Neurite extension promoting agent and method for producing the same

Abstract

To provide a novel neurite outgrowth promoter that can be effective in the prevention of and / or treatment of neurodegenerative disease and a method for producing the same.SOLUTION: A neurite outgrowth promoter includes 6-ginger diol as an active ingredient. The 6-ginger diol includes the (3R,5S)- and (3S,5S)-isomers, which are stereoisomers at the C3 and C5 positions of the side chain. In addition to the 6-ginger diol, the neurite outgrowth promoter includes components included in ginger.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a neurite outgrowth promoter and a method for producing the same.

Background Art

[0002] Neurodegenerative diseases represented by Alzheimer's disease (Alzheimer's dementia), Parkinson's disease, amyotrophic lateral sclerosis, etc. are considered to be pathological conditions caused by the breakdown of neural circuit networks based on systematic degeneration and loss of nerve cells. Many molecular groups are complexly involved in the mechanism of neurodegeneration, which is the cause of neurodegenerative diseases, and there are still many unclear parts.

[0003] For example, Alzheimer's disease is a disease in which a protein called amyloid-β accumulates in the brain, destroys normal brain nerve cells, and causes the brain to atrophy. The current treatment for Alzheimer's disease remains in the position of symptomatic treatment to improve symptoms, and has not reached etiological treatment to remove the cause itself.

[0004] On the other hand, in the treatment of neurodegenerative diseases, in addition to removing the cause, it is also considered important to reconstruct neural circuit networks. For example, in Alzheimer's disease, it is said that if neurons that have survived without degeneration and partially degenerated neurons can be activated, neurites can be extended, and synapses can be restored, then nerve function can be restored. Here, a nerve cell (neuron) is composed of a cell body with a nucleus and neurites extending from the cell body. Neurites include dendritic protrusions that branch like tree branches from the cell body and axons that usually extend only one from the cell body. Dendritic protrusions are the parts where nerve cells receive information from other cells, and axons are the parts where nerve cells output the information received to other cells. The information received by dendritic protrusions is aggregated in the cell body, and the information is transmitted by releasing neurotransmitters to other cells through axons.

[0005] Therefore, in the development of drugs for the treatment and prevention of neurodegenerative diseases, research is being conducted that focuses on the extension of neurites in nerve cells. For example, Patent Document 1 describes a neurite extension promoter containing phosphatidic acid, in which at least one of the constituent fatty acids is an unsaturated fatty acid, as the active ingredient. Patent Document 2 also describes a neurite extension agent containing shikimic acid or a salt thereof.

[0006] Incidentally, ginger is widely used around the world as a spice and folk medicine. In traditional Chinese medicine, it is called "shōkyō" and is believed to have the effect of improving metabolic function, and is used for vomiting, pain relief, and appetite stimulation. Various studies have been conducted on the pharmacological activity of the components contained in ginger. For example, Patent Document 3 reports that ginger extracts containing 6-gingerol and 6-shogaol, which are the pungent components of ginger, have bone formation promoting and bone resorption inhibiting effects.

[0007] However, there have been no reports on the neurite outgrowth-promoting effects of specific components found in ginger. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2009-280524 [Patent Document 2] Japanese Patent Publication No. 2018-035078 [Patent Document 3] Japanese Patent Publication No. 2014-43416 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The present invention aims to provide a novel neurite extension promoting agent and a method for producing the same. [Means for solving the problem]

[0010] The neurite extension promoting agent of the present invention is characterized by containing 6-gingerdiol as an active ingredient.

[0011] The above-mentioned neurite extension promoting agent is characterized by containing components found in ginger in addition to the above-mentioned 6-gingerdiol.

[0012] The 6-gingerdiol contained in the above-mentioned neurite extension promoting agent is characterized by being derived from ginger extract. Furthermore, in addition to the 6-gingerdiol, the other components contained in ginger are also characterized by being derived from ginger extract.

