Plant extract modified molecular probe and preparation method and application thereof

Abstract

The present invention belongs to the technical field of functional food application. Disclosed in the present invention are a plant extract modified molecular probe and a preparation method and an application thereof. The preparation method of the plant extract modified molecular probe comprises the following steps: dropping a 3-ethyl-2-methylbenzothiazole iodide solution into a saffron aldehyde solution to obtain a mixed solution; dropping an inorganic salt solution into the mixed solution, mixing and performing a condensation reaction to obtain a plant extract modified molecular probe. The obtained plant extract modified molecular probe has good chemical stability and can be stored for a long time. It has good biocompatibility, is non-toxic, and has good photostability, it is not prone to photobleaching during long-term irradiation.

Description

A plant extract modified molecular probe and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of functional food applications, and in particular to a plant extract modified molecular probe, a preparation method thereof, and an application thereof. Background Art

[0002] Viscous glycoprotein is a glycoprotein mainly composed of mucopolysaccharides. It has a strong flocculation function and is widely found in many plants in nature and in parts of the human body such as the knee synovium. Viscous glycoprotein is considered to be one of the most effective plant extracts for preventing cardiovascular fat deposition, preventing atherosclerosis, avoiding vasodilation and preventing obesity. It also has outstanding advantages such as enhancing human immunity, maintaining intestinal lubrication, and promoting cholesterol consumption. Therefore, viscous glycoprotein extracted from plants has been widely used in diet therapy. In fact, many common natural foods contain more or less viscous glycoprotein substances, such as okra, yam, and white fungus. However, the viscous glycoproteins of these plants are only present in some areas of these natural ingredients, and the relative content is limited. If the extraction process is inappropriate or the processing process is not appropriate, it is difficult to ensure the integrity of the viscous glycoprotein function, and its nutritional efficacy will be greatly reduced.

[0003] Traditionally, viscometers are mostly used for micro-area viscosity measurement, including falling ball viscometers, rotational viscometers, capillary viscometers, etc. These test methods are generally highly dependent on equipment, with relatively complex pre-treatment processes and time-consuming testing processes. More importantly, these test equipment generally have a large demand for samples, and in most cases, the samples need to be crushed to obtain the test specimens. In addition, these detection equipment may have insensitive accuracy for low viscosity detection, are difficult to apply to some acidic or alkaline solution environments, and are prone to corrosion of equipment. Moreover, these test equipment cannot achieve in-situ, visual, and real-time monitoring effects.

[0004] Therefore, it is of great significance to study a plant extract modified molecular probe and its preparation method, so that it can accurately detect the content of sticky glycoproteins in various polar solutions and pH ranges.

[0005] Summary of the Invention

[0006] In view of this, the present invention provides a plant extract modified molecular probe and its preparation method and application, the purpose of which is to obtain a molecular probe with good chemical stability, long-term preservation, good biocompatibility, non-toxicity, good photostability, and not prone to photobleaching during long-term irradiation.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a plant extract modified molecular probe, the structural formula of the modified molecular probe is shown in Formula I:

[0009] The present invention also provides a method for preparing a plant extract modified molecular probe, comprising the following steps:

[0010] (1) adding 3-ethyl-2-methylbenzothiazole iodide solution dropwise to safranal solution to prepare a mixed solution;

[0011] (2) The inorganic salt solution is added dropwise to the mixed solution, and after mixing, a condensation reaction is carried out to prepare a plant extract modified molecular probe.

[0012] Preferably, the structural formula of safranal in step (1) is as shown in Formula II:

[0013] Preferably, in step (1), the molar ratio of 3-ethyl-2-methylbenzothiazole iodide to safranal is 1:1-60, the concentration of the 3-ethyl-2-methylbenzothiazole iodide solution is 1-50M, and the concentration of the safranal solution is 1-200M.

[0014] Preferably, the solvents in the 3-ethyl-2-methylbenzothiazole iodide solution, the saffron aldehyde solution in step (1) and the inorganic salt solution in step (2) are independently one or more of N,N-dimethylformamide, ethyl acetate, ethanol, methanol, n-butanol, isopropanol, n-propanol, cyclohexanol, ethylene glycol, n-hexanol and propylene glycol.

