Application of alkaloid compound in preparation of product with effect of resisting respiratory syncytial virus

Abstract

The invention belongs to the technical field of medicinal chemistry, and particularly relates to application of an alkaloid compound in preparation of a product with a respiratory syncytial virus resisting effect. The alkaloid compound with a brand new chemical structure is extracted from peganum harmala, the compound shows very remarkable respiratory syncytial virus resistance activity, and the activity intensity of the compound is equivalent to that of a positive drug ribavirin. Meanwhile, the selection index (SI value) of the compound is greater than 13.8, which indicates that the safety range of the compound is larger, and the use safety can be better guaranteed while the drug effect is exerted. Therefore, the compound serving as an active ingredient is used for preparing medicines or health-care products with the effect of resisting the respiratory syncytial virus, and has important application value and wide development prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pharmaceutical chemistry, and particularly relates to application of an alkaloid compound in preparation of a product with an anti-respiratory syncytial virus effect. BACKGROUND

[0002] Respiratory syncytial virus (RSV) is a single-stranded RNA virus of the Paramyxoviridae family of the Pneumovirus genus. This virus can infect the respiratory mucosa and cause acute respiratory infections, especially in infants, the elderly, and people with weak immune systems, and can cause severe lower respiratory tract diseases such as bronchiolitis and pneumonia. According to the World Health Organization (WHO), RSV is one of the main causes of hospitalization of infants worldwide, with about 33 million children under the age of 5 infected with RSV each year, of which about 3 million cases require hospitalization and cause about 60,000 deaths. In addition, RSV infection is also common in the elderly, especially those over 65 years old, and can cause serious complications and even death after infection. RSV infection has strong seasonality, and is usually more common in winter and early spring. At present, the treatment methods for RSV are relatively limited, mainly supporting treatment, such as improving hypoxia symptoms by oxygen inhalation, and maintaining water and electrolyte balance by fluid infusion. In the prevention field, although Palivizumab can be used for RSV prevention in high-risk infants, due to its high cost and limited scope of application, its popularization and application are hindered to some extent. In addition, the high variability of RSV poses significant challenges to vaccine development, and so far no RSV vaccine has been widely used in the population. Therefore, to effectively deal with this global public health problem, developing new anti-RSV drugs and vaccines has become one of the core directions of current medical research.

[0003] Natural medicine has the advantages of wide range of action, safety and reliability, and gradually becomes the research hotspot of antiviral drugs. Among them, the Peganum harmala L. is the dried mature seeds of Peganum harmala L. of the family Zygophyllaceae, also known as Kukuxi, Shapengdou, Adiyesman (Uyghur medicine name), Umshi-Ubs (Mongolian medicine name) and so on, and is widely distributed in Asia, Europe, North Africa and other places. Peganum harmala L. has a long history of medicine, has the effects of promoting lung qi, relieving cough and asthma, expelling wind and dampness, and eliminating swelling and poison, and is recorded in a large number of Chinese medicine, Mongolian medicine and Uyghur medicine classics, and is often used for treating cough and asthma, rheumatic arthralgia, unknown swelling and poison, and skin itching. Modern pharmacological studies show that the Peganum harmala L. extract has antiviral, antitumor, antibacterial, anti-inflammatory, antioxidant and other pharmacological activities, and the alkaloid components rich in the Peganum harmala L. extract are the main pharmacodynamic material basis for exerting pharmacological effects. Therefore, if the Peganum harmala L. extract is developed into a drug for resisting respiratory syncytial virus (RSV), it will have important application value. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the Peganum harmala L. is used as a raw material to extract a novel alkaloid compound, and the alkaloid compound has very excellent anti-respiratory syncytial virus effect, and the anti-respiratory syncytial virus activity of the alkaloid compound is equivalent to that of the positive drug ribavirin, and shows important potential application value.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0006] The first aspect of the present application provides an alkaloid compound, and the alkaloid compound has the structure shown in formula I:

[0007]

[0008] The alkaloid compound (abbreviated as PL-30) shown in formula I is a novel compound; research shows that the IC 50 of the alkaloid compound shown in formula I to respiratory syncytial virus is 7.23±0.85 μM, which is equivalent to the IC 50 (6.9±0.63 μM) of the positive drug ribavirin to respiratory syncytial virus; this shows that the alkaloid compound shown in formula I has very significant anti-respiratory syncytial virus activity, and the anti-respiratory syncytial virus activity is equivalent to that of the positive drug ribavirin; and the technical effect is unpredictable by the person skilled in the art.

