Sugar ester compound as well as preparation method and application thereof

Abstract

The invention discloses a sugar ester compound as well as a preparation method and application thereof, and belongs to the field of medicinal chemistry. The compound has a structural general formula as shown in a formula (1), R1, R2 and R3 are-CH3 or-(CH2) XCH3, and X is 1-7. The preparation method comprises the following steps: with calyx seu fructus physalis as a raw material, carrying out ethanol extraction, silica gel column chromatography and thin-layer chromatography separation, recrystallization and the like. In-vitro alpha-glucosidase inhibition experiments show that the compound has significant inhibition activity, the IC50 of the physalis alkekengi glycosyl ester B1 is 3.49 + / -0.05 mu g / mL, and the activity is superior to that of acarbose. In an STZ-induced diabetic mouse model, the physalis alkekengi glycoester B1 (30 mg / kg) can significantly reduce fasting blood-glucose to a near-normal level, and the effect is superior to that of a positive control. According to the invention, a series of specific compounds (physalis alkekengi sugar esters B1-B8) with the structural characteristics of the general formula (1) are separated and identified from the physalis alkekengi for the first time, and specific substances with the hypoglycemic efficacy of the physalis alkekengi are defined.

Description

Technical Field

[0001] This invention relates to the field of medicinal chemistry, and in particular to a sugar ester compound, its preparation method, and its application. Background Technology

[0002] Isolating and identifying novel active ingredients from medicinal plants is crucial for elucidating the pharmacodynamic material basis of traditional Chinese medicine and is also an important pathway for discovering entirely new compounds and overcoming the limitations of existing drug structures. The hypoglycemic activity of *Physalis alkekengi* (also known as ground cherry), a plant in the Solanaceae family, has been preliminarily reported in traditional Chinese medicine.

[0003] In existing technologies, research on the hypoglycemic active ingredients of *Physalis alkekengi* mainly focuses on macromolecules or mixtures. For example, Chinese patent document CN117338808A discloses the application of *Physalis alkekengi* polysaccharides in the preparation of products for the prevention and treatment of diseases related to glucose and lipid metabolism. This prior art uses *Physalis alkekengi* as raw material, and obtains a mixture of *Physalis alkekengi* polysaccharides through steps such as water extraction and ethanol precipitation, and confirms that this mixture has the effects of regulating blood sugar, blood lipids, and intestinal flora. However, its active ingredients are a mixture of polysaccharides with unclear chemical structures. This application is the first to isolate and extract physalis ester compounds with specific alkyl substitution structures from *Physalis alkekengi*, and its preparation method and activity are studied for the first time. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention provides a compound represented by Formula 1 and its pharmaceutically acceptable salt, the structure of which is as follows:

[0005] (Equation 1)

[0006] Among them, R1, R2, and R3 are all -CH3 or -(CH2). X CH3, where X is 1 to 7

[0007] A further preferred embodiment has the following structural formula:

[0008] (Equation 2).

[0009] A second aspect of the present invention provides a method for preparing a compound as described in claim 1 or claim 2, the method comprising the following steps:

[0010] S1 involves pulverizing dried Physalis alkekengi and extracting it with an ethanol solution, then evaporating it to dryness to obtain a crude extract.

[0011] S2 The crude extract was initially separated using silica gel column chromatography, and eluted sequentially with petroleum ether, ethyl acetate, methanol and water. The extracts were collected and evaporated to dryness to obtain JP segment sample extract, JE segment sample extract, JM segment sample extract and JW segment sample extract.

[0012] S3. The JM segment sample extract was crudely separated using silica gel column chromatography, and the fraction was recovered under reduced pressure.

[0013] S4 The fractions are detected and separated by thin-layer chromatography, and the same components are combined to obtain components JM-Fr.A, JM-Fr.B, JM-Fr.C, JM-Fr.D, JM-Fr.E, and JM-Fr.F respectively;

[0014] S5 separates the component JM-Fr.C using a silica gel column, detects and separates it by thin-layer chromatography, combines the same components, and purifies it by preparative HPLC or repeatedly recrystallizes it to obtain the compound described in Formula 1 or Formula 2.

