Method for preparing tobacco extract based on selective extraction of macrocyclic molecules and application

Abstract

The invention discloses a method for preparing a tobacco extract based on selective extraction of macrocyclic molecules, which specifically comprises the following steps: by taking opium paste as a raw material, adding a macrocyclic molecule solution into the opium paste, extracting by utilizing macrocyclic molecules, reacting under the conditions of room temperature and stirring, carrying out solid-liquid separation, and drying a solid I to obtain an extract I; concentrating and drying the liquid I, adding absolute ethyl alcohol into a dried substance for extraction, and performing solid-liquid separation to obtain a solid II and a liquid II; concentrating the liquid II and recovering ethanol to obtain an extract II; dissolving the solid II with water, adding an ethanol solution with the concentration of 75-100% for precipitation and solid-liquid separation to obtain a solid III and a liquid III, and concentrating the liquid III to recover ethanol so as to obtain an extract III; drying the solid III to obtain macrocyclic molecules for reuse; the method is simple in process, mild in condition, high in extraction efficiency and suitable for raw material preparation of tobacco products such as reconstituted tobacco leaves, non-combustible cigarettes and electronic cigarettes, and has remarkable environmental protection advantages and industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of plant extract separation and purification technology, specifically a method for separating and optimizing tobacco extracts based on macrocyclic molecule selective extraction, and particularly to the application of supramolecular extractants, extraction processes, and strong mass transfer methods in this technology. Background Technology

[0002] Tobacco extract refers to a mixture or fraction of tobacco extractable components obtained from tobacco (tobacco leaves, stems, tobacco dust, reconstituted tobacco raw materials, etc.) through processes such as leaching, extraction, distillation, adsorption / desorption, separation and purification in media such as water, alcohol, organic solvents, and supercritical fluids.

[0003] Tobacco extracts, as a crucial component of tobacco products, are widely used in tobacco manufacturing and flavoring processes. Tobacco extracts primarily consist of nicotine, aroma compounds, and other organic compounds. Nicotine, a unique alkaloid found in tobacco, directly influences the irritant properties and physiological activity of tobacco products; aroma compounds determine the fragrance and taste. Traditional tobacco extract manufacturing processes often require the blending and optimization of these complex components to meet the needs of diverse consumers. However, due to the numerous and complex interactions among the components of tobacco extracts, efficiently and accurately separating and optimizing key components has become a pressing problem in the tobacco industry.

[0004] Currently, traditional separation techniques largely rely on physical methods (such as distillation and extraction) and chemical methods (such as solvent extraction and adsorption separation). Research on tobacco extraction methods can be broadly categorized into traditional solvothermal extraction, Soxhlet extraction, steam distillation, supercritical fluid extraction, column chromatography for batch preparation and extraction, and molecular distillation purification. These methods often suffer from problems such as prolonged reflux heating, reliance on organic solvents, and low extraction efficiency, resulting in unsatisfactory quality and low extraction yields of the obtained tobacco extracts. Exploring new tobacco extraction and preparation methods and investigating new effective tobacco extraction technologies is beneficial to the development of plant extract separation and purification technologies and the tobacco industry.

[0005] While existing methods can achieve the separation and purification of tobacco extracts to some extent, they often suffer from problems such as low separation efficiency, high energy consumption, and solvent contamination. This is particularly true when selective extraction of weak interactions between different molecules is required, where current technologies are particularly limited. Furthermore, traditional techniques struggle to precisely control intermolecular interactions, leading to unstable separation processes and impacting the quality and flavor characteristics of tobacco extract products. Additionally, previous methods only addressed the inclusion complexation of macrocyclic molecules with nicotine compounds in pure compounds, failing to address the separation and purification of components from complex, multi-component mixtures of tobacco extracts.

[0006] Although existing tobacco extract separation technologies can separate nicotine and other active ingredients from tobacco extracts to some extent, their efficiency and selectivity are often limited by the following: (1) Low selectivity and low efficiency: Traditional separation methods rely on physical or chemical mechanical principles, such as extraction and distillation. They usually require multiple steps and high energy consumption to obtain relatively pure target components, and some effective components are often lost during the separation process.

