B-ring split-ring flavone as well as preparation method and application thereof

Abstract

The invention discloses B-ring split-ring flavone as well as a preparation method and application thereof. The B-ring split-ring flavone is obtained by being separated from cinnamon bark; the structural formula of the compound is as shown in a formula (I) and / or a formula (II): # imgabs0 #; the B-ring split-ring flavone is separated from dried bark of cinnamomum cassia of a lauraceae cinnamomum plant, liver protection activity evaluation is carried out by using an alcohol-induced liver cell injury model, and the B-ring split-ring flavone is found to be capable of effectively relieving alcohol-induced normal liver cell injury of mice, reducing fat accumulation and improving the liver protection activity. The B-ring split-ring flavone provided by the invention has liver protection activity, can be applied to preparation of liver protection medicines, and has good research and development prospects.

Description

Technical Field

[0001] The invention belongs to the field of natural drug chemistry, and specifically relates to a B-ring split-ring flavonoid compound and a preparation method and application thereof. Background Art

[0002] Alcoholic liver disease is a liver disease caused by long-term excessive drinking. Clinically, the spectrum of alcoholic liver disease is mainly divided into: alcoholic fatty liver disease, alcoholic hepatitis, alcoholic liver fibrosis and alcoholic cirrhosis. Severe alcoholism can induce extensive liver cell necrosis and even cause liver failure. According to my country's "Guidelines for the Prevention and Treatment of Alcoholic Liver Disease", people with a long-term drinking history (generally more than 5 years), with an ethanol volume of ≥ 40g / day for men and ≥ 20g / day for women; or a history of heavy drinking within two weeks, with an ethanol volume of more than 80g / day, are considered to be excessive drinkers and have a higher risk of developing alcoholic liver disease.

[0003] The main clinical treatments for alcoholic liver disease include abstinence, nutritional support, drug therapy and liver transplantation. Abstinence and nutritional support are the most basic treatment measures. Complete abstinence can restore some patients with mild alcoholic liver disease to normal, slow down the process of fibrosis and improve the survival rate of patients. However, patients are prone to poor compliance and the improvement effect is not obvious. Moreover, sudden alcohol withdrawal may cause severe withdrawal reactions such as epilepsy, coma and even cardiac arrest in patients with alcohol dependence. For patients who have difficulty in actively abstaining from alcohol, acetaldehyde dehydrogenase inhibitors (such as disulfiram), central nervous system inhibitors (such as opioid receptor antagonist naltrexone, γ-aminobutyric acid receptor agonist baclofen) and liver protectors (such as trace element zinc) can be given to improve the clinical biochemical indicators of patients with alcoholic liver disease. For patients with alcohol withdrawal syndrome, tranquilizers (such as benzodiazepines) can be used. Patients with alcoholic liver disease also need good nutritional support. On the basis of abstinence, daily diet should pay attention to high protein and low fat, and timely supplement of vitamins and folic acid.

[0004] In terms of drug treatment, silymarin preparations have been listed as liver-protecting drugs in many liver disease diagnosis and treatment guidelines based on the accumulation of long-term evidence-based medicine. Silymarin can reduce the level of CYP2E1 in liver cells of patients with alcoholic liver disease, inhibit the production of ROS, MDA, etc., regulate glutathione metabolism, and reduce the levels of inflammatory factors such as IL-6 and TNF-α, thereby improving the symptoms of alcoholic liver disease. However, the therapeutic mechanism of silymarin is still unclear, and the oral bioavailability of the drug is poor and the effective dose is large. The liver-protecting drugs bicyclol, glycyrrhizic acid preparations, S-adenosylmethionine and N-acetylcysteine ​​also have similar effects on improving the relevant pathological indicators of patients with alcoholic liver disease. On the one hand, metadoxine acts as an antioxidant to improve the oxidative stress response of hepatocytes; on the other hand, it can accelerate the clearance of alcohol in the body, and has a good effect on patients with acute alcohol poisoning. Although there are many palliative therapies for drug treatment of alcoholic liver disease, they can only improve symptoms, and the relevant treatment mechanisms are not yet clear, and they are even prone to cause adverse reactions such as infection, hepatotoxicity and hepatorenal syndrome. In general, most of the existing drugs for the treatment of alcoholic liver disease in clinical practice play an auxiliary role and have limited efficacy. Therefore, it is imperative to find effective and safe drugs against alcoholic liver disease.

