Osteoclast differentiation inhibitor and method for inhibiting differentiation of osteoclast precursors into osteoclasts in vitro

Abstract

To provide a novel osteoclast differentiation inhibitor.SOLUTION: The osteoclast differentiation inhibitor comprises a compound represented by the general formula (I) in the figure, or a pharmaceutically acceptable salt, glycoside or ester thereof: (In the formula, R1, R2 and R3 are the same or different and each represent a linear or branched alkyl group having 1 to 6 carbon atoms, and m represents 0, 1, or 2.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present specification relates to an inhibitor of osteoclast differentiation and a method for inhibiting the differentiation of osteoclast precursor cells into osteoclasts in vitro. [Background technology]

[0002] Bones are constantly undergoing metabolism. In other words, bone resorption, in which osteoclasts destroy old bone, and bone formation, in which osteoblasts form new bone, are repeated, and this is called bone metabolism. When the rate of bone resorption increases with menopause and aging, osteoporosis is more likely to develop. Osteoporosis is a disease in which bone density and bone strength decrease, making bones more likely to break, and the risk of fracture increases as the disease progresses. In particular, fractures of the femur require hospitalization or nursing care, which may lead to a shortened healthy lifespan. Therefore, in order to extend healthy lifespan, it is important to prevent the progression of bone resorption, prevent the onset of osteoporosis, and suppress the progression of symptoms (Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2023-48160 [Patent Document 2] JP 2020-142993 A [Patent Document 3] JP 2020-045313 A [Patent Document 4] JP 2010-215607 A [Patent Document 5] JP 2009-167174 A Summary of the Invention [Problem to be solved by the invention]

[0004] As a drug that inhibits the progression of bone resorption, bisphosphonate preparations that suppress the excessive formation of osteoclasts are mainly used (Patent Documents 3 and 5). In addition, the use of anti-RANKL neutralizing antibodies (denosumab) that inhibit differentiation into osteoclasts has been increasing in recent years (Patent Document 3). However, these cannot be prescribed for the purpose of preventing the onset of osteoporosis. On the other hand, foods for specified health uses and foods with functional claims that are "useful for maintaining bone health" are being sold with the aim of preventing the onset of osteoporosis. The functional ingredients of many of these are nutrients necessary for bone formation, such as calcium, vitamin D, and vitamin K (Patent Documents 1, 2, 5), and the only functional ingredient that targets bone resorption is soy isoflavone, which suppresses the excessive formation of osteoclasts. Therefore, there is a need for novel inhibitors of osteoclast differentiation to prevent the onset of osteoporosis. An object of the present invention is to provide a novel agent for inhibiting osteoclast differentiation. [Means for solving the problem]

[0005] The present invention may include the following embodiments. Section 1. An osteoclast differentiation inhibitor comprising a compound represented by the following general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof: [ka] (In the formula, R 1 , R 2 and R 3 are the same or different and represent a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms. m represents 0, 1 or 2. Section 2. Item 2. The osteoclast differentiation inhibitor according to Item 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II): [ka] (R in the formula 1 , R 2 , R3 and m are as above.) Section 3. R 1 , R 2 and R 3 Item 3. The osteoclast differentiation inhibitor according to Item 2, wherein is a methyl group. Section 4. The osteoclast differentiation inhibitor according to any one of items 1 to 3, wherein the compound represented by the general formula (I) is a compound represented by any one of the following formulae (1) to (3): [ka] , [ka] , [ka] . Section 5. Item 5. The osteoclast differentiation inhibitor according to any one of Items 1 to 4, which is for use in pharmaceuticals, or foods and beverages. Section 6. The present invention relates to a method for treating osteoclasts comprising contacting osteoclast precursor cells with RANKL in the presence of a compound represented by the following general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof: Methods for inhibiting osteoclast differentiation from osteoclast precursor cells in vitro: [ka] (In the ceremony R 1 , R 2 and R 3 are the same or different and represent a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms. m represents 0, 1 or 2. Effect of the Invention

[0006] It is possible to provide a new agent for inhibiting osteoclast differentiation. [Brief description of the drawings]

