A method for efficiently extracting oleocanthal and oleacein from olive oil

Abstract

This invention provides a method for the efficient extraction of oleocanthal and oleacein from olive oil. The method involves screening a series of eutectic solvents suitable for extracting oleocanthal and oleacein from olive oil. During the screening process, not only extraction performance but also the physical properties of the eutectic solvents were considered, achieving highly efficient extraction of oleocanthal and oleacein from olive oil. This invention overcomes the shortcomings of traditional organic solvent extraction methods, such as large amounts of organic solvent used, toxic organic solvent residues, and cumbersome post-processing leading to the loss of oleocanthal and oleacein. Compared with the conventional method of empirically determining the type of eutectic solvent, this invention saves trial and error time and solvent consumption, significantly reducing the number of experiments. This method provides a feasible solution for the precise and efficient extraction of trace active ingredients from natural products.

Description

Technical Field

[0001] This invention belongs to the field of natural product extraction technology, specifically relating to a method for efficiently extracting oleocanthal and oleacein from olive oil. Background Technology

[0002] Olive oil, known as the "Queen of Vegetable Oils," is an essential part of the Mediterranean diet, rich in sterols, polyphenols, and numerous trace elements. Studies have shown that olive oil has effects such as preventing cardiovascular and cerebrovascular diseases, treating chronic kidney disease, lowering blood lipids, anti-aging, and anti-tumor properties. These effects are not only due to the unsaturated fatty acids and vitamins in olive oil but also closely related to the iridoids in it. Oleocanthal and oleacein are two iridoids in olive oil, present in extremely low amounts (50-100 μg / g). Oleocanthal can cause a pungent sensation in the throat through TRPA1 receptors. The difference between oleocanthal and oleacein is only the addition of a phenolic hydroxyl group, but sensorily, oleacein is more associated with bitterness. Although oleocanthal and oleacein possess excellent pharmacological activities, how to efficiently extract them remains crucial for their further development.

[0003] The conventional methods for extracting oleocanthal and oleacein from olive oil are based on volatile organic solvents such as acetonitrile or methanol; however, the large amount of solvent used in the extraction process can lead to potential environmental problems and complicate subsequent processing. Summary of the Invention

[0004] This invention provides a method for efficiently extracting oleocanthal and oleacein from olive oil. By screening specific eutectic solvents, the method achieves efficient extraction of oleocanthal and oleacein from olive oil, thereby overcoming the shortcomings of conventional organic solvent extraction methods, such as large amounts of organic solvent used, long extraction time, and cumbersome operation process leading to the loss of oleocanthal and oleacein.

[0005] The method for extracting oleocanthal and oleacein from olive oil provided by this invention involves mixing olive oil with a eutectic solvent for extraction, centrifuging the extract to collect the eutectic solvent phase, diluting it with an alcohol solvent, and then filtering it through a membrane to obtain a solution containing oleocanthal and oleacein. The eutectic solvent has an infinite dilution partition ratio >1 g / g, a eutectic point <298.15 K, and a viscosity <100 cP.

[0006] Furthermore, in the eutectic solvent, the molar ratio of hydrogen bond acceptor to hydrogen bond donor is 1:5-5:1;

[0007] As a specific example, the eutectic solvent is composed of choline chloride and phenol in a molar ratio of 1:4;

[0008] As a specific example, the eutectic solvent is composed of choline chloride and phenol in a molar ratio of 1:3.4;

[0009] As another specific embodiment, the eutectic solvent is composed of choline chloride and acetic acid in a molar ratio of 1:1.4;

[0010] Furthermore, the mass-to-volume ratio of the olive oil to the eutectic solvent is 1:1-24:1 (g / ml).

[0011] The centrifugation described herein is specifically characterized by a centrifugation speed of 2000-6000 rpm and a centrifugation time of 3-10 min.

[0012] The volume ratio of the eutectic solvent phase obtained after centrifugation to methanol is 5:1 to 1:5.

[0013] Preferably, the olive oil is extracted after being mixed with a eutectic solvent at an extraction temperature of not less than 60°C.

[0014] The membrane filtration described herein, as a specific example, is a 0.22 μm filter membrane.