[0005] Cinnamomum cassia Presl. is a medium-sized tree plant of the genus Cinnamomum in the family Lauraceae. It is also known as Jungui, Dugui, Dagui, Tonggui, etc. It is widely distributed in tropical and subtropical areas of East Asia and Southeast Asia. It is a traditional Chinese medicine with the same medicinal and edible properties. It has the effects of replenishing fire and yang, guiding fire back to the origin, dispelling cold and relieving pain, and warming the meridians. B-ring split-ring flavonoid compounds are a rare class of plant ingredients, and there is little research on them at present. The present invention is to discover and separate a class of B-ring split-ring flavonoid compounds from the dried bark of cinnamon, and experiments have proved that it has liver protection activity. Summary of the invention

[0006] The first object of the present invention is to provide a class of B-ring split ring flavonoids; The B-ring split ring flavonoid provided by the present invention is isolated from cinnamon bark, and its structural formula is shown in formula (I) or / and formula (II): .

[0007] The present invention has found through experiments that the B-ring split ring flavonoids of the present invention has good liver protection activity and can be used to prepare liver protection drugs.

[0008] Therefore, the second object of the present invention is to provide the use of the above-mentioned B-ring split ring flavonoids in the preparation of liver protection drugs.

[0009] The above-mentioned B-ring split ring flavonoids were isolated from the dried bark of Cinnamomum cassia, a plant of the Lauraceae family. The dried Cinnamomum cassia medicinal materials were purchased from the Qingping Traditional Chinese Medicine Market in Liwan District, Guangzhou City, Guangdong Province in April 2021. The samples were stored in the School of Biomedicine, Guangdong University of Technology (No.: CC-202104, Location: School of Biomedicine, Guangdong University of Technology, No. 100 Outer Ring West Road, Guangzhou University City, Guangzhou, China, 510006).

[0010] The preparation method of the above-mentioned B-ring split-ring flavonoid specifically comprises the following steps: (1) Take dried cinnamon bark and extract it with 60% ethanol aqueous solution by heating and refluxing for 2 times, each time for 2 hours, filter it, and concentrate the filtrate under reduced pressure to obtain a concentrated solution; (2) extracting the concentrated solution with dichloromethane to obtain a dichloromethane extract; (3) subjecting the obtained dichloromethane extract to normal pressure silica gel column chromatography, specifically using cyclohexane-ethyl acetate eluents with volume ratios of 99:1, 97:3, 95:5, 90:10, 85:15, 80:20, 70:30, 60:40 and 0:100 for gradient elution, to obtain 17 sub-fractions, namely C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16 and C17; (4) The subfraction C10 obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 80:20 was subjected to medium-low pressure reverse phase column chromatography and eluted with methanol-water-formic acid in a volume ratio of 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 60:40:0.1, 70:30:0.1, 80:20:0.1, and 100:0:0 to obtain C10.1 and C10. .2, C10.3, C10.4, C10.5, C10.6, C10.7, C10.8, C10.9, C10.10, C10.11, C10.12, C10.13, C10.14, C10.15, C10.16, C10.17, C10.18, C10.19, C10.20, C10.21, C10.22 and C10.23, a total of 23 sub-fractions; (5) The subfraction C10.9 obtained by elution with methanol-water-formic acid in a volume ratio of 45:55:0.1 was subjected to reverse phase preparative high performance liquid chromatography and eluted with acetonitrile-water-formic acid in a volume ratio of 32:68:0.1 at a flow rate of 10 mL / min to obtain a compound of formula (II); (6) The sub-fractions C15 and C16 obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 60:40 were combined and chromatographed on a medium-low pressure reverse phase column, and then eluted with 25:75:0.1, 30:70:0.1, 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 55:45:0.1, 60:40:0.1, 65:35:0.1, 70:30:0.1, Elution with methanol-water-formic acid at 80:20:0.1 and 100:0:0 gave 20 sub-fractions, namely C15&16.1, C15&16.2, C15&16.3, C15&16.4, C15&16.5, C15&16.6, C15&16.7, C15&16.8, C15&16.9, C15&16.10, C15&16.11, C15&16.12, C15&16.13, C15&16.14, C15&16.15, C15&16.16, C15&16.17, C15&16.18, C15&16.19 and C15&16.20; (7) The subfraction C15 & 16.9 obtained by elution with methanol-water-formic acid in a volume ratio of 45:55:0.1 was subjected to reverse phase preparative HPLC and eluted with methanol-water-formic acid in a volume ratio of 45:55:0.1 at a flow rate of 8 mL / min to obtain the compound of formula (I).

