Process for extracting melatonin from thyme

Abstract

The invention relates to a process for extracting melatonin from thyme, which comprises the following steps: (1) extraction: putting thyme coarse powder into an extraction tank, adding 5-10 times of 20-80% ethanol, heating to 20-95 DEG C, stirring and extracting for 0.5-2.5 hours, filtering with 40-200 meshes, adding 0-8 times of 20-80% ethanol into filter residues again, heating to 20-95 DEG C, stirring and extracting for 0.5-2 hours, and filtering with 40-200 meshes to obtain an extracting solution; (2) concentrating: concentrating the extracting solution in the step (1) under reduced pressure until the solid content is 5-30%, the concentration vacuum degree is greater than or equal to 0.07 MPa, and the temperature is less than or equal to 60 DEG C; (3) filtering to obtain supernate; (4) refining by adopting organic solvent extraction or resin adsorption; (5) concentrating the collected liquid until the solid content is 10-40%, the concentration vacuum degree is greater than or equal to 0.07 MPa, and the temperature is less than or equal to 60 DEG C; and (6) carrying out spray drying, vacuum drying or freeze drying on the extracted concentrated solution in the step (5) to obtain the brown thyme extract. The extraction efficiency and the purification efficiency of the melatonin in the thyme are improved, and the melatonin is extracted and purified from the thyme for the first time by screening specific varieties of the thyme.

Description

Technical Field

[0001] The invention belongs to the field of natural plant extraction, in particular to a process for extracting melatonin from thyme. Background Art

[0002] Thyme is a short semi-shrub belonging to the genus Thymus of the Lamiaceae family. It is native to the Mediterranean region and is distributed in Gansu, Shaanxi, Inner Mongolia and other places in China. It grows mostly in rocky mountains, slopes, valleys, gullies, roadsides and weeds. Thyme is cold-resistant, drought-resistant, barren-resistant, and disease-resistant. It likes a warm, light-loving and dry environment. It has low requirements for soil and grows well in well-drained calcareous soil. The "Compendium of Materia Medica" records that thyme has the effects of dispelling wind and relieving exterior symptoms, promoting qi and relieving pain. It is used to treat colds, toothaches, indigestion, acute gastroenteritis, hypertension and other diseases. Modern studies have shown that thyme contains a certain amount of melatonin.

[0003] Melatonin is a hormone secreted by the pineal gland in the brain, which has multiple physiological functions such as regulating sleep-wake cycles, anti-oxidation, and immune regulation. Melatonin can inhibit the excitability of the central nervous system, slow down brain activity, and make it easier for people to enter a quiet and relaxed sleep state.

[0004] In recent years, with the increase of work pressure and life pressure, a large number of people have excessive stress, and their nerves are in a state of excitement for a long time, leading to insomnia. Supplementing melatonin may help alleviate this situation and promote sleep. At present, most melatonin products on the market are chemically synthesized, which have certain side effects and safety issues. Therefore, extracting natural melatonin from natural plants has become a research hotspot. Thyme is a common aromatic plant with rich bioactive ingredients, but there is no report on the extraction of natural melatonin from thyme.

[0005] In summary, all melatonin products currently on the market are synthetic, and no melatonin products derived from natural extracts have been found. The main indicator of thyme extract is also thymol, and no reports on melatonin-related indicators have been found. Therefore, the inventors of this application attempted to propose a process for extracting melatonin from thyme, which can be effectively applied to industrialization. Summary of the invention

[0006] In view of the above problems, the present invention provides a process for extracting melatonin from thyme, which improves the extraction efficiency and purification efficiency of melatonin in thyme. By screening specific varieties of thyme, melatonin is extracted and purified from thyme for the first time.