[0007] (2) Environmental pollution issues: Many traditional chemical separation methods rely on organic solvents, which not only consume resources but may also pollute the environment during use and disposal. In addition, the recovery and reuse of solvents increases operating costs and complexity.

[0008] (3) Insufficient separation precision: Nicotine and other nicotine-like substances in tobacco extracts often have similar molecular weights or chemical structures, and traditional technologies have certain limitations in the precision of separating these molecules. Especially in large-scale production, it is difficult to accurately control the separation process, leading to fluctuations in product quality.

[0009] (4) High energy consumption and high cost: Many traditional separation methods need to be carried out under high temperature, high pressure or extreme conditions, which not only consumes a lot of energy, but also increases production costs. Long-term use may cause certain damage to production equipment and reduce production efficiency. Summary of the Invention

[0010] To address the limitations of the existing technology, this invention provides a method for preparing tobacco extract based on macrocyclic molecule selective extraction, achieving selective separation and purification of nicotine and other active ingredients in the tobacco extract. The specific steps are as follows: (1) Using tobacco paste as raw material, add macrocyclic molecule solution to tobacco paste, use macrocyclic molecules for extraction, solid-liquid separation, dry solid I to obtain extract I; concentrate and dry liquid I, add anhydrous ethanol to the dried material for extraction, solid-liquid separation, to obtain solid II and liquid II; The macrocyclic molecule is cucurbituril of formula I, or open-ring cucurbituril of structural formulas II and III; Formula I: Where m is 1-3; Formula II: ; Formula III: ; In the formula, R represents (CH2). n SO3Na or (CH2) n SO3H, n=1-3; The macrocyclic molecule was prepared according to the methods described in the literature Cong H, Ni XL, Xiao X, et al. Synthesis and separation of cucurbit[n]urils and their derivatives[J]. Organic & Biomolecular Chemistry, 2016, 14(19): 4335-4364. or Ma D, Hettiarachchi G, Nguyen D, et al. Acyclic cucurbit[n]uril molecular containers enhance the solubility and bioactivity of poorly soluble pharmaceuticals[J]. Nature chemistry, 2012, 4(6): 503-510.

[0011] The synthetic route for the above-mentioned cucurbituril is as follows: .

[0012] The tobacco paste is obtained by extracting tobacco leaves with alcohol or water, separating the solid and liquid, and then concentrating the liquid; or by extracting the solid with anhydrous ethanol, combining the alcohol solution with the liquid from the solid-liquid separation, and then concentrating the solution. The mass ratio of macrocyclic molecules to tobacco paste is 0.9–5:1; (2) After liquid II is concentrated and ethanol is recovered, extract II is obtained; (3) After dissolving solid II in water, add 75-100% ethanol solution for precipitation, separate solid and liquid to obtain solid III and liquid III. After concentrating liquid III to recover ethanol, extract III is obtained; solid III is dried to become macrocyclic molecules and reused in step (1).

[0013] The extract obtained by the method of this invention can be used as an additive in reconstituted tobacco, non-combustible tobacco, and electronic cigarettes.

[0014] Advantages and technical effects of the present invention: (1) Highly selective separation: The flexible cavity of anionic ring-opening cucurbituril forms an adaptive inclusion complex with nicotine and aroma components. The anionic ring-opening cucurbituril and nicotine groups have a dipole interaction, and with the cooperation of π-π conjugation and hydrogen bonding, a stable supramolecular inclusion complex can be formed, which can efficiently and selectively separate nicotine and aroma components from tobacco extracts, achieving highly selective separation; The hydrophobic cavity of cucurbituril forms a stable supramolecular complex with nicotine in tobacco extracts through non-covalent interaction, thereby achieving selective recognition and binding between molecules; High-purity valuable components can be selectively separated from complex tobacco mixtures; (2) Low cost and low energy consumption: Compared with traditional separation methods, this technology operates under milder conditions, can be carried out at room temperature and pressure, and does not require complex equipment and a large amount of organic solvents, which significantly reduces production costs and energy consumption; (3) High stability and recyclability: The macrocyclic molecules in this technology can stably recognize and bind to the target components and have good recyclability during use. They can be reused without significant loss of separation efficiency, providing good economic benefits and production stability for large-scale production.

