Composition for use in treatment or prevention of dementia

Abstract

The present invention pertains to: a composition for use in the treatment or prevention of dementia such as Alzheimer's disease; and a method for treating or preventing dementia.

Description

Composition for use in treating or preventing dementia

[0001] The present invention relates to a composition containing a glycyrrhizinic acid analogue for use in treating or preventing dementia such as Alzheimer's disease.

[0002] In recent years, the number of patients with impaired brain function, including those with cerebral infarction and head trauma, cognitive and memory disorders such as Alzheimer's disease and Parkinson's disease, and depression and anxiety caused by various stresses, has increased and become a social problem in developed countries. Alzheimer's disease is a neurodegenerative disease that accounts for 50-60% of dementia cases. The neuropathological hallmarks of Alzheimer's disease are neurofibrillary degeneration, senile plaques, and massive neuronal loss in the cerebral cortex and hippocampus. Neurofibrillary degeneration occurs when tau protein, a microtubule-associated protein, undergoes hyperphosphorylation to form fibrillary inclusions. Senile plaques are the extracellular accumulation of amyloid beta protein. In Alzheimer's disease, the accumulation of amyloid beta protein accelerates neurofibrillary degeneration, and the fibrillated tau protein inhibits intracellular transport. Furthermore, amyloid beta protein itself has cytotoxic properties, including synaptic dysfunction.

[0003] Currently, there is no cure for Alzheimer's disease, but drugs aimed at improving or suppressing the symptoms have already been reported (for example, Patent Documents 1 and 2).

[0004] With the coming of a super-aging society, there are concerns that the number of dementia patients will increase dramatically, becoming a social problem. Therefore, there is currently a need for research into preventing the onset, improving, and slowing the progression of dementia such as Alzheimer's disease, particularly through intervention in lifestyle habits such as diet.

[0005] Japanese Patent Application Publication No. 2014-009214 Japanese Patent Application Publication No. 2014-101324 Japanese Patent Application Publication No. 2022-025655

[0006] Naoki Yorozu et al., "A literature review on the relationship between the amount of licorice used and the incidence of pseudoaldosteronism," Nitto Medical Journal, Vol. 66, No. 3, 197-202, 2015; D. Classen-Houben et al., "Selective inhibition of 11β-hydroxysteroid dehydrogenase 1 by 18α-glycyrrhetic acid but not 18α-glycyrrhetic acid," Journal of Steroid Biochemistry & Molecular Biology, 113 (2009), 248-252 pp. Sanna et. al. , “11β-hydroxysteroid dehydrogenase inhibition as a new potential therapeutic target for alcohol abuse” Transl. Psychiatry (2016) 6, e760Chengxi Cai et. al. , “Clinical Observation of Magnesium Isoglycyrrhizinate in Treatment of HBV-Related Liver Cirrhosis” Traditional Chinese Medicine, 2016, 5(3), 91-96Yang, et. al. ”A melioration of concanavalin A-induced autoimmune hepatitis by magnetium isoglycyrrhizinate through inhibition of CD4+CD25-CD69+ subset proliferation” Drug Design,Development and Therapy 2016:10WU et. al.”Magnesium isoglycyrrhizinate ameliorates doxorubicin-induced acute cardiac and hepatic toxicity via anti-oxidant and anti-apoptotic mechanisms in mice” EXPERIMENTAL AND THERAPEUTIC MEDICINE 15: 1005-1012, 2018ZOU et. al.” Magnesium isoglycy has hepatoprotective effects in an oxaliplatin-induced model of liver injury” INTERNATIONAL JOURNAL OF MOle cular me 2020 dicine 42: 2020-2030, 2018Tang GH et al.,”Magnesium isoglycyrrhizinate inhibits inflammatory response through STAT3 pathway to protect remnant liver function” World J Gastroenterol 2015 November 21; 21(43): 12370-12380Q. Y. TAN ET AL.”Licorice root extract and magnesium isoglycyrrhizinate protect against triptolide-induced hepatotoxicity via up-regulation of the Nrf2 pathway” DRUG DELIVERY 2018, VOL. 25, NO. 1, 1213-1223Qu Y et. al.,”18a-Glycyrrhizin induces apoptosis and suppresses activation of rat hepatic stellate cells” Med Sci Monit, 2012: 18(1): BR24-32Y.He et. al.,” Protective Effect of Magnesium Isoglycyrrhizinate on Ethanol-Induced Testicular Injuries in Mice” Journal of Biomedical Research,2010,24(2):153-160Wenjiao J et. al.,”Magnesium isoglycyrrhizinate shows hepatoprotective effects in a cyclophosphamide-induced model of hepatic injury” Oncotarget, 2017, Vol. 8, (No. 20), pp: 33252-33264Z.W. Xiao et. al.,”Therapeutic effect ofmagnesiumisoglycyrrhizinate in rats on lung injury induced by paraquat poisoning” European Review for Medical and Pharmacological Sciences 2014; 18: 311-320Xinli H et. al.,”Magnesium isoglycyrrhizinate protects hepatic L02 cells from ischemia / reperfusion induced injury” Int J Clin Exp Pathol 2014;7(8):4755-4764Tee et. al.,”Magnesium Isoglycyrrhizinate Ameliorates Fibrosis and Disrupts TGF-β-Mediated SMAD Pathway in Activated Hepatic Stellate Cell Line LX2” September 2018|Volume 9 Article 1018J. Zheng et al.” Protective effects against and potential mechanisms underlying the effect of magnesium isoglycyrrhizinate in hypoxia-reoxygenation injury in rat liver cells” Genetics and Molecular Research 14 (4): 15453-15461 (2015)Q. Yang, et al.” Magnesium isoglycyrrhizinate ameliorates radiation-induced pulmonary fibrosis by inhibiting fibroblast differentiation via the p38MAPK / Akt / Nox4 pathway” Biomedicine & Pharmacotherapy 115 (2019) 108955HUO et al.,“ Optimal ratio of 18α- and 18β-glycyrrhizic acid for preventing alcoholic Hepatitis in Rats“ MENTAL AND THERAPEUTIC MEDICINE 18: 172-178, 2019Xu et al.,“Comparison of the Exposure of Glycyrrhizin and its Metabolites and the Pseudoaldosteronism after Intravenous Administration of Alpha- and Beta-glycyrrhizin in Rat” Drug Research 13: 620-624,2013Y. Li et al. (2019) Glycyrrhizin, an HMGB1 inhibitor, exhibits neuroprotective effects in rats after lithium-pilicarpine-induced status epilepticus. J. Pharm. Pharmacol. 71, 390-399. W. Liu et al. (2019) Suppressive effects of glycyrrhizic acid against lipopolysaccharide-induced neuroinflammation and cognitive impairment in C57 mice via toll-like receptor 4 signaling pathway. Food Nutr. Res. DOI: 10.29219 / fmr. v63.1516. ,