[0013] The above 6-zingerdiol is characterized by including the (3R,5S) and (3S,5S) isomers, which are stereoisomers (diastereomers) at the C3 and C5 positions of the side chain.

[0014] The present invention relates to a method for producing a neurite extension promoting agent, wherein the neurite extension promoting agent contains 6-gingerdiol derived from ginger extract as an active ingredient, and the 6-gingerdiol is obtained by extracting the ginger extract using n-hexane, and then eluting the ginger extract with a mixed solvent of acetone and ethanol by silica gel column chromatography. [Effects of the Invention]

[0015] The neurite extension promoter of the present invention contains 6-gingerdiol as an active ingredient, and therefore exhibits excellent neurite extension promoting effects, making it effective, for example, in the prevention and / or treatment of neurodegenerative diseases. Furthermore, since 6-gingerdiol is a component found in ginger, it has high biocompatibility, and the above-mentioned neurite extension promoter is highly safe.

[0016] The method for producing a neurite outgrowth promoter according to the present invention is such that the neurite outgrowth promoter contains, as an active ingredient, 6-gingerdione derived from ginger, and 6-gingerdione is obtained by extracting a ginger extract using normal hexane and then eluting the ginger extract with a mixed solvent of acetone and ethanol by silica gel column chromatography, so that it can be obtained by a simple operation.

Brief Description of Drawings

[0017] [Figure 1] It is the HPLC of the normal hexane extract of ginger pomace. [Figure 2] It is the evaluation result of the neurite outgrowth promoting action of fractions 1 to 7. [Figure 3] It is the evaluation result of the neurite outgrowth promoting action of fractions 6A to 6D. [Figure 4] It is the HPLC of fraction 6B. [Figure 5] It is a diagram showing the LC / MS analysis result of fraction 6B. [Figure 6] It is a diagram showing the LC / MS analysis result of 6-gingerdione. [Figure 7] It is the evaluation result of the neurite outgrowth promoting action of 6-gingerdione. [Figure 8] It is a diagram showing the detection image of Map2 protein. [Figure 9] It is a schematic diagram of the test apparatus in the learning test of zebrafish. [Figure 10] It is the evaluation result of the avoidance rate in the learning test of zebrafish.

Modes for Carrying Out the Invention

[0019] The neurite extension promoter of the present invention contains 6-gingerdiol as an active ingredient. In the present invention, a neurite extension promoter is an agent that promotes the extension of neurites of nerve cells. The term "neurite" encompasses both axons and dendrites, and the neurite extension promoter has the effect of extending axons and / or dendrites.

[0020] 6-Zingerdiol is a compound represented by the following formula (1).

[0021] [ka]

[0022] As shown in formula (1) above, 6-zingerdiol has hydroxyl groups at the C3 and C5 positions of its side chain. 6-zingerdiol has stereoisomers at the C3 and C5 positions, including the (3R,5S), (3S,5S), (3R,5R), and (3S,5R) isomers. In this invention, 6-zingerdiol is a concept that encompasses these stereoisomers.

[0023] 6-Gingerdiol can be obtained by chemical synthesis. For example, 6-gingerdiol can be obtained by reducing the C3 carbonyl group of the side chain of 6-gingerol, using 6-gingerol as the starting material.

[0024] Furthermore, 6-gingerdiol can also be obtained by extraction and isolation from natural products (extraction method). When extracting 6-gingerdiol from natural products, the whole or a part of the plant containing it (e.g., whole plant, leaves, roots, rhizomes, stems, root bark, or flowers) is used as is, or it is extracted using a lightly processed product (e.g., dried, cut, or powdered) (e.g., crude drug).

[0025] In this invention, the rhizome of ginger (Zingiber officinale), a perennial herb of the Zingiberaceae family native to tropical Asia, can be used as a natural product. Raw materials for obtaining the extract include fresh ginger, dried ginger, and processed products thereof. However, since the production of 6-gingerdiol is easily inhibited when dried (drying causes dehydration of 6-gingerol to produce 6-shogaol), it is preferable to use fresh ginger as the raw material. For example, the pulp remaining after extracting juice for use in beverages can be preferably used. In particular, this pulp is a resource that would otherwise be discarded, and its effective utilization can be achieved.

