Glycosides in the leaves of *Mallotus quassula*, their preparation methods and applications

Abstract

This invention belongs to the field of pharmaceutical technology and relates to eight glycoside compounds extracted and isolated from the dried leaves of *Picrasma quassioides* Benn, a plant belonging to the genus *Picrasma* in the family Simaroubaceae. The compounds were obtained using chromatographic methods including silica gel chromatography, HP20 column chromatography, ODS column chromatography, and HPLC. This invention also relates to the acetylcholinesterase inhibitory activity of compounds 1-8 and their pharmaceutical uses. The preparation method of this invention is simple, reproducible, and of high purity.

Description

Technical fields:

[0001] This invention belongs to the field of pharmaceutical technology, and mainly relates to glycoside compounds from the leaves of the medicinal plant *Melastoma canadensis*, their preparation methods, and applications. Specifically, it relates to eight glycoside compounds isolated from the dried leaves of the medicinal plant *Melastoma canadensis*. Background technology:

[0002] *Picrasma quassioides* Benn., belonging to the Simaroubaceae family and the *Picrasma* genus, is a deciduous shrub or small tree mainly distributed in southern China. Commonly known as the bitter-skinned tree, it is a traditional Chinese medicine used for clearing heat and detoxifying. *Picrasma quassioides* is cold in nature and bitter in taste, entering the lung and large intestine meridians. It has functions such as clearing heat and detoxifying, drying dampness and killing parasites. It is mainly used to treat upper respiratory tract infections, pneumonia, acute gastroenteritis, dysentery, biliary tract infections, boils, scabies, eczema, burns, and snake bites.

[0003] Modern pharmacological studies have shown that *Quercus acutissima* possesses antibacterial, anti-inflammatory, antipyretic, hypotensive, anticancer, anti-snake venom, antimalarial, and transaminase-lowering effects. However, current research on *Quercus acutissima* mainly focuses on its stem bark; therefore, research on the chemical components of its leaves is crucial. Summary of the Invention:

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide eight glycoside compounds with novel structures from the leaves of the *Quercus mongolica* tree, their preparation methods, and their applications in the preparation of cholinesterase inhibitors.

[0005] To achieve the objectives of this invention, the following technical solution is adopted:

[0006] In the first aspect, the present invention provides eight glycoside compounds isolated from the dried leaves of *Picrasma quassioides* Benn, a plant belonging to the genus *Picrasma* of the family Simaroubaceae, with the following structures:

[0007]

[0008] In a second aspect, the present invention provides a method for preparing the above-mentioned glycoside compounds, comprising the following steps:

[0009] Using dried leaves of the *Paspalum notatum* as raw material, the extract was obtained by extraction with 70% ethanol (v / v), concentrated to obtain a paste-like ethanol extract, which was then extracted with dichloromethane and n-butanol, and purified by various chromatographic methods. Specifically, this was achieved through the following steps:

[0010] 1. Take dried bitterwood leaves and reflux them four times with 70% ethanol.

[0011] 2. The ethanol extract was concentrated to obtain a paste-like ethanol extract, which was then extracted with dichloromethane and n-butanol to obtain a crude extract.

[0012] 3. The dichloromethane extract and the n-butanol extract were separated by silica gel column chromatography to obtain six fractions, Fr.AF.

[0013] 4. Fraction Fr.E was eluted using a polyamide column with a gradient elution of ethanol-water system from 20:80 to 90:10, followed by elution using an HP-20 column with a gradient elution of ethanol-water system from 10:90 to 90:10, an ODS column with an ethanol-water system from 20:80 to 80:20, and a silica gel column with a dichloro-methanol system from 80:20 to 10:90, yielding a total of 6 fractions, namely Fr.E1 to Fr.E6.

[0014] 5. The obtained component Fr.E5 was separated by preparative reversed-phase high-performance liquid chromatography using an acetonitrile-water mobile phase to obtain compounds 1-8.

[0015] Preferably, the leaves used in the preparation method are dried leaves of Picrasma quassioides Benn, a plant belonging to the genus Picrasma in the family Simaroubaceae.

[0016] The obtained compounds underwent systematic structural identification, and the corresponding spectra and data are as follows. Figures 1-27 and As shown in Tables 1-3.

