A method for the preparation of lycopene promoting cis-isomerization

Abstract

The application discloses a preparation method for promoting cis-isomerization of lycopene, and utilizes a double-metal organic framework material as a catalyst to catalyze lycopene to make it cis-isomerize. The catalyst catalyzes lycopene to make it cis-isomerize. The catalyst is more likely to attack the conjugated double bond of activated all-trans lycopene in an electron-rich environment, so as to rotate into the corresponding configuration. The method is green and efficient, and has great application prospect.

Description

Technical Field

[0001] This invention relates to a method for lycopene isomerization, and more particularly to a method for preparing lycopene by promoting cis isomerization. Background Technology

[0002] Over 90% of lycopene in natural plants is in the all-trans configuration, which has lower bioavailability and antioxidant activity compared to the cis configuration. Therefore, finding effective methods to promote the conversion of all-trans lycopene to the cis isomer has become a key research focus in the field of efficient lycopene utilization. The cis isomer of lycopene has higher bioavailability in the human body, meaning it is more easily absorbed and thus more effectively exerts its physiological functions. Simultaneously, the cis lycopene isomer exhibits stronger antioxidant activity compared to the all-trans isomer. Antioxidants neutralize free radicals and protect cells from oxidative stress, playing a crucial role in preventing cardiovascular disease and cancer. Due to the higher bioactivity and stability of the cis isomer, especially the 5-cis isomer, it has broad development and application prospects in the food, nutritional, and pharmaceutical fields. These characteristics give lycopene products with a high proportion of cis isomers higher added value in the market.

[0003] Common methods for lycopene cis isomerization include thermal isomerization, photoisomerization, catalytic isomerization, microwave isomerization, and electrochemical isomerization. Thermal isomerization, which promotes the conversion of lycopene from the all-trans isomer to the cis isomer through direct heating, is currently the most commonly used isomerization method in research. During heat treatment, increased temperature and prolonged processing time increase the proportion of cis isomers, but cause significant degradation of lycopene. Photoisomerization, under light conditions, especially with the use of photosensitizers, can effectively promote the conversion of lycopene from the all-trans to the cis isomers. However, the residue problem of photosensitizers makes it unsuitable for industrial production. Catalytic isomerization typically uses metal ion catalysts, which can significantly increase the content of cis isomers (especially 5-cis lycopene), but some metal catalyst residues are difficult to remove. Therefore, safer and more efficient lycopene isomerization methods urgently need to be developed. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide an efficient and safe method for promoting the cis-isomerization of lycopene.

[0005] Technical solution: This invention discloses a preparation method for promoting the cis isomerization of lycopene. The preparation method uses metal-organic framework material UIO-66 or bimetallic organic framework material as catalyst to catalyze the cis isomerization of lycopene.

[0006] The bimetallic organic framework material has an octahedral crystal structure, formed by coordination of the organic ligand tetrafluoroterephthalic acid and metal ions, wherein the metal ions are zirconium ions, copper ions, zinc ions, or iron ions.

[0007] In this context, the molar amount of the doped metal ions (copper ions, zinc ions, or iron ions) is 20-50% of the total molar amount of the metal ions.

[0008] The bimetallic organic framework material is Zn. 1 / 5 -UIO-66、Zn 1 / 4 -UIO-66、Zn 1 / 2 -UIO-66、Cu 1 / 5 -UIO-66、Cu 1 / 4 -UIO-66、Cu 1 / 2 -UIO-66、Fe 1 / 5 -UIO-66、Fe 1 / 4 -UIO-66 or Fe 1 / 2 -UIO-66.

[0009] The method for preparing the bimetallic organic framework material includes the following steps:

[0010] (1) Dissolve zirconium oxynitrate, copper nitrate trihydrate, zinc nitrate hexahydrate, and ferric nitrate nonahydrate in a solution of methanol and formic acid, and stir to dissolve to obtain a mixed solution;

[0011] (2) Add tetrafluoroterephthalic acid to the mixed solution and stir for a certain period of time;

[0012] (3) The obtained solid material is centrifuged, washed, and vacuum dried to obtain metal-organic framework material.