[0026] Methods for extracting ginger include organic solvent extraction, mixed solvent extraction with organic solvent and water, and supercritical fluid extraction. Examples of organic solvents include nitrous oxide, acetone, ethanol, ethyl methyl ketone, glycerin, ethyl acetate, methyl acetate, diethyl ether, cyclohexane, dichloromethane, edible oils and fats, 1,1,2-tetrafluoroethane, 1,1,2-trichloroethene, carbon dioxide, 1-butanol, 2-butanol, butane, 1-propanol, 2-propanol, propane, propylene glycol, n-hexane, water, and methanol. Among these, n-hexane, which is approved for use in the production of oils and fats, is preferred as an extraction solvent for the low-temperature extraction from ginger pulp described later.

[0027] In the extraction method described above, 6-gingerdiol is preferably separated from the ginger extract by a solid-phase adsorbent. Silica gel is preferred as the solid-phase adsorbent, and commercially available silica gel can be used. The average particle size of the silica gel can be, for example, 5 μm to 500 μm.

[0028] When performing silica gel column chromatography, any solvent can be used as the elution solvent, as long as the solvents do not separate from each other and do not irreversibly adsorb to the silica gel. Examples of elution solvents include n-hexane, acetone, ethanol, ethyl methyl ketone, ethyl acetate, diethyl ether, and cyclohexane. A single elution solvent may be used, or a mixed solvent of two or more solvents may be used.

[0029] An example of a procedure for separating 6-zingerdiol from ginger extract by silica gel column chromatography is shown below. After subjecting the ginger extract to silica gel column chromatography, it is first eluted with n-hexane only (100% n-hexane) for a predetermined time. Then, it is eluted with a mixed solvent consisting of n-hexane and acetone (the ratio of the mixed solvents is by volume, for example n-hexane:acetone = (98:2 to 70:30), n-hexane:acetone = (98:2 to 80:20) is preferred, and (98:2 to 85:15) is more preferred) for a predetermined time. Finally, 6-zingerdiol can be obtained by eluting with a mixed solvent consisting of acetone and ethanol (the ratio of the mixed solvents is by volume, for example acetone:ethanol = (80:20 to 20:80), acetone:ethanol = (70:30 to 30:70)) for a predetermined time.

[0030] In elution using a mixed solvent, gradient elution may be performed by gradually or continuously increasing the proportion of the highly polar solvent. As described above, by gradually or continuously increasing the polarity of the elution solvent, the main components contained in the ginger extract (various gingerols, various shogaols, terpene compounds, etc.) can be separated from 6-zingerdiol. 6-zingerdiol is a compound that is more polar than these main components.

[0031] Furthermore, when obtaining 6-zingerdiol by extraction, it is also acceptable to use 6-zingerdiol that is not in an isolated or purified state (crude extract).

[0032] The neurite extension promoter of the present invention may contain components found in ginger in addition to 6-gingerdiol. Examples of ginger components other than 6-gingerdiol include 6-gingerol, 8-gingerol, 10-gingerol, 1-dehydro-6-gingerdione, and 6-gingerdione. These components may also be ginger-derived components. For example, if 6-gingerdiol is obtained by extraction, the neurite extension promoter of the present invention may contain other ginger-derived components in addition to 6-gingerdiol.

[0033] On the other hand, from the perspective of potential damage to nerve cells, it is preferable that neurite extension promoters do not contain gingerols (e.g., 6-gingerol) as components found in ginger. Gingerols include 6-gingerol, 8-gingerol, and 10-gingerol.

