Sesquiterpene compounds in a wetland wormwood, preparation method and use thereof

Abstract

This invention relates to a sesquiterpene compound from Artemisia scoparia, its preparation method, and its uses. The method uses Artemisia scoparia (… Artemisia tournefortiana Using the dried aerial parts of *Reichb.* as raw material, a total extract was obtained by extraction with organic solvents. The extract was then extracted with petroleum ether, dichloromethane, and ethyl acetate. The dichloromethane extract was separated by silica gel column chromatography, rapid preparative purification system, and semi-preparative high-performance liquid chromatography to isolate a novel sesquiterpene compound, artemisinin N. Its structure was identified by high-resolution mass spectrometry, nuclear magnetic resonance spectroscopy, and single-crystal X-ray diffraction. Studies on the anti-vitiligo effect of artemisinin N showed that it promotes melanin production by dose-dependently increasing the expression of tyrosinase protein. These results indicate that the sesquiterpene compound artemisinin N from *Reichb.* has a melanin-promoting effect and could be used in the development of drugs for the treatment of vitiligo.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical technology, specifically to a sesquiterpene compound from Artemisia argyi, its preparation method, and its uses. Background Technology

[0002] Vitiligo is an acquired chronic skin pigmentation disorder affecting 1-4% of the global population, including adults and children. It is characterized by the selective destruction of melanocytes in the skin and hair, primarily manifesting as the expansion of pigmentary lesions. While the exact pathogenesis remains unclear, potential causes include genetics, immunity, oxidative stress, and the production of inflammatory mediators. According to the regulatory network of melanin formation, upregulation of the activity of the tyrosine residues (TYR), tyrosinase-associated protein 1 (TRP-1), and tyrosinase-associated protein 2 (TRP-2) genes of microbody-associated transcription factor (MITF) ultimately promotes melanin formation.

[0003] Sesquiterpenes are secondary metabolites found in higher plants. They are natural terpenoid compounds with 15 carbon atoms in their molecules, composed of three isopentenyl units. Sesquiterpenes have been reported to possess anti-inflammatory, antitumor, antibacterial, antioxidant, and anthelmintic activities. *Artemisia scoparia* (also known as wetland artemisia) Artemisia tournefortiana Reichb. is an annual herb belonging to the genus Artemisia in the family Asteraceae, mainly distributed in Xinjiang and Tibet in my country. Xinjiang has abundant wild Reichb. resources, which have an aromatic scent, and aromatic oil can be extracted from its stems and leaves. In Xinjiang, Reichb. is a folk herbal medicine with effects of clearing heat, detoxifying, reducing inflammation, and stopping bleeding. This invention aims to deeply explore the sesquiterpenoid compounds in Reichb. and study their anti-vitiligo effects, thereby obtaining drug lead compounds and even the drug itself, thus providing a reference for the development of anti-vitiligo drugs. Summary of the Invention

[0004] The purpose of this invention is to provide a sesquiterpene compound from Artemisia scoparia, its preparation method, and its uses. The sesquiterpene is derived from Artemisia scoparia (…). Artemisia tournefortiana Thin-layer chromatography (TLC) and analytical high-performance liquid chromatography (HPLC) were used to detect and analyze the aerial parts of *Reichb.*. Organic solvent extraction was employed, followed by separation using solvent extraction, silica gel column chromatography, rapid preparative purification, and semi-preparative HPLC to obtain sesquiterpene monomeric compounds. High-resolution mass spectrometry (HMS), nuclear magnetic resonance spectroscopy (NMR), and single-crystal X-ray diffraction (XRD) confirmed these monomers as novel sesquiterpenes. Furthermore, in vitro anti-vitiligo activity and mechanism of action of this compound were investigated using mouse melanoma B16F10 cells. Results showed that the sesquiterpene compound significantly promoted tyrosinase activity and melanin content, and exerted its melanin-promoting effect by promoting TYR protein expression in a dose-dependent manner. Therefore, it can be used to prepare anti-vitiligo drugs.

[0005] The present invention discloses a sesquiterpene compound from Artemisia argyi, the structural formula of which is:

[0006]

[0007] Among them, the name of compound formula (Ⅰ) is: Artemisia lactone N.

