Barbaloin composition for inhibiting growth of desulfurization vibrio and generation of hydrogen sulfide as well as screening method and application of barbaloin composition

Abstract

The invention belongs to the technical field of pharmaceutical compositions, and particularly relates to an aloin composition for inhibiting growth of desulfurization vibrio and generation of hydrogen sulfide as well as a screening method and application of the aloin composition. The barbaloin, the flavone, the hippophae rhamnoides extract, the sappan wood extract and the erigeron breviscapus extract are uniformly mixed to prepare a raw material mixture, and the obtained composition is light yellow powder and has good effects of inhibiting growth of sulfate reducing bacteria and desulfurization vibrio and reducing generation of hydrogen sulfide; the method is especially suitable for solving the problem of hydrogen sulfide emission caused by sulfate reducing bacteria such as desulfurization vibrio. The method for inhibiting growth of sulfate reducing bacteria and desulfurization vibrio and reducing generation of hydrogen sulfide into natural compounds through virtual screening is novel, the composition preparation method is easy to operate, raw materials are easy to obtain, cost is low, repetition is easy, and the method has important significance on preparation of products for inhibiting growth of desulfurization vibrio and generation of hydrogen sulfide.

Description

Technical Field

[0001] This invention belongs to the technical field of deodorizing additives, specifically relating to an aloe-emodin composition that inhibits the growth of desulfurized Vibrio and the generation of hydrogen sulfide, as well as its screening method and application. Background Technology

[0002] Hydrogen sulfide (H2S) is a colorless, highly toxic, flammable gas with a strong rotten egg odor. It is widely found in oil fields, wastewater treatment plants, livestock farms, chemical production facilities, and in the gut microbiota. Its main source is sulfate-reducing bacteria (SRBs) producing it under anaerobic conditions through dissimilatory sulfate reduction. Desulfovibrio is a typical and widely distributed genus of SRBs; the H2S produced during its metabolism not only corrodes metal pipes and pollutes the environment but also poses a serious threat to animal and human health, causing intestinal inflammation, metabolic disorders, and even neurotoxicity.

[0003] Currently, control methods for hydrogen sulfide generation mainly include physical adsorption, chemical oxidation, and biological inhibition. Commonly used chemical inhibitors such as molybdates, nitrates, and aldehydes have some effectiveness, but they suffer from high costs, environmental residues, low biocompatibility, and the potential for drug resistance. Therefore, developing efficient, safe, and environmentally friendly inhibitors from natural sources has become an important research direction.

[0004] In recent years, natural plant extracts have shown great application potential in the fields of antibacterial and metabolic regulation due to their wide availability, good biocompatibility, and environmental friendliness. Natural components such as aloe-emodin, flavonoids, sea buckthorn extract, sappanwood extract, and scutellaria baicalensis extract have been reported to possess various biological activities, including antibacterial, antioxidant, and anti-inflammatory effects. However, their synergistic mechanism in inhibiting the growth of sulfate-reducing bacteria, especially desulfurization bacteria, and H2S generation has not yet been systematically studied.

[0005] Furthermore, traditional inhibitor screening methods rely heavily on experimental trial and error, which is inefficient and costly. With the development of computational biology and structural biology, virtual screening methods based on target protein structures have become an important means of rapidly discovering highly effective inhibitors. Dissimilatory sulfite reductase (Dsr) is a key enzyme in SRB that catalyzes the reduction of sulfite to hydrogen sulfide, making it an ideal drug target. However, current research on screening natural inhibitors of Dsr remains limited, lacking systematic screening strategies and effective composition design.

[0006] Therefore, developing a virtual screening method based on Dsr target structure and selecting high-efficiency compound inhibitors from natural active ingredients is of great scientific significance and application value for solving the H2S pollution problem caused by desulfurization Vibrio. Summary of the Invention

[0007] To address the above-mentioned problems, the present invention aims to provide an aloe-emodin composition that inhibits the growth of desulfurized Vibrio and the generation of hydrogen sulfide, as well as its screening method and application.

[0008] The technical content of this invention is as follows: This invention provides an aloe-acid composition that inhibits the growth of desulfurized Vibrio and the generation of hydrogen sulfide, the aloe-acid composition comprising aloe-acid, flavonoids, sea buckthorn extract, sappanwood extract, and scutellaria baicalensis extract; By weight, the ingredients are: 200-250 parts aloe vera, 100-120 parts flavonoids, 30-40 parts sea buckthorn extract, 20-30 parts sappanwood extract, and 10-20 parts scutellaria baicalensis extract.