[0013] In step (1), the molar ratio of zirconium oxynitrate to copper nitrate trihydrate, zinc nitrate hexahydrate, and ferric nitrate nonahydrate is 4:1-1:1, and the volume ratio of methanol to formic acid is 5:1-2:1.

[0014] In step (2), the stirring temperature is 30℃~50℃ and the stirring time is 10~14h.

[0015] In step (3), the detergent is methanol, the centrifugation speed is 3000 rpm / min, the centrifugation time is 10 min, and the centrifugation temperature is 10℃~20℃; the vacuum drying temperature is 45℃~60℃, the time is 8~10 h, and the drying pressure is -0.09~-0.1 MPa.

[0016] The preparation method specifically involves taking metal-organic framework material and lycopene solution, stirring them, heating them in a hot reflux water bath, and reacting them in the dark; the resulting lycopene mixed solution is then filtered to obtain the final product.

[0017] The ratio of the metal-organic framework material to lycopene is 4:1-2:1, the lycopene solution concentration is 0.1 mmol / L, the heating temperature is 25-50℃, and the heating time is 0.5-2 h. The reaction is carried out using magnetic stirring in a hot reflux water bath, away from light; preferably, the heating temperature is 37.5℃ and the heating time is 1 h.

[0018] Invention Principle: The present invention provides a method for promoting the cis isomerization of lycopene using a transition metal (Cu, Fe)-doped bimetallic organic framework material as a catalyst to achieve the isomerization of all-trans lycopene, thereby enhancing its bioactivity. This catalyst has the ability to accept electron pairs and is a Lewis acid. All-trans lycopene, rich in conjugated double bonds, creates an electron-rich environment, making it susceptible to attack by electrophiles, thus forming a Lewis base. Therefore, the conjugated double bonds of all-trans lycopene are easily activated by the catalyst, rotating into the corresponding configuration. The appropriate doping of Cu and Fe enhances the electron-accepting ability of the material, allowing the bimetallic organic framework material Cu... 1 / 4 @UIO-66 and Fe 1 / 2 @UIO-66 exhibits the best catalytic effect. Therefore, Cu 1 / 4 @UIO-66 and Fe 1 / 2 @UIO-66 outperforms undoped, zinc-doped, and other doped UIO-66 in terms of retention rate, total isomerization rate, and 5-position isomerization rate, making it more environmentally friendly and efficient.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The preparation method of lycopene isomerization of the present invention uses metal-organic framework materials or bimetallic organic framework materials as catalysts, which is green and environmentally friendly and has no metal catalyst residue; (2) Compared with the existing thermal isomerization method (isomerization rate 45.6% and retention rate 65.6%), the preparation method of the present invention is more efficient in catalysis. Attached Figure Description

[0020] Figure 1 This is a graph showing the ratio of different types and proportions of metal-doped UIO-66 catalyzing lycopene isomerization.

[0021] Figure 2 This is a liquid phase diagram of lycopene isomerization catalyzed by UIO-66;

[0022] Figure 3 This is a graph showing the viability of HUVEC cells;

[0023] Figure 4 This is a graph from the NIH 3T3 cell viability assay.

[0024] Figure 5 It is a fluorescence image of cell viability;

[0025] Figure 6 This is a graph showing the hemolysis of the material. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the embodiments. The test materials used in the embodiments can all be purchased through conventional means.

[0027] Example 1

[0028] The preparation method for promoting cis-isomerization of lycopene in this invention uses Cu 1 / 4 -UIO-66 material was used as a catalyst to catalyze the cis-isomerization of lycopene.

[0029] Cu 1 / 4 Preparation of UIO-66 material:

[0030] (1) Weigh 0.045 mmol zirconium oxynitrate and 0.015 mmol copper nitrate trihydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0031] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40 °C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0032] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the precipitate to a pressure of -0.1MPa, thus obtaining the bimetallic organic framework material Cu of the present invention. 1 / 4 -UIO-66.

[0033] The specific method for preparing cis isomerization of lycopene is as follows: 1 mg of metal-organic framework material and 10 mL of lycopene solution (0.1 mmol / L) are added to a round-bottom flask and incubated at 37.5 °C for 1 h. The mixture is then stirred magnetically and heated in a hot reflux water bath. The reaction is carried out in the dark.