[0009] The second aspect of the present application provides a Peganum harmala L. extract containing the alkaloid compound of the first aspect.

[0010] The third aspect of the present application provides a preparation method of the Khat fruit extract of the second aspect, which comprises the following steps:

[0011] S1, taking Khat fruit medicinal materials and crushing, using ethanol for cold extraction to obtain total extract;

[0012] S2, the total extract is treated by "acid extraction and alkali precipitation", and the total alkaloid component is obtained: after the total extract is dispersed in water, the pH of the solution is adjusted to 2-3 with dilute hydrochloric acid, and the main acidic substances in the total extract are extracted with dichloromethane; then the pH of the acid solution is adjusted to 9-10 with ammonia water, and the total base is extracted with dichloromethane, that is, the total alkaloid is obtained;

[0013] S3, the total alkaloid is separated on a silica gel column to obtain a silica gel column chromatography elution fraction: the total alkaloid is separated by silica gel column chromatography, dichloromethane / methanol system is selected, and elution is carried out according to the concentration gradient of 1000 / 0→0 / 1000, and after TLC analysis, five fractions Fr.A-Fr.E are obtained;

[0014] S4, the silica gel column chromatography elution fraction is separated on an ODS column to obtain an ODS elution fraction: the fraction Fr.B is separated on an ODS column, first eluted with methanol / water solvent with a volume ratio of 60:40, and the eluate is discarded; then eluted with methanol / water solvent with a volume ratio of 80:20, and the eluate is collected, concentrated and dried to obtain the ODS elution fraction, that is, the Khat fruit extract containing the alkaloid compound of claim 1 is obtained.

[0015] The present application first separates the alkaloid compound of formula I from Khat fruit, and provides a novel method for preparing the alkaloid compound of formula I.

[0016] Preferably, in S1, the ethanol is 95% ethanol; in S3, the elution according to the concentration gradient of 100 / 0→0 / 100 refers to the elution according to the concentration gradient of 1000:0, 1000:10, 1000:50, 1000:500, 0:1000.

[0017] The fourth aspect of the present application provides a preparation method of the alkaloid compound of the first aspect, that is, after the Khat fruit extract is prepared by the preparation method of the third aspect, the alkaloid compound of the first aspect is prepared by HPLC, and the HPLC preparation adopts a C18 reverse phase preparative column, methanol-water-ammonia water as the mobile phase, and isocratic elution is carried out according to the volume ratio of methanol: water (0.2% ammonia water) = 85:15 (0.2%), and the fraction corresponding to the chromatographic peak with a retention time t R = 15.2 min is collected.

[0018] The fifth aspect of this invention provides the use of the alkaloid compounds described in the first aspect or the camel husk extract described in the second aspect in the preparation of products against respiratory syncytial virus.

[0019] Since alkaloid compounds with the structure shown in Formula I have excellent anti-respiratory syncytial virus (RSV) activity, those skilled in the art can expect that extracts containing the structure shown in Formula I will also have anti-RSV activity.

[0020] Preferably, the product comprises an effective dose of the alkaloid compound described in the first aspect or the camel nut extract described in the second aspect, as well as pharmaceutically acceptable excipients.

[0021] More preferably, the excipients include at least one of the following: excipients, propellants, solubilizers, cosolvents, emulsifiers, colorants, binders, disintegrants, fillers, lubricants, wetting agents, osmotic pressure regulators, stabilizers, flow aids, flavoring agents, preservatives, suspending agents, coating materials, fragrances, anti-adhesion agents, integrators, penetration enhancers, pH adjusters, buffers, plasticizers, surfactants, foaming agents, defoamers, thickeners, encapsulating agents, humectants, absorbents, diluents, flocculants and anti-flocculators, antioxidants, adsorbents, filter aids, and release inhibitors.

[0022] Preferably, the product includes a drug or health supplement.

[0023] Preferably, the dosage form of the product includes powder, pill, tablet, capsule, oral liquid, aerosol or injection.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention extracts an alkaloid compound from *Camelum cassia*, which possesses a novel chemical structure. Studies have verified that this compound exhibits significant anti-respiratory syncytial virus (RSV) activity, comparable to the positive control drug ribavirin. More importantly, the compound has a selectivity index (SI value) > 13.8, indicating a wider safety margin and better ensuring safety during use while maintaining efficacy. Based on these characteristics, this compound, as an active ingredient, has significant application value and broad development prospects for the preparation of drugs or health products with anti-RSV activity. Attached Figure Description

[0026] Figure 1 This is a high-resolution mass spectrometry of compound PL-30.