[0007] An object of the present invention is to provide a novel means that is effective in preventing the onset, ameliorating, and suppressing the progression of dementia such as Alzheimer's disease.

[0008] Under these circumstances, the present inventors have conducted extensive research to develop a composition effective in preventing and treating dementia such as Alzheimer's disease. As a result, they unexpectedly found for the first time that glycyrrhizinic acid analogs strongly inhibit cognitive function decline in a cognitive function test using an animal model. Based on these findings, the present invention was completed. Specifically, the composition of the present invention is used for the treatment or prevention of dementia and contains a glycyrrhizinic acid analog as an active ingredient. The composition of the present invention may be licorice extract itself, a glycyrrhizinic acid analog extracted and purified from licorice, or a pharmaceutically acceptable salt or solvate thereof.

[0009] Glycyrrhizic acid also has isomers based on the configuration of the hydrogen at the 18th position in its molecule. Typically, over 90% of glycyrrhizic acid produced by licorice plants is the 18β form, with a small proportion being the 18α form. While the 18α form shares many of the same physiological activities as the 18β form, its specific anti-inflammatory and anti-allergic activity is higher than that of the 18β form, leading to the development of pharmaceuticals primarily containing the 18α form. Furthermore, the 18α form differs in physical properties from the 18β form; for example, the 18α form does not gel in acidic solutions like the 18β form, making it advantageous for incorporation into relatively acidic cosmetics. Similar to the 18β form, the 18α form has also been confirmed to inhibit cognitive decline. Furthermore, it has been confirmed that the 18α form has a weaker inhibitory effect on 11β-hydroxysteroid dehydrogenase type 2 (hereinafter referred to as "11β-HSD2"), which causes pseudoaldosteronism, due to its metabolites (glycyrrhetinic acid or its sulfate conjugate, glycyrrhetinic acid-3-sulfate ester), compared to the 18β form, and therefore a safer pharmaceutical composition can be provided.

[0010] That is, the present invention includes, but is not limited to, the following inventions.

[0011] 1. A pharmaceutical composition for use in the treatment or prevention of dementia, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharmaceutically acceptable salts and solvates thereof.

[0012] 2. The pharmaceutical composition according to item 1, wherein the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, 18β-glycyrrhizinic acid, and pharmaceutically acceptable salts and solvates thereof.

[0013] 3. The pharmaceutical composition according to the preceding item 1, wherein the inhibitory activity of the glycyrrhizinic acid analog against 11β-hydroxysteroid dehydrogenase type 2 is lower than that of 18β-glycyrrhetinic acid.

[0014] 4. The pharmaceutical composition according to item 1, wherein the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and pharmaceutically acceptable salts and solvates thereof.

[0015] 5. The pharmaceutical composition according to any one of the preceding items 1 to 4, which is administered to a human.