[0034] Example 2

[0035] Compared to Example 1, in the preparation method for promoting cis-isomerization of lycopene, the catalyst is replaced with iron-doped Fe. 1 / 2 -UIO-66, the molar amount of doping is 50% of the total molar amount of metal ligands.

[0036] Fe 1 / 2 Preparation of UIO-66 material:

[0037] (1) Weigh 0.03 mmol zirconium oxynitrate and 0.03 mmol ferric nitrate nonahydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0038] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0039] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the air until the pressure reaches -0.1MPa, thus obtaining the bimetallic organic framework material Fe of the present invention. 1 / 2 -UIO-66.

[0040] Example 3

[0041] Compared with Example 1, in the preparation method for promoting cis-isomerization of lycopene, the catalyst is replaced with UIO-66 material without metal ion doping:

[0042] Preparation of UIO-66 material:

[0043] (1) Weigh 0.06 mmol of zirconium oxynitrate and dissolve it in 7 mL of methanol and 1.5 mL of acetic acid. Stir at 40 °C until completely dissolved.

[0044] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0045] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to draw a vacuum and dry to a pressure of -0.1MPa, thus obtaining the metal-organic framework material UIO-66 of the present invention.

[0046] Example 4

[0047] Compared to Example 1, in the preparation method for promoting cis-isomerization of lycopene, the catalyst is replaced with zinc ion-doped Zn. 1 / 5 -UIO-66, with a doping molar amount of 20% of the total metal ion molar amount.

[0048] Zn 1 / 5 Preparation of UIO-66 material:

[0049] (1) Weigh 0.048 mmol zirconium oxynitrate and 0.012 mmol zinc nitrate hexahydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0050] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0051] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the precipitate to a pressure of -0.1MPa, thus obtaining the bimetallic organic framework material Zn of the present invention. 1 / 5 -UIO-66.

[0052] Example 5

[0053] Compared to Example 1, in the method for promoting the cis-isomerization of lycopene, the catalyst was changed to zinc ion-doped Zn. 1 / 4 -UIO-66, with a doping molar amount of 25% of the total metal ion molar amount.

[0054] Zn 1 / 4 Preparation of UIO-66 material:

[0055] (1) Weigh 0.045 mmol zirconium oxynitrate and 0.015 mmol zinc nitrate hexahydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0056] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0057] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the precipitate to a pressure of -0.1MPa, thus obtaining the bimetallic organic framework material Zn of the present invention. 1 / 4 -UIO-66.

[0058] Example 6

[0059] Compared to Example 1, in the method for promoting the cis-isomerization of lycopene, the catalyst was changed to zinc ion-doped Zn. 1 / 2 -UIO-66, with a doping molar amount of 50% of the total metal ion molar amount.

[0060] Zn 1 / 2 Preparation of UIO-66 material:

[0061] (1) Weigh 0.03 mmol zirconium oxynitrate and 0.03 mmol zinc nitrate hexahydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0062] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0063] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the precipitate to a pressure of -0.1MPa, thus obtaining the bimetallic organic framework material Zn of the present invention. 1 / 2 -UIO-66.

[0064] Example 7

[0065] Compared to Example 1, in the method for promoting the cis-isomerization of lycopene, the catalyst was changed to copper-doped Cu. 1 / 5 -UIO-66, the molar amount added is 20% of the total molar amount of metal ions.

[0066] Cu 1 / 5 Preparation of UIO-66 material:

[0067] (1) Weigh 0.048 mmol zirconium oxynitrate and 0.012 mmol copper nitrate trihydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0068] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0069] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the precipitate to a pressure of -0.1MPa, thus obtaining the bimetallic organic framework material Cu of the present invention. 1 / 5 -UIO-66.

[0070] Example 8

[0071] Compared to Example 1, in the method for promoting the cis-isomerization of lycopene, the catalyst was changed to copper-doped Cu. 1 / 2 -UIO-66, the molar amount added is 50% of the total molar amount of metal ions.

[0072] Cu 1 / 2 Preparation of UIO-66 material:

[0073] (1) Weigh 0.03 mmol zirconium oxynitrate and 0.03 mmol copper nitrate trihydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0074] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0075] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the precipitate to a pressure of -0.1MPa, thus obtaining the bimetallic organic framework material Cu of the present invention. 1 / 2 -UIO-66.