[0017] The structures of compounds 1-8 were identified using a variety of spectroscopic techniques.

[0018] Compound 1:

[0019] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane and methanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na]. + Peak m / z 481.1357 (calcd for C 20 H 26 O 12 Na, 481.1316), its molecular formula was determined to be C 20 H 26 O 12 .

[0020] Compound 1 1 The low-field region of the H-NMR spectrum shows a pair of meta-coupled benzene ring proton signals δ H 7.28 (1H,d,J = 1.3Hz), 7.17 (1H,d,J = 1.3Hz), indicating the presence of 1,3,4,5-substituted benzene rings in the structure; δ H 6.04 (2H,s) is the characteristic proton signal of methylenedioxy; the two methoxy proton signals δ H3.71 (3H, s), 3.91 (3H, s); three methyl signals δ also exist in the high-field region. H 1.47 (3H, s), 1.51 (3H, s). 13 The C-NMR spectrum showed a total of 20 carbon signals, among which, δ C 166.1 and 175.9 represent carbonyl carbon signals; the aromatic region contains a total of 6 carbon signals, δ C 104.0,110.3,124.4,139.7,143.5,148.9; δ C 102.7 is the carbon signal for the methylenedioxy group; in addition, 1 H and 13 C NMR data at δ H 4.42 (1H, d, J = 7.2Hz) and δ C The characteristic signal of the glucose moiety is observed at 97.7. Correlation between H-7 and C-4, C-3 in the HMBC spectrum indicates that -OCH2O- is linked to C-3 and C-4. HMBC correlation from H-1′ to C-1″ confirms the link at C-1″ to the C-1′ of glucose. Therefore, compound 1 is confirmed as a glycoside with a tetrasubstituted benzene ring of 1,3,4,5.

[0021] Compound 1 (2 mg) was heated in 1 M HCl (4 mL) for 4 hours and extracted three times with an equal volume of water-saturated ethyl acetate. After drying the aqueous layer, the sugar obtained by hydrolysis was derivatized with L-cysteine ​​methyl ester hydrochloride and cyanosulfate using pyridine as solvent, and heated for 1 hour. The mixture was analyzed by HPLC and compared with the standard derivatives. The sugar fraction of compound 1 was identified as D-glucose (t...). R =5.5 minutes). The β configuration of D-glucose was confirmed by the coupling constant of the terminal carbon (J = 7.2 Hz).

[0022] Compound 2:

[0023] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane, methanol, and ethanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na]. + Peak m / z 423.1269 (calcd for C) 18 H 24 O 10 Na, 423.1262), its molecular formula is determined to be C 18 H 24 O 10 .

[0024] Comparing compound 2 and compound 1 1 H NMR and 13C10 NMR data indicate that compound 2 has a similar structure to compound 1, and compound 2 exhibits four hydrogen signals δ in the low-field region. H 6.98 (1H, m), 6.97 (1H, m), 7.53 (1H, m), 7.85 (1H, dd, J = 7.93, 1.6 Hz) indicate that the 1,3,4,5 tetrasubstituted benzene ring in compound 1 is replaced by a 1,2-disubstituted benzene ring. According to... 1 H- 1 The correlations between H-3 and H-4, H-4 and H-5, and H-5 and H-6 in the H COSY spectrum confirm the above arguments. This is based on the δ-terminal protons... H At 4.55 (1H, d, J = 7.7 Hz), the relative configuration of glucose was determined to be β. Similar to compound 1, the glucose configuration of compound 2 was determined to be D.

[0025] Compound 3:

[0026] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane, methanol, and ethanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na]. + Peak m / z 423.1372 (calcd for C 18 H 24 O 10 Na, 423.1362), its molecular formula was determined to be C 18 H 24 O 10 .

[0027] The 1D NMR of compound 3 is similar to that of compound 2, both being monobenzene glycosides. The difference lies in the shift of the hydroxyl group on the benzene ring from C-2 to C-4, which can be attributed to the interaction of H-2 and H-6 (δ¹⁴). H 7.83) to C-4(δ C The obvious HMBC correlation of 162.2) was inferred. Therefore, the structure of 3 was determined. Based on the terminal protons in δ H The large coupling constant at 4.40 (1H,d,J = 7.7 Hz) determined the relative configuration of glucose as β and the absolute configuration of glucose as D using the same method as compound 1.