[0011] Another technical solution of the present invention is the use of the above-mentioned B-ring split ring flavonoids in the preparation of liver protection drugs.

[0012] Another technical solution of the present invention is a liver protection drug, which uses B-ring split ring flavonoids as an active ingredient.

[0013] Compared with the prior art, the technical solution provided by the present invention has the following technical advantages: The technical solution provided by the present invention separates two flavonoid compounds from the bark of cinnamon tree, a plant of the genus Cinnamomum in the family Lauraceae, and uses an alcohol-induced liver cell injury model to evaluate the liver protection activity. It is found that the B-ring split-ring flavonoid compound of the present invention can effectively alleviate alcohol-induced normal liver cell injury in mice and reduce fat accumulation, indicating that the B-ring split-ring flavonoid compound provided by the present invention has liver protection activity, can be used in the preparation of liver protection drugs, and has good research and development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the 400 MHz H NMR spectrum of the compound of formula I in deuterated dimethyl sulfoxide; Figure 2 is the 100 MHz NMR carbon spectrum of the compound of formula I in deuterated dimethyl sulfoxide; Figure 3 is the 600 MHz H NMR spectrum of the compound of formula II in deuterated methanol; Figure 4 is the 150 MHz NMR carbon spectrum of the compound of formula II in deuterated methanol; Figure 5 This is a graph showing the hepatoprotective activity of B-ring split-ring flavonoid compounds. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto.

[0016] All the equipment in the following examples are as follows: The mass spectrometer is a Bruker Amazon SL mass spectrometer produced by Burker Daltonics, USA. The superconducting nuclear magnetic resonance spectrometers are Bruker AV-400 and Bruker AV-600. The X-ray single crystal diffractometer is Bruker D8 venture. The silica gel GF254 for thin layer chromatography and the silica gel for column chromatography (200‒300 mesh) are both products of Qingdao Ocean Chemical Plant. The reversed phase ODS filler (50 μ m) was produced by YMC Co., Ltd. of Japan. The medium and low pressure liquid chromatograph was produced by Shanghai Lisui Electronic Technology Co., Ltd. The preparative chromatographic column used for liquid phase separation was Cosmosil Packed C18 column (20.0 × 250 mm, 5 μ m). Acetonitrile or methanol was chromatographically pure for liquid chromatography, water was double distilled water, and other reagents were analytically pure. The multifunctional microplate reader was the Infinite F50 microplate reader from Tecan, Switzerland. Normal mouse liver cells were purchased from the cell bank of the Chinese Academy of Sciences. Silymarin was a product of Shanghai Aladdin Company.

[0017] Example 1 Preparation of compounds of formula (I) to (II)

[0018] 20.0 kg of dried cinnamon bark was extracted twice with 200 L of ethanol-water (60:40, v / v) by heating and refluxing, each time for 2 hours. After filtration, the filtrate was concentrated under reduced pressure to obtain a concentrate. The concentrate was successively extracted with 39 L of dichloromethane to obtain a dichloromethane extract.