[0008] The method for preparing the sesquiterpene compound from Artemisia argyi is carried out according to the following steps:

[0009] a. Take the dried aerial parts of Artemisia scoparia as raw material, crush them, and then extract them by percolation and cold soaking at room temperature 3-5 times with 2-5 times the volume of 70-99% ethanol aqueous solution. Combine the extracts and concentrate to obtain crude extract of Artemisia scoparia.

[0010] b. Disperse the crude extract obtained in step a with water, and extract it 3-5 times by adding petroleum ether, dichloromethane and ethyl acetate in a volume ratio of 1:1 to 1:2 with water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0011] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure, with a gradient elution using petroleum ether-ethyl acetate at a volume ratio of 100:0-0:100. The eluent of petroleum ether:ethyl acetate at a ratio of 3:1 was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography, with a gradient elution using dichloromethane-ethyl acetate at a volume ratio of 100:0-0:100. The eluent was collected and concentrated to obtain 11 fractions Fr.E1-Fr.E. 11; After combining components Fr.E3, Fr.E4 and Fr.E5, component Fr.Ea was obtained; Fr.Ea was subjected to gradient elution with a 5-80% methanol-water solution using a rapid preparative purification instrument to obtain 10 components Fr.Ea-1-Fr.Ea-10; Component Fr.Ea-6 was separated by semi-preparative liquid chromatography and eluted with a 10-99% acetonitrile-water solution or a 20-99% methanol-water solution to obtain compound (Ⅰ). The compound is Artemisia lactone N.

[0012] The use of sesquiterpenoid compounds from Artemisia argyi in the preparation of anti-vitiligo drugs.

[0013] This invention discloses a sesquiterpene compound from Artemisia scoparia, its preparation method, and its uses. Research on the anti-vitiligo mechanism of this compound shows that Artemisia scoparia lactone N has a good concentration-dependent effect on promoting tyrosinase activity and melanin content. It promotes the expression of TYR protein in a dose-dependent manner, thereby promoting melanin production. The results indicate that Artemisia scoparia lactone N promotes melanin production in mouse melanoma B16F10 cells.

[0014] The present invention describes a sesquiterpene compound from Artemisia argyi, its preparation method, and its uses. The structure of the compound was determined using high-resolution mass spectrometry, one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy, and single-crystal X-ray diffraction. The structural identification process is as follows:

[0015] Compound formula (Ⅰ): colorless, transparent crystals; HRESIMS [M+H] + 265.1435 m / z (Calculated value 265.1434) m / z C 15 H 21 O4 + ); [ α ]25 D+37.540 ( c 1.270, MeOH); 1 H and 13 The C NMR assignments are shown in Table 1; the single-crystal X-ray diffraction results are shown in Table 2. Figure 3 (CCDC 235611).

[0016] Attached Figure Description

[0017] Figure 1 This invention relates to the effects of the present invention on the melanin content and tyrosinase content of B16F10 cells;

[0018] Figure 2 This invention relates to the effect of the present invention on the expression of TYR protein in B16F10 cells;

[0019] Figure 3 For the present invention 1 H NMR spectrum (600MHz, CD3OD);

[0020] Figure 4 For the present invention 13 C10 NMR spectrum (150MHz, CD3OD);

[0021] Figure 5 This is the single-crystal X-ray diffraction pattern of the present invention;

[0022] Figure 6 This is the high-resolution mass spectrum of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual scope of protection of the present invention.

[0024] The solvent used for column chromatography was analytical grade (Tianjin Xinbote Chemical Co., Ltd.); the solvent used for high performance liquid chromatography was chromatographic grade (Merck, Germany); 100-200 mesh and 200-300 mesh silica gel (Qingdao Haiyang Chemical); Sephadex LH-20 (Stopfan); high performance liquid chromatography was equipped with a full-wavelength ultraviolet detector (Shimadzu); semi-preparative liquid chromatography (Shimadzu); mass spectrometry was performed using a quadrupole-time-of-flight hybridization mass spectrometer (Applied Biosystems, USA); nuclear magnetic resonance was performed using a VARIANV NMRS 600 MHz NMR spectrometer; optical rotation values ​​were recorded using an Autopol VI automatic polarimeter; and crystal structure was determined using a Bruker D8 VENTURE X-ray diffractometer.