[0015] This invention screens a series of eutectic solvents suitable for extracting oleocanthal and oleacein from olive oil. During the screening process, not only extraction performance (the infinite dilution partition ratio of oleocanthal and oleacein in the eutectic solvent) was considered, but also the physical properties of the eutectic solvent (the eutectic point and viscosity), achieving highly efficient extraction of oleocanthal and oleacein from olive oil. This invention overcomes the shortcomings of traditional organic solvent extraction methods, such as large amounts of organic solvent used, toxic organic solvent residues, and cumbersome post-treatment leading to the loss of oleocanthal and oleacein. Compared with the conventional method of empirically determining the type of eutectic solvent, this invention saves trial and error time and solvent consumption, significantly reducing the number of experiments. This method provides a feasible solution for the precise and efficient extraction of trace active ingredients from natural products. Attached Figure Description

[0016] Figure 1 : Figure 1 (a) is a liquid chromatogram of the extract obtained using acetonitrile, a traditional organic solvent. Figure 1(b) is a liquid chromatogram of the eutectic solvent extract composed of choline chloride and phenol used in Example 1;

[0017] Figure 2 Surface shielding charge density diagrams of oleocanthal and the eutectic solvent composed of choline chloride and phenol in Example 1;

[0018] Figure 3 : Viscosity-temperature curves of the eutectic solvents composed of choline chloride and phenol, and choline chloride and o-cresol, respectively, in Examples 1 and 2, in the range of 20-60°C. Detailed Implementation

[0019] This invention fully considers the physical properties of eutectic solvents and their extraction performance on oleocanthal and oleacein, and optimizes the composition and ratio of eutectic solvents, thereby achieving efficient and precise extraction of oleocanthal and oleacein from olive oil.

[0020] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0021] Example 1:

[0022] 1) A low-melting-point solvent composed of choline chloride and phenol was selected, and its infinite dilution partition ratio was determined to be 1.89 g / g, eutectic point to be 243.02 K, and viscosity to be 40.55 cP.

[0023] 2) Dry choline chloride and phenol in a desiccator for 72 hours, and place olive oil in a water bath at 40°C for 2 hours;

[0024] 3) Add choline chloride:phenol = 1:4 (molar ratio) to a round-bottom flask and stir in a magnetic stirrer at 80°C for 1 hour to obtain a uniform and transparent eutectic solvent.

[0025] 4) Mix 6g of olive oil with 0.5mL of eutectic solvent in a vortex mixer at 1500rpm for 10min. After extraction, centrifuge at 4000rpm for 5min.

[0026] 5) Collect the eutectic solvent phase, dilute it with 0.5 mL of methanol, filter it through a 0.22 μm filter membrane, and perform HPLC analysis on the filtrate.

[0027] Example 2:

[0028] 1) A eutectic solvent composed of choline chloride and o-cresol, with an infinite dilution partition ratio of 1.46 g / g, a eutectic point of 237.06 K, and a viscosity of 56.39 cP;

[0029] 2) Dry choline chloride and o-cresol in a desiccator for 24 hours, and place olive oil in a water bath at 50°C for 1 hour;

[0030] 3) Add choline chloride:phenol = 1:3.4 (molar ratio) to a round-bottom flask and heat in a rotary evaporator at 65°C for 2 hours to obtain a uniform and transparent eutectic solvent;

[0031] 4) Mix 6g of olive oil with 1mL of eutectic solvent on a shaker at 100rpm for 1h. After extraction, centrifuge at 2000rpm for 10min.

[0032] 5) Collect the eutectic solvent phase, dilute it with 2 mL of methanol, filter it through a 0.22 μm filter membrane, and perform HPLC analysis on the filtrate.

[0033] Example 3:

[0034] 1) A eutectic solvent composed of choline chloride and acetic acid, with an infinite dilution partition ratio of 1.44 g / g, a eutectic point of 216.95 K, and a viscosity of 75.26 cP;

[0035] 2) Dry choline chloride and acetic acid in a desiccator for 36 hours, and place olive oil in a water bath at 60°C for 3 hours;

[0036] 3) Add choline chloride:acetic acid = 1:1.4 (molar ratio) to a round-bottom flask and stir in a magnetic stirrer at 70°C for 3 hours to obtain a uniform and transparent eutectic solvent.