[0034] As one form of neurite extension promoter, 6-gingerdiol includes the (3R,5S) and (3S,5S) stereoisomers at the C3 and C5 positions of the side chain. In this form, the total mol% of the (3R,5S) and (3S,5S) isomers is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 80 mol% or more, relative to the total number of moles of 6-gingerdiol (100 mol%).

[0035] Furthermore, the neurite extension promoter may contain one of the stereoisomers of 6-gingerdiol, either the (3R,5S) or (3S,5S) isomer.

[0036] The neurite extension promoting agent of the present invention can be manufactured, for example, by following the extraction method described above. Specifically, it is obtained by eluting and separating a ginger extract obtained from the rhizome of ginger using silica gel column chromatography, concentrating a predetermined fraction, and removing the solvent. The obtained fraction can be used as is. Alternatively, it may be diluted in an appropriate solvent before use, or it may be processed into a powder using an adsorbent material or into a paste before use.

[0037] The neurite extension promoting agent of the present invention can be used as a pharmaceutical or food, or as an ingredient to be incorporated into pharmaceuticals or foods. As a food, it can be used as a health functional food (food for specified health uses, food with functional claims, food with nutritional function claims) that claims or labels the prevention and improvement of neurodegenerative diseases, dementia, etc., as well as the improvement of memory and learning function.

[0038] Examples of foods in which the neurite extension promoter of the present invention can be used include various foods such as bread, cakes, noodles, confectionery, jellies, frozen foods, ice cream, dairy products, and beverages. To prepare various forms of food, the neurite extension promoter of the present invention can be used alone or in appropriate combination with other food ingredients, solvents, softeners, oils, emulsifiers, preservatives, flavorings, stabilizers, colorants, antioxidants, humectants, thickeners, etc.

[0039] As shown in the examples described below, 6-gingerdiol is useful as a drug because it has an effect of promoting neurite extension. Specifically, it can be used as a preventive and therapeutic agent for neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS).

[0040] Drugs containing 6-gingerdiol as the active ingredient can be administered in a manner that suits their intended use, with appropriate determination of dosage form and dosage. While not particularly limited, the dosage form of the drug may include external preparations such as liquids, lotions, emulsions, ointments, and creams; oral preparations such as tablets, liquids, and powders; and injectable preparations. The above drugs are manufactured using known manufacturing methods commonly used in the pharmaceutical field. These drugs may be appropriately compounded with excipients, binders, disintegrants, lubricants, surfactants, sweeteners, suspending agents, emulsifiers, preservatives, colorants, fragrances, flavoring agents, viscosity modifiers, and stabilizers, as needed.

[0041] Furthermore, the neurite extension promoter of the present invention can also be used as a reagent for neuronal cell differentiation. As shown in the examples described below, differentiation of rat adrenal medulla pheochromoma-derived PC12 cells into neurons can be effectively promoted by using the neurite extension promoter without adding NGF (nerve growth factor). [Examples]

[0042] As the ginger raw material, ginger pulp (moisture content approximately 75% by mass) left over after juicing was prepared. 60 kg of this pulp was frozen to below -10°C. Approximately twice the volume of n-hexane (extraction solvent) was added to this frozen raw material, and after stirring and crushing, it was immersed at below 0°C for 15 minutes. Subsequently, the n-hexane solution (layer) was recovered, and the n-hexane was removed at a temperature below room temperature using a centrifugal thin-film concentrate and a vacuum distillation apparatus. The resulting ginger extract was a brown, transparent, oil-soluble liquid with a refreshing aroma similar to that of grated ginger and the characteristic pungent components of ginger.

[0043] The components of the obtained ginger extract were analyzed by high-performance liquid chromatography (HPLC). The HPLC measurement conditions were as follows: the column was Wakosil II-5C18HG φ4.6 mm × 250 mm, the mobile phase was hydrated acetonitrile, and the spectroscopy was performed using a gradient from 30% acetonitrile to 90% acetonitrile (0-20 min), followed by a gradient from 90% acetonitrile to 30% acetonitrile (20-40 min). A 228 nm ultraviolet absorbance detector (column temperature 40°C) was used. The mobile phase flow rate was 0.8 mL / min. The results of the above HPLC are shown in Figure 1.