[0025] The *Artemisia serrata* was collected in September 2020 from the Nanshan area of ​​Urumqi, Xinjiang Uygur Autonomous Region, and identified as *Artemisia serrata* by Associate Researcher Lu Chunfang of the Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. Artemisia tournefortiana The above-ground parts of Reichb. Example 1

[0026] a. Take 10 kg of dried Artemisia scoparia aerial parts, crush them, and extract them 5 times with 20 L of 95% ethanol at room temperature. Combine the extracts and concentrate to obtain crude extract of Artemisia scoparia.

[0027] b. Disperse the crude extract obtained in step a with water, and extract it five times in sequence with petroleum ether, dichloromethane and ethyl acetate in a volume ratio of 1:1 to water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0028] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure. Gradient elution was performed using petroleum ether-ethyl acetate mobile phases at volume ratios of 100:0, 50:1, 20:1, 10:1, 5:1, 3:1, 2:1, and 1:1. The eluent at a petroleum ether:ethyl acetate ratio of 3:1 was collected and concentrated to obtain fraction (Fr.E) of compound (Ⅰ). Fraction Fr.Ea was then subjected to silica gel column chromatography using dichloromethane-ethyl acetate mobile phases at volume ratios of 100:0–0:100 for gradient elution. The eluent was concentrated to obtain 11 fractions Fr.E1-Fr.E11; fractions Fr.E3, Fr.E4 and Fr.E5 were combined to obtain fraction Fr.Ea; Fr.Ea was subjected to gradient elution with a 5-80% methanol aqueous solution using a Flash rapid preparative purifier to obtain 10 fractions Fr.Ea-1-Fr.Ea-10; fraction Fr.Ea-6 was separated by semi-preparative liquid chromatography and isocratic elution with a 30% acetonitrile-0.1% formic acid aqueous solution to obtain the sesquiterpene compound of formula (I) Artemisia lactone N. Example 2

[0029] a. Take 10 kg of dried Artemisia argyi aerial parts, crush them, and extract them 5 times with 20 L of 70% ethanol at room temperature. Combine the extracts and concentrate to obtain crude extract of Artemisia argyi.

[0030] b. Disperse the crude extract obtained in step a with water, and extract it 5 times each with petroleum ether, dichloromethane and ethyl acetate in a volume ratio relative to water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0031] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure. Gradient elution was performed using petroleum ether-ethyl acetate with volume ratios of 100:0, 50:1, 20:1, 10:1, 5:1, 3:1, 2:1, and 1:1. The eluent at a petroleum ether:ethyl acetate ratio of 3:1 was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography with gradient elution using dichloromethane-ethyl acetate with volume ratios of 100:0–0:100. The eluent was collected. The solution was concentrated to obtain 11 components Fr.E1-Fr.E11; components Fr.E3, Fr.E4 and Fr.E5 were combined to obtain component Fr.Ea; Fr.Ea was subjected to gradient elution with a 20-80% methanol aqueous solution using a Flash rapid preparative purifier to obtain 10 components Fr.Ea-1-Fr.Ea-10; component Fr.Ea-6 was separated by semi-preparative liquid chromatography and isocratically eluted with a 45% methanol-0.1% formic acid aqueous solution to obtain the sesquiterpene compound of formula (I) as Artemisia lactone N. Example 3

[0032] a. Take 10 kg of dried Artemisia argyi aerial parts, crush them, and extract them three times with 30 L of 99% ethanol at room temperature. Combine the extracts and concentrate them to obtain crude extract of Artemisia argyi.