[0016] 6. The pharmaceutical composition according to any one of the preceding items 1 to 5, wherein the dementia is Alzheimer's disease.

[0017] 7. A food composition for use in the treatment or prevention of dementia, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharmaceutically acceptable salts and solvates thereof.

[0018] 8. The food composition according to item 7 above, wherein the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, 18β-glycyrrhizinic acid, and pharmaceutically acceptable salts and solvates thereof.

[0019] 9. The food composition according to item 7 above, wherein the glycyrrhizinic acid analog has a lower inhibitory activity against 11β-hydroxysteroid dehydrogenase type 2 than that of 18β-glycyrrhetinic acid.

[0020] 10. The food composition according to item 7 above, wherein the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and pharmaceutically acceptable salts and solvates thereof.

[0021] 11. The food composition according to any one of the preceding items 7 to 10, which is intended for human ingestion.

[0022] 12. The food composition according to any one of the preceding items 7 to 11, wherein the dementia is Alzheimer's disease.

[0023] 13. A pharmaceutical composition for use in improving intestinal bacterial flora, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and derivatives thereof, and pharmaceutically acceptable salts and solvates thereof.

[0024] 14. A food composition for use in improving intestinal bacterial flora, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharmaceutically acceptable salts and solvates thereof.

[0025] The present invention provides a composition for use in the treatment or prevention of dementia. The composition of the present invention contains glycyrrhizinic acid, which has been used for a long time, as an active ingredient, and is highly safe even when taken over a long period of time at normal doses, making it suitable for use as a therapeutic or preventative drug for dementia. Furthermore, if the active ingredient is 18α-glycyrrhizinic acid, even greater safety can be achieved.

[0026] Comparison of learning and memory ability in a step-through passive avoidance experiment. Accumulation of phosphorylated tau protein in the hippocampus of the brain. Accumulation of amyloid beta in the hippocampus of the brain. Concentration of short-chain fatty acids in the feces of senescence-accelerated mice. Occupancy of intestinal bacterial species in senescence-accelerated mice.

[0027] Embodiments of the present invention are described in detail below. The present invention relates to a composition comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharmaceutically acceptable salts and solvates thereof. In one embodiment, the composition of the present invention is a pharmaceutical composition. In one embodiment, the composition of the present invention is a pharmaceutical composition for use in the treatment or prevention of dementia. In one embodiment, the composition of the present invention is a food composition. In one embodiment, the composition of the present invention is a food composition for use in the treatment or prevention of dementia. The terms "analog" and "derivative" of a compound generally refer to other compounds having a structure similar to that of the compound. However, for convenience in the present invention, an "analog" of a compound also includes the compound itself, and a "derivative" of a compound does not include the compound itself. Examples of derivatization to give glycyrrhizinic acid derivatives include, but are not limited to, the introduction of substituents (hydrocarbon groups, halogen atoms, oxygen-containing functional groups (hydroxyl groups, alkoxy groups, epoxy groups, oxo groups, carboxyl groups, etc.), nitrogen-containing functional groups (unsubstituted or substituted amino groups, cyano groups, etc.), sulfur-containing functional groups (thiol groups, sulfo groups, etc.)), oxidation, reduction, esterification, amidation, isomerization (including stereoisomerization), and sugar chain modification (including removal of sugar chains). Salts and solvates are also included in the derivatives and analogs. In the present invention, these glycyrrhizinic acid analogs may be used alone or in combination of two or more.

[0028] In the present invention, the term "pharmaceutically acceptable salt" of the glycyrrhizinic acid analog refers to a salt of the glycyrrhizinic acid analog that retains the biological properties (including pharmacological activity) of the glycyrrhizinic acid analog and is free from biological or other undesirable properties. When the glycyrrhizinic acid analog is a basic compound, its pharmaceutically acceptable salt can be prepared by the addition of an inorganic or organic acid. Salts derived from inorganic acids include, but are not limited to, salts with hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, etc. Salts derived from organic acids include, but are not limited to, salts with acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, N-acetylcysteine, etc. When the glycyrrhizinic acid analog is an acidic compound, its pharmaceutically acceptable salt can be prepared by the addition of an inorganic or organic base. Salts derived from inorganic bases include, but are not limited to, salts with sodium, potassium, lithium, ammonium, calcium, magnesium, etc. Salts derived from organic bases include, but are not limited to, salts with primary, secondary, and tertiary amines (e.g., isopropylamine, trimethylamine, diethylamine, triethylamine, and tripropylamine), substituted amines (e.g., ethanolamine, lysine, and arginine), cyclic amines (e.g., N-ethylpiperidine and piperidine), etc.