[0007] To this end, the present invention adopts the following technical solution: a process for extracting melatonin from thyme, characterized by comprising the following steps:

[0008] (1) Extraction: Place thyme powder in an extraction tank, add 5-10 times the amount of 20-80% ethanol, heat to 20-95° C., stir and extract for 0.5-2.5 hours, filter through 40-200 mesh, add 0-8 times the amount of 20-80% ethanol to the residue, heat to 20-95° C., stir and extract for 0.5-2 hours, filter through 40-200 mesh to obtain an extract;

[0009] (2) Concentration: The extract in step (1) is concentrated under reduced pressure to a solid content of 5-30%, with a concentration vacuum degree of ≥0.07 MPa and a temperature of ≤60°C;

[0010] (3) Filtration: Centrifuge and filter the concentrated solution in step (2) again to obtain a supernatant;

[0011] (4) Purification: Purifying the concentrated solution in step (3) by organic solvent extraction or resin adsorption;

[0012] (5) Concentration: Concentrate the collected liquid in step (4) to a solid content of 10-40%, with a concentration vacuum degree of ≥0.07 MPa and a temperature of ≤60°C;

[0013] (6) The extract concentrate in step (5) is spray dried (inlet air temperature 180±20°C, outlet air temperature 90±5°C, atomization frequency 30Hz), vacuum dried (temperature 50-80°C, vacuum degree ≥0.07MPa) or freeze dried (material freezing temperature ≤45°C, material temperature ≤55°C, partition temperature ≤60°C, front box pressure ≤90Pa, rear box pressure ≤70Pa) to obtain a brown thyme extract.

[0014] Preferably, in the step (4), resin adsorption purification is adopted, the pH of the concentrated solution in step (3) is adjusted to 5-11, the resin is applied at a flow rate of 0.5-2BV / h, purified water is used to rinse 0.5-2BV at 0.5-1.5BV / h, 30% ethanol is used to rinse 0.5-2BV at 0.5-1.5BV / h, 65% ethanol is used to rinse 0.5-2BV at 0.5-1.5BV / h, and 65% eluate is collected.

[0015] Preferably, the resin used in step (4) is D101, AB-8, HPD-100, D301 or 001*7.

[0016] Preferably, the resin adsorption refining is to adjust the pH of the concentrated solution in step (3) to 9, apply resin S1 at a flow rate of 0.5BV / h, rinse 1.5BV with purified water at 1BV / h, rinse 1BV with 30% ethanol at 1BV / h, rinse 1.5BV with 65% ethanol at 0.5BV / h, and collect 65% of the eluate.

[0017] Preferably, in the step (4), an organic solvent is used for extraction, and the ratio of organic solvent to concentrated solution (w:w) is 1-4:1, and the mixture is stirred for 0.5-2 h. After stirring, the mixture is allowed to stand for 2-24 h to separate the layers, and the organic solvent layer is collected. The aqueous layer is further extracted with an organic solvent to concentrated solution (w:w) in a ratio of 0-4:1, and stirred for 0.5-2 h. After stirring, the mixture is allowed to stand for 2-24 h, and the collected organic solvent layer is combined with the first organic solvent layer.

[0018] Preferably, in step (4), the ratio of organic solvent to concentrated solution (w:w) is 2:1, stirred for 1 hour, allowed to stand for 12 hours after stirring to separate the layers, the organic solvent layer is collected, and the aqueous layer is further stirred for 1 hour with the ratio of organic solvent to concentrated solution (w:w) = 1:1, stirred for 1 hour, allowed to stand for 12 hours after stirring, and the collected organic solvent layer is combined with the first organic solvent layer.

[0019] Preferably, in step (1), 10 times the amount of 60% ethanol is added, heated to 80°C and stirred for extraction for 2 hours, filtered through 60 mesh, and 8 times the amount of 60% ethanol is added to the residue again, heated to 80°C and stirred for extraction for 1 hour.

[0020] Preferably, the solid content in step (2) is 10%, the centrifugal filtration mesh size in step (3) is 400 mesh, the solid content in step (5) is 25%, and water is added twice during the concentration in step (5) to remove the residual solvent.

[0021] Preferably, the organic solvent in step (4) is water-saturated n-butanol or ethyl acetate.

[0022] Preferably, in step (5), after adding water for concentration, the concentrate needs to be free of organic solvent, and in step (6), the drying is freeze-drying to obtain a brown extract dry powder.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. A new, multi-step extraction and refining process is adopted, including specific solvent selection, temperature control, extraction time setting, specific extraction solvent, adsorption resin and elution condition setting. This process significantly improves the extraction efficiency and purification efficiency of melatonin in thyme.