[0015] As consumers increasingly demand higher quality and taste from tobacco products, tobacco companies urgently need to adopt novel separation technologies to enhance product quality and market competitiveness. The separation and optimization technology of tobacco extracts based on macrocyclic molecules, with its high efficiency, environmental friendliness, and low cost, has broad application prospects, especially in the manufacturing process of high-end tobacco products. In summary, the tobacco extract separation and optimization technology based on selective extraction of macrocyclic molecules proposed in this invention provides the tobacco industry with an innovative, efficient, and economical separation method, possessing broad application prospects and significant market value. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the method flow of the present invention; Figure 2 It is the standard curve of anhydrous nicotine ethanol solution; Figure 3 It is a pure nicotine HPLC standard curve; Figure 4 These are the UV-Vis absorption spectra of solid I and liquid I in Example 1; Figure 5 These are the UV-Vis absorption spectra of solid I and liquid I in Example 2; Figure 6 These are the UV-Vis absorption spectra of samples 1-4 in Example 3; Figure 7 These are the UV-Vis absorption spectra of samples 5-7 in Example 4; Figure 8This is the UV-Vis absorption spectrum of sample 8 in Example 4; Figure 9 This is the liquid chromatogram of sample 1 in Example 3; Figure 10 These are the liquid chromatograms of samples 2 and 3 in Example 3; Figure 11 This is the liquid chromatogram of sample 4 in Example 3; Figure 12 This is the liquid chromatogram of sample 5 in Example 4; Figure 13 These are the liquid chromatograms of samples 6 and 7 from Example 4. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, the scope of protection of the present invention is not limited to the contents described. Unless otherwise specified, the reagents and methods used in the embodiments are all commercially available reagents and conventional methods. In the following examples, the peak intensity and content of nicotine were detected using a UV spectrophotometer, and other components in tobacco leaves were determined by the wavelength range of the UV spectrum. Specifically, pure nicotine was prepared into anhydrous ethanol solutions of different concentrations (0.0125, 0.025, 0.0375, 0.05, 0.0625 mg / mL), and their absorbance was measured at 259 nm. A standard curve was plotted with the concentration of pure nicotine on the x-axis and the absorbance of different concentrations of nicotine ethanol solutions at 259 nm on the y-axis. Figure 2 The tobacco extract sample was dissolved in anhydrous ethanol solution and sonicated for 10 min. The solution was filtered through a 0.45 μm microporous membrane and the absorbance (A) was measured at 259 nm using a UV spectrophotometer. The nicotine content was calculated based on the absorbance and the standard curve. The method for determining nicotine content by high performance liquid chromatography (HPLC) involves dissolving 20 mg of pure nicotine in chromatographic grade methanol and diluting the solution to a 25 mL volumetric flask. The solution is then thoroughly mixed to prepare an 800 mg / L nicotine standard solution. This standard solution is diluted to different concentrations for HPLC analysis, and the data are compiled to obtain a standard curve. Figure 3 The extract sample was dissolved in quantitative chromatographic grade methanol solution by sonication and then filtered through a 0.45 μm microporous membrane. The solution was then analyzed by liquid chromatography in sample vials. The chromatographic conditions were as follows: reversed-phase column, namely octadecylsilane-bonded silica gel column (C18 column), (column length 250 mm, inner diameter 4.6 mm, column volume 2.49 mL), mobile phase of methanol and 0.02 mol / L phosphate buffer (30:70, v / v), flow rate 1 mL / min, isocratic elution, column temperature 25℃, injection volume 10 μL, UV detector detection wavelength 259 nm, and analysis time 10 min. Example 1: In this example, tobacco extract was prepared by selective extraction of open-ring cucurbituril using the following formula ( Figure 1 ) 1. Tetramer (76 g, 97 mmol) and sodium sulfonate benzene ring side arm (154 g, 387 mmol) were added to 700 mL of trifluoroacetic acid solution. The reaction solution was stirred at 70 °C for 3 h. The precipitate was then poured into 1.5 L of methanol. The obtained solid was dried in a vacuum drying oven. The dried solid was washed with a 1:1 acetone / water (1.5 L, 2 times) mixture. The washed solid was dissolved in water (500 mL). The pH was adjusted to 7 with 1 M sodium hydroxide. The solvent was removed by rotary evaporation. The solid was dried in a vacuum drying oven to obtain a white open-ring cucurbita urea solid (60 g, 40%). R is (CH2)3SO3Na; 1 H NMR (400MHz, D2O): 6.72(s, 4H), 5.50(d, 2H), 5.38(d, 4H), 5.31(d,2H), 5.25(d, 2H), 5.19(d, 4H), 4.10(d, 4H), 4.06(d, 4H), 3.97(d, 2H), 3.91(m,4H), 3.79(m, 4H), 2.98(m, 8H), 2.06(m, 8H), 1.64(n, 6H), 1.61(s, 6H). 2. Weigh 5.25g (3.4mmol) of the above-mentioned open-ring cucurbituril and dissolve it in 100mL of distilled water. Stir at 25℃ until dissolved. Add 2.625g of crude tobacco extract (alcohol-extracted tobacco paste, from Yunnan Peilin Technology Co., Ltd., containing 10% nicotine) to the open-ring cucurbituril aqueous solution. Stir in a homogenizer at room temperature (10000rpm). Centrifuge to obtain solid I and liquid I. Vacuum dry solid I at 50℃ to obtain extract I, 0.5g (black solid, nicotine content of 0.47%). 3. Liquid I was concentrated and dried under vacuum at 50℃ to obtain 6.25g of dried product. Anhydrous ethanol was added to the dried product for extraction, and centrifugation was performed to obtain solid II and liquid II. After liquid II was concentrated and the ethanol was recovered, extract II (black liquid with nicotine content of 19%) was obtained. 4. After dissolving solid II in water, add anhydrous ethanol solution to precipitate, centrifuge to obtain solid III and liquid III. Solid III is dried to obtain open-ring cucurbituril and reused in the extraction of tobacco paste. Liquid III is concentrated by vacuum rotary evaporation at 50℃ to recover ethanol, and extract III 0.2g (brown liquid with nicotine content of 0.63%) is obtained.