[0015] Preferably, the dropping speeds in steps (1) and (2) are independently 1 to 10 drops / 10s.

[0016] Preferably, the inorganic salt in step (2) is sodium carbonate, sodium bicarbonate, calcium acetate, cesium carbonate, potassium carbonate, tin acetate, potassium bicarbonate or calcium carbonate; the concentration of the inorganic salt solution is 1 to 100 M; and the molar ratio of the inorganic salt to 3-ethyl-2-methylbenzothiazole iodide is 1 to 50:1.

[0017] Preferably, the mixing temperature in step (2) is 23-28° C., the mixing time is 1-24 h, and the mixing is carried out under stirring at a stirring rate of 100-800 rpm.

[0018] Preferably, the temperature of the condensation reaction in step (2) is 45-110° C., the time of the condensation reaction is 1-48 h, and the condensation reaction is carried out under stirring at a stirring rate of 100-1500 rpm.

[0019] The present invention also provides the use of a plant extract modified molecular probe in measuring the content of sticky glycoprotein.

[0020] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The modified molecular probe of the present invention is obtained by chemically modifying the plant extract crocinaldehyde. The modification process adopts a one-step method. The raw materials are mainly derived from plant extracts, which has high cost performance and low overall preparation cost. The preparation process is relatively green, environmentally friendly, and pollution-free. The final yield is also high, suitable for large-scale preparation, simple post-processing, and in line with the concept of environmental protection and sustainable development.

[0022] (2) The plant extract modified molecular probe of the present invention can be applied to the measurement of the content of sticky glycoproteins, has the effect of visual detection and imaging, and can provide a molecular-level auxiliary tool for the dosage control of sticky glycoproteins and the preparation process of some health foods;

[0023] (3) The plant extract modified molecular probe of the present invention has strong chemical stability and photostability, can release relatively stable light signals in a variety of polar solutions and pH ranges, and is not easily interfered by complex plant foods. As the content of sticky glycoprotein increases, its fluorescence intensity increases from weak to strong, which is a typical "turn-on" type molecular tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0025] FIG1 is a schematic diagram of the mechanism of action of the plant extract modified molecular probe prepared in the present invention on sticky glycoproteins;

[0026] FIG2 is a mass spectrum of the plant extract modified molecular probe prepared in Example 1;

[0027] FIG3 is a fluorescence mass spectrum of the plant extract modified molecular probe prepared in Example 1 in a glycerol / water mixture system, wherein the curves in the figure are, from bottom to top, plant extract mixture systems with glycerol volume fractions of 0%, 10%, 30%, 50%, 70%, and 100%;

[0028] FIG4 is a logarithmic function of the fluorescence intensity and viscosity of the plant extract modified molecular probe prepared in Example 1 in a glycerol / water mixture system;

[0029] FIG5 is a graph showing the photostability of the plant extract-modified molecular probe prepared in Example 1 in deionized water with a viscosity of 1.0 cP and in a glycerol solution with a viscosity of 956.0 cP;

[0030] FIG6 is an absorption spectrum of the plant extract modified molecular probe prepared in Example 1 in solutions of different polarities;

[0031] FIG7 is a graph showing emission spectra of the plant extract-modified molecular probe prepared in Example 1 in solutions with different pH values;

[0032] FIG8 is an emission spectrum of the plant extract modified molecular probe prepared in Example 1 in different okra slurries. DETAILED DESCRIPTION

[0033] The present invention provides a plant extract modified molecular probe, the structural formula of the modified molecular probe is shown in Formula I:

[0034] The present invention provides a method for preparing a plant extract modified molecular probe, comprising the following steps:

[0035] (1) adding 3-ethyl-2-methylbenzothiazole iodide solution dropwise to safranal solution to prepare a mixed solution;

[0036] (2) The inorganic salt solution is added dropwise to the mixed solution, and after mixing, a condensation reaction is carried out to prepare a plant extract modified molecular probe.