[0027] Figure 2 The image shows the UV spectrum of compound PL-30 (soluble in methanol).

[0028] Figure 3The outer infrared spectrum of compound PL-30 (KBr pellet).

[0029] Figure 4 Nuclear magnetic resonance of compound PL-30 1 H spectrum (600MHz, dissolved in DMSO).

[0030] Figure 5 Nuclear magnetic resonance of compound PL-30 13 C spectrum (150MHz, dissolved in DMSO).

[0031] Figure 6 The NMR spectrum of compound PL-30 is DEPT-135 (150 MHz, dissolved in DMSO).

[0032] Figure 7 Nuclear magnetic resonance of compound PL-30 1 H- 1 H COSY spectrum (150 MHz, dissolved in DMSO).

[0033] Figure 8 The HSQC NMR spectrum of compound PL-30 (150 MHz, dissolved in DMSO).

[0034] Figure 9 The nuclear magnetic resonance HMBC spectrum of compound PL-30 (150 MHz, dissolved in DMSO).

[0035] Figure 10 The NMR NOESY spectrum of compound PL-30 (150 MHz, dissolved in DMSO).

[0036] Figure 11 To evaluate the cytotoxicity and anti-RSV activity of PL-30 in vitro; (A) Cell viability of PL-30 in Hep-2 cell line by CCK8 assay; (B) Cell pathological effects of PL-30, scale bar: 100 μm; (C) Effect of PL-30 on RSV infection at different MOIs: 100 μm; (D) Effect of PL-30 on RSV growth; (E) Effect of PL-30 at different addition times on viral infection. Detailed Implementation

[0037] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0039] Example 1: Extraction of compound PL-30

[0040] (1) Take 30.0 kg of dried camel pea seeds and crush them (about 80 mesh). Use 95% ethanol for cold soaking extraction (extract three times at room temperature, each extraction lasts 2 days, and each extraction uses 50L of 95% ethanol). A total of 2.3 kg of total extract was prepared.

[0041] (2) To further concentrate the alkaloid components, the total extract was subjected to an "acid extraction and alkali precipitation" treatment, ultimately yielding 1.1 kg of total alkaloid components. The specific operation of the "acid extraction and alkali precipitation" was as follows: 2 L of water was added to the total extract, and the pH of the solution was adjusted to 2-3 with 1% dilute hydrochloric acid. Then, twice the volume of dichloromethane was added for three extractions at room temperature (one day each time). The extract was discarded, and the acid solution was retained. Subsequently, 25% ammonia was added to adjust the pH of the acid solution to 9-10. Finally, twice the volume of dichloromethane was added for three extractions at room temperature (one day each time), yielding 812.3 g of extract, which is the total alkaloids.

[0042] (3) The total alkaloids were subjected to silica gel column chromatography (80-100 mesh silica gel for mixing and 200-300 mesh silica gel for loading). A gradient elution system of dichloromethane / methanol (1000 / 0→0 / 1000) was used (1000:0, 1000:10, 1000:50, 1000:500, 0:1000). After TLC analysis, five fractions, Fr.A to E, were obtained.

[0043] (4) Load the fraction Fr.B (120.0g) onto an ODS column, first elute with a methanol / water solvent with a volume ratio of 60:40, and discard the eluent; then elute with a methanol / water solvent with a volume ratio of 80:20, collect the eluent, concentrate and dry it to obtain the ODS eluent fraction.

[0044] (5) The ODS elution fraction was subjected to HPLC again (using a C18 reversed-phase preparative column, with methanol-water-ammonia as the mobile phase, and isocratic elution at a volume ratio of methanol:water (0.2% ammonia) = 85:15 (0.2%), and the retention time t was collected). R The fraction corresponding to the chromatographic peak at 15.2 min was used to prepare compound PL-30, an alkaloid compound with the structure shown in Formula I.

[0045]

[0046] The structure of compound PL-30 was identified as follows:

[0047] The structure of compound PL-30 was obtained by analyzing high-resolution mass spectrometry (HRESIMS), infrared spectroscopy (IR), and one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy (NMR).