[0015] More preferably, in S1, the ethanol solution is a 60%–80% ethanol solution; and the extraction is ultrasonic extraction at room temperature.

[0016] In a further preferred embodiment, in S3, the mobile phase elution for silica gel column chromatography is first gradient elution with dichloromethane-methanol solutions of decreasing concentration, followed by elution with methanol-water solution.

[0017] More preferably, the gradients of the dichloromethane-methanol solution are 7:1 to 5:1, 4:1 to 2:1, and 3:1 to 1:1, respectively; and the gradient of the methanol-water solution is 15:1 to 10:1.

[0018] More preferably, in S5, the elution of the silica gel column chromatography mobile phase is first eluted with a gradient of dichloromethane-methanol solutions of decreasing concentration, and then eluted with methanol; the preparative HPLC purification conditions are: mobile phase methanol-water (70:30 to 90:10, v / v).

[0019] More preferably, the gradients of the dichloromethane-methanol solution are 25:1 to 20:1, 15:1 to 10:1, 10:1 to 8:1, 7:1 to 5:1, 4:1 to 2:1, and 2:1 to 1:1.

[0020] A third aspect of the present invention provides a pharmaceutical composition comprising a compound according to any one of claims 1 to 8, or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable excipient.

[0021] A fourth aspect of the present invention provides the use of the compound as described in claim 1 or 2 in the preparation of a hypoglycemic drug.

[0022] The present invention has the following beneficial effects:

[0023] This invention is the first to isolate and identify a class of trisubstituted glycoester compounds with the general structure shown in formula (1) from Physalis alkekengi, providing novel structural guide compounds for the development of hypoglycemic drugs. Through in vitro α-glucosidase inhibition experiments and an in vivo STZ-induced diabetic mouse model, the significant hypoglycemic activity of this class of compounds was confirmed for the first time. Among them, the in vitro inhibitory activity (IC50) of the preferred compound, syrup glycoester B1, was [missing information]. 50 The concentration of 3.49 ± 0.05 μg / mL was significantly superior to that of the commonly used clinical drug acarbose (IC50). 50 = 23.34 ± 0.26 μg / mL), and was able to lower fasting blood glucose to near-normal levels in animal models. This invention clarifies the structure-activity relationship of this class of compounds, namely, that the fact that the R1, R2, and R3 positions are all straight-chain alkyl groups is the structural basis for their α-glucosidase inhibitory activity and hypoglycemic effect in vivo. Attached Figure Description

[0024] Figure 1 It is the acid syrup ester B1 of the present invention. 1 H nuclear magnetic resonance (H nuclear magnetic resonance) 1 ¹H NMR spectrum.

[0025] Figure 2 It is the acid syrup ester B1 of the present invention. 13 C nuclear magnetic resonance (C10) 13 C NMR spectrum.

[0026] Figure 3 This is the heteronuclear single quantum correlation (HSQC) spectrum of the acid syrup ester B1 of the present invention.

[0027] Figure 4 This is the heteronuclear multibond correlation (HMBC) spectrum of the acid syrup ester B1 of the present invention. Detailed Implementation

[0028] To make the objectives and technical solutions of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0029] Experimental materials, instruments and reagents:

[0030] Physalis Calyx seu Fructus: Purchased in Daqing City, Heilongjiang Province, and identified by Professor Wang Zhenyue of Heilongjiang University of Traditional Chinese Medicine as Physalis Calyx seu Fructus, sample number 20210915. The specimen is currently preserved in the Natural Products Chemistry Research Laboratory of Jinggangshan University, Ji'an City, Jiangxi Province.