[0019] 434.3 g of the dichloromethane extract was subjected to normal pressure silica gel column chromatography, and gradient elution was performed with cyclohexane-ethyl acetate eluents in volume ratios of 99:1, 97:3, 95:5, 90:10, 85:15, 80:20, 70:30, 60:40 and 0:100, to obtain 17 sub-fractions, namely C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16 and C17 (the corresponding sub-fractions obtained by elution with cyclohexane-ethyl acetate in different volume ratios are shown in Table 1).

[0020] Then, the subfraction C10 (8.2 g) obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 80:20 was subjected to medium-low pressure reverse phase column chromatography and eluted with methanol-water-formic acid in a volume ratio of 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 60:40:0.1, 70:30:0.1, 80:20:0.1, and 100:0:0 to obtain C10.1, C10.2, C10.3, C10.4, C10.5, C10.6, and C10.7. There are 23 sub-fractions in total, including C10.7, C10.8, C10.9, C10.10, C10.11, C10.12, C10.13, C10.14, C10.15, C10.16, C10.17, C10.18, C10.19, C10.20, C10.21, C10.22 and C10.23 (see Table 2 for the fractions corresponding to the elution with different volume ratios of methanol-water-formic acid).

[0021] The subfraction C10.9 (114.3 mg) obtained by elution with methanol-water-formic acid in a volume ratio of 45:55:0.1 was subjected to reverse phase preparative HPLC and eluted with acetonitrile-water-formic acid in a volume ratio of 32:68:0.1 at a flow rate of 10 mL / min to obtain the compound of formula (II) ( t R : 83.4 min, 9.8 mg, purity 95%);

[0022] Similarly, the sub-fractions C15 and C16 obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 60:40 were combined (15.4 g) and subjected to medium-low pressure reverse phase column chromatography, and then purified by column chromatography with a volume ratio of 25:75:0.1, 30:70:0.1, 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 55:45:0.1, 60:40:0.1, 65:35:0.1, 70:30:0.1, Elution with methanol-water-formic acid at 80:20:0.1 and 100:0:0 gave 20 sub-fractions, namely C15&16.1, C15&16.2, C15&16.3, C15&16.4, C15&16.5, C15&16.6, C15&16.7, C15&16.8, C15&16.9, C15&16.10, C15&16.11, C15&16.12, C15&16.13, C15&16.14, C15&16.15, C15&16.16, C15&16.17, C15&16.18, C15&16.19 and C15&16.20 (see Table 3 for the fractions corresponding to elution with cyclohexane-ethyl acetate at different volume ratios).

[0023] The sub-fraction C15 & 16.9 (149.1 mg) obtained by elution with methanol-water-formic acid in a volume ratio of 45:55:0.1 was subjected to reverse phase preparative high performance liquid chromatography. The high performance liquid chromatography preparation conditions were: elution with methanol-water-formic acid in a volume ratio of 45:55:0.1 at a flow rate of 8 mL / min to obtain the compound of formula (I) ( t R : 39.5 min, 13.9 mg, purity 95%).

[0024]

[0025] The physicochemical constants are as follows: Compound of formula (I): white needle-shaped crystals; mp 158.1−160.0 ℃; [ α ]25 D +21.7 ( c 0.1, methanol); UV (methanol) λ max (log ε ) 218 ​​(4.34), 270 (3.26) nm; IR (KBr) v max 3449,2934, 2841, 1775, 1624, 1596, 1501, 1152, 1050 cm -1 ; ESIMS (positive ion) m / z 351.2[M + H] + ; HRESIMS (positive ion) m / z 351.1076 [M + H] + (Calculated value [C 17 H 19 O8] + , 351.1074), the molecular formula of the compound is determined to be C 17 H 18 O8; hydrogen spectrum reference Figure 1 , carbon spectrum is shown in 2, data is shown in Table 4; single crystal diffraction data of the compound of formula (I) is shown in Table 5.

