An ester-substituted sugar ester compound, and a method for preparing and using the same

Abstract

The application discloses an ester-substituted sugar ester compound, a preparation method and application thereof, and belongs to the technical field of medicinal chemistry. The compound has a structural general formula shown in formula (1), wherein R1, R2 and R3 are all -CH3 or -(CH2) X CH3, and X is 1-7. The application first separates and identifies a class of sugar ester compounds with ester substitution on a sucrose parent nuclear skeleton from Physalis alkekengi L. and establishes a high-efficiency preparation method through steps of ethanol extraction, silica gel column chromatography and preparative high performance liquid chromatography. In vitro alpha-glucosidase inhibition experiments show that the compound has significant inhibition activity, wherein the IC 50 value of Physalis alkekengi L. sugar ester C1 reaches 1.05±0.01 μg / mL, and the activity intensity is significantly better than that of the drug acarbose. In a STZ-induced diabetic mouse model, the fasting blood glucose of the Physalis alkekengi L. sugar ester C1 can be reduced from 23.4 mmol / L to 6.2 mmol / L, and the effect is better than that of a positive control group. It is further revealed that introduction of straight-chain alkyl groups at R1, R2 and R3 positions is a structural basis for the class of compounds to exert hypoglycemic activity.

Description

Technical Field

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

[0002] Physalis alkekengi (Chinese ground cherry), a plant in the Solanaceae family, is a traditional and commonly used Chinese medicinal herb with multiple effects, including clearing heat and detoxifying, relieving sore throat and resolving phlegm. Modern pharmacological studies have shown that its extracts exhibit certain biological activities in anti-inflammatory, antioxidant, and anti-tumor aspects. Currently, studies have isolated polysaccharides, flavonoids, and some esters from Physalis alkekengi, and have conducted preliminary evaluations of the activities of some components. However, research on the material basis of its hypoglycemic effect remains relatively weak, and its chemical structure and pharmacology are still unclear. Summary of the Invention

[0003] 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:

[0004] (Equation 1)

[0005] Among them, R1, R2, and R3 are all -CH3 or -(CH2). X CH3, where X is 1 to 7.

[0006] A further preferred embodiment has the following structural formula:

[0007] (Equation 2).

[0008] 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:

[0009] S1 involves pulverizing dried Physalis alkekengi and extracting it with an ethanol solution, then evaporating it to dryness to obtain a crude extract.

[0010] 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.

[0011] S3 will say J Ⅲ The fractions of the sample extract were initially separated by silica gel column chromatography and then recovered under reduced pressure.

[0012] 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;

[0013] S5 separates the combined components using a silica gel column, detects and combines identical components by thin-layer chromatography, and then purifies them by preparative HPLC to obtain the compound described in Formula 1 or Formula 2.

[0014] More preferably, in S1, the ethanol solution is a 60%–80% ethanol solution; and the extraction is ultrasonic extraction at room temperature.

[0015] 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.

[0016] 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.

[0017] More preferably, 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 parameters of the preparative HPLC are: the eluent is an 80:20 (v / v) methanol-water solution, and the flow rate is 12 mL / min.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] Beneficial effects:

[0022] This invention is the first to isolate and identify a class of glycoester compounds with ester groups substituted at positions 2, 3, and 4 of the sucrose backbone from Physalis alkekengi, among which the syrup glycoester C1 exhibits in vitro inhibitory activity against α-glucosidase (IC50). 50The concentration (1.05±0.01 μg / mL) was significantly superior to the clinical drug acarbose and showed excellent hypoglycemic effects in diabetic model mice. Furthermore, this invention clarifies for the first time that the activity of this type of compound depends on specific straight-chain alkyl substituents; the hypoglycemic effect is best when R1, R2, and R3 are all -(CH2)5CH3. This invention further establishes an efficient preparation method, providing novel compounds with clearly defined activities and their extraction methods for developing new hypoglycemic drugs. Attached Figure Description

[0023] Figure 1 It is the acid syrup ester C1 of the present invention. 1 H nuclear magnetic resonance (H nuclear magnetic resonance) 1 ¹H NMR spectrum.