[0007] [Figure 1-1] The structure of a flavone having a methoxy group used in the examples is shown below. [Figure 1-2] The structure of a flavone having a methoxy group used in the examples is shown below. [Figure 1-3] The structure of a flavone having a methoxy group used in the examples is shown below. [Diagram 2] 4 shows the inhibitory effect of TML on osteoclast differentiation. [Figure 3-1] (A) shows the inhibitory effect of various tetramethoxyflavones on osteoclast differentiation when added to the medium at a final concentration of 10 μmol / L. (B) shows the inhibitory effect of Nobiletin and Tangeretin on osteoclast differentiation when added to the medium at a final concentration of 10 μmol / L. [Figure 3-2] (A) shows the inhibitory effect on osteoclast differentiation when various trimethoxyflavones were added to the medium at a final concentration of 10 μmol / L. (B) shows the inhibitory effect on osteoclast differentiation when various dimethoxyflavones were added to the medium at a final concentration of 10 μmol / L. [Figure 4] The expression of osteoclast differentiation marker genes in the presence and absence of TML is shown. [Diagram 5] 4 shows bone density in the femurs of mice administered TML. [Figure 6] 1 shows bone density at various sites in the femur of mice administered TML. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1. Osteoclast differentiation inhibitors Certain embodiments relate to agents that inhibit osteoclast differentiation. The osteoclast differentiation inhibitor includes a compound represented by the following general formula (I), or a pharma- ceutically acceptable salt, glycoside, or ester thereof: [ka] (In the formula, R 1 , R2 and R 3 are the same or different and each represents a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms. m represents 0, 1 or 2.

[0009] Preferably, R 1 , R 2 and R 3 are the same or different and represent a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms. As the straight-chain or branched-chain alkyl group, an alkyl group having 1 to 2 carbon atoms is more preferable, and a methyl group is further preferable. Preferably, R 1 , R 2 and R 3 are identical. Preferably, the compound represented by the general formula (I) is a compound represented by the following general formula (II): [ka] (R in the formula 1 , R 2 , R 3 and m are as above.) The compound represented by the general formula (I) is a compound represented by any one of the following formulae (1) to (3): [ka] , [ka] , [ka] .

[0010] Pharmaceutically acceptable salts of the compound represented by general formula (I) include, but are not limited to, sodium salts, potassium salts, magnesium salts, calcium salts, and the like.

[0011] The compound represented by the general formula (I) may contain a pharma- ceutically acceptable glycoside, such as a glycoside of a monosaccharide such as glucose or galactose, or a glycoside of a disaccharide or oligosaccharide.

[0012] The compound represented by formula (I) may contain a pharma- ceutically acceptable ester such as acetate, propionate, phosphate, sulfate, etc. The compounds represented by the above general formula (I) are known compounds.

[0013] The osteoclast differentiation inhibitor may include pharmaceuticals (including those for human use and those for animals), general foods (including beverages), health foods (including foods for specified health uses, foods with nutritional functions, and foods with functional claims), animal feed, etc. Animals may include dogs, cats, rabbits, rats, mice, monkeys, cows, horses, sheep, etc.

[0014] The osteoclast differentiation inhibitor can be prepared by combining it with a suitable carrier or additive for preparation. The carrier or additive used for preparation of the preparation can be various substances commonly used in ordinary medicines depending on the dosage form of the preparation, such as excipients, binders, disintegrants, lubricants, colorants, flavorings, odorants, surfactants, etc.

[0015] When the osteoclast differentiation inhibitor is administered orally (including sublingually), the dosage form is not particularly limited, and examples include tablets, powders, granules, capsules (including hard capsules and soft capsules), liquids, pills, suspensions, jelly preparations, and emulsions. When the osteoclast differentiation inhibitor is administered parenterally, examples of the agent include injections, drip infusions, suppositories, nasal drops, and pulmonary preparations.

[0016] When the osteoclast differentiation inhibitor is prepared in the form of an oral solid preparation such as a tablet, powder, granule, pill, or capsule, the carrier may be, for example, lactose, sucrose, sodium chloride, glucose, urea, starch, calcium carbonate, kaolin, crystalline cellulose, silicic acid, methylcellulose, glycerin, sodium alginate, or gum arabic; simple syrup, glucose liquid, starch liquid, gelatin solution, polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, carboxymethylcellulose, shellac, methylcellulose, ethylcellulose, water, ethanol, or potassium phosphate. Examples of suitable binders that can be used include: binders such as dried starch, sodium alginate, powdered agar, powdered laminaran, sodium bicarbonate, calcium carbonate, polyoxyethylene sorbitan fatty acid esters, sodium lauryl sulfate, stearic acid monoglyceride, starch, and lactose; disintegration inhibitors such as sucrose, stearic acid, cocoa butter, and hydrogenated oil; absorption promoters such as sodium lauryl sulfate; moisturizers such as glycerin and starch; adsorbents such as starch, lactose, kaolin, bentonite, and colloidal silicic acid; and lubricants such as purified talc, stearates, powdered boric acid, and polyethylene glycol.