[0037] In the present invention, the structural formula of safranal in step (1) is shown in Formula II:

[0038] In the present invention, the molar ratio of 3-ethyl-2-methylbenzothiazole iodide to safranal in step (1) is preferably 1:1-60, more preferably 1:10-50, more preferably 1:20-30, the concentration of the 3-ethyl-2-methylbenzothiazole iodide solution is preferably 1-50M, more preferably 5-40M, more preferably 20-30M, and the concentration of the safranal solution is preferably 1-200M, more preferably 50-150M, more preferably 100-125M.

[0039] In the present invention, the solvents in the 3-ethyl-2-methylbenzothiazole iodide solution, the saffron aldehyde solution in step (1) and the inorganic salt solution in step (2) are independently preferably one or more of N,N-dimethylformamide, ethyl acetate, ethanol, methanol, n-butanol, isopropanol, n-propanol, cyclohexanol, ethylene glycol, n-hexanol and propylene glycol.

[0040] In the present invention, the dropping speeds in steps (1) and (2) are independently preferably 1 to 10 drops / 10 s, more preferably 2 to 8 drops / 10 s, and even more preferably 4 to 6 drops / 10 s.

[0041] In the present invention, the inorganic salt in step (2) is preferably sodium carbonate, sodium bicarbonate, calcium acetate, cesium carbonate, potassium carbonate, tin acetate, potassium bicarbonate or calcium carbonate; the concentration of the inorganic salt solution is preferably 1 to 100 M, more preferably 10 to 80 M, more preferably 50 to 60 M; the molar ratio of the inorganic salt to 3-ethyl-2-methylbenzothiazole iodide is preferably 1 to 50:1, more preferably 5 to 45:1, more preferably 20 to 30:1.

[0042] In the present invention, the mixing temperature in step (2) is preferably 23-28°C, more preferably 24-27°C, more preferably 25-26°C, the mixing time is preferably 1-24h, more preferably 4-20h, more preferably 8-16h, and the mixing is preferably carried out under stirring conditions, and the stirring rate is preferably 100-800rpm, more preferably 200-700rpm, more preferably 300-500rpm.

[0043] In the present invention, the atmosphere during the mixing process in step (2) is nitrogen.

[0044] In the present invention, the condensation reaction in step (2) is a Knoevenagel condensation reaction. The temperature of the condensation reaction is preferably 45 to 110° C., more preferably 55 to 100° C., and more preferably 70 to 80° C. The time of the condensation reaction is preferably 1 to 48 h, more preferably 8 to 40 h, and more preferably 20 to 30 h. The condensation reaction is preferably carried out under stirring, and the stirring rate is preferably 100 to 1500 rpm, more preferably 500 to 1200 rpm, and more preferably 800 to 1000 rpm.

[0045] In the present invention, after the condensation reaction in step (2), the product is preferably purified and separated, and the purification and separation is preferably carried out in sequence by concentration, chromatography, washing and drying.

[0046] In the present invention, the concentration is preferably carried out under a low-pressure environment, the concentration pressure is preferably -0.09 to -0.08 MPa, the concentration temperature is preferably 25 to 80°C, more preferably 35 to 70°C, more preferably 40 to 50°C, and the concentration time is preferably 10 to 80 min, more preferably 20 to 65 min, more preferably 40 to 50 min.

[0047] In the present invention, the concentration is preferably carried out in a rotary evaporator, and the rotation speed of the rotary evaporator is preferably 10 to 300 rpm, more preferably 100 to 280 rpm, and even more preferably 150 to 200 rpm.

[0048] In the present invention, the chromatography is preferably plate chromatography, and the chromatography solution used for chromatography is preferably a mixed solution of methanol and ethyl acetate, and the volume ratio of methanol to ethyl acetate is preferably 1:1-20, more preferably 1:5-15, and more preferably 1:8-12.