[0025] 2. The present invention extracts and purifies melatonin from thyme for the first time by screening specific varieties of thyme, which is beneficial to the development of subsequent functional products.

[0026] 3. The melatonin content is greater than 0.5% by using the production process of the present invention followed by extraction and purification; the melatonin content is greater than 2.5% by using the production process of the present invention followed by extraction and purification by resin adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1This is the HPLC spectrum of melatonin standard.

[0028] Figure 2 This is the HPLC spectrum of thyme extract. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific embodiments.

[0030] 1. Example 1: 20 kg thyme powder, containing 0.024% melatonin, was added with 160 L 60% ethanol, and heated at 80 °C.

[0031] After stirring and extracting for 2 hours, the extract was passed through a 200-mesh sieve. 160L of 60% ethanol was added to the extract residue. After stirring and extracting for 1 hour at 80°C, the extract was passed through a 200-mesh sieve. The filtrates were combined and concentrated in vacuo to a solid content of 10.23%. The pH of the solution was adjusted to 9.10, and the resin HPD-100 was adsorbed at 0.5BV / h. 1.5BV was washed with purified water at a flow rate of 1BV / h, 1BV was rinsed with 30% ethanol at a flow rate of 1BV / h, and 1.5BV was rinsed with 65% ethanol at 0.5BV / h. The 65% ethanol eluate was concentrated to 25% solids, and freeze-dried (material freezing temperature ≤45°C, material temperature ≤55°C, partition temperature ≤60°C, front box pressure ≤90Pa, and rear box pressure ≤70Pa) to obtain 83.27g of brown thyme extract with a melatonin content of 4.81%.

[0032] 2. Example 2: 20 kg thyme powder, containing 0.024% melatonin, added with 200 L 20% ethanol, 80 ° C

[0033] After stirring and extracting for 2 hours, the extract was passed through a 200-mesh sieve. 200L of 20% ethanol was added to the extract residue. After stirring and extracting for 1 hour at 80°C, the extract was passed through a 200-mesh sieve. The filtrates were combined and concentrated in vacuo to a solid content of 10.37%. The pH of the solution was adjusted to 8.05, and the resin HPD-100 was adsorbed at 0.5BV / h. 1.5BV was washed with purified water at a flow rate of 1BV / h, 1BV was rinsed with 20% ethanol at a flow rate of 1BV / h, and 1.5BV was rinsed with 65% ethanol at 0.5BV / h. The 65% ethanol eluate was concentrated to 25% solids, and freeze-dried (material freezing temperature ≤45°C, material temperature ≤55°C, partition temperature ≤60°C, front box pressure ≤90Pa, and rear box pressure ≤70Pa) to obtain 101.3g of brown thyme extract with a melatonin content of 3.21%.

[0034] 3. Example 3: 20 kg of thyme powder, containing 0.024% melatonin, was added with 120 L of 40% ethanol, stirred and extracted at 60 ° C for 2 hours, and then sieved through a 100-mesh sieve. 120 L of 40% ethanol was added to the extract residue, stirred and extracted at 60 ° C for 1 hour, and then sieved through a 100-mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 10.56% in the feed liquid. The pH of the solution was adjusted to 10.08, and the resin HPD-100 was adsorbed at 0.5 BV / h. Purified water was added at 1 B V / h flow rate of 1.5BV, 20% ethanol at a flow rate of 1BV / h to wash 1BV, 65% ethanol at a flow rate of 0.5BV / h to wash 1.5BV, the 65% ethanol eluate was concentrated to 25% solids, freeze-dried (material freezing temperature ≤45 ° C, material temperature ≤55 ° C, partition temperature ≤60 ° C, front box pressure ≤90Pa, rear box pressure ≤70Pa), to obtain 104.5g brown thyme extract with a melatonin content of 3.52%.