[0017] Here, tablets include oral tablets (plain tablets, sugar-coated tablets, gelatin-coated tablets, enteric-coated tablets, film-coated tablets, double-layered tablets, multi-layered tablets, etc.), chewable tablets (including those that are taken by chewing in the oral cavity), lozenges (including those that are taken after dissolving in the oral cavity, such as lozenges), sublingual tablets, and buccal tablets.

[0018] When the osteoclast differentiation inhibitor is prepared as a solid oral preparation in the form of a pill, the following carriers can be used: excipients such as glucose, lactose, starch, cocoa butter, hardened vegetable oil, kaolin, talc, etc.; binders such as powdered gum arabic, powdered tragacanth, gelatin, etc.; disintegrants such as laminaran, agar, etc.

[0019] When the osteoclast differentiation inhibitor is prepared as an oral solid formulation in the form of a capsule, the capsule is prepared by mixing the active ingredient with the various carriers exemplified above and filling the mixture into a hard capsule, a soft capsule, or the like.

[0020] When the osteoclast differentiation inhibitor is a liquid, it may be in the form of a liquid, such as an aqueous or oily suspension, solution, syrup, elixir, or drink. The liquid is prepared by a conventional method using a conventional additive. The container in which the liquid is filled is not limited as long as it can be sealed, and may be a glass container, an aluminum container, or a plastic container.

[0021] When the osteoclast differentiation inhibitor is prepared as an injection, the following carriers may be used: diluents such as water, ethyl alcohol, macrogol, propylene glycol, ethoxylated isostearyl alcohol, polyoxylated isostearyl alcohol, polyoxyethylene sorbitan fatty acid esters, etc.; pH adjusters such as sodium citrate, sodium acetate, sodium phosphate, etc.; buffers such as dipotassium phosphate, trisodium phosphate, sodium hydrogen phosphate, sodium citrate, etc.; stabilizers such as sodium pyrosulfite, EDTA, thioglycolic acid, thiolactic acid, etc.; and sugars such as mannitol, inositol, maltose, sucrose, lactose, etc., as molding agents for lyophilization. In this case, glucose or glycerin may be contained in the pharmaceutical preparation in an amount sufficient to adjust the solution to an isotonicity, and conventional solubilizers, pain relievers, local anesthetics, etc. may also be added. By adding these carriers, subcutaneous, intramuscular, and intravenous injections can be prepared by conventional methods.

[0022] When the osteoclast differentiation inhibitor is in the form of an infusion, the compound to be administered can be prepared by dissolving it in an isotonic electrolyte infusion preparation based on physiological saline, Ringer's solution or the like.

[0023] When the osteoclast differentiation inhibitor is a general food or a health functional food, there are no particular limitations on the types thereof, and examples thereof include beverages (e.g., milk drinks, lactic acid bacteria drinks, soft drinks containing fruit juice, carbonated drinks, fruit juice drinks, vegetable drinks, vegetable and fruit drinks, alcoholic drinks, sports drinks, powdered drinks, tea drinks, etc.), frozen desserts (e.g., jellies, bavarois, puddings, etc.), frozen desserts (e.g., ice cream, ice milk, lacto ice cream, sorbet), confectioneries (e.g., cookies, biscuits, rice crackers, candies, chocolates, gums), breads, noodles (e.g., Chinese noodles, pasta, udon, buckwheat, somen), soups (including powdered or solid soups), and seasonings (e.g., dressings, jellies, sauces, mayonnaise-like sauces, and sauces).

[0024] The osteoclast differentiation inhibitor can be administered in a dose of, for example, 0.1 to 3000 mg / kg body weight, preferably 1 to 300 mg / kg body weight per day, calculated as the compound represented by general formula (I), once or in divided doses.