[0076] Example 9

[0077] Compared to Example 1, in the preparation method for promoting cis-isomerization of lycopene, the catalyst was changed to iron-doped Fe. 1 / 5 -UIO-66, with a doping molar amount of 20% of the total metal ion molar amount.

[0078] Fe 1 / 5 Preparation of UIO-66 material:

[0079] (1) Weigh 0.048 mmol zirconium oxynitrate and 0.012 mmol ferric nitrate nonahydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0080] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0081] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the air until the pressure reaches -0.1MPa, thus obtaining the bimetallic organic framework material Fe of the present invention. 1 / 5 -UIO-66.

[0082] Example 10

[0083] Compared to Example 1, in the preparation method for promoting cis-isomerization of lycopene, the catalyst was changed to iron-doped Fe. 1 / 4 -UIO-66, with a doping molar amount of 25% of the total metal ion molar amount.

[0084] Fe 1 / 4 Preparation of UIO-66 material:

[0085] (1) Weigh 0.045 mmol zirconium oxynitrate and 0.015 mmol ferric nitrate nonahydrate and dissolve them in 7 mL methanol and 1.5 mL acetic acid. Stir at 40 °C until completely dissolved.

[0086] (2) Add 1.429 mL of a methanol solution of tetrafluoroterephthalic acid (10 mg / mL) to the above solution, stir at 40°C for 12 h, and wash three times by centrifugation at 3000 rpm / min for 1 min each time.

[0087] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50°C, 8h). The vacuum pump is turned on to evacuate the air until the pressure reaches -0.1MPa, thus obtaining the bimetallic organic framework material Fe of the present invention. 1 / 4 -UIO-66.

[0088] The preparation method of cis-isomerization of lycopene in Examples 1-10 involved filtering the resulting lycopene mixture through a 0.22 μm polytetrafluoroethylene (PTFE) membrane filter followed by high-performance liquid chromatography (HPLC) analysis. Figure 2 As shown, the chromatographic peak at retention time 34 min represents 13-cis-lycopene, at 38 min 9-cis-lycopene, at 42 min all-trans-lycopene, and at 43 min 5-cis-lycopene. The total cis isomer content (%), single isomer content (%), and lycopene retention rate (%) were calculated as follows:

[0089]

[0090] The isomerization results are shown in Table 1:

[0091] Table 1. Results of cis-isomerization of lycopene

[0092]

[0093]

[0094] As shown in Table 1, Cu 1 / 4- The retention rate of UIO-66 was 82.63%, the total isomerization rate was 60.30%, and the 5-cis isomerization rate was 40.20%. Fe 1 / 2 The retention rate of -UIO-66 was 84.47%, the total isomerization rate was 46.95%, and the 5-cis isomerization rate was 24.75%. Analysis combining the retention rate, total isomerization rate, and 5-cis isomerization rate indicates that Cu... 1 / 4 -UIO-66 and Fe 1 / 2 -UIO-66 showed the best effect in the cis isomerization of lycopene. This is because the doping of appropriate amounts of Fe and Cu enhances the electron-accepting ability of UIO-66, resulting in a higher cis isomerization rate of lycopene.

[0095] In the above embodiments, Cu 1 / 4 -UIO-66 and Fe 1 / 2 -Studies on the biocompatibility of UIO-66:

[0096] Preferred methods for Cu production include using human venous endothelial cells (HUVECs) and mouse embryonic fibroblasts (NIH 3T3). 1 / 4 -UIO-66 and Fe 1 / 2 - Cytotoxicity assay of UIO-66. Both cell lines were cultured in DMEM at 37°C in humid air containing 5% CO2.

[0097] The cytotoxicity of HUVECs and NIH 3T3 cells was assessed using the CCK-8 assay. Cells were seeded in 96-well plates and cultured in DMEM containing triple antibodies for 24 h. Subsequently, the original medium was discarded, and Cu was added to the medium. 1 / 4 -UIO-66 and Fe 1 / 2 Fresh UIO-66 medium (0.2, 0.1 mg / mL) was added. After incubation for 24 hours, cells were washed three times with PBS to remove adhering material. Then, fresh medium containing 10% CCK-8 was added. Cells were incubated at 37°C for 0.5 hours. Relative cell viability was determined by measuring absorbance at 450 nm using an enzyme-linked immunosorbent assay (ELISA) labeling.