[0029] In the present invention, the glycyrrhizinic acid analogs may be in the form of pharmaceutically acceptable solvates. A "solvate" of a compound refers to a complex having a structure in which a stoichiometric or non-stoichiometric amount of a solvent molecule is added to the compound molecule. Examples of solvents that form solvates include, but are not limited to, water, alcohols (methanol, ethanol, n-propanol, isopropanol, etc.), DMSO, ethyl acetate, etc. A solvate in which the solvent is water is called a "hydrate." A "pharmaceutically acceptable solvate" of a compound refers to a solvate of the compound that retains the biological properties (including pharmacological activity) of the compound and is free from biological or other undesirable properties.

[0030] In the present invention, the glycyrrhizinic acid analog is preferably at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, 18β-glycyrrhizinic acid, and pharmaceutically acceptable salts and solvates thereof. Among these glycyrrhizinic acid analogs, 18β-glycyrrhizinic acid is a major saponin contained in the underground parts of plants of the genus Licorice (Glycyrrhiza uralensis, G. glabra, G. inflata, etc.) of the family Leguminosae, which have long been used as medicines, and is represented by the following formula: It has the structure shown below. The compound that has traditionally simply been referred to as "glycyrrhizinic acid" is usually this 18β-glycyrrhizinic acid. Currently, (18β-)glycyrrhizinic acid extracted and purified from the underground parts of Glycyrrhiza plants is used in pharmaceuticals indicated for anti-inflammatory, anti-allergic, or anti-chronic hepatitis, as well as in quasi-drugs and cosmetics that take advantage of its anti-inflammatory and anti-allergic effects. It is also used as a food additive, taking advantage of its sweetness.

[0031] 18α-glycyrrhizinic acid is one of the stereoisomers of 18β-glycyrrhizinic acid (the configuration of the 18th carbon is reversed), and is represented by the following formula: The saponin obtained from the above-mentioned Glycyrrhiza plants may contain a large amount of 18β-glycyrrhizinic acid as well as a very small amount of 18α-glycyrrhizinic acid. As described below, 18α-glycyrrhizinic acid can be synthesized from 18β-glycyrrhizinic acid.

[0032] 18α-glycyrrhetinic acid has the following formula: 18α-Glycyrrhetinic acid can be prepared by known methods, for example, by heating and hydrolyzing 18α-glycyrrhizinic acid in a strong acid aqueous solution (e.g., hydrochloric acid). 18-α-Glycyrrhetinic acid-3-O-monoglucuronide has the following formula: It has a structure in which one of the two glucuronic acid residues has been removed from 18α-glycyrrhizinic acid, as shown below. 18α-Glycyrrhetinic acid-3-O-monoglucuronide can be prepared by known methods, such as enzymatic hydrolysis of 18α-glycyrrhizinic acid (for example, treating 18α-glycyrrhizinic acid in a culture medium of the fungus Cryptococcus magnus MG-27 strain) (T. Kuramoto et al., Microbial Production of Glycyrrhetic Acid 3-O-Mono-β-D-Glucuronide from Glycyrrhizin by Cryptococcus magnus MG-27, Bioscience, Biotechnology, and Biochemistry (1994), 58:3, 455-458).

[0033] The present inventors have confirmed that glycyrrhizinic acid analogs significantly improve learning and memory ability in a learning and memory test using a passive avoidance experiment. Furthermore, the present inventors have confirmed that glycyrrhizinic acid analogs suppress the accumulation of phosphorylated tau protein and amyloid beta in brain tissue (particularly the hippocampus), which is important in the pathology of Alzheimer's disease. Based on these findings, it has been shown that glycyrrhizinic acid analogs are effective in the treatment and prevention of dementia. Glycyrrhizinic acid analogs (particularly 18β-glycyrrhizinic acid) are known to exhibit various useful pharmacological effects, such as antiallergic and anti-inflammatory effects. The use of this anti-inflammatory effect in the improvement of central nervous system disorders caused by brain injury and / or neuroinflammation is also known (Non-Patent Documents 20 and 21). However, the effectiveness of glycyrrhizinic acid analogs in the treatment and prevention of dementia was first discovered by the present inventors.

[0034] Furthermore, the present inventors have confirmed that glycyrrhizinic acid analogs improve the intestinal flora of patients who have become unfavorable in certain types of dementia. That is, the composition of the present invention containing a glycyrrhizinic acid analog is effective in improving the intestinal flora. In one embodiment, the composition of the present invention is a pharmaceutical composition used for improving the intestinal flora. In one embodiment, the composition of the present invention is a food composition used for improving the intestinal flora.