[0035] 4. Example 4: 20 kg of thyme powder, containing 0.024% melatonin, was added with 160 L of 60% ethanol, stirred and extracted at 80 ° C for 2 hours, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, stirred and extracted at 80 ° C for 1 hour, and then sieved through a 200-mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 20.32%. The solution pH was adjusted to 9.10, and the resin AB-8 was adsorbed at 0.5 BV / h. Purified water was added at 0.5 BV / h. / h flow rate of 1.5BV, 30% ethanol at a flow rate of 0.5BV / h to wash 1BV, 65% ethanol at a flow rate of 1BV / h to wash 1BV, the 65% ethanol eluate was concentrated to 25% solids, freeze-dried (material freezing temperature ≤45 ° C, material temperature ≤55 ° C, partition temperature ≤60 ° C, front box pressure ≤90Pa, rear box pressure ≤70Pa), to obtain 102.21g brown thyme extract with a melatonin content of 3.88%.

[0036] 5. Example 5: 20 kg of thyme powder, containing 0.041% melatonin, was added with 160 L of 60% ethanol, stirred and extracted at 80 ° C for 2 hours, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, stirred and extracted at 80 ° C for 1 hour, and then sieved through a 200-mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 10.88% in the feed liquid. The pH of the solution was adjusted to 9.10, and the resin HPD-100 was adsorbed at 0.5 BV / h. Purified water was added at 1 BV / h flow rate of 1.5BV, 30% ethanol at a flow rate of 1BV / h to wash 1BV, 65% ethanol at a flow rate of 0.5BV / h to wash 1.5BV, the 65% ethanol eluate was concentrated to 25% solids, freeze-dried (material freezing temperature ≤45 ° C, material temperature ≤55 ° C, partition temperature ≤60 ° C, front box pressure ≤90Pa, rear box pressure ≤70Pa), to obtain 127.52g of brown thyme extract with a melatonin content of 5.21%.

[0037] 6. Example 6: 20 kg of thyme powder, containing 0.024% melatonin, was added with 160 L of 60% ethanol, stirred and extracted at 80°C for 2 h, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, stirred and extracted at 80°C for 1 h, and then sieved through a 200-mesh sieve. The filtrate was combined and concentrated in vacuo to a solid content of 10.11% in the feed liquid. The extract was extracted with 2 times the amount of ethyl acetate, stirred for 1 h, and allowed to stand for 12 h. The aqueous layer was extracted once with 2 times the amount of ethyl acetate, stirred for 1 h, and allowed to stand for 12 h. The two ethyl acetate layers were combined and concentrated. Water was added during the concentration process to concentrate to a solid content of 25.56%. The extract was freeze-dried (material freezing temperature ≤45°C, material temperature ≤55°C, partition temperature ≤60°C, front box pressure ≤90 Pa, and rear box pressure ≤70 Pa) to obtain 701 g of brown thyme extract with a melatonin content of 0.61%.

[0038] 7. Example 7: 20 kg of thyme powder, containing 0.024% melatonin, was added with 160 L of 60% ethanol, stirred and extracted at 80° C. for 2 h, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, stirred and extracted at 80° C. for 1 h, and then sieved through a 200-mesh sieve. The filtrate was combined and concentrated in vacuo to a solid content of 10.11% in the feed liquid. The extract was extracted with 2 times the amount of water-saturated n-butanol, stirred for 1 h, and allowed to stand for 12 h. The water layer was extracted once with 2 times the amount of water-saturated n-butanol, stirred for 1 h, and allowed to stand for 12 h. The two water-saturated n-butanol layers were combined and concentrated. Water was added during the concentration process to concentrate to a solid content of 25.56%. The extract was freeze-dried (material freezing temperature ≤45° C., material temperature ≤55° C., partition temperature ≤60° C., front box pressure ≤90 Pa, and rear box pressure ≤70 Pa) to obtain 855 g of brown thyme extract with a melatonin content of 0.39%.

[0039] 8. Implementation Case Eight: 20 kg of thyme powder, containing 0.024% melatonin, was added with 160 L of 60% ethanol, extracted with stirring at 80° C. for 2 h, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, and the mixture was extracted with stirring at 80° C. for 1 h, and then sieved through a 200-mesh sieve. The filtrates were combined and concentrated in vacuo to a solid content of 10.11%. The mixture was extracted with 1 times the amount of ethyl acetate, stirred for 1.5 h, and allowed to stand for 24 h. The aqueous layer was extracted once with 1 times the amount of ethyl acetate, stirred for 1.5 h, and allowed to stand for 24 h. The two ethyl acetate layers were combined and concentrated. Water was added during the concentration process to concentrate the mixture to a solid content of 25.56%. The mixture was freeze-dried (material freezing temperature ≤45° C., material temperature ≤55° C., partition temperature ≤60° C., front box pressure ≤90 Pa, and rear box pressure ≤70 Pa) to obtain 689 g of brown thyme extract with a melatonin content of 0.52%.