[0024] Figure 2 It is the acid syrup ester C1 of the present invention. 13 C nuclear magnetic resonance (C10) 13 C NMR spectrum.

[0025] Figure 3 This is the heteronuclear single quantum correlation (HSQC) spectrum of the acid syrup ester C1 of the present invention.

[0026] Figure 4 This is the heteronuclear multibond correlation (HMBC) spectrum of the C1 syrup ester of this invention. Detailed Implementation

[0027] 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.

[0028] Experimental materials, instruments and reagents:

[0029] Physalis CClyx seu Fructus: Purchased in Daqing City, Heilongjiang Province, and identified by Professor Wang Zhenyue of Heilongjiang University of Traditional Chinese Medicine as Physalis CClyx 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.

[0030] Experimental apparatus:

[0031] Table 1 Experimental Apparatus

[0032]

[0033] Experimental reagents and consumables:

[0034] Table 2 Experimental Reagents and Consumables

[0035]

[0036] Example 1

[0037] This embodiment provides a compound represented by formula (2), specifically including the following steps:

[0038] 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.

[0039] 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.

[0040] S3: J Ⅲ The 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 to 90.

[0041] S4: The recovered fractions 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.

[0042] 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.C6 was analyzed by preparative HPLC (methanol-water 80:20, flow rate 12 mL / min, retention time (t)). R The compound acid syrup ester C1 was obtained by 28 min.

[0043] Example 2

[0044] This embodiment follows the same steps as Example 1, except that in step S1, a 60% ethanol solution is used for extraction, ultimately yielding compound acid syrup ester C1.

[0045] Example 3

[0046] This embodiment is the same as the steps in Embodiment 1, except that in step S1, an 80% ethanol solution is used for extraction, and finally the compound acid syrup ester C1 is obtained.

[0047] Example 4

[0048] The preparation method in this embodiment differs from that in Example 1 in that: the JM-Fr.C7 fraction was passed through an ODS column and eluted with a methanol-water (MeOH-H2O) (60:40–90:10, v / v) solvent system. Fractions from different time points were collected, analyzed by HPLC, and then combined with identical fractions to obtain JM-Fr.C7D1–JM-Fr.C7D9. Subsequently, JM-Fr.C7D9 was purified by preparative HPLC using methanol-water (65:35, v / v) as the mobile phase to obtain compound acid syrup ester C2 (t R =28.0 min).

[0049] Example 5

[0050] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C7D8 was purified by preparative HPLC using methanol-water (70:30, v / v) as the mobile phase to obtain compound acid syrup ester C3 (t R =26.0 min).

[0051] Example 6

[0052] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C7D7 was purified by preparative HPLC using methanol-water (69:31, v / v) as the mobile phase to obtain compound acid syrup ester C4 (t R =29.0 min).

[0053] Example 7

[0054] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C7D6 is purified by preparative HPLC using methanol-water (72:28, v / v) as the mobile phase to obtain compound acid syrup ester C5 (t R =36.0 min).

[0055] Example 8

[0056] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C7D5 was purified by preparative HPLC using methanol-water (75:15, v / v) as the mobile phase to obtain compound acid syrup ester C5 (t R =36.0 min).

[0057] Example 9

[0058] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C7D4 was purified by preparative HPLC using methanol-water (78:22, v / v) as the mobile phase to obtain compound acid syrup ester C7 (t R =40.0 min).

[0059] Example 10

[0060] The preparation method in this embodiment differs from that in Example 4 in that JM-Fr.C7D3 was purified by preparative HPLC using methanol-water (81:29, v / v) as the mobile phase to obtain compound acid syrup ester C8 (t R =28.0 min).

[0061] Compare with Example 1

[0062] The preparation method of this comparative example differs from that of Example 1. The JM-Fr.C7 fraction was eluted using an ODS column with a methanol-water (MeOH-H2O) (50:50–98:2, v / v) solvent system. Fractions were collected at different time points in 500 ml increments. After HPLC analysis, identical fractions were combined to obtain JM-Fr.C7D1–JM-Fr.C7D5. Subsequently, JM-Fr.C7D1 was purified by preparative HPLC using methanol-water (60:40, v / v) as the mobile phase to obtain compound acid syrup ester C1' (t R =36.0 min).