[0025] Inhibiting osteoclast differentiation means inhibiting differentiation of osteoclast precursor cells into osteoclasts in vivo or in vitro. Inhibition means that (i) the differentiation rate into osteoclasts when osteoclast precursor cells are contacted with RANKL (Receptor activator of nuclear factor-κB ligand) and cultured in the presence of a compound represented by general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof is 70% or less, preferably 60% or less, more preferably 50% or less, and even more preferably 30% or less, compared with (ii) the differentiation rate into osteoclasts when osteoclast precursor cells are contacted with RANKL and cultured in the absence of a compound represented by general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof.

[0026] Whether or not osteoclast precursor cells have differentiated into osteoclasts can be determined using as indicators the activity of tartrate-resistant acid phosphatase, the expression level of Nfatc1 gene, and the expression level of Acp5 gene, which are specifically expressed in osteoclasts. Since the activity of tartrate-resistant acid phosphatase, the expression level of Nfatc1 gene, and the expression level of Acp5 gene increase when osteoclast precursor cells differentiate into osteoclasts, the measured value of at least one of these indicators in (i) above is compared with the measured value of at least one of these indicators in (ii) above, and when the measured value in (i) above is 70% or less, preferably 60% or less, more preferably 50% or less, and even more preferably 30% or less of the corresponding measured value in (ii) above, it can be determined that osteoclasts have not differentiated into osteoclasts.

[0027] Osteoclast differentiation inhibitors can be used, in particular, for the prevention of osteoporosis. Prevention can include the prevention of the onset of osteoporosis and the prevention of the progression of osteoporosis that has already developed.

[0028] 2. Method for inhibiting osteoclast differentiation One embodiment relates to a method for inhibiting differentiation of osteoclast precursor cells into osteoclasts in vitro, comprising contacting osteoclast precursor cells with RANKL in the presence of a compound represented by general formula (I) described in 1 above, or a pharma- ceutically acceptable salt, glycoside, or ester thereof (hereinafter simply referred to as the "method").

[0029] Examples of osteoclast precursor cells include macrophage-like cells, such as RAW264 cells and RAW264.7 cells.

[0030] Contact between osteoclast precursor cells and RANKL can be carried out, for example, in a culture plate or culture bottle containing a medium to which fetal bovine serum has been added to give a final concentration of 5% to 15%. RANKL can be added to the medium to a final concentration of about 70 ng / mL to 300 ng / mL depending on the type of osteoclast precursor cells.

[0031] The compound represented by general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof can be added so that the final concentration, calculated as the compound represented by general formula (I), is about 5 μmol / L to 500 μmol / L. The osteoclast precursor cells can be contacted with RANKL, for example, in a CO 2 incubator at 35° C. to 38° C. for about 4 to 6 days. The method for determining whether or not osteoclast precursor cells have differentiated into osteoclasts is as described in 1 above. EXAMPLES

[0032] The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to these examples.

[0033] 1. Materials and Methods (1) Test compound Some of the structures of the compounds used in this experiment are shown in Figures 1-1 to 1-3. The compounds used in this study were Nobiletin and Tangeretin, which are flavones with five or more methoxy groups; 5,7,3',4'-Tetramethoxyflavone (Tetramethoxyluteolin; TML), 3,6,3',4',-Tetramethoxyflavone (3,6,3',4'-TMF), 7,8,3',4'-Tetramethoxyflavone (7,8,3',4'-TMF), 5,6,7,4'-Tetramethoxyflavone (5,6,7,4'-TMF), and 3,5,7,4'-Tetramethoxyflavone (3,5,7,4'-TMF), which are tetramethoxyflavones with four methoxy groups; and 5,7,4'-Trimethoxyflavone (5,7,4'-TriMF), which are trimethoxyflavones with three methoxy groups. (5,6,7-TriMF); dimethoxyflavones with two methoxy groups, 3',4'-dimethoxyflavone (3',4'-DMF), 3,2'-dimethoxyflavone (3,2'-DMF), 5,7-dimethoxyflavone (5,7-DMF), 5,2'-dimethoxyflavone (5,2'-DMF), and 3,6-dimethoxyflavone (3,6-DMF); monomethoxyflavones with one methoxy group, 3-monomethoxyflavone (3-MMF), 5-monomethoxyflavone (5-MMF), and 7-monomethoxyflavone (3-MMF).