[0031] Experimental apparatus:

[0032] Table 1 Experimental Apparatus

[0033]

[0034] Experimental reagents and consumables:

[0035] Table 2 Experimental Reagents and Consumables

[0036]

[0037] Example 1

[0038] This embodiment provides a compound represented by Formula 2, specifically including the following steps:

[0039] S1: Take 10 kg of dried Physalis alkekengi, crush it, and extract it three times with 70% ethanol solution at room temperature using ultrasound. Combine the three extracts and evaporate them to dryness using a rotary evaporator to obtain crude extract.

[0040] S2: The crude extract was initially separated by elution with petroleum ether, ethyl acetate, methanol and water using a chromatographic column with silica gel as the stationary phase. After being dried by rotary evaporation, four corresponding sample extracts were obtained, which were named JP segment, JE segment, JM segment and JW segment sample extracts, respectively.

[0041] S3: The JM segment sample extract was crudely separated by silica gel column chromatography. The mobile phase used was dichloromethane-methanol (gradient of 5:1, 2:1, 1:1) and methanol-water (10:1). One fraction was collected for every 1000 mL, for a total of 90 fractions. The fractions were recovered under reduced pressure and labeled as fractions 1-90.

[0042] S4: The fractions recovered in S3 were analyzed by thin-layer chromatography (TLC), and the same components were combined to obtain JM-Fr.A, JM-Fr.B, JM-Fr.C, JM-Fr.D, JM-Fr.E, and JM-Fr.F.

[0043] S5: JM-Fr.C was separated by silica gel column chromatography using dichloromethane-methanol (gradients of 20:1, 10:1, 8:1, 5:1, 2:1, 1:1) and methanol as the mobile phase. One fraction was collected for every 800 mL of mobile phase and analyzed by thin-layer chromatography. Identical fractions were combined to obtain 12 fractions (JM-Fr.C1~JM-Fr.C12). Fraction JM-Fr.C5 was dissolved in dichloromethane-methanol (10:1, v / v) and allowed to stand at room temperature for 48 hours, resulting in a crystalline precipitate. The precipitate was collected by filtration and washed three times with a small amount of methanol (1 mL) to finally obtain compound syrup ester B1.

[0044] Example 2

[0045] This embodiment follows the same steps as Embodiment 1, except that in step S1, a 60% ethanol solution is used for extraction to obtain compound acid syrup ester B1.

[0046] Example 3

[0047] This embodiment is the same as the steps in Embodiment 1, except that in step S1, an 80% ethanol solution is used for extraction to obtain compound acid syrup ester B1.

[0048] Example 4

[0049] The preparation method in this embodiment differs from that in Example 1 in that: some sample components of the JM-Fr.C5 mother liquor were passed through an ODS column and eluted with a methanol-water (MeOH-H2O) (70:30-90:10, v / v) solvent system. Components at different time points were collected, analyzed by HPLC, and the same components were combined to obtain JM-Fr.C5D1 to JM-Fr.C5D8. Then, JM-Fr.C5D7 was purified by preparative HPLC using methanol-water (78:22, v / v) as the mobile phase to obtain compound acid syrup ester B2 (retention time (t...). R =12.0 min).

[0050] Example 5

[0051] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C5D6 was purified by preparative HPLC using methanol-water (80:20, v / v) as the mobile phase to obtain compound acid syrup ester B3 (t R =18.0 min).

[0052] Example 6

[0053] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C5D4 was purified by preparative HPLC using methanol-water (83:17, v / v) as the mobile phase to obtain compound acid syrup ester B4 (t R =19.0 min).

[0054] Example 7

[0055] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C5D3 was purified by preparative HPLC using methanol-water (83:17, v / v) as the mobile phase to obtain compound acid syrup ester B5 (t R =16.0 min).

[0056] Example 8

[0057] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C5D2 was purified by preparative HPLC using methanol-water (85:15, v / v) as the mobile phase to obtain compound acid syrup ester B6 (t R =16.0 min).

[0058] Example 9

[0059] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C5D2 was purified by preparative HPLC using methanol-water (85:15, v / v) as the mobile phase to obtain compound acid syrup ester B7 (t R =23.0 min).