[0048] The molecular weight of compound PL-30 was determined to be 492.2396 [M+H] using high-resolution mass spectrometry (HRESIMS: m / z). + (Theoretical value: 492.2394), indicating the molecular formula is C. 30 H 30 N5O2( Figure 1 ).

[0049] UV spectroscopy (CH3OH) showed that compound PL-30 had maximum absorption peaks at 221, 249, 277, 328, and 353. Figure 2 The results of the infrared spectroscopy determination show that ( Figure 3 Compound PL-30 contains hydroxyl groups (3370 cm). -1 ), amide (1671cm) -1 ) and benzene ring (1587cm) -1 ).

[0050] The proton NMR spectrum of compound PL-30 1 HNMR data and attribution are shown in Table 1. Figure 4 Data shows that compound PL-30 has 13 aromatic proton signals [δ]. H 7.28–7.25 (5H), 7.21–7.18 (5H), 7.08 (1H, t, J = 5.8 Hz), 7.05 (1H, t, J = 7.4 Hz), 6.80 (1H, d, J = 7.4 Hz)], one olefin proton [δ H 4.86 (1H, s)], a proton signal of a methine proton with an oxygen bond [δ H 4.01 (1H,t,J=8.0Hz)], the signal of four methylene protons bonded to nitrogen atoms [δ H 4.89(2H,m),4.45(1H,d,J=14.6Hz),4.24(1H,d,J=14.6Hz),3.30(2H,m),3.10(1H,m),2.97(1H,m)].

[0051] According to the carbon NMR spectrum of compound PL-30 13 The C NMR data and their attribution are shown in Table 1. Figure 5 Thirty carbon atom signals were observed. Further analysis using the DEPT135 spectrum revealed that the compound contains nine quaternary carbons, 15 methines, and six methylenes. It also contains three groups of benzene ring carbon signals (δ¹²).C 148.6, 141.2, 139.3, 128.8, 128.7, 128.7, 128.5, 128.3, 128.3, 128.2, 128.0, 127.4, 126.4, 126.2, 126.2, 123.1, 122.7, 121.3), four methylene groups (δ-) bonded to nitrogen atoms. C 45.0, 42.7, 42.4, 41.3), a hydroxylated methine (δ C 68.9), an amide carbonyl signal (δ C 173.5).

[0052] The data and binding relationships of the two-dimensional nuclear magnetic resonance spectrum of compound PL-30 are shown in Table 1 and Figures 6-10 As shown, the structure of compound PL-30 can be obtained from this.

[0053] The molecular designation of compound PL-30 is shown below:

[0054]

[0055] Table 1. One-dimensional and two-dimensional NMR spectra of compound PL-30 (DMSO, δin ppm, J in Hz)

[0056]

[0057] Example 2: Test of the anti-respiratory syncytial virus activity of compound PL-30

[0058] 1. CCK-8 Experiment

[0059] (1) According to 1.5×10 4 HEp-2 cells were seeded into 96-well plates to form a monolayer. After removing the culture medium (DMEM medium containing 10% FBS and 1% PS), different concentrations (3.125, 6.25, 12.5, 25, 50, 100 μM) of drug-containing medium were added. At the same time, a cell control group and a positive control group containing ribavirin were set up.

[0060] (2) After incubating in a 5% CO2 incubator at 37°C for 48 hours, add 10 μL of CCK-8 solution and incubate in the dark for about half an hour.

[0061] (3) The microplate reader is set to a wavelength of 450 nm, and the absorbance of each well in the 96-well plate is detected at this wavelength to obtain the cell viability.

[0062] (4) Calculate the half-maximal toxicity concentration (CMC) of the compound using cell viability at different drug concentrations. 50).

[0063] 2. Cytopathic Effect Method (CPE)

[0064] HEp-2 cells were seeded in 96-well plates and cultured until a cell monolayer was formed. The culture medium was discarded, and each well was added a mixture containing 50 μL of LRSV virus dilution (Mouse anti-RSV F virus, purchased from ABcam; MOI=1) and equal volumes of drug-containing culture medium at different concentrations (3.125, 6.25, 12.5, 25, 50, 100 μM). Cell control, RSV control, and Ribavirin positive control groups were also set up. After 48 hours, complete cytopathic effect was observed in the virus control group. The cytopathic effect in each group was observed and recorded. Complete cytopathic effect in the virus control group was used as the reference standard: no cytopathic effect was indicated by "-"; 0-25% cytopathic effect was indicated by "+"; 25%-50% cytopathic effect was indicated by "++"; 50%-75% cytopathic effect was indicated by "+++"; and 75%-100% cytopathic effect was indicated by "++++". The concentration corresponding to a lesion severity of "++" is the half-maximal inhibitory concentration (IC50) of the compound against RSV. 50 Afterwards, the culture medium was aspirated, paraformaldehyde was added, and then Triton solution was added to break the membrane. Then, BSA blocking buffer was added to block non-specific sites, followed by incubation with primary antibody mouse anti-RSV F overnight, and then further incubation... 488mouse fluorescent secondary antibody was applied for 2 hours. Finally, the fluorescence intensity of each well was measured using a microplate reader.