[0034] (2) Evaluation of the inhibitory effect of tetramethoxyl luteolin (5,7,3',4'-tetramethoxyflavone, TML) on osteoclast differentiation Mouse macrophage-like cell line RAW264 cells suspended in Minimum Essential Medium α (MEMα) containing 10% fetal bovine serum (FBS) were cultured in a 96-well culture plate at 1.5 × 10 3The cells were seeded at a density of 1000 cells / well. RANKL (Receptor activator of nuclear factor-κB ligand, Oriental Yeast Co., Ltd.) at a final concentration of 140 ng / mL and TML at final concentrations of 0.625, 1.25, 2.5, 5, 10, and 20 μmol / L were added to the medium. For the differentiation control, RANKL at a final concentration of 140 ng / mL and dimethyl sulfoxide (DMSO) at a final concentration of 0.1% were added to the medium. For the non-differentiation control, DMSO at a final concentration of 0.1% was added to the medium. After culturing the cells in each group for 5 days in a 37°C, 5% carbon dioxide incubator, the medium was removed and 0.1 mL of 10% paraformaldehyde solution was added to each well. After leaving the cells for 5 minutes, the 10% paraformaldehyde solution was removed, and the cells were washed twice with 0.5 mol / L acetate buffer (pH 5.2). Then, 50 μL of a substrate solution for tartrate-resistant acid phosphatase, which is specifically expressed in osteoclasts (0.5 mol / L acetate buffer containing 50 mmol / L sodium tartrate, 0.01% naphthol AS-MX phosphate, and 0.06% Fast Red Violet LB salt), was added to each well and incubated at 37°C for several hours. When the osteoclasts were sufficiently stained, the substrate solution was removed, and 0.1 mL of DMSO was added to each well. The absorbance at 540 nm was then measured. A graph was created by setting the absorbance of the differentiation-induced control group as 100%, the absorbance of the non-differentiation-induced control group as 0%, and the absorbance of the TML-treated group as the osteoclast differentiation rate (%).

[0035] (3) Comparison of the inhibitory effects of various methoxyflavones on osteoclast differentiation In the sample treatment group, each test compound was added to the medium so as to have a final concentration of 10 μmol / L.Other than that, the experiment was carried out in the same manner as in (2) above.

[0036] (4) Evaluation of the effect of TML on the expression of osteoclast differentiation marker genes Mouse macrophage-like cell line RAW264 cells suspended in MEMα medium containing 10% FBS were cultured in a 6-well culture plate at 2.0 × 10 5The cells were seeded at a density of 10 ... To measure the transcriptional levels of the Nfatc1 gene, a master regulator of osteoclast differentiation, and the Acp5 gene, which is specifically expressed in osteoclasts, oligonucleotides complementary to the nucleotide sequence of each gene were used as primers. To standardize the amount of cDNA, oligonucleotides complementary to the nucleotide sequence of the Gapdh gene were used as primers. The comparative Ct method was used to quantify cDNA. The expression level of each gene in the non-differentiation control group was set to 1, and a graph was created.

[0037] (5) Evaluation of the effect of TML on femoral bone mineral density in osteoporosis model mice Eight-week-old female C57BL / 6 mice were ovariectomized or sham-operated. After a one-week recovery period, TML suspended in 0.5% (w / v) methylcellulose 400 solution was orally administered to the ovariectomized mice at a rate of 10 mg / kg body weight every other day (OVX+TML group). Mice in the ovariectomized control group (OVX group) and sham-operated group (Sham group) were orally administered 0.5% (w / v) methylcellulose 400 solution. After 90 days of administration (45 administrations in total), the bone mineral density of the femur was measured by DXA. Furthermore, the femur was divided into 20 parts based on the measurement data, and the bone mineral density in each area was graphed to evaluate the site of action of TML in the femur.

[0038] 2.Results (1) Inhibitory effect of TML on osteoclast differentiation As shown in FIG. 2, TML inhibited osteoclast differentiation in a concentration-dependent manner between 1.25 and 20 μmol / L, and when 20 μmol / L TML was added, the differentiation rate of RAW264 cells into osteoclasts was almost 0%. This result indicates that TML has a strong inhibitory effect on the differentiation of osteoclast precursor cells.