[0060] Example 10

[0061] The preparation method in this embodiment differs from that in Example 1 in that JM-Fr.C5D1 was purified by preparative HPLC using methanol-water (86:14, v / v) as the mobile phase to obtain compound acid syrup ester B8 (t R =20.0 min).

[0062] Compare with Example 1

[0063] The preparation method of this comparative example differs from that of Example 1 in that: the JM-Fr.C1 fraction was passed through an ODS column and eluted with a methanol-water (MeOH-H2O) (70:30-90:10, v / v) solvent system. Fractions from different time points were collected in 500 ml increments. After HPLC analysis, identical fractions were combined to obtain JM-Fr.C1D1 to JM-Fr.C1D5. Subsequently, JM-Fr.C1D5 was purified by preparative HPLC using methanol-water (50:50, v / v) as the mobile phase to obtain compound acid syrup ester B1' (t... R =30.0min).

[0064] Compare with Example 2

[0065] The preparation method of this comparative example differs from that of Comparative Example 1 in that JM-Fr.C1D4 was purified by preparative HPLC using methanol-water (60:40, v / v) as the mobile phase to obtain compound acid syrup ester B2' (t R =22.0 min).

[0066] Compare with Example 3

[0067] The preparation method of this comparative example differs from that of Comparative Example 1: JM-Fr.C1D3 was purified by preparative HPLC using methanol-water (78:22, v / v) as the mobile phase to obtain compound acid syrup ester B3' (t R =18.0 min).

[0068] Compare with Example 4

[0069] The preparation method of this comparative example differs from that of Comparative Example 1: JM-Fr.C1D1 was purified by preparative HPLC using methanol-water (88:12, v / v) as the mobile phase to obtain compound acid syrup ester B4' (t R =36.0 min).

[0070] The compounds prepared in Examples 1-3 are now being identified:

[0071] For the compounds obtained in Examples 1-3: the [M+Na]⁺ molecular ion peak at m / z 701.3730 (C) was detected by high-resolution electrospray ionization mass spectrometry (HRESIMS). 33 H 58 NaO 14 The theoretical calculated value is 701.3724), and its molecular formula is determined to be C. 33 H 58 O 14 The infrared spectrum is at 3380 cm⁻¹ -1 and 1715 cm -1 Strong absorption peaks are observed at these locations, corresponding to hydroxyl and ester functional groups, respectively.

[0072] Nuclear magnetic resonance (NMR) data showed that this compound contains sucrose and long-chain fatty acid ester structural units. Combined with NMR spectrum analysis, the terminal hydrogen and carbon signals (δ¹⁸O) of the pyranose group were analyzed. C 90.6, CH-1), and the terminal carbon signal of furanylfructose (δ C The presence of sucrose units can be inferred from the 105.9 (C-2′) spectral data. Further confirmation of the sucrose structure was obtained through alkaline hydrolysis and comparison of its spectral data with literature reports.

[0073] Electrospray ionization mass spectrometry (ESIMS), proton NMR (1H NMR), carbon NMR (13C NMR), and hydrogen-hydrogen chemical shift correlation spectra were used. 1 H- 1 Analysis using H COSY, heteronuclear single quantum correlation (HMQC), and heteronuclear multibond correlation (HMBC) spectra identified that the compound contains three n-heptanoyl groups.

[0074] The relevant signals from the HMBC spectrum confirmed the acyl linkage site: H-2 (δ) of pyranose.H 4.80) and the C-1 (δ) of the n-heptanoyl group C 174.8), H-3 (δ) of pyranose H 5.41) and the C-1 (δ) of the n-octanoyl group C 174.4), H-6 (δ) of pyranose H 4.45, 4.22) and the C-1 (δ) of the n-octanoyl group C 175.4) There is a correlation.

[0075] In summary, the structure of this compound is identified as Formula 2, and it is named syrup ester B1:

[0076] (Equation 2).