[0035] One aspect of the present invention provides the glycyrrhizinic acid analog for use in the treatment or prevention of dementia. Another aspect of the present invention provides a pharmaceutical composition comprising the glycyrrhizinic acid analog and a pharmaceutically acceptable carrier and / or a pharmaceutically acceptable excipient. Another aspect of the present invention provides use of the glycyrrhizinic acid analog for the treatment or prevention of dementia. Another aspect of the present invention provides use of the glycyrrhizinic acid analog for the manufacture of a medicament for the treatment or prevention of dementia. Another aspect of the present invention provides a method for the treatment or prevention of dementia, comprising the step of administering the glycyrrhizinic acid analog to a human or animal. The carriers and excipients used to prepare the pharmaceutical composition are not particularly limited, and conventionally known carriers and excipients can be used. The pharmaceutical composition may contain conventionally known additives, such as binders, disintegrants, coating agents, lubricants, preservatives, stabilizers, buffers, surfactants, antioxidants, isotonicity agents, and colorants, if desired.

[0036] In one embodiment of the present invention, the dementia is characterized by accumulation of phosphorylated tau protein and / or amyloid beta in brain tissue (particularly the hippocampus). In one embodiment of the present invention, the dementia is Alzheimer's disease (Alzheimer's type dementia).

[0037] In the present invention, from the viewpoint of safety, it is preferable that the glycyrrhizinic acid analog comprises at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and pharmaceutically acceptable salts and solvates thereof, particularly 18α-glycyrrhizinic acid. 18β-Glycyrrhetinic acid is known to be absorbed in vivo after being metabolized to its aglycone, 18β-glycyrrhetinic acid. 18α-Glycyrrhetinic acid and 18-α-glycyrrhetinic acid-3-O-monoglucuronide are also presumed to be absorbed in vivo after being metabolized to their aglycone, 18α-glycyrrhetinic acid. Both 18α-glycyrrhetinic acid and 18β-glycyrrhetinic acid exhibit inhibitory activity against 11β-HSD2. Pseudoaldosteronism, a known side effect of pharmaceuticals containing licorice ingredients, is caused by this inhibitory activity. The inhibitory activity of 18α-glycyrrhetinic acid is lower than that of 18β-glycyrrhetinic acid. Therefore, the above three glycyrrhizinic acid analogs are safer than 18β-glycyrrhizinic acid in that they are less likely to cause pseudoaldosteronism.

[0038] Pseudoaldosteronism, a side effect of glycyrrhizinic acid analogs, has long been known, and it has been confirmed that the incidence of this side effect correlates with the dose of glycyrrhizinic acid-containing preparations (Non-Patent Document 1). This side effect is primarily caused by 18β-glycyrrhizinic acid (or more precisely, its metabolites), a major saponin found in plants of the genus Glycyrrhiza. The existence of 18α-glycyrrhizinic acid, a stereoisomer of 18β-glycyrrhizinic acid, has long been known, and various reports have been published on the physiological activity and pharmacokinetics of this compound (Non-Patent Documents 2-19). Some of these reports relate to the inhibitory activity against 11β-HSD2 (the cause of pseudoaldosteronism) (Non-Patent Documents 2 and 3). However, because information regarding this inhibitory activity has been inconsistent, the relationship between the stereoconfiguration at the 18th position of glycyrrhizinic acid analogs and their inhibitory activity against 11β-HSD2 was unclear until recently. However, it has recently been confirmed that 18β-glycyrrhetinic acid (the aglycone of 18β-glycyrrhizinic acid) exhibits similar inhibitory activity against both human 11β-HSD2 and rat 11β-HSD2, whereas 18α-glycyrrhetinic acid (the aglycone of 18α-glycyrrhizinic acid) exhibits inhibitory activity against rat 11β-HSD2 equivalent to that of 18β-glycyrrhetinic acid and exhibits higher inhibitory activity against human 11β-HSD2 than 18β-glycyrrhetinic acid (Patent Document 3). Therefore, from the perspective of prioritizing safety, it is clear that the use of 18α-glycyrrhizinic acid is more desirable. In one embodiment of the present invention, the inhibitory activity of a glycyrrhizinic acid analog against 11β-hydroxysteroid dehydrogenase type 2 is lower than that of 18β-glycyrrhetinic acid.

[0039] On the other hand, from the viewpoints of availability and cost, in the present invention, it is preferred that the glycyrrhizinic acid analog comprises at least one selected from the group consisting of 18β-glycyrrhizinic acid and pharmaceutically acceptable salts and solvates thereof, particularly 18β-glycyrrhizinic acid.

[0040] In another embodiment, the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and pharmaceutically acceptable salts and solvates thereof. In another embodiment, the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18β-glycyrrhetinic acid, and pharmaceutically acceptable salts and solvates thereof. In another embodiment, the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, and pharmaceutically acceptable salts and solvates thereof. In another embodiment, the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid and 18β-glycyrrhizinic acid, and pharmaceutically acceptable salts and solvates thereof. In another embodiment, the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid and pharmaceutically acceptable salts and solvates thereof. In another embodiment, the glycyrrhizinic acid analog is at least one selected from the group consisting of 18β-glycyrrhizinic acid and pharmaceutically acceptable salts and solvates thereof.