[0037] 4) Mix 6g of olive oil with 1.5mL of eutectic solvent in a rotary mixer at 100rpm for 3h. After extraction, centrifuge at 6000rpm for 3min.

[0038] 5) Collect the eutectic solvent phase, dilute it with 4.5 mL of methanol, filter it through a 0.22 μm filter membrane, and perform HPLC analysis on the filtrate.

[0039] Example 4: Detection of Filtrate

[0040] The contents of oleocanthal and oleacein in the filtrates extracted with three different eutectic solvents composed of hydrogen bond donors and acceptors were determined by HPLC. The HPLC chromatographic conditions are as follows:

[0041] Agilent SB-C18 1.8μm 4.6×150mm, flow rate: 0.2mL / min, injection volume: 2μL.

[0042] The compositions of mobile phase A and mobile phase B are shown in Table 1 below.

[0043] Table 1 Composition of mobile phase A and mobile phase B

[0044]

[0045]

[0046] Figure 1 (a) is the liquid chromatogram of the extract obtained by acetonitrile, a common organic solvent. Figure 1 (b) is the liquid chromatogram of the eutectic solvent extract composed of choline chloride and phenol used in Example 1. The extraction rate of oleacein was 91.37%, and the extraction rate of oleocanthal was 94.82%. By comparison, the extraction rates were increased by 17.11% and 24.3% respectively compared with conventional organic solvents.

[0047] Figure 2 The surface charge density (SCD) plots are shown for oleocanthal and the eutectic solvent composed of choline chloride and phenol in Example 1. The efficient enrichment of target substances by eutectic solvents can be explained by their surface charge density plots, which can be divided into three regions: hydrogen bond donor region, neutral region, and hydrogen bond acceptor region. As shown in the left figure, the surface charge density plot of oleocanthal shows a small peak near -0.02, indicating its ability to provide hydrogen bonds. The eutectic solvent composed of choline chloride and phenol contains Cl ions and shows a large peak in the hydrogen bond acceptor region. Therefore, there is a strong interaction between the eutectic solvent composed of choline chloride and phenol and oleocanthal, which helps to improve its extraction efficiency. The surface charge density plot can intuitively reflect the interaction between oleocanthal and the eutectic solvent, and its model parameters are expressed as the infinite dilution partition ratio C. ∞ The larger the value, the stronger the interaction.

[0048] Figure 3 The viscosity-temperature curves of the eutectic solvents composed of choline chloride and phenol, and choline chloride and o-cresol, respectively, in Examples 1 and 2, are shown in the range of 20-60°C. As can be seen from the figure, there are significant differences in viscosity among the different eutectic solvents. Since eutectic solvents can achieve ideal dispersion in olive oil and increase the contact area between the target substance and the solvent, selecting eutectic solvents with low viscosity plays a decisive role in improving extraction efficiency.

Claims

1. A method for extracting oleocanthal and oleacein from olive oil, characterized in that, The method involves mixing olive oil with a eutectic solvent for extraction, centrifuging the extract to collect the eutectic solvent phase, diluting the eutectic solvent phase with an alcohol solvent, and then filtering it through a membrane to obtain a solution containing oleocanthal and oleacein; wherein the eutectic solvent is composed of choline chloride and phenol in a molar ratio of 1:

4.

2. The method as described in claim 1, characterized in that, The mass-to-volume ratio of the olive oil to the eutectic solvent is 1:1 to 24:

1.

3. The method as described in claim 1, characterized in that, The centrifugation is carried out at a speed of 2000-6000 rpm for a time of 3-10 min.

4. The method as described in claim 1, characterized in that, The volume ratio of the eutectic solvent phase to the alcohol solvent is 5:1 to 1:

5.

5. The method as described in claim 1, characterized in that, The olive oil is mixed with a eutectic solvent and then extracted at a temperature not lower than 60°C.

6. The method as described in claim 1, characterized in that, The membrane filtration described herein, wherein the membrane is a 0.22 µm filter membrane.

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