[0028] Compound 4:

[0029] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane, methanol, and ethanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na]. + Peak m / z 453.1377 (calcd for C 19 H 26 O 11Na, 453.1367), its molecular formula was determined to be C 19 H 26 O 11 .

[0030] The 1D NMR spectrum of compound 4 shows a high degree of similarity to the NMR spectra of compounds 2 and 3. (The text repeats itself here, so the translation will only include the first instance.) 13 Compared to CNMR data, compound 4 in δ C An additional methoxy group signal was clearly observed at 52.2. The position of 3-OCH3 was determined by observing the HMBC spectrum and correlating it with C-3. Therefore, the structure of 4 was determined. Based on δ... H The coupling constant of the terminal proton signal at 4.41 (1H, d, J = 7.7 Hz) was determined by acid hydrolysis and HPLC analysis, and its glucose configuration was determined to be β,D-glucose.

[0031] Compound 5:

[0032] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane, methanol, and ethanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na]. + Peak m / z 509.1641 (calcd for C 22 H 30 O 12 Na, 509.1629), its molecular formula was determined to be C 22 H 30 O 12 .

[0033] The 1D NMR spectrum of compound 5 showed that it shared the same glycoside fragments as compounds 1-4. Furthermore, observations of compound 5 revealed... 1 ¹H NMR revealed that it possessed a set of hydrogen signals δ on the 1,3,4,5-tetrasubstituted benzene rings. H 7.02 (2H, s), Group 1 olefin signal δ H 6.50 (1H,d,J=15.2Hz), 7.57 (1H,d,J=15.2Hz), 3 methoxy signals δ H 3.59 (3H, s), 3.80 (6H, s), and two groups of methyl signal δ H 1.38(3H,s), 1.39(3H,s). 13 The C-NMR spectrum showed 22 carbon signals, including 6 aromatic carbon δ-axis signals. C 148.6, 148.6, 138.3, 124.3, 105.9, 2 olefinic carbons δ C 145.1, 114.4, 2 carbonyl carbons δ C173.9, 166.5, 3 methoxy carbons δ C 56.1, 56.1, 51.8, two methyl carbon signals δ C 25.0, 23.8 and 1 quaternary carbon signal δ C 76.8, The precise structure of the compound was confirmed by two-dimensional spectroscopy. According to the HMBC spectrum, H-7 and H-8 are correlated with C-9, H-8 with C-1, H-7 with C-2 and C-6, and the correlation between H-6′ and C-9 indicates that the glycoside and benzene ring fragments are linked together through α,β-unsaturated ketone fragments. Based on H-7 (δ... H 7.57, d, J = 15.8 Hz) and H-8 (δ H The coupling constant (6.50, d, J = 15.8 Hz) determines that the olefin in compound 5 has a trans configuration. The relative configuration of glucose is inferred to be β(δ). H The terminal proton signal at 4.40 (1H, d, J = 7.7 Hz) was used to determine the absolute configuration of 5 by glycoside hydrolysis experiments and HPLC analysis, and its glycoside fragment was identified as β,D-glucose.

[0034] Compound 6:

[0035] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane and methanol. HRESIMS spectra show a quasi-molecular ion peak [M+Na]. + Peak m / z 479.1533 (calcd for C 21 H 18 O 11 Na, 479.1524), combined with proton and carbon spectra, determined its molecular formula to be C. 21 H 18 O 11 .

[0036] The NMR data of compound 6 are highly similar to those of compound 5. Observation of their 1D NMR reveals that the main difference between compound 6 and compound 5 is the absence of a methoxy group in compound 6. This difference was observed at δ¹⁸O. H 3.62(2H,m,H-5) and δ C Supported by the HMBC correlations at 147.8 (C-3) and 122.8 (C-6). Similar to compound 5, the olefin configuration of compound 6 is determined by the coupling constants of H-7 and H-8, identifying it as trans, and the glycoside fragment as β,D-glucose.