[0077] Structural analysis revealed that the compounds obtained in Examples 1-3, namely syrup ester B1, and the compounds obtained in Examples 4-10, all share a common structure as shown in Formula (1). The difference between them lies in the different substituents R1, R2, and R3 in the general formula (see Table 3 for details). Therefore, this invention not only provides syrup ester B1, but also confirms a class of glycoester compounds as shown in Formula (1).

[0078] (Equation 1)

[0079] Table 3. Structures of syrup esters B1–B8 and B1'–B4'

[0080]

[0081] Experimental Example 1: Study on α-glucosidase inhibitory activity

[0082] This experiment used 4-nitrophenyl-α-D-glucoside (PNPG) as the reaction substrate to screen compounds isolated from Physalis alkekengi that possess α-glucosidase inhibitory activity. In the presence of α-glucosidase, PNPG hydrolyzes into glucose and p-nitrophenol. p-Nitrophenol exhibits maximum absorption at 405 nm. When a substance inhibiting α-glucosidase activity is present in the reaction system, the amount of p-nitrophenol produced by PNPG hydrolysis decreases, resulting in a corresponding decrease in absorbance.

[0083] Solution preparation:

[0084] (1) 0.1 M hydrochloric acid solution: Take 9 mL of 36%~38% concentrated hydrochloric acid and add it to an appropriate amount of distilled water while stirring. Then dilute it with distilled water to 1 L and shake well.

[0085] (2) 0.1 M PBS buffer solution: Accurately weigh 3.5510 g of anhydrous Na2HPO4 and 3.901 g of anhydrous NaH2PO4 and place them in two beakers respectively. Add 250 mL of distilled water to each beaker to obtain 0.1 M Na2HPO4 solution and 0.1 M NaH2PO4 solution respectively. Then mix the two in a volume ratio (61:39) and adjust the pH to 7 with 0.1 M hydrochloric acid solution to obtain 0.1 M PBS buffer solution for later use.

[0086] (3) Substrate PNPG solution: Accurately weigh 7.5 mg of PNPG solid powder and place it in a 10 mL volumetric flask. Add 0.1 M PBS buffer solution to make up to the volume to obtain a 2.5 mM PNPG solution. Prepare fresh before use.

[0087] (4) α-glucosidase solution: Take the lyophilized enzyme powder (enzyme activity is 69.6 U / mg), first prepare a 10 U / mL α-glucosidase stock solution with 0.1 M PBS buffer solution, and then dilute it with buffer solution to a 0.5 U / mL α-glucosidase solution. Prepare and use immediately.

[0088] (5) Acarbose (positive control) solution: Accurately weigh 10.0 mg of acarbose solid, dissolve it in 10 mL of DMSO, shake well to obtain the mother solution, and use it for later use;

[0089] (6) Termination solution: Accurately weigh 2.1201 g of anhydrous Na2CO3 solid and place it in a 100 mL volumetric flask.

[0090] Dilute with distilled water to obtain a 0.2 M Na₂CO₃ solution;

[0091] (7) Sample solutions: Accurately weigh 7.5 mg of syrup ester B1-syrup ester B8 and syrup ester B1'-syrup ester B4' solid powder respectively and place them in a 10 mL volumetric flask. Add 0.1 M PBS buffer solution to make up to volume to obtain 2.5 mM syrup ester B1-syrup ester B8 and syrup ester B1'-syrup ester B4' solutions respectively. Prepare and use immediately.

[0092] Test method:

[0093] Four groups were set up in this experiment, and the reaction was carried out in 96-well cell culture plates. According to the data in Table 4, PBS buffer solution, α-glucosidase solution, sample solvent (DMSO) and positive control solution or monomeric compound sample solution of different concentrations were accurately transferred, mixed, and incubated at 37°C for 10 min. Then, substrate (PNPG solution) was added, mixed thoroughly, and incubated at 37°C for 20 min. Finally, stop solution was added to terminate the reaction. The absorbance value was measured at a wavelength of 405 nm using an ELISA reader. The α-glucosidase inhibition rate was calculated according to the formula (1), and the obtained data were processed. Then, a scatter plot was drawn using Origin software to calculate IC50. 50 value.