[0049] In the present invention, the washing is preferably centrifugal washing, the reagent for centrifugal washing is preferably ethanol, and the solution is preferably subjected to ultrasound before centrifugal washing. The power of ultrasound is preferably 5-50KHz, more preferably 10-45KHz, more preferably 20-30KHz, the time of ultrasound is preferably 10-80min, more preferably 20-60min, more preferably 30-45min, the rate of centrifugal washing is preferably 1000-10000r / min, more preferably 2000-8000r / min, more preferably 4000-5000r / min, the time of centrifugal washing is preferably 5-60min, more preferably 15-45min, more preferably 25-30min, and the number of centrifugal washings is preferably 1-5 times, more preferably 2-4 times, more preferably 3 times.

[0050] In the present invention, the drying is preferably freeze drying, the drying temperature is preferably -60 to -5°C, more preferably -50 to -15°C, more preferably -40 to -30°C, and the drying time is preferably 1 to 48 hours, more preferably 10 to 36 hours, more preferably 18 to 24 hours.

[0051] The present invention also provides the use of a plant extract modified molecular probe in measuring the content of sticky glycoprotein.

[0052] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] (1) 0.6 g of 3-ethyl-2-methylbenzothiazole iodide was dissolved in anhydrous ethanol to prepare solution A (the concentration of 3-ethyl-2-methylbenzothiazole iodide was 2 M); 6 g of safranal was dissolved in anhydrous ethanol to prepare solution B (the concentration of safranal was 40 M); 5.3 g of sodium carbonate was dissolved in anhydrous ethanol to prepare solution C (the concentration of sodium carbonate was 50 M);

[0055] (2) Solution A was added dropwise to solution B at a rate of 3 s / drop to prepare a mixed solution, and solution C was added dropwise to the mixed solution at a rate of 2 s / drop. The mixture was stirred at 25°C for 2 h (stirring rate was 600 rpm), and a Knoevenagel condensation reaction was carried out at 60°C under a nitrogen atmosphere. The stirring rate was controlled to 1200 rpm and the reaction was carried out for 24 h to obtain a primary product.

[0056] (3) The primary product was concentrated at a low pressure of -0.09 MPa and a temperature of 60°C for 60 min using a rotary evaporator (rotation speed of 200 rpm) to remove anhydrous ethanol; the concentrated product was subjected to plate chromatography (the chromatography liquid was a mixed solution of methanol and ethyl acetate with a volume ratio of 1:10); the chromatographic product was dissolved in anhydrous ethanol and ultrasonicated (power of 10 kHz) for 30 min, and then centrifuged and washed at a speed of 8000 r / min for 30 min, and centrifuged and washed 3 times in total; the product after centrifugation and washing was freeze-dried at -30°C for 24 h to obtain a plant extract modified molecular probe.

[0057] Example 2

[0058] (1) 0.305 g of 3-ethyl-2-methylbenzothiazole iodide was dissolved in ethyl acetate to prepare solution A (the concentration of 3-ethyl-2-methylbenzothiazole iodide was 1 M); 0.15 g of safranal was dissolved in ethyl acetate to prepare solution B (the concentration of safranal was 1 M); 0.074 g of sodium bicarbonate was dissolved in ethyl acetate to prepare solution C (the concentration of sodium bicarbonate was 1 M);

[0059] (2) Solution A was added dropwise to solution B at a rate of 10 s / drop to prepare a mixed solution, and solution C was added dropwise to the mixed solution at a rate of 1 s / drop. The mixture was stirred at 23°C for 1 h (stirring rate was 800 rpm), and a Knoevenagel condensation reaction was carried out at 45°C under a nitrogen atmosphere. The stirring rate was controlled to 1500 rpm and the reaction was carried out for 48 h to obtain a primary product.

[0060] (3) The primary product was concentrated at a low pressure of -0.08 MPa and a temperature of 25°C for 80 min using a rotary evaporator (rotation speed of 10 rpm) to remove ethyl acetate; the concentrated product was subjected to plate chromatography (the chromatography liquid was a mixed solution of methanol and ethyl acetate with a volume ratio of 1:1); the chromatographic product was dissolved in anhydrous ethanol and ultrasonicated (power of 5 kHz) for 10 min, and then centrifuged and washed at a speed of 1000 r / min for 60 min; the centrifuged and washed product was freeze-dried at -10°C for 48 h to obtain a plant extract modified molecular probe.