[0037] Compound 7:

[0038] White amorphous powder (methanol), readily soluble in solvents such as dichloromethane, methanol, and ethanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na].+ Peak m / z 657.2194(calcd for 657.2154,C 31 H 38 O 14 Na), its molecular formula is determined to be C. 31 H 38 O 14 .

[0039] Comparison of the 1D NMR spectra of compounds 7 and 1-6 indicates that they possess similar glycosidic fragments. 7's... 1 H NMR spectra show two mutually coupled proton δ H 7.27 (1H,d,J = 6.7 Hz), 7.24 (1H,d,J = 6.7 Hz), and three aromatic protons δ H 6.76 (2H, s) and 6.92 (1H, s) belong to 1,3,4,5-tetrasubstituted benzene rings and symmetrical 1,3,4-trisubstituted benzene rings, with two methylene protons δ H 5.54 (1H, d, J = 6.7 Hz), 3.50 (1H, m), one methylene proton δ H 3.72 (1H, s), 3.67 (1H, d, J = 1.2 Hz), and a pair of trans-double bond protons δ H 7.60(1H,d,J=15.6Hz), 6.50(1H,d,J=15.6Hz). 13 C10 NMR data and HSQC spectra show that compound 7 has two benzene rings and two olefinic carbons. C 132.6, 124.1, two benzyl carbons δ C 88.9, 50.6, two δ-oxide methylene groups C 87.9, 52.9 and two methoxy carbon δ C 58.1, 56.1. All this evidence suggests that compound 7 contains benzodihydrofuran neolignans. The correlations of H-7′, H-8′ with C-9′, H-8′ with C-4, and H-7′ with C-3 and C-5 in the HMBC spectra indicate that C-4 is linked to an α,β-unsaturated ketone. The HMBC correlation of H-6″ with C-9′ indicates that the glycoside fragment is linked to C-9′ via oxygen atoms.

[0040] The NOE correlation between H-7 and H2-9 confirmed that compound 7 is in the trans configuration. The absolute configuration of compound 7 was determined by ECD analysis; the negative Cotton effect observed at 270 nm in its ECD spectrum confirmed the absolute configuration as 7R,8S. This was further confirmed by δ¹⁸O₂. HThe terminal proton signal at 4.40 (1H,d,J = 7.7 Hz), along with glycoside hydrolysis experiments and HPLC analysis, identified the glycoside fragment as β,D-glucose.

[0041] Compound 8:

[0042] It is a colorless, oily substance (methanol), readily soluble in solvents such as dichloromethane, methanol, and ethanol. High-resolution mass spectrometry (HRESIMS) yields a quasi-molecular ion peak [M+Na]. + Peak m / z 543.1493 (calcd for C 25 H 28 O 12 Na, 543.1473), its molecular formula was determined to be C 25 H 28 O 12 .

[0043] Comparison of the 1D NMR data of compound 8 and compound 7 indicates that compound 8 is a benzodihydrofuran lignan. Compound 8's... 1 ¹H NMR spectra showed a group of 1,3,4,5-substituted benzene rings at δ¹⁸ ppm. H 7.46 (1H, s), 7.59 (1H, s), a symmetrical 1,3,4-trisubstituted benzene ring δ H 6.89 (2H,s), 6.93 (1H,s), a low-field signal δ H 6.00 (2H, d, J = 2.3 Hz), two methine protons δ H 5.73 (1H, d, J = 5.5 Hz), 3.67 (1H, m), and a methylene proton δ H 4.09 (1H, dd, J=8.9, 5.0Hz), 3.67 (1H, m). 13 C10 NMR and HSQC spectra show that compound 8 has two benzene rings and two benzyl carbons. C 88.9, 50.6, two δ-methylene oxides C 87.9, 52.9 and two methoxy carbon δ C 55.8, 51.6, and the methylenedioxy signal δ C 101.9. 1 H and 13 C NMR data showed that the glucose moiety was at δ H 4.42 and δ C Characteristic signal at 97.7. Glucose at δ CThe 4.51 terminal proton correlation with the HMBC of C-9 indicates that the glucose unit is attached at C-9. The position of the methylenedioxy group was also determined by the HMBC correlations of H-10 with C-3 and C-4. Based on the NOESY correlation (H-7 correlated with H2-9), the relative configurational chemistry of compound 8 at C-7 and C-8 positions confirmed a trans configuration. The negative Cotton effect (CE) near 270 nm, based on the P / M helix rule of the dihydrobenzofuran chromophore, confirmed the R-configuration of C-7 and the S-configuration of C-8. Acid hydrolysis confirmed compound 8 as D-glucose. The β-configuration of glucose is determined by the large coupling constant (7.8 Hz) of its terminal proton, thus confirming the glucose in compound 8 as β,D-glucose.