[0026] Formula (II) compound: white amorphous powder; α ]25 D +22.5 ( c 0.1, methanol); UV (methanol) λ max (log ε ) 208 (3.91), 233 (3.18) nm; ECD ( c 1.60 × 10 −3 M, methanol) λ max (Δ ε ) 208(4.56); IR (KBr) v max 3449, 2936, 2842, 1778, 1622, 1595, 1503, 1147, 1057 cm -1 ; ESIMS (positive ion) m / z 307.1 [M + H] + ; HRESIMS (positive ion) m / z 329.0996 [M + Na] + (Calculated value [C 16 H 18 O6Na] + , 329.0996), the molecular formula of the compound is determined to be C 16 H 18 O6; hydrogen spectrum reference Figure 3 , carbon spectrum see 4, data see Table 4.

[0027] Table 1 Correlation table of subfractions obtained by using cyclohexane-ethyl acetate as eluent with the same volume ratio

[0028] Table 2 Correlation table of subfractions obtained with different volume ratios of methanol-water-formic acid eluents

[0029] Table 3 Correlation table of subfractions obtained with different volume ratios of cyclohexane-ethyl acetate eluents

[0030] Table 4 Carbon spectrum and hydrogen spectrum data of compounds of formula (I) and formula (II) and their attribution

[0031] a The test solvent is deuterated dimethyl sulfoxide (H spectrum frequency 400 MHz, C spectrum frequency 100 MHz) b The test solvent is deuterated methanol (hydrogen spectrum frequency 600 MHz, carbon spectrum frequency 150 MHz) Table 5 Single crystal diffraction data of compound of formula (I)

[0032] Example 2 Analysis of the hepatoprotective activity of B-ring split-ring flavonoid compounds The following shows the in vitro hepatoprotective activity of the B-ring split-ring flavonoid compounds of formula (I) and formula (II) disclosed in this patent and the positive control drug silymarin.

[0033] The specific method is as follows: Establishment of alcoholic hepatocyte injury model: In a 96-well plate (100 μ L / well) and 24-well plates (500 μ L / well) were used to culture normal mouse hepatocytes at 1×10 4 and 5×10 4 The cells were plated at a density of 100 μmol / L and adhered to the wall for 24 hours. The culture medium in the wells was aspirated, and the treatment group was added with DMEM / F-12 culture medium containing 10 μmol / L of the monomer to be tested (the monomer to be tested is a B-ring split-ring flavonoid compound with a structural formula as shown in formula (Ⅰ) or a B-ring split-ring flavonoid compound with a structural formula as shown in formula (Ⅱ)) or 10 μmol / L of the positive control drug silymarin and 1000 mmol / L of anhydrous ethanol; the model group was added with DMEM / F-12 culture medium containing 1000 mmol / L anhydrous ethanol, and the blank group was added with blank culture medium, and culture was continued for 24 hours. The 96-well plate was tested for cell viability using CCK-8 assay, and the 24-well plate was stained with Oil Red O for qualitative photography and quantitative detection.

[0034] Cell viability test: After 24 hours of modeling and drug administration, the cells in the 96-well wells were cultured, the culture medium in the wells was aspirated, and DMEM / F-12 culture medium containing 10% CCK-8 reagent was added, and incubated in a 37°C cell culture incubator in the dark for 2.5 hours. Subsequently, the absorbance values ​​of the above-mentioned treatment group and blank group were detected at a wavelength of 450 nm using an ELISA reader. The formula cell viability (%) = [A (treatment group) - A (blank group)] × 100%.

[0035] Preparation of Oil Red O mother liquor: Weigh 150 mg of Oil Red O solid in a dark place, add 25 mL of isopropanol, and dissolve by ultrasonication.

[0036] Preparation of Oil Red O working solution: In the dark, mix Oil Red O mother solution and ultrapure water in a ratio of 3:2, and use 0.22 μ m microporous membrane filtration.

[0037] Oil Red O staining and detection: After 24 hours of modeling and drug administration, the cells in the 24-well plate were cultured, the culture medium in the wells was aspirated, and 500 μL of μ L phosphate buffered saline was used to wash twice. Then 4% paraformaldehyde was added to fix for 30 minutes at room temperature in the dark, 60% isopropanol was rinsed twice, Oil Red O working solution was added to stain for 30 minutes in the dark, and the 24-well plate was washed with phosphate buffered saline and photographed under an inverted microscope. Finally, 250 μl of phosphate buffered saline was added to each well. μ L of isopropanol, shake gently. Pipette 200 μ L was placed in a 96-well plate and the absorbance was measured at 492 nm by an ELISA reader.