[0061] Example 3

[0062] (1) 3.05 g of 3-ethyl-2-methylbenzothiazole iodide was dissolved in N,N-dimethylformamide to prepare solution A (the concentration of 3-ethyl-2-methylbenzothiazole iodide was 50 M); 88 g of safranal was dissolved in N,N-dimethylformamide to prepare solution B (the concentration of safranal was 200 M); 69 g of potassium carbonate was dissolved in N,N-dimethylformamide to prepare solution C (the concentration of potassium carbonate was 100 M);

[0063] (2) adding solution A to solution B at a rate of 1 s / drop to prepare a mixed solution, adding solution C to the mixed solution at a rate of 1 s / drop, stirring at 28°C for 24 h (stirring rate of 800 rpm), and performing Knoevenagel condensation reaction at 110°C under a nitrogen atmosphere, controlling the stirring rate to 100 rpm and reacting for 1 h to obtain a primary product;

[0064] (3) The primary product was concentrated at a low pressure of -0.08 MPa and a temperature of 80°C for 10 min using a rotary evaporator (rotation speed of 300 rpm) to remove N,N-dimethylformamide; the concentrated product was subjected to plate chromatography (the chromatography liquid was a mixed solution of methanol and ethyl acetate with a volume ratio of 1:10); the chromatographic product was dissolved in anhydrous ethanol and ultrasonicated (power of 50 kHz) for 80 min, and then centrifuged and washed at a speed of 10,000 r / min for 5 min, and centrifuged and washed 5 times in total; the product after centrifugation and washing was freeze-dried at -60°C for 1 h to obtain a plant extract modified molecular probe.

[0065] A schematic diagram of the mechanism of the action of the plant extract-modified molecular probe prepared by the present invention on sticky glycoproteins is shown in Figure 1. As can be seen from Figure 1, the chemical structure of the molecular probe contains multiple freely rotatable conjugated structures. It can rotate freely in a relatively dilute solution, but its rotation is restricted in a relatively thick solution. The energy excited by the external excitation light source transitions back to the ground state from mechanical dissipation (non-radiation) to radiation transition, thereby releasing a strong light signal.

[0066] The mass spectrum of the plant extract modified molecular probe obtained in Example 1 is shown in FIG2 . As can be seen from FIG2 , the relative molecular mass of the plant extract modified molecular probe obtained in Example 1 is 312.10534 [M] + The theoretical relative mass estimation value is 312.10528. It can be determined that the synthesized product is a plant extract modified molecular probe 3-ethyl-2-(4-hydroxy-3-methoxyphenyl)benzo[d]thiazol-3-ium salt, having the structural formula shown in Formula I. The molecular formula of Formula I is C 18 H 18 NO2S + .

[0067] The performance test of the plant extract modified molecular probe of Example 1 was performed:

[0068] Viscosity response performance test:

[0069] 3.12 mg of the plant extract-modified molecular probe prepared in Example 1 was dissolved in deionized water to obtain a plant extract solution with a concentration of 10 mM. The plant extract solution was added to glycerol to prepare mixed systems with glycerol volume fractions of 0%, 10%, 30%, 50%, 70%, and 100%, respectively. After storage at room temperature for 1 hour, the system was tested at room temperature at a test wavelength of 520 nm. The test results are shown in Figure 3.

[0070] The fluorescence mass spectrum of the plant extract modified molecular probe prepared in Example 1 in a glycerol / water mixture system is shown in FIG3 . As can be seen from FIG3 , with the increase of the glycerol volume fraction, the system viscosity of the mixed solution gradually increases and the light signal intensity gradually increases.

[0071] The values ​​of viscosity and fluorescence intensity shown in Figure 3 were converted into logarithmic functions and fitted into a straight line, as shown in Figure 4. The specific values ​​are shown in Table 1:

[0072] Table 1 Logarithm of viscosity and logarithm of fluorescence intensity

[0073] The logarithmic function of the fluorescence intensity and viscosity value of the plant extract modified molecular probe prepared in Example 1 in the glycerol / water mixed system is shown in Figure 4. As can be seen from Figure 4, the relationship between the viscosity of the plant extract modified molecular probe and the intensity of the light signal release is consistent with From this relationship, it can be seen that the sensitivity coefficient of the plant extract modified molecular probe to viscosity is 0.39 and the coefficient of determination is 0.98. It can be seen that the plant extract modified molecular probe of the present invention has a high sensitivity to the micro-region viscosity of the solution and is suitable for the detection of the content of sticky glycoproteins.