[0044] The advantage of this invention is that all the compounds are new compounds with novel structures and are worthy of further development.

[0045]

[0046]

[0047]

[0048]

[0049] In a third aspect, the present invention provides a pharmaceutical composition comprising the glycoside compound described in the first aspect and a pharmaceutically acceptable carrier or excipient.

[0050] In a fourth aspect, the present invention provides the use of the glycoside compounds described in the first aspect above in the preparation of acetylcholinesterase inhibitors.

[0051] The acetylcholinesterase inhibitory activity of the eight glycoside compounds described in this invention was investigated, and compound 6 showed relatively strong acetylcholinesterase inhibitory activity.

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] 1. Compared with the prior art, the present invention can quickly isolate glycoside compounds from the leaves of the quassula.

[0054] 2. This invention can determine the acetylcholinesterase activity of glycoside compounds. Attached image description:

[0055] Figure 1 HSQC spectrum of compound 1 (600MHz, CDCl3).

[0056] Figure 2.HMBC spectrum of compound 1 (600MHz, CDCl3).

[0057] Figure 3. Compound 1 1 H- 1 HCOSY spectrum (600MHz, CDCl3).

[0058] Figure 4. HSQC spectrum of compound 2 (600MHz, DMSO-d6).

[0059] Figure 5. HMBC spectrum of compound 2 (600MHz, DMSO-d6).

[0060] Figure 6. Compound 2 1 H- 1 HCOSY spectrum (600MHz, DMSO-d6).

[0061] Figure 7. HSQC spectrum of compound 3 (600MHz, DMSO-d6).

[0062] Figure 8. HMBC spectrum of compound 3 (600 MHz, DMSO-d6).

[0063] Figure 9. Compound 3 1 H- 1 HCOSY spectrum (600MHz, DMSO-d6).

[0064] Figure 10. HSQC spectrum of compound 4 (600 MHz, DMSO-d6).

[0065] Figure 11. HMBC spectrum of compound 4 (600 MHz, DMSO-d6).

[0066] Figure 12. Compound 4 1 H- 1 HCOSY spectrum (600MHz, DMSO-d6).

[0067] Figure 13. HSQC spectrum of compound 5 (600 MHz, DMSO-d6).

[0068] Figure 14. HMBC spectrum of compound 5 (600 MHz, DMSO-d6).

[0069] Figure 15. Compound 5 1 H- 1HCOSY spectrum (600MHz, DMSO-d6).

[0070] Figure 16. HSQC spectrum of compound 6 (600 MHz, DMSO-d6).

[0071] Figure 17. HMBC spectrum of compound 6 (600 MHz, DMSO-d6).

[0072] Figure 18. Compound 6 1 H- 1 HCOSY spectrum (600MHz, DMSO-d6).

[0073] Figure 19. HSQC spectrum of compound 7 (600 MHz, DMSO-d6).

[0074] Figure 20. HMBC spectrum of compound 7 (600MHz, DMSO-d6).

[0075] Figure 21. Compound 7 1 H- 1 HCOSY spectrum (600MHz, DMSO-d6).

[0076] Figure 22. NOESY spectrum of compound 7 (600MHz, DMSO-d6).

[0077] Figure 23. HSQC spectrum of compound 8 (600 MHz, DMSO-d6).

[0078] Figure 24. HMBC spectrum of compound 8 (600 MHz, DMSO-d6).

[0079] Figure 25 Compound 8 1 H- 1 HCOSY spectrum (600MHz, DMSO-d6).

[0080] Figure 26. NOESY spectrum of compound 8 (600MHz, DMSO-d6).