[0038] The results are as follows Figure 5 As shown, from Figure 5 A (cell survival rate of normal mouse liver cells induced by alcohol after 24 hours of treatment with B-ring split-ring flavonoid compounds), Figure 5 B in (quantification of Oil Red O in normal mouse hepatocytes induced by alcohol 24 h after exposure to B-ring split-ring flavonoid compounds), Figure 5 C in (ratio of Oil Red O quantification to cell survival rate of normal mouse liver cells induced by alcohol 24 hours after the B-ring split-ring flavonoid compounds were applied), Figure 5 It can be seen from D (Oil Red O staining picture of normal mouse liver cells 24 hours after the action of B-ring split-ring flavonoid compounds on alcohol-induced normal liver cells of mice) that the two B-ring split-ring flavonoid compounds of the present invention can significantly alleviate alcohol-induced normal liver liver cell damage in mice, reduce fat accumulation, and have good liver protective activity. Therefore, the two B-ring split-ring flavonoid compounds of the present invention can be used to prepare liver protective drugs.

[0039] The two B-ring split-ring flavonoid compounds prepared in the present application can significantly alleviate alcohol-induced normal liver cell damage in mice, reduce fat accumulation, and have good liver-protecting activity. Therefore, the two B-ring split-ring flavonoid compounds of the present invention can be used to prepare liver-protecting drugs.

[0040] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A B-ring split ring flavonoid, characterized in that The B-ring split ring flavonoid is isolated from cinnamon bark; its structural formula is shown in formula (I) or / and formula (II): 。 2. Use of the B-ring split-ring flavonoids according to claim 1 in the preparation of liver protection drugs.

3. A liver protection drug, characterized in that: The medicine uses the B-ring split-ring flavonoid described in claim 1 as an active ingredient.

4. The method for preparing the B-ring split-ring flavonoid according to claim 1, characterized in that: The B-ring split ring flavonoids are separated from cinnamon bark.

5. The method for preparing the B-ring split-ring flavonoid according to claim 4, characterized in that: The B-ring split ring flavonoids are obtained from cinnamon bark by extraction, concentration, extraction, column chromatography separation and reverse phase high performance liquid chromatography separation.

6. The method for preparing the B-ring split-ring flavonoid according to claim 5, characterized in that: The extraction is carried out by heating and refluxing with a 60% volume fraction ethanol aqueous solution.

7. The method for preparing the B-ring split-ring flavonoid according to claim 5, characterized in that: The extraction is carried out using dichloromethane in sequence.

8. The method for preparing the B-ring split-ring flavonoid according to claim 5, characterized in that: The specific method of separating the dichloromethane by column chromatography and reversed-phase high performance liquid chromatography is as follows: 1) gradient elution was performed with cyclohexane-ethyl acetate in a volume ratio of 99:1, 97:3, 95:5, 90:10, 85:15, 80:20, 70:30, 60:40 and 0:100 to obtain C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16 and C17, a total of 17 sub-fractions; 2) The subfraction C10 obtained by gradient elution with cyclohexane-ethyl acetate in a volume ratio of 80:20 was subjected to medium-low pressure reverse phase column chromatography, and gradient elution was performed with methanol-water-formic acid in a volume ratio of 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 60:40:0.1, 70:30:0.1, 80:20:0.1, and 100:0:0 to obtain C C10.1, C10.2, C10.3, C10.4, C10.5, C10.6, C10.7, C10.8, C10.9, C10.10, C10.11, C10.12, C10.13, C10.14, C10.15, C10.16, C10.17, C10.18, C10.19, C10.20, C10.21, C10.22 and C10.23, a total of 23 sub-fractions; 3) Using reverse phase high performance liquid chromatography, the sub-fraction C10.9 was eluted with acetonitrile-water-formic acid at a flow rate of 10 mL / min and a volume ratio of 32:68:0.1 to obtain the compound of formula (II).