[0074] Test of photostability in solutions with different viscosities:

[0075] 4.68 mg of the plant extract-modified molecular probe obtained in Example 1 was dissolved in deionized water to a concentration of 10 μM. The probe was added to deionized water with a viscosity of 1.0 cP and a glycerol solution with a viscosity of 956.0 cP, respectively. The probe was excited continuously for 60 minutes under a 520 nm excitation light source. The change pattern of the optical signal intensity was tested. The test results are shown in FIG5 , and the obtained data are shown in Table 2:

[0076] Table 2 Optical signal strength test results

[0077] The photostability test graphs of the plant extract modified molecular probe prepared in Example 1 in high viscosity and low viscosity solutions are shown in FIG5 . As can be seen from Table 2 and FIG5 , the plant extract modified molecular probe prepared in Example 1 has good photostability and can release stable light signals under long-term irradiation of the excitation light source.

[0078] Absorbance test in solutions of different polarity

[0079] 1.56 mg of the plant extract-modified molecular probe obtained in Example 1 was dissolved in deionized water at a concentration of 1 mM. The resulting plant extract-modified molecular probe solution was then added to six common solutions of varying polarity: glycerol, dimethyl sulfoxide, tetrahydrofuran, dichloromethane, toluene, and anhydrous ethanol, each at a concentration of 10 μM. These six solutions were tested at room temperature. The results are shown in Figure 6.

[0080] The absorption spectra of the plant extract modified molecular probe prepared in Example 1 in solutions of different polarities are shown in Figure 6. As can be seen from Figure 6, the absorbance and absorption wavelength of the plant extract modified molecular probe in solutions of different polarities are not significantly different, that is, it can effectively absorb the energy of the excitation light in solutions of different polarities, and the change in the polarity of the solution will not cause changes in the absorption spectrum, indicating that it has good universality in complex plant foods, and the fluctuation of the solution polarity will not affect its measurement effect on viscosity.

[0081] Test of photostability under different pH conditions

[0082] 6.24 mg of the plant extract-modified molecular probe obtained in Example 1 was dissolved in deionized water at a concentration of 2 mM. Six aliquots of the plant extract-modified molecular probe solution were then taken and their pH values ​​were adjusted to 3, 5, 6.8, 7.4, 8, and 9, respectively, with a concentration of 10 μM. The spectral changes under complex and varying pH conditions were then tested. The six different solutions were tested at room temperature, and the results are shown in Figure 7.

[0083] The emission spectra of the plant extract modified molecular probe prepared in Example 1 in solutions of different pH values ​​are shown in FIG7 . As can be seen from FIG7 , the light signal intensity released by the plant extract modified molecular probe in solutions with a pH value of 3 to 9 does not change significantly (the spectral overlap is high), and the light signal release stability is good within the pH range of 3 to 9, indicating that the prepared plant extract modified molecular probe can be used in solutions with a wide pH value, that is, it is suitable for use in a variety of plant extract foods.

[0084] Application of plant extract modified molecular probes in detecting sticky glycoprotein content

[0085] 2.5 mg of the plant extract-modified molecular probe obtained in Example 1 was dissolved in deionized water to a concentration of 2 mM. The resulting plant extract-modified molecular probe solutions were then added to okra slurry 1 (viscosity 3.5 cP), okra slurry 2 (viscosity 6.0 cP), and okra slurry 3 (viscosity 9.8 cP), respectively, with the concentration of the plant extract-modified molecular probe controlled at 10 μM. The three different okra molecular probe solutions were stored at room temperature for 30 minutes and tested under an external light source excitation wavelength of 520 nm. The results are shown in Figure 8.