[0040] 9. Implementation Case 9: 20 kg of thyme powder, containing 0.031% melatonin, was added with 160 L of 60% ethanol, extracted with stirring at 80°C for 2 h, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, and the mixture was extracted with stirring at 80°C for 1 h, and then sieved through a 200-mesh sieve. The filtrates were combined and concentrated under vacuum until the solid content of the feed liquid was 10.56%. The pH of the solution was adjusted to 10.03, and the resin HPD-100 was adsorbed at 1 BV / h. 1.5 BV was washed with purified water at a flow rate of 1 BV / h, 1 BV was rinsed with 30% ethanol at a flow rate of 1 BV / h, and 1.5 BV was rinsed with 65% ethanol at a flow rate of 1.5 BV / h. The 65% ethanol eluate was concentrated to 25.14% solids, and vacuum dried (temperature 50-80°C, vacuum degree ≥ 0.07 MPa) to obtain 91.03 g of brown thyme extract with a melatonin content of 3.15%.

[0041] 10. Implementation Case 10: 20 kg of thyme powder, containing 0.031% melatonin, was added with 160 L of 60% ethanol, extracted with stirring at 40°C for 1 hour, and then sieved through a 200-mesh sieve. 160 L of 60% ethanol was added to the extract residue, and extracted with stirring at 40°C for 1 hour, and then sieved through a 200-mesh sieve. The filtrate was combined and concentrated in vacuo to a solid content of 10.88%. The pH of the solution was adjusted to 7.18, and adsorbed on resin D101 at a rate of 1 BV / h. 1 BV was washed with purified water at a flow rate of 1 BV / h, 1 BV was rinsed with 30% ethanol at a flow rate of 1 BV / h, 1.5 BV was rinsed with 65% ethanol at a flow rate of 1 BV / h, and the 65% ethanol eluate was concentrated to 26.33% solids, and vacuum dried (temperature 50-80°C, vacuum degree ≥ 0.07 MPa) to obtain 91.03 g of brown thyme extract with a melatonin content of 2.76%.

[0042] 11. Implementation Case 11: 20 kg thyme powder, containing 0.027% melatonin, was added with 160 L 60% ethanol, stirred and extracted at 80 ° C for 2 hours, and then sieved through a 200 mesh sieve. 160 L 60% ethanol was added to the extract residue, stirred and extracted at 80 ° C for 1 hour, and then sieved through a 200 mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 10.08%. The solution pH was adjusted to 5.60 and the resin HPD-100 was added at 0.5 BV / h. After adsorption, 1.5 BV was washed with purified water at a flow rate of 1 BV / h, 1 BV was washed with 30% ethanol at a flow rate of 1 BV / h, 1.5 BV was washed with 65% ethanol at a flow rate of 0.5 BV / h, and the 65% ethanol eluate was concentrated to 25% solids, spray-dried (inlet air temperature 180±20°C, outlet air temperature 90±5°C, atomization frequency 30 Hz), and 78.82 g of brown thyme extract was obtained with a melatonin content of 4.52%.

[0043] 12. Implementation Case 12: 20 kg thyme powder, containing 0.027% melatonin, was added with 160 L 60% ethanol, stirred and extracted at 80 ° C for 2 hours, and then sieved through a 200-mesh sieve. 160 L 60% ethanol was added to the extract residue, stirred and extracted at 80 ° C for 1 hour, and then sieved through a 200-mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 10.21%. The solution pH was adjusted to 9.02 and adsorbed on resin 001*7 at 0.5 BV / h. , wash 1.5BV with purified water at a flow rate of 1BV / h, rinse 1BV with 30% ethanol at a flow rate of 1BV / h, rinse 1.5BV with 65% ethanol at 0.5BV / h, concentrate the 65% ethanol eluate to 24.58% solids, spray dry (inlet air temperature 180±20℃, outlet air temperature 90±5℃, atomization frequency 30Hz), and obtain 89.13g of brown thyme extract with a melatonin content of 2.52%.