[0018] In this embodiment, the nicotine content was determined by ultraviolet spectrophotometry. Figure 4 The results showed that after extraction of tobacco paste with an aqueous solution of open-ring cucurbitacin, almost all nicotine was extracted into liquid I, with a nicotine content of 2.45%; less nicotine was found in extract I, with a nicotine content of 0.47%. The resulting sample had an extraction rate of 59.27% ​​for nicotine in the tobacco paste. These results indicate that open-ring cucurbitacin has good selective extraction properties for alcohol-extracted tobacco paste, capable of extracting most of the nicotine components to prepare a high-nicotine tobacco extract, while also producing a low-nicotine tobacco extract.

[0019] Example 2: In this example, tobacco extract was prepared by selective extraction of open-ring cucurbituril using the following formula. 1. Tetramer (2.67 g, 3.42 mmol) and sodium sulfonate naphthalene ring (6.13 g, 13.7 mmol) were added to 25 mL of trifluoroacetic acid solution. The reaction solution was stirred at 70 °C for 3 h. The precipitate was then poured into 1.5 L of methanol. The obtained solid was dried in a vacuum drying oven. After drying, it was dissolved in a small amount of water. The pH was adjusted to 7 with 1 M sodium hydroxide. The solution was cooled to room temperature and filtered to obtain a white open-ring cucurbita solid (1.7 g, 30%). R is (CH2)3SO3Na; 1H NMR (600MHz D2O): 7.72(m, 4H), 7.27 (m, 4H), 5.48(d, 2H), 5.42(d,4H), 5.31 (d, 2H), 5.25(d, 2H), 5.12(d, 4H), 4.30(d, 4H), 4.12(d, 4H), 4.00(m, 4H), 3.96(d, 2H), 3.74(m, 4H), 3.08(m, 8H), 2.13(m, 8H), 1.66(s, 6H),1.61(s, 6H). 2. Weigh 5.25g (3.4mmol) of the above-mentioned open-ring cucurbituril and dissolve it in 100mL of distilled water. Stir at 25℃ until dissolved. Add 2.625g of crude tobacco extract (alcohol-extracted tobacco paste, from Yunnan Peilin Technology Co., Ltd., containing 10% nicotine) to the open-ring cucurbituril aqueous solution. Stir in a homogenizer at room temperature (10000rpm). Centrifuge to obtain solid I and liquid I. Dry solid I under vacuum at 50℃ to obtain extract I, 0.44g (black solid, nicotine content = 0). 3. Liquid I was concentrated and dried under vacuum at 50℃ to obtain 5.55g of dried product. Anhydrous ethanol was added to the dried product for extraction, and centrifugation was performed to obtain solid II and liquid II. After liquid II was concentrated and the ethanol was recovered, extract II, 0.6g (black liquid, nicotine content of 41.05%) was obtained. 4. After dissolving solid II in water, add anhydrous ethanol solution to precipitate, centrifuge to obtain solid III and liquid III. Solid III is dried to obtain open-ring cucurbituril and reused in the extraction of tobacco paste. Liquid III is concentrated by vacuum rotary evaporation at 50℃ to recover ethanol and obtain extract III. Extract III 0.3g (brown liquid, nicotine content = 0.9%).