[0041] The glycyrrhizinic acid analog itself, or a licorice extract containing the same, can also be used in the composition of the present invention. The glycyrrhizinic acid analog used in the present invention can be extracted, isolated, and purified from licorice extract by a conventional method. That is, a purified product with a purity of 70% or more can be obtained by removing fat-soluble coloring components from licorice extract by organic solvent extraction and then purifying the extract using means such as crystallization. On the other hand, when using licorice extract in the composition of the present invention, one extracted from the roots and / or stems of the plant by a conventional method known in the art can be used. Commercially available licorice extracts can also be used in the present invention. The glycyrrhizinic acid analog content of the licorice extract used in the present invention is 5% or more, preferably 10% or more, and more preferably 13% or more.

[0042] The extraction solvent used in producing licorice extract is not particularly limited, and examples that can be used include water, alcohol (e.g., methanol, ethanol, n-propanol, n-butanol, etc.), acetone, ethyl acetate, etc. Furthermore, when obtaining a dry powder of licorice extract, it can be obtained by removing the solvent from the extract using a method commonly used by those skilled in the art, such as vacuum drying or spray drying.

[0043] To produce the above-mentioned 18α-glycyrrhizinic acid from 18β-glycyrrhizinic acid, as described in Patent Publication No. 1610300 (registered July 15, 1990), the raw material 18β-glycyrrhizinic acid is heated to 70-200°C under atmospheric or elevated pressure in a 2-6N aqueous solution of sodium hydroxide or potassium hydroxide. The reaction is terminated when isomerization reaches 60-80%, and the resulting 18α-glycyrrhizinic acid and 18β-glycyrrhizinic acid are then separated. This results in 18α-glycyrrhizinic acid of the desired purity. To isolate 18α-glycyrrhizinic acid from the reaction mixture, the 18α-isomer and the 18β-isomer are first precipitated together with a mineral acid such as sulfuric acid or hydrochloric acid at a pH of 1-2, followed by filtration and subsequent fractionation by column chromatography or other methods. Alternatively, the 18α-isomer can be isolated as follows:

[0044] The glycyrrhizinic acid mixture is diluted to a concentration of approximately 0.5-2%, and mineral acid is added to adjust the pH to approximately 2, followed by filtration through filter paper. In this case, the 18α-isomer is precipitated in crystalline form and remains on the filter paper, while the 18β-isomer separates in a gel-like form and passes through the filter paper, entering the filtrate. Since a significant amount of the 18β-isomer is still present in the precipitate on the filter paper, this is dissolved in dilute aqueous ammonia and then separated again by the same acid precipitation and filtration process. Repeating this process increases the purity of the 18α-isomer, and removal of the 18β-isomer is usually completed after three to five repeated treatments.

[0045] Uses of the composition of the present invention for application to living bodies Examples of uses of the composition of the present invention include pharmaceuticals, quasi-drugs, cosmetics, and foods. The target of application of this composition is preferably humans. In one embodiment, the pharmaceutical composition of the present invention is administered to humans. In one embodiment, the food composition of the present invention is ingested by humans.

[0046] The form of the composition of the present invention is not particularly limited, and the composition can take any commonly used form depending on its intended use. The forms of the pharmaceutical composition of the present invention used as a medicine are broadly divided into forms suitable for oral administration and forms suitable for parenteral administration. Examples of the former include tablets, troches, pills, suspensions (aqueous or oily), powders, granules, emulsions, hard or soft capsules (e.g., gelatin capsules), syrups, elixirs, etc. Examples of the latter include injections, creams, ointments, inhalants, eye drops, nasal drops, suppositories, etc. The pharmaceutical composition of the present invention used as a quasi-drug (including medicated cosmetics) may take the form of various conventionally used cosmetics, such as dentifrice. The food composition of the present invention may take the form of various conventionally used cosmetics.

[0047] The dosage of the glycyrrhizinic acid analog contained in the composition of the present invention is 5 to 120 mg / day / human, preferably 10 to 60 mg / day / human. In this case, the above dosage is divided and administered two to three times a day. When licorice extract is used in the composition of the present invention, the dosage of the glycyrrhizinic acid analog contained therein is adjusted to be the same as above, taking into consideration the content of the glycyrrhizinic acid analog.