[0044] 13. Example 13: 20 kg of thyme powder, containing 0.027% melatonin, was added with 120 L of 40% ethanol, stirred and extracted at 60 ° C for 2 hours, and then sieved through a 100-mesh sieve. 120 L of 40% ethanol was added to the extract residue, stirred and extracted at 60 ° C for 1 hour, and then sieved through a 100-mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 10.98% in the feed liquid. The pH of the solution was adjusted to 9.08, and the resin D301 was adsorbed at 0.5 BV / h. Purified water was added at 1 BV / h flow rate of 1.5BV, 20% ethanol at a flow rate of 1BV / h to wash 1BV, 65% ethanol at a flow rate of 0.5BV / h to wash 1.5BV, the 65% ethanol eluate was concentrated to 25% solids, freeze-dried (material freezing temperature ≤45 ° C, material temperature ≤55 ° C, partition temperature ≤60 ° C, front box pressure ≤90Pa, rear box pressure ≤70Pa), to obtain 104.5g of brown thyme extract with a melatonin content of 3.52%.

[0045] 14. Example 14: 20 kg of thyme powder, containing 0.027% melatonin, was added with 200 L of 20% ethanol, stirred and extracted at 80 ° C for 2 hours, and then sieved through a 200-mesh sieve. 200 L of 20% ethanol was added to the extract residue, stirred and extracted at 80 ° C for 1 hour, and then sieved through a 200-mesh sieve. The filtrate was combined and vacuum concentrated to a solid content of 11.01% in the feed liquid. The pH of the solution was adjusted to 5.05, and the resin D301 was adsorbed at 1 BV / h. Purified water was added at 1 BV / h. / h flow rate of 1.5BV, 30% ethanol at a flow rate of 1BV / h to wash 1BV, 80% ethanol at a flow rate of 1BV / h to wash 1.5BV, the 80% ethanol eluate was concentrated to 25% solids, freeze-dried (material freezing temperature ≤45 ° C, material temperature ≤55 ° C, partition temperature ≤60 ° C, front box pressure ≤90Pa, rear box pressure ≤70Pa), to obtain 110.9g of brown thyme extract with a melatonin content of 2.02%.

[0046] 15. Implementation Case 15: 20 kg thyme powder, containing 0.031% melatonin, was added with 160 L 60% ethanol, stirred and extracted at 80 ° C for 2 hours, and then passed through a 200 mesh sieve. 160 L 60% ethanol was added to the extract residue, and then 80 ° C

[0047] After stirring and extracting for 1 hour, the mixture was passed through a 200-mesh sieve, the filtrate was combined, and vacuum concentrated to a solid content of 10.01%. The pH of the solution was adjusted to 5.22, and the resin 001*7 was adsorbed at 0.5 BV / h. Purified water was used to wash 1.5 BV at a flow rate of 1 BV / h, 10% ethanol was used to wash 1 BV at a flow rate of 1 BV / h, and 75% ethanol was used to wash 1.5 BV at a flow rate of 0.5 BV / h. The 75% ethanol eluate was concentrated to 24.58% solids, and spray dried (inlet air temperature 180

[0048] ±20°C, air outlet temperature 90±5°C, atomization frequency 30Hz), and 92.23g of brown thyme extract was obtained with a melatonin content of 1.89%.