[0044] As shown in Figure 1, the ginger extract contains, as its main components, 6-gingerol (a pungent component), neral (a monoterpene), geranial (an isomer of neral), 8-gingerol, 6-shogaol, 10-gingerol, and zingiberene. These components make up the majority of the components in the ginger extract.

[0045] Next, to separate the components of the ginger extract, preparative extraction was performed using a silica gel open column (manufactured by Sogo Rikagaku Glass Manufacturing Co., Ltd., φ20 × 300 mm). As the eluent, we started with n-hexane alone, then switched to a mixed solvent of n-hexane and acetone, gradually increasing the acetone ratio to increase the polarity of the mixed solvent, and then eluted with a mixed solvent of acetone and ethanol, and finally eluted the ginger extract with ethanol alone. We collected a total of 7 fractions by taking samples for each elution solvent. Details of the elution conditions are shown in Table 1.

[0046] [Table 1]

[0047] The above ginger extract (GHE) was subjected to a silica gel column equilibrated with n-hexane. As shown in Table 1, fraction 1 was collected by eluting with n-hexane alone, fraction 2 was collected by eluting with n-hexane:acetone = (96:4), fraction 3 was collected by eluting with n-hexane:acetone = (93:7), fraction 4 was collected by eluting with n-hexane:acetone = (88:12), fraction 5 was collected by eluting with n-hexane:acetone = (85:15), fraction 6 was collected by eluting with acetone:ethanol = (50:50), and fraction 7 was collected by eluting with ethanol alone. Each of the obtained fractions was concentrated to obtain test fractions.

[0048] Each of the fractions obtained above (Fractions 1 to 7) was used to treat PC12 cells derived from adrenal medullary pheochromoma, which is considered a model of nerve cells, and neurite extension was evaluated.

[0049] <Culture of PC12 cells derived from rat adrenal medullary pheochromoma> PC12 cells were cultured in 8-well multiwell plates (ibidi) coated with Collagen IV (Corning). Pre-culture was performed in DMEM Low Glucose medium containing 10% horse serum, 5% calf serum, 50 units / mL penicillin, and 50 μg / mL streptomycin, in a humidified incubator at 37°C and 5% CO2 for 24 hours. Differentiation induction into nerve cells was initiated by replacing the medium with DMEM Low Glucose medium containing 1% horse serum, 50 units / mL penicillin, and 50 μg / mL streptomycin. Each fraction obtained from ginger extract was suspended in the medium and administered at the start of induction. Each fraction was added at a final concentration of 10 ug / mL and cultured for 7 days at 37°C and 5% CO2. NGF (10 ng / mL) stimulation was used as a positive control.

[0050] <Measurement of the number of PC12 cells showing neurite outgrowth> Cells whose neurites had grown longer than their cell length were considered to have undergone induced differentiation into nerve cells (Reference: PLoS One, 2011, 6(11), e28280). Actual measurements were performed using ImageJ image analysis software (National Institutes of Health, USA). The degree of differentiation induction was calculated as the percentage of cells showing neurite extension relative to the total number of cells in the captured field of view. Figure 2(a) shows the captured images for each fraction, and Figure 2(b) shows the percentage of cells showing neurite extension in each fraction.

[0051] As shown in Figure 2, fraction 6 (eluted with acetone:ethanol = (50:50)) showed a neurite elongation promoting effect. On the other hand, no neurite elongation promoting effect was observed in the remaining fractions. In the case of NGF stimulation, which is the positive control, neurite elongation was observed.

[0052] Next, fraction 6 was further analyzed. To subdivide fraction 6, fractions 6A, 6B, 6C, and 6D were obtained by eluting with acetone:ethanol = (50:50) in that order. Each of these fractions was concentrated to obtain the test fractions.