[0048] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0049] The method for measuring the dementia prevention effect of the test substance is outlined below. Specifically, 40-week-old SAMP8 mice were used as test animals and bred for 12 weeks. SAMR1 mice were used as a comparison group (control group). SAMP8 mice and SAMR1 mice (both available from Japan SLC Co., Ltd.) are often used in animal experiments on age-related decline in learning and memory ability, with the latter serving as the control. SAMP8 mice are an established senescence-accelerated mouse model that exhibits age-related learning and memory disorders, emotional disorders, etc. earlier than normal mice. SAMR1 mice, derived from the same mouse colony as SAMP8 mice, exhibit a normal aging profile. These mice were divided into experimental and control groups, and the experimental group mice were orally administered 18α-glycyrrhizinic acid or 18β-glycyrrhizinic acid at a dose of 15 mg / kg three times a week. Water and food were provided as usual. The following measurements and tests were performed on these test animals. Furthermore, when the body weights of the SAMP8 mice and SAMR1 mice were measured every four weeks from 40 to 52 weeks of age, the body weight of the SAMP8 mice was clearly lighter than that of the SAMR1 mice. A tendency for weight loss due to aging was observed in the SAMP8 mice. Although no effect of glycyrrhizinic acid administration on the tendency for weight loss due to aging was observed, there was a tendency for weight loss to be alleviated.

[0050] Spontaneous locomotor activity was measured using a locomotor activity measuring device, which quantified the amount of activity using an infrared sensor attached to the bottom of the cage. Each test mouse was placed in a novel environment (without acclimation), and the amount of spontaneous locomotor activity for each mouse was measured for 20 minutes.

[0051] Learning and memory test using passive avoidance experiment As one of the dementia tests, learning and memory abilities were compared using a step-through passive avoidance experiment. When the mice entered the dark compartment, an electric current was applied, allowing them to learn that this behavior was dangerous. One day later, the mice were placed in the lighted compartment and the time spent in the lighted compartment was measured. If learning and memory were established, the mice would avoid entering the dark compartment, and the time spent in the lighted compartment would be extended. The results are shown in Figure 1. In the SAMP8 mouse group not administered glycyrrhizinic acid, learning and memory abilities were reduced, and no difference was observed between the acquisition trial (a test during learning) and the play-back trial (a test based on memory one day later). On the other hand, in the glycyrrhizinic acid-administered groups of SAMP8 mice, both the 18α- and 18β-forms showed a step-through latency time (time spent in the lighted room) that was more than three times longer in the play-back trial than in the control group (P<0.05), demonstrating a significant improvement in learning and memory abilities.

[0052] Amount of accumulated protein in brain tissue (immunostaining) The amount of accumulated protein in brain tissue of SAMP8 mice and SAMR1 mice was compared using a known method using immunostaining. The results are shown in Figures 2 and 3. The accumulation of phosphorylated tau protein (Figure 2) and amyloid beta (Figure 3), which are pathologically important in Alzheimer's disease, in the hippocampus of the brain was suppressed in the 18β-glycyrrhizinic acid-administered group.

[0053] Fecal Short-Chain Fatty Acid Concentration Fecal short-chain fatty acid concentrations were measured for SAMP8 mice using a known method. The results are shown in Figure 4. It is believed that fecal concentrations of certain short-chain fatty acids are reduced in individuals with Alzheimer's disease. Among these short-chain fatty acids, the concentrations of acetic acid and propionic acid were higher in the 18β-glycyrrhizinic acid-administered group than in the 18β-glycyrrhizinic acid-unadministered group.

[0054] Distribution of Intestinal Bacteria Species The distribution of intestinal bacterial species in SAMP8 mice was measured using a known method. The results are shown in Figure 5. In the 18β-glycyrrhizinic acid-administered group, the fecal occupancy rates of intestinal bacteria belonging to the family Coriobacteriaceae, class Alphaproteobacteria, and family Paraprevotellaceae were lower than in the 18β-glycyrrhizinic acid-unadministered group. The fecal occupancy rates of these intestinal bacteria are known to tend to increase in individuals with Alzheimer's disease. On the other hand, in the 18β-glycyrrhizinic acid-administered group, the fecal occupancy rates of intestinal bacteria belonging to the genera Bacteroides and Parabacteroides were higher than in the 18β-glycyrrhizinic acid-unadministered group. The fecal occupancy rates of these intestinal bacteria are known to tend to decrease in individuals with Alzheimer's disease. The family Coriobacteriaceae belongs to the order Coriobacteriales, and includes the genera Collinsella, Coriobacterium, Atopobium, Olsenella, etc. Examples of enterobacteria belonging to this family include Collinsella aerofaciens and Eggerthella lenta. The class Alphaproteobacteria includes the order Hyphomicrobiales and Sphingomonadales. The family Paraprevotellaceae belongs to the order Bacteroidales, and includes the genus Paraprevotella. Examples of enterobacteria belonging to this family include Paraprevotella clara and Paraprevotella xylaniphila. The genus Bacteroides belongs to the family Bacteroidaceae. Examples of enterobacteria belonging to this genus include Bacteroides vulgatus and Bacteroides dorei. The genus Parabacteroides belongs to the family Bacteroidaceae. Examples of enterobacteria belonging to this genus include Parabacteroides distasonis and Parabacteroides merdae.