[0094] Table 4 Amount of each reactant added

[0095]

[0096] Formula for calculating α-glucosidase inhibition rate:

[0097] Inhibition rate (%) = [(A k -A kb )-(A s -A sb )] / (A k -A kb Formula (3)*100

[0098] Note A k : Absorbance of blank control; A kb : Absorbance of blank background group; A s : Absorbance of the experimental group; A sb : Absorbance of the experimental background group.

[0099] Experimental results:

[0100] 1. Experimental results of acarbose's inhibitory activity against α-glucosidase

[0101] The positive control stock solution of acarbose was first diluted 1000 times with DMSO, and then diluted twice to obtain six concentrations, namely 3.125, 6.25, 12.5, 25.0, 50.0 and 100.0 μg / mL.

[0102] The inhibition rate corresponding to each concentration was calculated according to the above experimental method, and the half-maximal inhibitory concentration (IC50) of the positive control was calculated. 50 It was 23.34 ± 0.26 μg / mL.

[0103] 2. Determination of the inhibitory activity of compounds syrup esters B1-B8 and B1'-B4' against α-glucosidase.

[0104] Table 5. Results of the assay of the inhibitory activity of syrup esters B1-B8 and B1'-B4' on α-glucosidase.

[0105]

[0106] Results analysis:

[0107] Analysis of the data in Table 5 shows that the compounds syrup esters B1–B8 isolated from Physalis alkekengi all exhibited significant inhibitory activity against α-glucosidase, with IC50 values ​​of [missing data]. 50 The values ​​ranged from 3.49 ± 0.05 μg / mL to 42.22 ± 2.28 μg / mL, significantly superior to the control compounds syrup esters B1' to B4' (IC50). 50 The value ranged from 74.3 ± 4.68 μg / mL to 198.8 ± 8.53 μg / mL.

[0108] Among them, syrup ester B1 showed the best inhibitory effect on α-glucosidase activity (IC50). 50 The concentration was 3.49 ± 0.05 μg / mL, and its activity was approximately the same as that of the positive control group (acarbose, IC50). 50 The concentration was 6.7 times higher than that of 23.34 ± 0.26 μg / mL, demonstrating a more beneficial inhibitory effect. Syrup esters B6–B8 exhibited good inhibitory effects on α-glucosidase activity (IC50). 50 The effective concentrations were 15.05±1.29 μg / mL, 8.67±2.85 μg / mL, and 15.18±0.96 μg / mL, respectively), all of which showed superior activity compared to acarbose.

[0109] Analysis of Table 3 revealed that among the series of compounds (glycoesters B1–B8) where R1, R2, and R3 are all straight-chain alkyl groups, the inhibitory activity initially increased and then decreased with increasing alkyl carbon chain length (C1–C8). When all three substituents were -(CH2)5CH3, the corresponding compound, glycoester B1, reached its peak activity. This indicates that among glycoester structures with different straight-chain alkyl substitutions, the n-hexyl group with 6 carbon atoms exhibits the best inhibitory effect on α-glucosidase activity.

[0110] In contrast, the control compound, syrup ester B1' (R1, R2, and R3 are all -H), showed almost no activity (IC50). 50 The activity was 198.8 ± 8.53 μg / mL. The activities of syrup ester B2' (-Ar aryl substituted) and syrup ester B3' (-CH(CH3)2 branched alkyl substituted) were also much lower than their corresponding straight-chain alkyl analogs, indicating that the straight-chain alkyl structure plays an important role in inhibiting the α-glucosidase activity of the compound. Syrup ester B4' (-(CH2)2 branched alkyl substituted) 10The activity of CH3 and long-chain C11 alkyl groups also decreased significantly, further confirming that too long carbon chains may lead to loss of activity due to steric hindrance or solubility problems.