[0053] The neurite extension promoting effect was evaluated using each fraction obtained above (fractions 6A to 6D). The culture of PC12 cells and the calculation of the percentage of PC12 cells showing neurite extension were performed using the method described above. Figure 3(a) shows the images of each fraction, and Figure 3(b) shows the percentage of cells showing neurite extension in each fraction.

[0054] As shown in Figure 3, a significant effect of promoting neurite extension was observed only in fraction 6B.

[0055] The mechanisms by which neurite elongation is promoted include pathways mediated by NGF receptors, activation of Protein kinase A or Protein kinase C due to increased intracellular cAMP, and ultimately, induction of the expression of nerve cell-specific genes through activation by phosphorylation of the transcription regulator cyclic AMP response element-binding protein (CREB) (see references above). The results in Figure 3 suggest that the components in fraction 6B promote neurite elongation by activating these factors.

[0056] Furthermore, the yield of fraction 6B was approximately 7% of the amount of ginger extract subjected to silica gel column. In addition, the fraction treated with activated carbon from fraction 6B was less than 1 / 10, and the yield of this decolorized fraction 6B was approximately 0.4% of the total.

[0057] As shown in Figure 4, specific peaks Pa and Pb were detected around RT15-16 min and RT29-30 min in HPLC of fraction 6B. These peaks were not detected in the other fractions. Identification of the components of the specific peaks in fraction 6B revealed that peak Pa is 6-gingerdiol and peak Pb is 10-shogaol. Furthermore, thin-layer chromatography (TLC) analysis of fraction 6B confirmed the presence of a compound with lower polarity than curcumin, and since this compound was an antioxidant compound with radical scavenging ability, it is thought to be 10-shogaol.

[0058] LC / MS analysis was performed on fraction 6B under the following conditions. <Liquid chromatography conditions> Analytical column: TSKgel ODS-100V (2mm id × 75mm, 3μm) Column temperature: 40℃ Mobile phase: Aqueous methanol (10% methanol to 100% methanol gradient (0-10 min)) Flow rate: 0.2mL / min Detection wavelengths: 210nm, 254nm, 280nm

[0059] As shown in Figure 5, the 6-zingerdiol contained in fraction 6B was a mixture of the (3R,5S) and (3S,5S) isomers, with the peak at RT8.97 being the (3R,5S) isomer and the peak at RT9.13 being the (3S,5S) isomer. This analytical result was consistent with the result obtained for 6-zingerdiol prepared chemically from 6-gingerol (see Figure 6).

[0060] Furthermore, the elongation of neurites in PC12 cells was evaluated using chemically synthesized 6-gingerdiol and 6-gingerol in the same manner as described above. These compounds were added at a final concentration of 10 ug / mL, and the cells were cultured at 37°C under 5% CO2 for 7 days. Images of the cultured PC12 cells are shown in Figure 7. From Figure 7, neurite elongation was observed in many cells with 6-gingerdiol. On the other hand, no neurite elongation promoting effect was observed with 6-gingerol.

[0061] The above test results revealed that 6-gingerdiol, a rare component found in ginger, exhibits an effect that promotes the extension of nerve cells.

[0062] <Detection of Map2 protein by immunofluorescence staining> Next, in the above experiment using PC12 cells, we detected the Map2 protein to confirm that the PC12 cells had differentiated into nerve cells. The Map2 protein is a microtubule-associated protein that controls structural stability and is abundant in vertebrate nerve cells. In mature nerve cells, it is specifically localized to the dendrites and cell body, and is therefore used as a marker for these areas.

[0063] Using fraction 6B or 6-gingerdiol, PC12 cells were cultured at 37°C under 5% CO2 for 7 days, following the same procedure as in the above test. The cells were then fixed with 4% paraformaldehyde solution. After blocking the cell specimens, the expressed Map2 protein was primarily detected with a Map2 antibody, followed by detection with a secondary antibody (red-violet). The nuclei were then counterstained with DAPI (blue). After mounting the specimens with an anti-bleaching agent, the cells were observed under a fluorescence microscope and images were taken (see Figure 8).