[0033] b. Disperse the crude extract obtained in step a with water, and extract it three times in sequence with petroleum ether, dichloromethane and ethyl acetate in a volume ratio relative to water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0034] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure. Gradient elution was performed using petroleum ether-ethyl acetate mobile phases at volume ratios of 100:0, 50:1, 20:1, 10:1, 5:1, 3:1, 2:1, and 1:1. The eluent at a petroleum ether:ethyl acetate ratio of 3:1 was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography with gradient elution using dichloromethane-ethyl acetate mobile phases at volume ratios of 100:0–0:100. The eluent was collected. The liquid was concentrated to obtain 11 components Fr.E1-Fr.E11; components Fr.E3, Fr.E4 and Fr.E5 were combined to obtain component Fr.Ea; Fr.Ea was subjected to gradient elution with a 10-80% methanol aqueous solution using a Flash rapid preparative purifier to obtain 10 components Fr.Ea-1-Fr.Ea-10; component Fr.Ea-6 was separated by semi-preparative liquid chromatography and isocratically eluted with a 30% acetonitrile-0.1% formic acid aqueous solution to obtain sesquiterpene compound of formula (I) as Artemisia lactone N. Example 4

[0035] a. Take 10 kg of dried Artemisia argyi aerial parts, crush them, and extract them three times by percolation with 40 L of 90% ethanol at room temperature. Combine the extracts and concentrate to obtain crude extract of Artemisia argyi.

[0036] b. Disperse the crude extract obtained in step a with water, and extract it 5 times each with petroleum ether, dichloromethane and ethyl acetate in a volume ratio relative to water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0037] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure. Gradient elution was performed using petroleum ether-ethyl acetate with volume ratios of 100:0, 50:1, 20:1, 10:1, 5:1, 4:1, 3:1, 2:1, and 1:1. The eluent in a 3:1 ratio of petroleum ether:ethyl acetate was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography with gradient elution using dichloromethane-ethyl acetate with volume ratios of 100:0–0:100. The eluent was collected... Eleven fractions, Fr.E1-Fr.E11, were obtained by dehydration and concentration. Fractions Fr.E3, Fr.E4, and Fr.E5 were combined to obtain fraction Fr.Ea. Fr.Ea was then subjected to gradient elution with a 10-80% methanol aqueous solution using a Flash purification instrument to obtain ten fractions, Fr.Ea-1-Fr.Ea-10. Fraction Fr.Ea-6 was separated by semi-preparative liquid chromatography and eluted with a gradient of 20-99% acetonitrile-0.1% formic acid aqueous solution to obtain a sesquiterpene compound of formula (I) as Artemisia lactone N. Example 5

[0038] a. Take 10 kg of dried Artemisia scoparia aerial parts, crush them, and extract them four times with 50 L of 80% ethanol at room temperature. Combine the extracts and concentrate to obtain crude extract of Artemisia scoparia.

[0039] b. Disperse the crude extract obtained in step a with water, and extract it four times in sequence with petroleum ether, dichloromethane and ethyl acetate in a volume ratio relative to water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0040] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure. Gradient elution was performed using petroleum ether-ethyl acetate with volume ratios of 100:0, 50:1, 20:1, 10:1, 5:1, 3:1, 2:1, and 1:1. The eluent at a petroleum ether:ethyl acetate ratio of 3:1 was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography with gradient elution using dichloromethane-ethyl acetate with volume ratios of 100:0–0:100. The eluent was collected. Eleven fractions, Fr.E1-Fr.E11, were obtained by concentration. Fractions Fr.E3, Fr.E4, and Fr.E5 were combined to obtain fraction Fr.Ea. Fr.Ea was then subjected to gradient elution with a 5-80% methanol-water solution using a Flash rapid preparative elution apparatus to obtain ten fractions, Fr.Ea-1-Fr.Ea-10. Fraction Fr.Ea-6 was separated by semi-preparative liquid chromatography with gradient elution using a 20-99% methanol-0.1% formic acid-water solution to obtain a sesquiterpene compound of formula (I) as Artemisia lactone N. Example 6

[0041] a. Take 10 kg of dried Artemisia argyi aerial parts, crush them, and extract them three times with 50 L of 95% ethanol at room temperature. Combine the extracts and concentrate them to obtain crude extract of Artemisia argyi.

[0042] b. Disperse the crude extract obtained in step a with water, and extract it 5 times each with petroleum ether, dichloromethane and ethyl acetate in a volume ratio relative to water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste.