[0063] Compare with Example 2

[0064] The preparation method of this comparative example differs from that of Comparative Example 1: JM-Fr.C7D2 was purified by preparative HPLC using methanol-water (80:20, v / v) as the mobile phase to obtain compound acid syrup ester C2' (t R =45.0 min).

[0065] Compare with Example 3

[0066] The preparation method of this comparative example differs from that of Comparative Example 1: JM-Fr.C7D3 was purified by preparative HPLC using methanol-water (80:20, v / v) as the mobile phase to obtain compound acid syrup ester C3'(t R =41.0 min).

[0067] Compare with Example 4

[0068] The preparation method of this comparative example differs from that of Comparative Example 1: JM-Fr.C7D4 was purified by preparative HPLC using methanol-water (92:8, v / v) as the mobile phase to obtain compound acid syrup ester C4'(tR =33.0 min).

[0069] The compounds prepared in Examples 1-3 are now being identified:

[0070] For the compounds obtained in Examples 1-3: the [M+Na]⁺ molecular ion peak at m / z 701.3730 (C) was obtained 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 3373 cm⁻¹ -1 and 1716 cm -1 Strong absorption peaks are observed at these locations, corresponding to hydroxyl and ester functional groups, respectively.

[0071] Nuclear magnetic resonance (NMR) data showed that it contains sucrose and long-chain fatty acid ester structural units. NMR spectral analysis revealed the presence of sucrose and long-chain fatty acid ester structural units at the terminal hydrogen and carbon groups of the pyranose group. C 90.6, CH-1), and the terminal carbon signal of furanylfructose (δ C The presence of sucrose units can be inferred from the 106.1, C-2′; the presence of sucrose structure was further confirmed by alkaline hydrolysis and comparison of its spectral data with literature reports.

[0072] Electrospray ionization mass spectrometry (ESIMS) and proton spectroscopy were used. 1 H NMR, carbon spectrum ( 13 C NMR) 1 H- 1 HCl COSY, HMQC, and HMBC spectral analyses identified three n-heptanoyl groups in the compound. The relevant signal from the HMBC spectrum confirmed the acyl group linkage site: H-2 (δ) of pyranose. H 4.79) and the C-1 (δ) of the n-octanoyl group C 174.5), H-3 (δ) of pyranose H 5.43) and the C-1 (δ) of the n-octanoyl group C 174.4), H-4 (δ) of pyranose H 5.00) and the C-1 (δ) of the n-octanoyl group C 174.1) There is a correlation.

[0073] In summary, the structure of this compound is identified as formula (2), and it is named syrup ester C1:

[0074] (Equation 2).

[0075] Structural identification showed that the compounds obtained in Examples 1-3, namely syrup ester C1, and the compounds obtained in Examples 4-10, all have 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, the present invention not only provides syrup ester C1, but also confirms a class of glycoester compounds as shown in general formula (1).

[0076] (Equation 1)

[0077] Table 3. Structures of syrup esters C1–C8 and C1'–C4'

[0078]

[0079] Experimental Example 1: Study on α-glucosidase inhibitory activity

[0080] 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.

[0081] Solution preparation:

[0082] (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.

[0083] (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.

[0084] (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.

[0085] (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.

[0086] (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 liquor, and use it for later use;

[0087] (6) Termination solution: Accurately weigh 2.1201 g of anhydrous Na2CO3 solid and place it in a 100 mL volumetric flask.

[0088] Dilute with distilled water to obtain a 0.2 M Na₂CO₃ solution;

[0089] (7) Sample solutions: Accurately weigh 7.5 mg of syrup ester C1 to syrup ester C8 and syrup ester C1' to syrup ester C4' 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 C1 to syrup ester C8 and syrup ester C1' to syrup ester C4' solutions respectively. Prepare and use immediately.

[0090] Test method:

[0091] 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.