[0064] As a result, in PC12 cells, fraction 6B and 6-gingerdiol increased the expression of Map2 protein, indicating that 6-gingerdiol actually promotes differentiation into nerve cells.

[0065] <Learning test using zebrafish> Next, an active avoidance test was conducted as a learning test using zebrafish as the test animals. This test used the apparatus shown in Figure 9. The apparatus consists of a tank divided into two areas, A1 and A2. These two areas are connected by a passageway, allowing the zebrafish to move freely between them. Green or white LEDs are installed on both sides of the tank, illuminating each area. The apparatus is also configured to apply electrical stimulation to each area separately.

[0066] First, we defined the following steps 1-3 as "one cycle". 1. Turn on the green LED for 1.12 seconds (light stimulation only). 2. Apply electrical stimulation to the area where the green LED is lit for 12 seconds, while leaving the area where the white LED is lit unstimulated (the green LED remains lit). 3. Light both LEDs white for 12 seconds (light stimulation only).

[0067] Furthermore, the above cycle was repeated 10 times, followed by a 15-minute interval (period of no stimulation), which was defined as "1 trial," and 5 such trials were conducted. Through the repeated execution of this series of operations, the zebrafish learned to avoid the next electrical stimulus (green) at the stage of light stimulation, that is, to move to the other area before the electrical stimulus. In the experiment, the avoidance rate was calculated as [(number of avoidances) / (number of trials)] × 100, and the learning function was evaluated based on this avoidance rate. Specifically, each zebrafish underwent a total of 50 trials, and the number of avoidances was divided by 50 and multiplied by 100 to obtain the avoidance rate. The number of trials was n=8 to 10 fish.

[0068] 6-Gingerdiol was administered intraperitoneally at a dose of 12.5 mg / kg BW for three doses, every two days. The above test was performed on the start day (S) and one week later (day 7). The avoidance rate at one week later was calculated, with the avoidance rate at the start day set to 100. The results are shown in Figure 10.

[0069] As shown in Figure 10, the evasion rate significantly improved when 6-gingerdiol was administered. It is thought that the learning function of zebrafish was actually improved by the neurite extension-promoting effect of 6-gingerdiol.

[0070] Although the zebrafish brain is simpler than that of other vertebrates, its basic structure is considered to be very similar, sharing features with mammals such as the distinction between the forebrain, midbrain, and hindbrain, and the fact that the hindbrain consists of a series of segments. These results suggest that the improvement in learning function by 6-zingerdiol can also be expected in humans. [Industrial applicability]

[0071] The neurite extension promoter of the present invention, by containing 6-gingerdiol, has the effect of promoting the extension of neurites in nerve cells, and can therefore be effectively used for the prevention and / or treatment of neurodegenerative diseases. Furthermore, since 6-gingerdiol is a component found in ginger, it is highly safe and useful as a new neurite extension promoter.

Claims

1. A neurite extension promoting agent characterized by containing 6-zingerdiol as an active ingredient.

2. The neurite extension promoting agent according to claim 1 is characterized in that it contains components found in ginger in addition to 6-gingerdiol.

3. The neurite extension promoter according to claim 1 or 2, characterized in that the 6-gingerdiol contained in the neurite extension promoter is derived from ginger extract.

4. The neurite extension promoter according to claim 1 or 2, characterized in that the 6-zingerdiol comprises stereoisomers at the C3 and C5 positions of the side chain, namely the (3R,5S) and (3S,5S) forms.

5. A method for producing a neurite extension promoting agent, A method for producing a neurite extension promoter, characterized in that the neurite extension promoter contains 6-gingerdiol derived from ginger extract as an active ingredient, and the 6-gingerdiol is obtained by extracting the ginger extract using n-hexane, and then eluting the ginger extract with a mixed solvent of acetone and ethanol by silica gel column chromatography.

Images