[0020] In this embodiment, the nicotine content was determined by ultraviolet spectrophotometry. Figure 5 The results showed that after extraction of tobacco paste with an aqueous solution of open-ring cucurbitacin, almost all nicotine was extracted into liquid I, with a nicotine content of 4.54%; extract I contained no nicotine, with a nicotine content of 0%. The obtained sample showed an extraction rate of 96% for nicotine in the tobacco paste. These results indicate that open-ring cucurbitacin in this embodiment has good selective extraction properties for alcohol-extracted tobacco paste, capable of extracting most of the nicotine components to prepare a high-nicotine tobacco extract, while also producing low-nicotine and nicotine-free tobacco extracts.

[0021] Example 3: In this example, tobacco extract was prepared by selective extraction with cucurbituril (m=1). 1. After selecting, removing impurities, and crushing the tobacco leaves, 15.4g of tobacco leaf fragments were placed in a water bath with a layer of 200mL of ultrapure water. The mixture was extracted at 60℃ for 2 hours, filtered, and the aqueous solution was vacuum-evaporated at 60℃ to obtain 5.25g of black concentrated tobacco paste. The water extraction rate of the tobacco paste was 34.1%. The filter residue was extracted three times with anhydrous ethanol. The ethanol extracts were collected and combined, and concentrated to obtain 0.77g of black, thick, high-nicotine tobacco paste (sample 4, with a nicotine content of 10.06%). 2. Take 5.25g of cucurbituril (m=1) and add it to 200 mL of ultrapure water. Add 20g of KCl to dissolve it, and then add 2.625g of concentrated tobacco paste. After stirring and mixing thoroughly, centrifuge to obtain solid I and liquid I. Dry solid I under vacuum at 50℃ to obtain 0.28g of black extract I (sample 1, in which the nicotine content is 0.16%). 3. Liquid I was concentrated and dried under vacuum at 50℃. 300 mL of anhydrous ethanol was added to the dried product for extraction. After centrifugation and filtration, solid II and liquid II were obtained. After concentration and ethanol recovery of liquid II, 0.76 g of brown extract II (sample 2, with a nicotine content of 28.22%) was obtained. 4. After dissolving solid II in 100 mL of water, precipitate it by adding 600 mL of anhydrous ethanol, centrifuge to obtain solid III and liquid III. Solid III is dried to obtain cucurbituril and KCl, which are then reused in the extraction of tobacco paste. Liquid III is concentrated by vacuum rotary evaporation at 50 °C to recover ethanol, yielding 6.71 g of brown extract III (sample 3, with a nicotine content of 0.39%). The extract in this embodiment was determined using ultraviolet spectrophotometry, and the results are as follows: Figure 6 As shown, Sample 4 contains some unextracted nicotine (nicotine content is 10%), as well as pigments such as chlorophyll and lutein; Sample 1 has almost no UV absorption of nicotine, and is a low-nicotine tobacco extract (nicotine content is 0.5%); Sample 2 shows high UV absorption at 259, with a high nicotine concentration (nicotine content is 50%), and is a high-nicotine tobacco extract; Sample 3 shows UV absorption at 259, but its nicotine concentration is not high (nicotine content is 4%), and is a low-nicotine tobacco extract. Figure 6 The results showed that cucurbituril could efficiently extract and separate nicotine from tobacco paste, yielding tobacco extracts with both high and low nicotine content.