[0098] Live and dead cells were determined using an AO / PI dual reagent kit. Specifically, the cell culture and material incubation procedures were the same as for CCK-8, but 14-well plates were used for seeding, and the seeding concentration was 1*10⁵. Additionally, considering the concentration of materials used in actual applications, the material incubation concentration was changed (0.5 mg / mL). After incubation, staining agents were added, and cell fluorescence was recorded under an inverted fluorescence microscope (Nikon 80i).

[0099] like Figure 3 , Figure 4 The results of the CCK-8 cell viability assay showed that when the material concentration reached 0.2 mg / mL, the survival rate of HUVECs and NIH 3T3 cells remained above 80%. Furthermore, the cell live-death fluorescence assay also verified that the live cells maintained green fluorescence after incubation with the material, while the dead cells showed almost no red fluorescence. Figure 5 The experimental results were consistent with those of the CC-K8 assay. Simultaneously, the mouse erythrocyte hemolysis experiment showed that ( Figure 6 ), 0.2 mg / mL Cu 1 / 4 -UIO-66 and Fe 1 / 2 -UIO-66 has a blood cell rupture rate far below 5%. In summary, Cu 1 / 4 -UIO-66 and Fe 1 / 2-UIO-66 has high biocompatibility and has great application prospects in the food packaging field.

Claims

1. A method for preparing lycopene by promoting cis-isomerization, characterized in that, The preparation method involves using a bimetallic organic framework material as a catalyst to catalyze the cis-isomerization of lycopene; the bimetallic organic framework material is Cu. 1 / 4 -UIO-66、Cu 1 / 2 -UIO-66 or Fe 1 / 2 -UIO-66 has an octahedral crystal structure, formed by coordination of the organic ligand tetrafluoroterephthalic acid and metal ions; the metal ions are zirconium ions, copper ions, or iron ions; among the metal ions, the copper or iron ions are doped metal ions; the Cu... 1 / 4 -UIO-66 has a Cu doping molar amount of 25% of the total metal ion molar amount, wherein Cu 1 / 2 -UIO-66 has a Cu doping molar amount of 50% of the total metal ion molar amount, wherein the Fe 1 / 2 -UIO-66 has a Fe doping molar amount of 50% of the total metal ion molar amount.

2. The preparation method according to claim 1, characterized in that, The method for preparing the bimetallic organic framework material includes the following steps: (1) Dissolve zirconium oxynitrate, copper nitrate trihydrate, and ferric nitrate nonahydrate in a solution of methanol and formic acid, respectively, and stir to dissolve to obtain a mixed solution; (2) Add tetrafluoroterephthalic acid to the mixed solution and stir for a certain period of time; (3) The obtained solid material is centrifuged, washed, and vacuum dried to obtain metal-organic framework material.

3. The method according to claim 2, characterized in that, In step (1), the molar ratio of zirconium oxynitrate to copper nitrate trihydrate and ferric nitrate nonahydrate is 4:1-1:1, and the volume ratio of methanol to formic acid is 5:1-2:

1.

4. The preparation method according to claim 2, characterized in that, In step (2), the stirring temperature is 30℃~50℃ and the stirring time is 10~14h.

5. The preparation method according to claim 2, characterized in that, In step (3), the detergent is methanol, the centrifugation speed is 3000 rpm / min, the centrifugation time is 10 min, and the centrifugation temperature is 10℃~20℃; the vacuum drying temperature is 45℃~60℃, the time is 8~10 h, and the drying pressure is -0.09~-0.1 MPa.

6. The preparation method according to claim 1, characterized in that, The preparation method specifically involves taking metal-organic framework material and lycopene solution separately, stirring, heating in a hot reflux water bath, and reacting in the dark; the resulting lycopene mixed solution is then filtered to obtain the final product.

7. The preparation method according to claim 6, characterized in that, The ratio of the metal-organic framework material to lycopene is 4:1-2:1, the heating temperature is 25-50℃, the heating time is 0.5-2 h, magnetic stirring is used, and the reaction is carried out in a hot reflux water bath in the dark.

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