[0081] Figure 27. ECD diagrams of compounds 7-8.

[0082] Figure 28. Compounds 1-8 exhibit inhibitory activity against acetylcholinesterase. Detailed implementation method:

[0083] The embodiments listed below are intended to help those skilled in the art better understand the present invention, but do not limit the invention in any way.

[0084] Example 1: Preparation of compounds 1-8

[0085] 50.0 kg of dried leaves of *Mallotus latatus* were refluxed four times with 70% ethanol to obtain 9.0 kg of extract. The EtOH extract was concentrated in dichloromethane and n-butanol to obtain a crude extract. The dichloromethane extract (1244.0 g) was chromatographically separated on a silica gel column, eluted with petroleum ether-ethyl acetate (20:1-1:1) and dichloromethane-methanol (50:1-0:1). The n-butanol extract (3157.0 g) was eluted on a silica gel column with a dichloromethane-methanol (50:1-0:1) gradient system. Six fractions, Fr.AF, were obtained. The fraction Fr.E was then eluted using a polyamide column with a gradient elution of ethanol-water system (20:80–90:10), an HP-20 column with a gradient elution of ethanol-water system (10:90–90:10), an ODS column with a 20:80–80:20 ethanol-water system, and a silica gel column with a dichloro-methanol system (80:20–10:90), yielding six fractions, Fr.E1–Fr.E6. Fraction Fr.E5 was then separated using preparative reversed-phase high-performance liquid chromatography with an acetonitrile-water (20:80, v / v) mobile phase to obtain compounds 1–8.

[0086] Example 2: Investigation of the inhibitory activity of compounds 1-8 on acetylcholinesterase

[0087] The inhibitory activity of compounds 1-8 on acetylcholinesterase was investigated using donepezil as a positive control. All experiments were performed three times. Results were analyzed using GraphPad Prism 8.0 (GraphPad Software, San Diego, CA, USA) and are expressed as mean ± SEM.

[0088] Add 50 μL of PBS (pH = 7.4), 25 μL of sample, 12.5 μL of 0.2 U / mL enzyme solution, and 125 μL of 5,5'-dithiobis(2-nitrobenzoic acid) sequentially to a 96-well plate, let stand overnight, and terminate the reaction with 50 μL of thioacetylcholine iodide. Measure the absorbance at 412 nm.

[0089] Experimental results are as follows Figure 28 The results showed that compounds 1-8 all exhibited acetylcholinesterase inhibitory activity. Among them, compound 6 showed relatively strong acetylcholinesterase inhibitory activity, comparable to the positive control.

[0090] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A glycoside compound from the leaves of *Paspalum notatum*, characterized in that: The compound has any of the following structures: 。 2. The method for preparing the glycoside compound according to claim 1, characterized in that: The preparation method includes the following steps: (1) The dried leaves of the bitter tree were used as raw material. They were extracted with 70% ethanol by volume, concentrated to obtain an ethanol extract in the form of a paste, and then extracted with dichloromethane and n-butanol to obtain a crude extract. (2) The dichloromethane extract and the n-butanol extract were separated by silica gel column chromatography to obtain six fractions, Fr.AF; (3) Fraction Fr.E was eluted by a polyamide column with a gradient elution of ethanol-water system 20:80-90:10, by an HP-20 column with a gradient elution of ethanol-water system 10:90-90:10, by an ODS column with a gradient elution of ethanol-water system 20:80-80:20, and by a silica gel column with a gradient elution of dichloro-methanol system 80:20-10:90, yielding a total of 6 fractions, namely Fr.E1-Fr.E6; (4) The obtained fraction Fr.E5 was separated by acetonitrile-water mobile phase in preparative reversed-phase high-performance liquid chromatography to obtain compound 5 and compound 6.

3. The preparation method according to claim 2, characterized in that: In step (1), the extraction was performed four times with 70% ethanol, and in step (4), the separation was performed with 20% acetonitrile-water.

4. A pharmaceutical composition, characterized in that: It comprises the glycoside compound of claim 1 and a pharmaceutically acceptable carrier or excipient.

5. The use of the glycoside compound of claim 1 in the preparation of acetylcholinesterase inhibitors.

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