[0043] c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure. Gradient elution was performed using petroleum ether-ethyl acetate mobile phases at volume ratios of 100:0, 50:1, 20:1, 10:1, 5:1, 3:1, 2:1, and 1:1. The eluent in a 3:1 ratio of petroleum ether to ethyl acetate was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography with gradient elution using dichloromethane-ethyl acetate mobile phases at volume ratios of 100:0–0:100. The eluent was collected... Eleven fractions, Fr.E1-Fr.E11, were obtained by dehydration and concentration. Fractions Fr.E3, Fr.E4, and Fr.E5 were combined to obtain fraction Fr.Ea. Fr.Ea was subjected to gradient elution with a 10-80% methanol-water solution using a Flash rapid preparative purifier to obtain ten fractions, Fr.Ea-1-Fr.Ea-10. Fraction Fr.Ea-6 was separated by semi-preparative liquid chromatography and isocratically eluted with a 10-99% acetonitrile-water solution to obtain a sesquiterpene compound of formula (I) Artemisia lactone N. Example 7

[0044] The detection of melanin synthesis and tyrosinase activity in melanoma B16F10 cells by the sesquiterpene compound (I) obtained from Examples 1-6:

[0045] Cell viability assay: Cell viability was assessed using a cell viability assay kit (CCK-8). Cells were resuscitated and seeded into 96-well plates. Cells were cultured until adherent, the supernatant was discarded, and medium containing 1, 5, 10, or 50 µM of the test compound was added. After culturing for 24 h, 10 µM of the test compound was added. μ Cells were cultured in L CCK-8 solution for 2 h, and the absorbance was measured at 450 nm. Untreated cells served as a blank control. Each sample was tested three times. Cell viability (%) = (OD) / (Cell Viability (%)) 450 sample-OD 450 (sample control) / (OD) 450 Comparison - OD 450 (culture medium) × 100%;

[0046] Melanin content detection: The melanin content in B16F10 cells was determined using the sodium hydroxide (NaOH) lysis method. B16F10 cells were digested, seeded in 6-well plates, and cultured overnight at 37°C. After cell attachment, the cells were drug-treated and cultured for another 48 h. The supernatant was removed, and the cells were washed twice with phosphate-buffered saline (PBS). After scraping off the cells, 100 mg of sodium hydroxide solution was added to each well. μ After complete lysis with L lysis buffer, centrifuge at 12000 rpm for 20 min, and measure the protein concentration in the supernatant; add 190 μL of lysis buffer to the precipitate. μ The absorbance of 1M NaOH lysis buffer was measured at 405 nm after incubation at 80℃ for 1 h. Dimethyl sulfoxide (DMSO) was used as a blank control, and 8-methoxypsoralen (8-MOP) was used as a positive control. Each sample was repeated three times. The relative melanin content was calculated as follows: (OD...) 405 (sample / protein concentration) / (OD) 405 (blank / protein concentration) × 100%;

[0047] Tyrosinase activity assay: using levodopa (LDOPA) L The activity of intracellular tyrosinase in B16F10 cells was detected by the DOPA oxidation method. Cells were revived, seeded into 6-well plates, and cultured overnight at 37°C. After cell attachment, the cells were drug-treated and cultured for another 24 h. The supernatant was aspirated, and the cells were washed twice with phosphate-buffered saline (PBS). 100 μL of lysis buffer containing 1% sodium deoxycholate and 1% Triton X-100 was added to each well. μL; freeze at -20℃ for 30 min, thaw at 4℃, centrifuge at 12000 rpm for 15 min; add the supernatant to a 96-well plate, adding 10 μL to each well. μ L 10 mM L Mix DOPA thoroughly and incubate at 37°C for 30 min until a light brown color appears in each well. Measure the absorbance at 490 nm. Determine the protein concentration using the remaining supernatant. Use dimethyl sulfoxide (DMSO) as a blank control and 8-MOP as a positive control. Each sample is repeated three times. Relative tyrosinase activity = (OD200 - DOPA) / (OD200 - DOPA) 490 (sample / protein concentration) / (OD) 490 (blank / protein concentration) × 100%;

[0048] Western blot analysis: All protein samples were separated by 10% SDP-PAGE, transferred to PVDF membranes, and then sealed in TBST buffer with 5% skim milk for 1 h at 20°C. Subsequently, they were incubated with specific antibodies overnight at 4°C. Protein band signals were then detected using an enhanced chemiluminescent protein blot assay kit, and quantification was performed using the Chemi-Doc MP imaging system.