9. The method for preparing the B-ring split-ring flavonoid according to claim 8, characterized in that: The subfractions C15 and C16 obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 60:40 were combined and purified by medium and low pressure reverse phase column chromatography, and then eluted with 25:75:0.1, 30:70:0.1, 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 55:45:0.1, 60:40:0.1, 65:35:0.1, 70:30:0.1, Gradient elution was performed with methanol-water-formic acid eluent of 80:20:0.1 and 100:0:0 to obtain C15&16.1, C15&16.2, C15&16.3, C15&16.4, C15&16.5, C15&16.6, C15&16.7, C15&16.8, C15&16.9, C15&16.10, C15&16.11, C15&16.12, A total of 20 sub-fractions were obtained, namely, C15&16.13, C15&16.14, C15&16.15, C15&16.16, C15&16.17, C15&16.18, C15&16.19 and C15&16.20; the sub-fraction C15&16.9 obtained by eluting with methanol-water-formic acid in a volume ratio of 45:55:0.1 was prepared by reverse phase preparative high performance liquid chromatography and eluted with methanol-water-formic acid in a volume ratio of 45:55:0.1 at a flow rate of 8 mL / min to obtain a compound of formula (I).

10. The method for preparing the B-ring split-ring flavonoid according to any one of claims 4 to 9, characterized in that: The steps are as follows: (1) Take dried cinnamon bark and extract it with 60% ethanol aqueous solution by heating and refluxing for 2 times, each time for 2 hours, filter it, and concentrate the filtrate under reduced pressure to obtain a concentrated solution; (2) extracting the concentrate with dichloromethane and collecting the extract; (3) subjecting the extract to normal pressure silica gel column chromatography, using cyclohexane-ethyl acetate with a volume ratio of 99:1, 97:3, 95:5, 90:10, 85:15, 80:20, 70:30, 60:4 and 0:100 as the elution procedure, to obtain C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16 and C17, a total of 17 sub-fractions; (4) The subfraction C10 obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 80:20 was subjected to medium-low pressure reverse phase column chromatography, and the elution procedure was 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 60:40:0.1, 70:30:0.1, 80:20:0.1, and 100:0:0 methanol-water-formic acid to obtain C10.1 and C1. C10.2, C10.3, C10.4, C10.5, C10.6, C10.7, C10.8, C10.9, C10.10, C10.11, C10.12, C10.13, C10.14, C10.15, C10.16, C10.17, C10.18, C10.19, C10.20, C10.21, C10.22 and C10.23, a total of 23 sub-fractions; (5) using reverse phase high performance liquid chromatography at a flow rate of 10 mL / min and an acetonitrile-water-formic acid eluent in a volume ratio of 32:68:0.1 to elute sub-fraction C10.9 to obtain a compound of formula (II); (6) The sub-fractions C15 and C16 obtained by eluting with cyclohexane-ethyl acetate in a volume ratio of 60:40 were combined and chromatographed on a medium-low pressure reverse phase column, and then purified by eluting with 25:75:0.1, 30:70:0.1, 35:65:0.1, 40:60:0.1, 45:55:0.1, 50:50:0.1, 55:45:0.1, 60:40:0.1, 65:35:0.1, 70:30:0.1, Elution with methanol-water-formic acid at 80:20:0.1 and 100:0:0 gave 20 sub-fractions, namely C15&16.1, C15&16.2, C15&16.3, C15&16.4, C15&16.5, C15&16.6, C15&16.7, C15&16.8, C15&16.9, C15&16.10, C15&16.11, C15&16.12, C15&16.13, C15&16.14, C15&16.15, C15&16.16, C15&16.17, C15&16.18, C15&16.19 and C15&16.20; (7) Reverse phase high performance liquid chromatography was used at a flow rate of 8 mL / min and an eluent of methanol-water-formic acid in a volume ratio of 45:55:0.1 to elute sub-fractions C15 & 16.9 to obtain the compound of formula (I).

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