[0039] (2) Inhibitory effect of various methoxyflavones on osteoclast differentiation Figure 3-1(A) shows the inhibitory effect on osteoclast differentiation when various tetramethoxyflavones were added to the medium at a final concentration of 10 μmol / L. Of the tetramethoxyflavones, only TML exhibited an inhibitory effect on osteoclast differentiation.

[0040] Figure 3-1(B) shows the inhibitory effect on osteoclast differentiation when Nobiletin and Tangeretin were added to the medium at a final concentration of 10 μmol / L. Both compounds did not exhibit inhibitory effect on osteoclast differentiation.

[0041] Figure 3-2(A) shows the inhibitory effect on osteoclast differentiation when various trimethoxyflavones were added to the medium at a final concentration of 10 μmol / L. 5,7,4'-TMF exhibited an inhibitory effect on osteoclast differentiation by about 50%. 5,6,7-TriMF did not exhibit this effect.

[0042] Figure 3-2(B) shows the inhibitory effect on osteoclast differentiation when various dimethoxyflavones were added to the medium at a final concentration of 10 μmol / L. 5,7-DMF showed a high inhibitory effect on osteoclast differentiation, but other dimethoxyflavones did not show this effect.

[0043] Figure 3-2(C) shows the inhibitory effect on osteoclast differentiation when various monomethoxyflavones were added to the medium at a final concentration of 10 μmol / L. Three types of monomethoxyflavones did not exhibit inhibitory effect on osteoclast differentiation.

[0044] (3) Effect of TML on expression of osteoclast differentiation marker genes As shown in Figure 4, the transcriptional level of Nfatc1 was significantly increased in the differentiation-induced control group (RANKL+) compared to the non-differentiation-induced control group (RANKL-) (****P<0.0001 vs RANKL+). On the other hand, the transcriptional level of Nfatc1 was significantly decreased in the differentiation-induced group treated with TML (RANKL+TML) compared to the RANKL+ (***P<0.001 vs RANKL+). Furthermore, the transcriptional level of Acp5 was significantly increased in the differentiation-induced control group (RANKL+) compared to the non-differentiation-induced control group (RANKL-) (**P<0.01 vs RANKL+). On the other hand, the transcriptional level of Acp5 was significantly decreased in the differentiation-induced group treated with TML (RANKL+TML) compared to the RANKL+ (**P<0.01 vs RANKL+). These results indicate that TML suppresses the osteoclast differentiation-inducing activity of RANKL.

[0045] (4) Effect of TML on femoral bone mineral density Figure 4 shows femoral bone mineral density in the sham, OVX, and OVX+TML groups. The OVX group had a significantly decreased bone mineral density compared to the sham group (***P<0.001 vs. OVX). On the other hand, the decrease in femoral bone mineral density was significantly suppressed in the OVX+TML group compared to the OVX group (*P<0.05 vs. OVX).

[0046] The bone density at each site of the femur of mice administered TML is shown in Figure 5. In Section 14, a significant difference was observed between the OVX group and the OVX+TML group (P<0.0326 vs OVX). These results demonstrated that TML has the effect of suppressing the decrease in femoral bone mineral density induced by OVX in vivo.

Claims

1. An osteoclast differentiation inhibitor comprising a compound represented by the following general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof: 【Chemistry 1】 (In the formula, R １ , R ２ and R ３ are the same or different and each represents a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms. m represents 0, 1 or 2.

2. The osteoclast differentiation inhibitor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II): 【Chemistry 2】 (In the formula R １ , R ２ , R ３ and m are as above.

3. R １ , R ２ and R ３ The osteoclast differentiation inhibitor according to claim 2 , wherein is a methyl group.

4. The osteoclast differentiation inhibitor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by any one of the following formulas (1) to (3): 【Chemistry 3】 、 【Chemistry 4】 、 【Chemistry 5】 。

5. The osteoclast differentiation inhibitor according to claim 1 , which is for use in pharmaceuticals or foods and beverages.

6. The present invention relates to a method for treating osteoclasts comprising contacting osteoclast precursor cells with RANKL in the presence of a compound represented by the following general formula (I) or a pharma- ceutically acceptable salt, glycoside, or ester thereof: Method for inhibiting differentiation of osteoclast precursor cells into osteoclasts in vitro: 【Chemistry 6】 (In the ceremony R １ , R ２ and R ３ are the same or different and each represents a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms. m represents 0, 1 or 2.

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