[0111] In summary, the R1, R2, R3 trisubstituted sugar ester compounds (physalis sugar esters B1-B8) provided by the present invention are a new type of highly efficient α-glucosidase inhibitor. Their high activity depends on the straight-chain alkyl substituents with specific lengths at the R1, R2, and R3 positions. Among them, physalis sugar ester B1 with all three being n-hexyl substituents has the best activity, significantly superior to the existing drug acarbose.

[0112] Test Example 2 Therapeutic effect on streptozotocin (STZ)-induced diabetic mice

[0113] Experimental animals:

[0114] SPF-grade Kunming mice were purchased from Hunan Slack Jingda Experimental Animal Co., Ltd., and the use license number is: SCXK (Xiang) 2019-0004. The mice were housed in a clean animal room, with the feeding temperature at 20-25°C, the relative humidity maintained at 50%-70%, and a 12h light and dark cycle. During the experiment, the animals had free access to water and food. This experiment was approved by the Medical Ethics Committee of Jinggangshan University [No. 11].

[0115] Test methods:

[0116] 1. Establish an STZ-induced diabetic mouse model: The mice were adaptively fed for one week, with free access to food and water during this period. Before model establishment, the mice were fasted for 12 hours without water restriction, and a 1% STZ-sodium citrate buffer solution was intraperitoneally injected at a dose of 50 mg / kg of STZ once a day for 5 consecutive days. After 48 hours of injecting STZ, a 10% sucrose solution was used as the only source of water. After 72 hours, the fasting blood glucose of the mice was measured. If the fasting blood glucose > 11.1 mmol / L, the diabetic mouse model was successfully established.

[0117] 2. Grouping and administration: The diabetic model mice were randomly divided into a model control group, a positive control (acarbose) group (100 mg / kg), a 70% ethanol extract group of Physalis alkekengi (750 mg / kg), a physalis sugar ester B1 group (30 mg / kg) to a physalis sugar ester B8 group (30 mg / kg), and a physalis sugar ester B1' group (30 mg / kg) to a physalis sugar ester B4' group (30 mg / kg), with 5 mice in each group. Another 5 normal mice were used as the blank control group. The blank control group and the model control group were intragastrically administered an equal volume of normal saline, and the remaining groups were administered the corresponding drugs suspended in normal saline according to the dose once a day for 21 consecutive days.

[0118] 3. Index detection:

[0119] (2) Measurement of fasting blood glucose (FBG): Mice were fasted overnight but allowed to drink water. Blood was collected from the orbital bone and then measured with a blood glucose meter (the experiment was conducted to minimize stimulation to the mice). Fasting blood glucose levels were measured and recorded before administration on day 0 and after administration on days 7, 14 and 21.

[0120] Table 6 Fasting blood glucose levels in mice of each group

[0121]

[0122] Results analysis:

[0123] As shown in Table 6, during the 21-day administration period, the fasting blood glucose (FBG) level of the model control mice remained consistently high at 21.5–24.3 mmol / L, indicating the successful establishment of the diabetes model. Both the positive control group (acarbose, 100 mg / kg) and the 70% ethanol extract group of *Physalis alkekengi* (750 mg / kg) showed some hypoglycemic effects, with FBG decreasing to 14.3 mmol / L and 10.6 mmol / L on day 21, respectively. The extract group showed a better hypoglycemic effect, which may be due to the synergistic effect of multiple hypoglycemic components in the extract, resulting in a better hypoglycemic effect.