[0049] Experimental results: Sesquiterpene compound (I) at 50 μ At the tested concentration of M, no significant cytotoxicity was observed, and the relative melanin content test results are shown in Table 2; the effects of sesquiterpene compound formula (Ⅰ) on melanin production and tyrosinase activity of B16F10 at concentrations of 1, 5, and 10 µM are shown in Table 2. Figure 1 As shown, treatment of B16F10 cells with 1, 5, and 10 µM sesquiterpene compound (I) significantly increased the relative melanin content, exhibiting highly significant differences; at a concentration of 50 µM, sesquiterpene compound (I) resulted in a relative melanin content of 122.36 ± 6.79% in B16F10 cells (**). p <0.01); Tyrosinase activity results showed that at a concentration of 50 μM, the sesquiterpene compound (Ⅰ) activated tyrosinase at a rate of 113.90 ± 2.52% (*). p <0.05), and at the same time, sesquiterpene compound (I) also promotes tyrosinase activity at the lowest concentration of 1 µM;

[0050]

[0051] Note: ± represents the error, n = 3; NC represents the solvent (DMSO) control group; 8-MOP is the positive control group with a concentration of 50. µ M; Compared with the blank control group (NC), ***p<0.001; ****p<0.0001;

[0052] The effect of sesquiterpene compound (I) at concentrations of 1, 5, and 10 µM on the expression level of tyrosinase protein (TYR) in B16F10 cells was detected by Western blotting. Compared with the blank control group, the expression level of TYR protein was significantly increased. The results are as follows: Figure 2 As shown, the effect of increasing concentration on promoting TYR protein expression is more significant, and data analysis shows that the difference is statistically significant.

[0053] The above experimental results indicate that sesquiterpene compound (I) promotes the expression of TYR protein in a dose-dependent manner, thereby promoting melanin production in B16F10 cells, and can be used in the development of drugs for the treatment of vitiligo.

Claims

1. A sesquiterpene compound from Artemisia argyi, characterized in that... The structural formula of this compound is: Among them, the name of compound formula (Ⅰ) is: Artemisia lactone N.

2. The method for preparing sesquiterpenoid compounds from Artemisia argyi according to claim 1, characterized in that... Follow these steps: a. Take the dried aerial parts of Artemisia scoparia as raw material, crush them, and then extract them by percolation and cold soaking at room temperature 3-5 times with 2-5 times the volume of 70-99% ethanol aqueous solution. Combine the extracts and concentrate to obtain crude extract of Artemisia scoparia. b. Disperse the crude extract obtained in step a with water, and extract it 3-5 times by adding petroleum ether, dichloromethane and ethyl acetate in a volume ratio of 1:1 to 1:2 with water. Concentrate the dichloromethane extract to obtain dichloromethane extract paste. c. The dichloromethane extract obtained in step b was subjected to silica gel column chromatography at atmospheric pressure, with a gradient elution using petroleum ether-ethyl acetate at a volume ratio of 100:0-0:

100. The eluent of petroleum ether:ethyl acetate at a ratio of 3:1 was collected and concentrated to obtain fraction Fr.E of compound (Ⅰ). Fraction Fr.E was then subjected to silica gel column chromatography, with a gradient elution using dichloromethane-ethyl acetate at a volume ratio of 100:0-0:

100. The eluent was collected and concentrated to obtain 11 fractions Fr.E1-Fr.E. 11; After combining components Fr.E3, Fr.E4 and Fr.E5, component Fr.Ea was obtained; Fr.Ea was subjected to gradient elution with a 5-80% methanol-water solution using a rapid preparative purification instrument to obtain 10 components Fr.Ea-1-Fr.Ea-10; Component Fr.Ea-6 was separated by semi-preparative liquid chromatography and eluted with a 10-99% acetonitrile-water solution or a 20-99% methanol-water solution to obtain compound (Ⅰ). The compound is Artemisia lactone N.

3. The use of the sesquiterpene compounds from Artemisia scoparia according to claim 1 in the preparation of anti-vitiligo drugs.

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