[0092] Table 4 Amount of each reactant added

[0093]

[0094] Formula for calculating α-glucosidase inhibition rate:

[0095] Inhibition rate (%) = [(C k -C kb )-(C s -C sb )] / (C k-C kb Formula (3)*100

[0096] Note C k : Absorbance of blank control group; C kb : Absorbance of blank background group; C s : Absorbance of the experimental group; C sb : Absorbance of the experimental background group.

[0097] Experimental results:

[0098] 1. Experimental results of acarbose's inhibitory activity against α-glucosidase

[0099] 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.

[0100] 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.

[0101] 2. Determination of the inhibitory activity of compound syrup esters C1-C8 and C1'-C4' against α-glucosidase.

[0102] Table 4. Results of the assay of the inhibitory activity of syrup esters C1-C8 and C1'-C4' on α-glucosidase.

[0103]

[0104] Results analysis:

[0105] As shown in Table 4, the compounds syrup esters C1 to C8 isolated from Physalis alkekengi in this invention all exhibited inhibitory activity against α-glucosidase. Among them, compound syrup ester C1 showed the most prominent inhibitory activity, with an IC50 value of [missing value]. 50 The concentration was as low as 1.05 ± 0.01 μg / mL, and its activity was significantly better than that of the positive control drug acarbose (IC50). 50 (23.34 ± 0.26 μg / mL).

[0106] By comparing the activity data of syrup esters C1-C8 with those of controls 1-4 (syrup esters C1'-C4'), it can be seen that syrup esters C1'-C4' have poor inhibitory activity against α-glucosidase. The only difference between them and syrup esters C1-C8 is the different substituents R1, R2, and R3. This indicates that the structure of the substituents R1, R2, and R3 is a key factor in regulating the inhibitory activity of syrup ester compounds against α-glucosidase.

[0107] Referring to Table 5, a comparison of the alkyl chain lengths of the C1–C8 substituents (R1, R2, R3) in syrup esters reveals that, within the range of straight-chain alkyl groups (1–8 carbon atoms), the inhibitory activity against α-glucosidase initially increases and then decreases with increasing carbon number. The inhibitory activity reaches its peak when the number of carbon atoms is between 4 and 6. Among these, syrup esters with R1, R2, and R3 all being n-hexyl (-(CH2)5CH3) exhibit the best C1 activity.

[0108] Further analysis of syrup esters C1'–C8' revealed that syrup ester C1' (R1, R2, and R3 are -H) exhibited almost no inhibitory activity (IC50). 50 184.3±8.23 μg / mL); IC50 of syrup ester C2' 50 The value was 124.6 ± 5.46 μg / mL, and its inhibitory activity was much lower than that of syrup ester C1–C8; R1, R2, and R3 of syrup ester C3' were isopropyl (-CH(CH3)2), and its activity (IC50) was low. 50 The concentration of 88.2 ± 4.52 μg / mL is significantly lower than that of the syrup ester C4 (IC) with the same number of carbon atoms but a n-propyl (-(CH2)2CH3) group. 50 (25.45±1.89 μg / mL), indicating that alkyl substitution in the branched structure disrupts the inhibitory activity; the syrup ester has an undecyl (-(CH2) group at C4'). 10 CH3), its activity (IC) 50 The concentration of 86.3 ± 3.88 μg / mL was far below that of compounds with the optimal chain length. This is because excessively long carbon chains (more than 8 carbon atoms) cause steric hindrance or solubility problems, resulting in poor inhibitory activity and thus decreased activity.

[0109] In summary, the highly efficient inhibitory activity of syrup esters C1 to C8 depends on the specific lengths of the straight-chain alkyl groups R1, R2, and R3. Straight-chain alkyl groups with 4 to 6 carbon atoms exhibit more significant inhibitory activity, with the n-hexyl-modified syrup ester C1 showing the best activity. Comparative Examples 1 to 4 demonstrate that structures deviating from the scope defined in this application, even when maintaining the same parent skeleton, do not exhibit inhibitory effects on α-glucosidase activity or show poor inhibitory activity.