[0124] In the groups containing syrup esters B1–B8 (30 mg / kg), syrup esters B1 and B5–B7 showed better in vivo hypoglycemic effects. Other compounds (syrup esters B2–B4) showed some hypoglycemic trend, but their effects were limited. In contrast, the control compounds syrup esters B1'–B4' showed no significant difference in FBG levels (18.2–19.9 mmol / L on day 21) between the mice and the model control group throughout the experiment, indicating poor in vivo hypoglycemic effects. The in vivo hypoglycemic effect (FBG value on day 21) was compared with the in vitro α-glucosidase inhibitory activity (IC50). 50 By comparing the values, it can be found that the two structures have similar trends. As the chain length of the straight-chain alkyl substituent increases, the effect first increases and then decreases, indicating that the hypoglycemic mechanism of this type of compound is related to the inhibition of α-glucosidase activity.

[0125] In summary, the syrup ester B1 provided by this invention not only exhibits excellent enzyme inhibitory activity in vitro, but also demonstrates a good hypoglycemic effect in an STZ-induced diabetic mouse model, effectively controlling fasting blood glucose levels in diabetic mice to near-normal levels, with better results than the positive control drug. Based on its chemical structural characteristics, this experimental example further verifies that straight-chain alkyl groups with 1 to 8 carbon atoms (R1, R2, R3) have a better hypoglycemic effect, with straight-chain alkane substitutions with 6 carbon atoms showing the best effect.

[0126] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A compound of Formula 1 and a pharmaceutically acceptable salt thereof, characterized in that, The structure of the compound is as follows: (Equation 1) Among them, R1, R2, and R3 are all -CH3 or -(CH2). X CH3, where X is 1 to 7.

2. A compound represented by Formula 2, characterized in that, Its structural formula is: (Equation 2).

3. A method for preparing a compound as described in claim 1 or claim 2, characterized in that, The preparation method includes the following steps: S1 involves pulverizing dried Physalis alkekengi and extracting it with an ethanol solution, then evaporating it to dryness to obtain a crude extract. S2 The crude extract was initially separated using silica gel column chromatography, and eluted sequentially with petroleum ether, ethyl acetate, methanol and water. The extracts were collected and evaporated to dryness to obtain JP segment sample extract, JE segment sample extract, JM segment sample extract and JW segment sample extract. S3. The JM segment sample extract was crudely separated using silica gel column chromatography, and the fraction was recovered under reduced pressure. S4 The fractions are detected and separated by thin-layer chromatography, and the same components are combined to obtain components JM-Fr.A, JM-Fr.B, JM-Fr.C, JM-Fr.D, JM-Fr.E, and JM-Fr.F respectively; S5 separates the component JM-Fr.C using a silica gel column, detects and separates it by thin-layer chromatography, combines the same components, and purifies it by preparative HPLC or repeatedly recrystallizes it to obtain the compound described in Formula 1 or Formula 2.

4. The preparation method according to claim 3, characterized in that, In S1, the ethanol solution is a 60%–80% ethanol solution; the extraction is ultrasonic extraction at room temperature.

5. The preparation method according to claim 3, characterized in that, In S3, the mobile phase elution for silica gel column chromatography is first gradient elution with dichloromethane-methanol solution of decreasing concentration, followed by elution with methanol-water solution.

6. The preparation method according to claim 5, characterized in that, The gradients of the dichloromethane-methanol solution are 7:1 to 5:1, 4:1 to 2:1, and 3:1 to 1:1, respectively; the gradient of the methanol-water solution is 15:1 to 10:

1.

7. The preparation method according to claim 3, characterized in that, In S5, the elution of the silica gel column chromatography mobile phase is first gradient elution with dichloromethane-methanol solution of decreasing concentration, followed by elution with methanol; the preparative HPLC purification conditions are: mobile phase methanol-water (70:30 to 90:10, v / v).

8. The preparation method according to claim 7, characterized in that, The gradients of the dichloromethane-methanol solution are 25:1 to 20:1, 15:1 to 10:1, 10:1 to 8:1, 7:1 to 5:1, 4:1 to 2:1, and 2:1 to 1:

1.

9. A pharmaceutical composition, characterized in that, The pharmaceutical composition comprises the compound according to any one of claims 1 to 8, or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable excipient.

10. The use of a compound as described in claim 1 or 2 in the preparation of a hypoglycemic drug.

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