[0086] The emission spectra of the plant extract modified molecular probe prepared in Example 1 in different okra slurries are shown in Figure 8. As can be seen from Figure 8, the light signal release intensity of the plant extract modified molecular probe in three different okra slurries is different, indicating that there is a certain viscosity difference between the three okra slurries. The test results show that the plant extract modified molecular probe provided by the present invention is suitable for the detection of sticky glycoprotein content, fully perceives the changes in solution micro-area viscosity caused by sticky glycoprotein, and expresses it through the strength of the light signal, which is of great significance for studying the addition of sticky glycoprotein content at different concentrations and the preparation process of plant extract foods.

[0087] Based on the above content, it can be known that the plant extract modified molecular probe 3-ethyl-2-(4-hydroxy-3-methoxyphenyl)benzo[d]thiazol-3-ium salt provided by the present invention, referred to as (EHMBI), has a freely rotatable conjugated structure, can release light signals of different intensities in solutions of different viscosities, presenting a visual detection effect, and can be used as a molecular-level tool platform for tracking changes in viscosity of micro-regions within the solution. The test results show that the EHMBI has good photostability and is suitable for application in solutions within a wide pH range. Its absorption spectra are not much different in solutions of various polarities, and its universality is strong. Its emission wavelength is 580nm, and it is not easily affected by other additives contained in plant extract foods containing sticky glycoproteins. It still has a visual monitoring effect for liquid foods containing sticky glycoproteins with a smaller volume.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A plant extract modified molecular probe, characterized in that: The structural formula of the modified molecular probe is shown in Formula I:

2. The method for preparing a plant extract modified molecular probe according to claim 1, characterized in that: The steps include: (1) adding a 3-ethyl-2-methylbenzothiazole iodide solution dropwise to a saffron aldehyde solution to prepare a mixed solution; (2) The inorganic salt solution is added dropwise to the mixed solution, and after mixing, a condensation reaction is carried out to obtain a plant extract modified molecular probe.

3. The method for preparing a plant extract modified molecular probe according to claim 2, characterized in that: The structural formula of saffron aldehyde in step (1) is shown in Formula II:

4. The method for preparing a plant extract modified molecular probe according to claim 2, characterized in that: In step (1), the molar ratio of 3-ethyl-2-methylbenzothiazole iodide to safranal is 1:1-60, the concentration of the 3-ethyl-2-methylbenzothiazole iodide solution is 1-50M, and the concentration of the safranal solution is 1-200M.

5. The method for preparing a plant extract modified molecular probe according to claim 4, characterized in that: The solvents in the 3-ethyl-2-methylbenzothiazole iodide solution, the saffron aldehyde solution in step (1) and the inorganic salt solution in step (2) are independently one or more of N,N-dimethylformamide, ethyl acetate, ethanol, methanol, n-butanol, isopropanol, n-propanol, cyclohexanol, ethylene glycol, n-hexanol and propylene glycol.

6. The method for preparing a plant extract modified molecular probe according to claim 2 or 5, characterized in that: The dropping speeds in steps (1) and (2) are independently 1 to 10 drops / 10s.

7. A method for preparing a plant extract modified molecular probe according to claim 2, characterized in that the inorganic salt in step (2) is sodium carbonate, sodium bicarbonate, calcium acetate, cesium carbonate, potassium carbonate, tin acetate, potassium bicarbonate or calcium carbonate; the concentration of the inorganic salt solution is 1 to 100 M; and the molar ratio of the inorganic salt to 3-ethyl-2-methylbenzothiazole iodide is 1 to 50:

1.

8. The method for preparing a plant extract modified molecular probe according to claim 7, characterized in that: The mixing temperature in step (2) is 23-28° C., the mixing time is 1-24 h, and the mixing is carried out under stirring at a rate of 100-800 rpm.

9. The method for preparing a plant extract modified molecular probe according to claim 8, characterized in that: The temperature of the condensation reaction in step (2) is 45-110° C., the time of the condensation reaction is 1-48 hours, and the condensation reaction is carried out under stirring at a rate of 100-1500 rpm.

10. Use of the plant extract modified molecular probe according to claim 1 in measuring the content of sticky glycoprotein.

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