[0022] The extract was analyzed by HPLC. Figure 9-11 As shown, the peak area of ​​nicotine in Sample 4 is 12843.4, and the calculated nicotine content using the pure nicotine HPLC standard curve is 10.06%, indicating it is a high-nicotine tobacco extract. The peak area of ​​nicotine in Sample 1 is 17.71303, and the calculated nicotine content using the pure nicotine HPLC standard curve is 0.16%. The peak area of ​​nicotine in Sample 2 is 4888.13428, and the calculated nicotine content using the pure nicotine HPLC standard curve is 28.22%. The peak area of ​​nicotine in Sample 3 is 211.23865, and the calculated nicotine content using the pure nicotine HPLC standard curve is 0.39%. The total nicotine content of the four samples is calculated to be 10.68%, with 64.83% of the nicotine in Sample 2, and only 0.323% and 10.21% in Samples 1 and 3, respectively. Figure 9-11 The HPLC results further calculated the accurate nicotine content in each tobacco extract, verifying the successful preparation of high-nicotine and low-nicotine tobacco extracts.

[0023] In the above results, the nicotine content obtained by ultraviolet spectrophotometry was higher than that obtained by HPLC. This may be because the presence of compounds in the sample that have ultraviolet absorption at 259 nm interfered with the ultraviolet absorption value of nicotine. However, it is clear that the trend of nicotine content measured by the two methods is consistent. Most of the nicotine was extracted into sample 2 by macrocyclic molecules, while samples 1 and 3 contained only a small amount of nicotine.

[0024] Example 4: In this example, tobacco extract was prepared by selective extraction with cucurbituril (m=1). 1. After selecting, removing impurities, and crushing the raw tobacco leaves, 15.4g of tobacco leaf fragments were placed in a water bath with a layer of separation. 250mL of ultrapure water was added, and the mixture was extracted at 60℃ for 2h. Solid-liquid separation was performed, and 300mL of anhydrous ethanol was added to the solid tobacco residue for extraction for 3h. The solid tobacco residue was filtered and discarded. The extracted ethanol solution was combined with the aqueous solution after solid-liquid separation and vacuum rotary evaporation was performed at 60℃ to obtain 6.468g of concentrated tobacco paste (extraction rate of 42%). 2. Take 10.5g of cucurbituril (m=1) and add it to 200 mL of ultrapure water. Add 40g of KCl to dissolve it, and then add 5.25g of concentrated tobacco paste. After stirring and mixing thoroughly, centrifuge to obtain solid I and liquid I. Solid I is dried under vacuum at 50℃ to obtain extract I 0.3g (sample 5, in which the nicotine content is 0). 3. Liquid I was concentrated and dried at 50℃ (the dried product was sample 8, with a nicotine content of 10.28%). 300 mL of anhydrous ethanol was added to the dried product for extraction, and centrifugation was performed to obtain solid II and liquid II. After the ethanol was recovered from liquid II, 0.76 g of extract II was obtained (sample 6, with a nicotine content of 57%). 4. After dissolving solid II in 100 mL of water, precipitate it by adding 600 mL of anhydrous ethanol, centrifuge to obtain solid III and liquid III. Solid III is dried to obtain cucurbituril and KCl, which are then reused in the extraction of tobacco paste. Liquid III is concentrated by vacuum rotary evaporation at 50 °C to recover ethanol, and extract III 6.89 g (sample 7, with a nicotine content of 7.8%) is obtained. The extract in this embodiment was determined using ultraviolet spectrophotometry, and the results are as follows: Figure 7 , 8 As shown, Sample 5 showed no UV absorption of nicotine and contained no nicotine (nicotine content was 0), only showing UV absorption peaks of pigments such as chlorophyll and xanthophyll; Sample 8 showed very high UV absorption of nicotine and was a high-nicotine tobacco extract (nicotine content was 10.28%); Sample 6 showed high UV absorption at 259 and had a high nicotine concentration (nicotine content was 60%), and was a high-nicotine tobacco extract; Sample 7 showed UV absorption at 259 and was a low-nicotine tobacco extract (nicotine content was 8%). Figure 7 The results in section 8 were consistent with the previous results, showing that high-nicotine and low-nicotine tobacco extracts were effectively prepared through extraction.