[0055] The outline of the method for measuring the inhibition of human 11β-hydroxysteroid dehydrogenase type 2 by test substances is as follows. Specifically, 250 μL of 0.1 M phosphate buffer (pH = 6.0) containing rat kidney microsome fraction (final concentration 2 mg / mL), 20 nM 1,2,6,7-[3H]-cortisol (Perkin Elmer, Waltham, MA, USA), 1.2 mM NAD+ (Fujifilm), and various samples was prepared. 25 μL of 0.1 M phosphate buffer (pH = 6.0) containing rat kidney microsome fraction (final concentration 2 mg / mL) or human kidney microsome fraction (Sekisui XenoTech, Kansas City, KA, USA) (final concentration 0.2 mg / mL), 20 nM 1,2,6,7-[3H]-cortisol, 1.2 mM NAD+, and various samples was prepared. Each mixture was incubated at 37°C for 30 minutes, and then 25 µL of methanol containing 1 mg / mL cortisol and 1 mg / mL cortisone (Nacalai Tesque, Kyoto) was added to the reaction solution to terminate the reaction.

[0056] A 20 μL portion of this liquid was spotted onto a thin-layer chromatography plate (Silica Gel 60, Merck, Darmstadt, Germany) and developed over approximately 18 cm with chloroform:methanol (9:1) to separate cortisol and cortisone. The cortisone spot (Rf value approximately 0.43) was detected using a UV lamp, and the stationary phase containing cortisone was scraped and transferred to a vial containing 3 mL of Clear-sol I (Nacalai). Radioactivity was measured using a liquid scintillation counter. Each sample was counted in four samples, and the mean ± standard deviation was used as the data. The IC50 value was calculated as the concentration at which 50% inhibition was observed on a linear approximation of the logarithmic concentration versus inhibition curve, using three points surrounding 50% inhibition.

[0057] In the case of 18β-glycyrrhetinic acid, 50% inhibition was achieved at a concentration of 0.2 to 0.4 μM for both the human-derived and rat-derived enzymes. In contrast, in the case of 18α-glycyrrhetinic acid, 50% inhibition was achieved for the rat-derived enzyme at a concentration similar to that for the 18β form, but for the human-derived enzyme, this concentration was 15.1 μM, approximately 70 times higher, confirming that this compound has little risk of causing pseudoaldosteronism in humans.

[0058] The composition of the present invention containing a glycyrrhizinic acid analogue is useful for preventing the onset or progression of dementia, such as Alzheimer's disease, in animals, particularly humans.

[0059] The disclosure of Japanese Patent Application No. 2023-118834 (filing date: July 21, 2023) is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A pharmaceutical composition for use in the treatment or prevention of dementia, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharma- ceutically acceptable salts and solvates thereof.

2. The pharmaceutical composition according to claim 1, wherein the glycyrrhizinic acid analog is at least one member selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and 18β-glycyrrhizinic acid, as well as pharma-ceutically acceptable salts and solvates thereof.

3. The pharmaceutical composition according to claim 1, wherein the inhibitory activity of the glycyrrhizinic acid analogue against 11β-hydroxysteroid dehydrogenase type 2 is lower than that of 18β-glycyrrhetinic acid.

4. The pharmaceutical composition according to claim 1, wherein the glycyrrhizinic acid analog is at least one member selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and pharma- ceutically acceptable salts and solvates thereof.

5. A pharmaceutical composition according to any one of claims 1 to 4, for administration to humans.

6. The pharmaceutical composition according to any one of claims 1 to 5, wherein the dementia is Alzheimer's disease.

7. A food composition for use in the treatment or prevention of dementia, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharma- ceutically acceptable salts and solvates thereof.

8. The food composition according to claim 7, wherein the glycyrrhizinic acid analog is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and 18β-glycyrrhizinic acid, as well as pharma-ceutically acceptable salts and solvates thereof.

9. The food composition according to claim 7, wherein the inhibitory activity of the glycyrrhizinic acid analogue against 11β-hydroxysteroid dehydrogenase type 2 is lower than that of 18β-glycyrrhetinic acid.

10. The food composition according to claim 7, wherein the glycyrrhizinic acid analogue is at least one selected from the group consisting of 18α-glycyrrhizinic acid, 18α-glycyrrhetinic acid, 18α-glycyrrhetinic acid-3-O-monoglucuronide, and pharma-ceutically acceptable salts and solvates thereof.

11. The food composition according to any one of claims 7 to 10, which is intended for human consumption.

12. The food composition according to any one of claims 7 to 11, wherein the dementia is Alzheimer's disease.

13. A pharmaceutical composition for use in improving intestinal flora, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharma- ceutically acceptable salts and solvates thereof.

14. A food composition for use in improving intestinal flora, comprising at least one glycyrrhizinic acid analog selected from the group consisting of glycyrrhizinic acid and its derivatives, and pharma- ceutically acceptable salts and solvates thereof.

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