[0065] 3. Titration endpoint test (EPTT)

[0066] (1) HEp-2 cells were seeded in 96-well plates to form a monolayer. After the culture medium was removed, RSV virus solution diluted 50, 400, and 800 times (MOI=1) was used to infect the cells. At the same time, appropriate concentrations (20 μM) of compound PL-30 and ribavirin drug-containing culture medium were added and the cells were incubated in an incubator for 48 hours. In addition, a cell control group and an RSV control group were set up.

[0067] (2) Cells were then treated, including paraformaldehyde fixation, Triton solution permeabilization, and BSA blocking solution to block nonspecific sites.

[0068] (3) First, incubate overnight with the primary antibody mouse anti-RSVF, then proceed with... After 2 hours of incubation with 488mouse fluorescent secondary antibody, fluorescence images were captured using a live cell workstation.

[0069] 4. Virus growth curve

[0070] HEp-2 cells were seeded into 24-well plates and cultured until a cell monolayer was formed. The culture medium was discarded, and the cells were infected with RSV (MOI = 0.1), with PL-30 or Ribavirin (20 μM) added simultaneously. A cell control group and an RSV control group were established. On days 1, 2, 3, and 4 post-infection, the supernatant was collected by centrifugation and diluted 10-fold serially before being added back into the 24-well plates containing a confluent cell monolayer. After 2 hours, the virus solution was discarded, and 500 μL of gel covering medium was added to each well. After solidification, 500 μL of fresh maintenance medium (MM solution, i.e., DMEM containing 2% FBS) was added, and the plates were incubated for another 4 days. Formaldehyde was added to each well for fixation, followed by crystal violet solution. The number of plaques in each group was counted to determine the virus titer. Virus titer (PFU / mL) = [(P1 + P2 + ... + Pn) / n] × dilution × 1 / V (P represents the number of plaques, n represents the number of replicates, and V represents the inoculated virus volume).

[0071] 5. Time-point experiments

[0072] HEp-2 cells were seeded in 96-well plates and cultured until a monolayer was formed. The culture medium was aspirated, and cells were infected with RSV (MOI = 1, 50 μL), recorded as 0 h. Two hours after infection, the supernatant was aspirated, and unadsorbed virus was removed with PBS. Equal volumes of PL-26 and Ribavirin (20 μM) were added at 0, 1, 2, 6, 10, and 18 h post-infection, respectively, to establish cell control and RSV control groups. Twenty-four hours after infection, paraformaldehyde was added, followed by Triton solution to lyse the cell membrane, and then BSA blocking solution was added to block non-specific sites. Cells were then incubated overnight with mouse anti-RSV F. 488mouse fluorescent secondary antibody was applied for 2 hours. Finally, the fluorescence intensity of each well was measured using a microplate reader.

[0073] The experimental data in Table 2 show that compound PL-30, which has the structure of Formula I, exhibits significant inhibitory activity against respiratory syncytial virus (RSV), with a half-maximal inhibitory concentration (IC50) of [missing data]. 50 The value was 7.2 ± 0.85 μM. This activity was similar to that of the positive control drug ribavirin. 50 The values ​​(6.9±0.63 μM) are comparable, indicating that compound PL-30 has antiviral efficacy comparable to clinically used drugs. Notably, the anti-respiratory syncytial virus activity of compound PL-30 is close to that of the positive control drug acyclovir. This superior technical effect exceeds the expectations of those skilled in the art, demonstrating the innovativeness and potential application value of this compound.