[0025] The extract was analyzed by HPLC. Figure 12As shown in Figure 13, the peak area of ​​nicotine in sample 5 is 7, and the calculated nicotine content using the pure nicotine HPLC standard curve is 0%, indicating it is a high-nicotine tobacco extract. The peak area of ​​nicotine in sample 6 is 6019, and the calculated nicotine content using the pure nicotine HPLC standard curve is 57%. The peak area of ​​nicotine in sample 7 is 247, and the calculated nicotine content using the pure nicotine HPLC standard curve is 7.8%. The total nicotine content of the three samples is calculated to be 9.43%, of which 81.78% of the nicotine is in sample 6, while samples 5 and 7 contain only 0% and 9.98%, respectively, indicating that some nicotine was lost during the drying process. Figure 12 HPLC results of 13 showed that cucurbituril can effectively extract and prepare tobacco extract.

[0026] In the above results, the nicotine content obtained by ultraviolet spectrophotometry was consistent with the results obtained by HPLC. Most of the nicotine was extracted into sample 6 by macrocyclic molecules. Samples 5 and 7 contained no or a small amount of nicotine. Meanwhile, sample 8, which was a cleaned tobacco paste with chlorophyll and other pigments removed, was obtained.

[0027] Extract II, sample 8, obtained by the above method can be used as a raw material or additive for the preparation of tobacco products such as reconstituted tobacco, non-combustible tobacco and e-cigarettes; extracts I and III can be added to tobacco products as low-nicotine or nicotine-free tobacco extracts as needed.

Claims

1. A method for preparing tobacco extract based on selective extraction of macrocyclic molecules, characterized in that, The steps are as follows: (1) Using tobacco paste as raw material, a macrocyclic molecule solution was added to the tobacco paste and extracted using macrocyclic molecules. After the reaction was completed at room temperature and under stirring conditions, solid and liquid were separated. Solid I was dried to obtain extract I; liquid I was concentrated and dried, and anhydrous ethanol was added to the dried material for extraction. Solid and liquid were separated to obtain solid II and liquid II. (2) After liquid II is concentrated and ethanol is recovered, extract II is obtained; (3) After dissolving solid II in water, add 75-100% ethanol solution for precipitation, separate solid and liquid to obtain solid III and liquid III. After concentrating liquid III to recover ethanol, extract III is obtained; solid III is dried to become macrocyclic molecules and reused in step (1).

2. The method for preparing tobacco extract based on macrocyclic molecule selective extraction according to claim 1, characterized in that: The macrocyclic molecules are cucurbituril with structural formula I, and open-ring cucurbituril with structural formulas II and III; Formula I: , where m is 1-3; Formula II: ; Formula III: ; In the formula, R represents (CH2). n SO3Na or (CH2) n SO3H, n=1-3.

3. The method for preparing tobacco extract based on macrocyclic molecule selective extraction according to claim 1, characterized in that: The mass ratio of macrocyclic molecules to tobacco paste is 0.9 to 5:

1.

4. The method for preparing tobacco extract based on macrocyclic molecule selective extraction according to claim 1, characterized in that: Tobacco paste is obtained by extracting tobacco leaves with alcohol or water, separating the solid and liquid, and then concentrating the liquid; or by extracting the solid with anhydrous ethanol, combining the alcohol solution with the liquid from the solid-liquid separation, and then concentrating the solution.

5. The extract prepared by the method of selective extraction of macrocyclic molecules for preparing tobacco extract as described in claim 1 is used as an additive in reconstituted tobacco, non-combustible tobacco and electronic cigarettes.

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