[0110] Experimental Example 2: Therapeutic effect of streptozotocin (STZ)-induced diabetic mice

[0111] Laboratory animals:

[0112] SPF-grade Kunming mice were purchased from Hunan Slack Jingda Experimental Animal Co., Ltd., license number: SCXK (Xiang) 2019-0004. The mice were housed in a clean animal facility at a temperature of 20–25℃ and a relative humidity of 50%–70%, with a 12-hour light-dark cycle. The animals had free access to water and food during the experiment. This experiment was approved by the Medical Ethics Committee of Jinggangshan University [Ethics Approval No. (011)].

[0113] Test method:

[0114] 1. Establishment of STZ-induced diabetic mouse model: Mice were acclimatized for one week, during which they had free access to food and water. Before modeling, they were fasted for 12 hours but allowed free access to water. They were injected intraperitoneally with 1% STZ-sodium citrate buffer solution at a dose of 50 mg / kg of STZ once a day for 5 consecutive days. After 48 hours of STZ injection, 10% sucrose solution was used as the only water source. Fasting blood glucose was measured 72 hours later. If the fasting blood glucose was >11.1 mmol / L, the diabetic mouse model was successfully established.

[0115] 2. Grouping and Administration: 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 syrup ester C1 group (30 mg / kg) to a syrup ester C8 group (30 mg / kg), and a syrup ester C1' group (30 mg / kg) to a syrup ester B4' group (30 mg / kg), with 5 mice in each group. Five normal mice were also included as a blank control group. The blank control group and the model control group were administered an equal volume of physiological saline, while the other groups were given the corresponding drug suspended in physiological saline at the prescribed doses, once daily for 21 consecutive days.

[0116] 3. Indicator Testing:

[0117] Fasting blood glucose (FBG) measurement: Mice were fasted overnight but allowed free water. Blood was collected from the orbital sinus and measured using a blood glucose meter (the experiment was conducted with minimal stimulation to the mice). Fasting blood glucose levels were measured and recorded on day 0 before drug administration and on days 7, 14, and 21 after drug administration.

[0118] Table 5 Fasting blood glucose levels in mice of each group

[0119]

[0120] Results analysis:

[0121] As shown in Tables 5 and 6, the in vivo experimental results (Table 5) are highly consistent with the in vitro enzyme inhibition activity trend, further verifying the hypoglycemic effect of the compounds of this invention. Specifically, after 21 days of continuous administration, syrup ester C1 caused a sustained decrease in fasting blood glucose in mice from 23.4 mmol / L to a final level of 6.2 mmol / L, significantly better than the positive control drug acarbose (100 mg / kg, decreased to 14.3 mmol / L). Furthermore, compounds syrup esters C5 to C7 also showed a good hypoglycemic trend. Other compounds (syrup esters C2 to C4, and C8) showed some hypoglycemic trend, but their effects were limited. The 70% ethanol extract of *Physalis alkekengi* also showed a good hypoglycemic effect (decreased to 10.6 mmol / L), which is attributed to the presence of multiple hypoglycemic components in the extract, which worked synergistically to produce a significant effect. The control compound, syrup ester C1'–C4', showed no significant difference in FBG levels (18.2–19.9 mmol / L on day 21) between mice and the model control group throughout the experiment, indicating a poorer in vivo hypoglycemic effect. 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 carbon chain length of the substituent straight-chain alkyl groups R1, R2, and R3 increases, the hypoglycemic effect in vivo first increases and then decreases. This further indicates that the hypoglycemic mechanism of this type of compound is related to the inhibition of α-glucosidase activity.

[0122] In summary, the syrup ester C1 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, and its effect is superior to 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 have a better hypoglycemic effect, with those having 4 to 7 carbon atoms showing even better results.

[0123] 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 1-7.

2. A compound of Formula 2 and a pharmaceutically acceptable salt thereof, 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 combined components using a silica gel column, detects and combines identical components by thin-layer chromatography, and then purifies them by preparative HPLC 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 a gradient elution with dichloromethane-methanol solutions of decreasing concentration, followed by elution with methanol-water solutions.

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 parameters of the preparative HPLC are: the eluent is a methanol-water solution of 60:40 to 80:20 (v / v), and the flow rate is 12 mL / min.

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.

Images