory 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 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 Examples 1-4 and Comparative Examples 1-2 was 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, holding 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 hydrolysis 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. Improper use can cause pollution and safety hazards.

[0097] The above description is only a specific embodiment 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 fall 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 the mixed solution B is reacted at a constant temperature. After adding tetraethyl orthosilicate, the reaction is continued at a constant temperature. The solution 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 solution is stirred for reaction and allowed to stand overnight. The solution is then filtered and washed to obtain pre-dried modified silica, and the modified silica is dried to obtain modified silica. S2: Clean, dry, and chop borneol camphor leaves to obtain borneol camphor leaf powder; soak the borneol camphor leaf powder in a buffer solution, add cellulase to obtain a mixture, and perform 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 has adsorbed borneol; S4: Preliminarily washing the modified silica adsorbing borneol with n-hexane, immersing the washed modified silica adsorbing borneol in ethyl acetate, stirring, separating the upper liquid with a separatory funnel, and rotary evaporating the upper liquid to obtain borneol; The molar ratio of the tetraethyl orthosilicate to the ammonia water is (1-2):1; The mass ratio of the nano-silicon dioxide to chitosan is 1:(1-2); The temperature of the constant temperature enzymolysis is 35-40°C.

2. The method for preparing borneol according to claim 1, wherein In S1, The molar ratio of ammonia water 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 mixed solution A is 80-90°C; The time for the constant temperature reaction of the mixed solution A is 15-30 minutes.

3. The method for preparing borneol according to claim 1, wherein In S1, 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, wherein In S1, The mass fraction of chitosan in the chitosan / acetic acid solution is 1-3%.

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

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

7. The method for preparing borneol according to claim 1, wherein: In S2, The pH of the mixture is 5.0-6.0; The stirring speed during the constant temperature enzymolysis is 200-300 rpm; The time of the constant temperature enzymolysis is 4-5 hours.

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

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