[0049] It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A process for extracting melatonin from thyme, characterized in that The following steps are involved: (1) Extraction: Place thyme powder in an extraction tank, add 5-10 times the amount of 20-80% ethanol, heat to 20-95° C., stir and extract for 0.5-2.5 hours, filter through 40-200 mesh, add 0-8 times the amount of 20-80% ethanol to the residue, heat to 20-95° C., stir and extract for 0.5-2 hours, filter through 40-200 mesh to obtain an extract; (2) Concentration: The extract in step (1) is concentrated under reduced pressure to a solid content of 5-30%, with a concentration vacuum degree of ≥0.07 MPa and a temperature of ≤60°C; (3) Filtration: Centrifuge and filter the concentrated solution in step (2) again to obtain a supernatant; (4) Purification: Purifying the concentrated solution in step (3) by organic solvent extraction or resin adsorption; (5) Concentration: Concentrate the collected liquid in step (4) to a solid content of 10-40%, with a concentration vacuum degree of ≥0.07 MPa and a temperature of ≤60°C; (6) The extract concentrate in step (5) is spray dried (inlet air temperature 180±20°C, outlet air temperature 90±5°C, atomization frequency 30Hz), vacuum dried (temperature 50-80°C, vacuum degree ≥0.07MPa) or freeze dried (material freezing temperature ≤45°C, material temperature ≤55°C, partition temperature ≤60°C, front box pressure ≤90Pa, rear box pressure ≤70Pa) to obtain a brown thyme extract.

2. The process for extracting melatonin from thyme according to claim 1, characterized in that In the step (4), resin adsorption purification is adopted, the pH of the concentrated solution in step (3) is adjusted to 5-11, the resin is applied at a flow rate of 0.5-2BV / h, purified water is used to rinse 0.5-2BV at 0.5-1.5BV / h, 30% ethanol is used to rinse 0.5-2BV at 0.5-1.5BV / h, 65% ethanol is used to rinse 0.5-2BV at 0.5-1.5BV / h, and 65% eluate is collected.

3. The process for extracting melatonin from thyme according to claim 2, characterized in that The resin used in the step (4) is D101, AB-8, HPD-100, D301 or 001*7.

4. The process for extracting melatonin from thyme according to claim 3, characterized in that The resin adsorption refining is to adjust the pH of the concentrated solution in step (3) to 9, apply resin S1 at a flow rate of 0.5BV / h, rinse 1.5BV with purified water at 1BV / h, rinse 1BV with 30% ethanol at 1BV / h, rinse 1.5BV with 65% ethanol at 0.5BV / h, and collect 65% of the eluate.

5. The process for extracting melatonin from thyme according to claim 1, characterized in that In the step (4), an organic solvent is used for extraction, and the ratio of organic solvent to concentrated solution (w:w) is 1-4:

1. The mixture is stirred for 0.5-2 hours, and then allowed to stand for 2-24 hours to separate the layers. The organic solvent layer is collected, and the aqueous layer is further extracted with an organic solvent to concentrated solution (w:w) in a ratio of 0-4:1, and stirred for 0.5-2 hours. The mixture is allowed to stand for 2-24 hours to collect the organic solvent layer and combine it with the first organic solvent layer.

6. The process for extracting melatonin from thyme according to claim 5, characterized in that In step (4), the ratio of organic solvent to concentrated solution (w:w) = 2:1 is used for stirring for 1 hour, and the mixture is allowed to stand for 12 hours after stirring to separate the layers. The organic solvent layer is collected, and the aqueous layer is further treated with organic solvent to concentrated solution (w:w) = 1:1, and stirred for 1 hour. The mixture is allowed to stand for 12 hours after stirring, and the collected organic solvent layer is combined with the first organic solvent layer.

7. The process for extracting melatonin from thyme according to claim 1, characterized in that In step (1), 10 times the amount of 60% ethanol was added, heated to 80°C, stirred and extracted for 2 hours, filtered through 60 mesh, and 8 times the amount of 60% ethanol was added to the residue again, heated to 80°C, stirred and extracted for 1 hour.

8. The process for extracting melatonin from thyme according to claim 1, characterized in that The solid content in step (2) is 10%, the centrifugal filtration mesh in step (3) is 400 mesh, the solid content in step (5) is 25%, and water is added twice during the concentration in step (5) to remove the residual solvent.

9. A process for extracting melatonin from thyme according to claim 1, characterized in that The organic solvent in step (4) is water-saturated n-butanol or ethyl acetate.

10. A process for extracting melatonin from thyme according to claim 1, characterized in that: In step (5), after adding water and concentrating, the concentrate must not contain any organic solvent. In step (6), the drying is freeze-drying to obtain a brown extract dry powder.

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