[0074] According to the experimental data in Table 2, the selectivity index (SI) of compound PL-30 against respiratory syncytial virus (RSV) reached over 13.8, significantly higher than the minimum standard value of 10.0 (the source of the SI standard value can be found in the literature "Indrayanto G, Putra GS, Suhud F. Validation of in-vitro bioassay methods: Application in herbal drug research[J]. Profiles of drug substances, excipients and relatedmethodology, 2021, 46: 273-307."). This result indicates that compound PL-30 has a wide safety window in the development of anti-RSV drugs, providing a good safety guarantee for its clinical application.

[0075] Meanwhile, this invention first determined using the CCK-8 method that compound PL-30 had no significant toxicity to HEp-2 cells. 50 >100( Figure 11 A). Further treatment of virus-infected HEp-2 cells with PL-30 resulted in reduced syncytial formation, and no obvious lesions were observed. Figure 11 B). Twenty-four hours after virus infection, further immunofluorescence experiments revealed that compound PL-30 at a concentration of 20 μM significantly inhibited RSV infection, comparable to the positive control drug ribavirin (20 μM). Figure 11 C). During the 0-72 hour period of virus infection in cells, the virus grows in pairs. The addition of PL-30 significantly reduced viral production without affecting the RSV proliferation pattern. Furthermore, the inhibitory effect of PL-30 was comparable to that of the positive control drug ribavirin. Figure 11 D). Finally, time-point experiments revealed that the inhibitory effect of compound PL-30 on RSV may occur in the early stages of the viral infection process ( Figure 11 E). In summary, compound PL-30 exhibits in vitro anti-RSV activity.

[0076] Table 2. Anti-respiratory syncytial virus activity of compound PL-30

[0077]

[0078] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. An alkaloid compound, characterized in that, The alkaloid compound has the structure shown in Formula I:

2. A camel nut extract, characterized in that, The camel husk extract contains the alkaloid compound as described in claim 1.

3. The method for preparing the camel husk extract according to claim 2, characterized in that, Includes the following steps: S1. Take the camel burdock medicinal material and crush it, then use ethanol for cold soaking extraction to obtain the total extract; S2. The total extract is subjected to "acid extraction and alkali precipitation" treatment to obtain the total alkaloid components: After dispersing the total extract in water, the pH of the solution is adjusted to 2-3 with dilute hydrochloric acid, and then the main acidic substances in the total extract are extracted with dichloromethane; then the pH of the acid solution is adjusted to 9-10 with ammonia water, and the total alkali is extracted with dichloromethane to obtain the total alkaloids. S3. Separate the total alkaloids by silica gel column chromatography to obtain the silica gel column elution fraction: Separate the total alkaloids by silica gel column chromatography using a dichloromethane / methanol system with a concentration gradient of 1000 / 0→0 / 1000. After TLC analysis, five fractions, Fr.A to E, were obtained. S4. Separate the silica gel column chromatography elution fraction onto an ODS column to obtain the ODS elution fraction: Load fraction Fr.B onto an ODS column, first elute with a methanol / water solvent at a volume ratio of 60:40, and discard the eluent; then elute again with a methanol / water solvent at a volume ratio of 80:20, collect the eluent, concentrate and dry it to obtain the ODS elution fraction, which is the camel nut extract containing the alkaloid compounds described in claim 1.

4. The method for preparing camel husk extract according to claim 3, characterized in that, In S1, the ethanol is 95% ethanol; in S3, elution according to the concentration gradient of 100 / 0→0 / 100 means elution according to the concentration gradients of 1000:0, 1000:10, 1000:50, 1000:500, and 0:1000.

5. The method for preparing the alkaloid compound according to claim 1, characterized in that, After obtaining the camel burdock extract according to claim 3 or 4, the alkaloid compound described in claim 1 is obtained by HPLC preparation. The HPLC preparation uses a C18 reversed-phase preparative column with methanol-water-ammonia as the mobile phase and isocratic elution at a volume ratio of methanol:water (0.2% ammonia) = 85:15 (0.2%). The retention time t is collected. R = The fraction corresponding to the chromatographic peak at 15.2 min.

6. The use of the alkaloid compound of claim 1 or the camel husk extract of claim 2 in the preparation of products against respiratory syncytial virus.

7. The application according to claim 6, characterized in that, The product comprises an effective dose of the alkaloid compound of claim 1 or the camel nut extract of claim 2, and pharmaceutically acceptable excipients.

8. The application according to claim 6, characterized in that, The products include medicines or health supplements.

9. The application according to claim 6, characterized in that, The dosage forms of the products include powders, pills, tablets, capsules, oral liquids, aerosols, or injections.

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