[0009] This invention provides a method for screening aloin compositions that inhibit the growth of desulfurized Vibrio and the generation of hydrogen sulfide, comprising the following steps: 1) Identification of the protein target: Phylogenetic analysis and sequence alignment of homologous proteins of the target protein dissimilatory sulfite reductase (Dsr). 1.1) Obtain the sequence and crystal structure of the target enzyme (Dsr) from the Uniprot and PDB databases: Download the amino acid sequence and protein crystal structure of the dissimilatory sulfite reductase produced by Desulfovibrio vulgaris from the Uniprot and PDB databases, respectively. 1.2) Perform phylogenetic analysis and sequence multiple alignment: The Dsr phylogenetic tree was generated using MEGA X (neighbor-join method). The crystal protein structure was aligned using Parwise Structure Alignment from the RCSB PDB. 1.3) Using structural analysis software to determine the enzyme's active pocket and key amino acid residues: The Site Finder module of the MOEv2015.10011 software was used to analyze different active sites to determine the amino acid residues involved in the substrate binding pocket. Clustal Omega was used to perform multiple alignments of Dsr homologous protein sequences, and Jalview was used to edit, visualize, and analyze the sequence alignments.

[0010] 2) Virtual screening based on Dsr enzyme structure to identify potential compounds. 2.1) Establish a preliminary screening compound library and perform similarity screening with known inhibitors: Randomly select 320,000 molecules from the ChemBridge compound database as a virtual screening database, compare the two-dimensional structural similarity of the 320,000 molecules with inhibitor molecules with known Dsr structures, and calculate the similarity value. 2.2) Molecular filtering using drug-likeness rules: The top 10,000 molecules with the highest similarity values ​​(minimum similarity value 0.53) were selected and filtered using the opera's slead-like filter in MOE. Molecules that did not meet the following conditions were removed: a) Number of N or O atoms acting as hydrogen bond donors ≤ 5; b) Number of N and O atoms acting as hydrogen bond acceptors ≤ 8; c) Molecular weight ≤ 450; d) LogP value in the range of [-3.5-4.5]; e) Number of tricyclic to octagonal rings ≤ 4; f) Number of rotatable bonds ≤ 10. The filtered molecules were further processed using the Wash module in MOE. 2.3) Molecular docking calculations were performed using the Dsr protein as the acceptor: Molecular docking was performed using Dsr as the acceptor. The binding pocket in the protein was determined using the Site Finder module in MOE. Before docking, the AMBER10:EHT force field and R-field implicit solvent model were selected, and docking was performed using the induced fit mode. After the acceptor was imported into the MOE software, the protonation state of the protein and the position of hydrogen atoms were determined using the LigX module in the MOE software, with pH=7 and temperature set at 300K. 2.4) Based on docking scoring and cluster analysis, 20 diverse candidate compounds (hit compounds) were finally selected: The binding patterns of ligands and receptors were ranked using the London dG scoring function, and the top 10 conformations were then evaluated again using the GBVI / WSAdG method to obtain the final conformations. After docking, the 100 compounds with the lowest docking scores were selected for molecular fingerprint clustering analysis, and a diverse subset with 20 matching compounds was finally identified. Five compounds were screened: flavonoids, aloin, isorhamnetin, rutin, and baicalin. The best potential compound selected was aloin. 3) Preliminary screening of sulfate-reducing bacteria enrichment communities using compounds. 3.1) Microbial enrichment and culture: Enrichment of SRB mixed microbiota from fecal samples When poultry and livestock manure is cultured, a black precipitate (FeS) appears in the culture system, accompanied by the release of a rotten egg odor (H2S), indicating that sulfate-reducing bacteria (SRB) in the manure have been enriched and can be used for further isolation of desulfovibrio (DSV). The enriched SRB bacterial solution was serially diluted with sterile physiological saline and spread on Postgate solid medium. The appropriate gradient plate was selected, and different colonies were streaked according to different colony morphology, size and other indicators until the colony morphology and size were uniform. Finally, single colonies with different morphology, size and other indicators were inoculated into Postgate medium for anaerobic culture. 3.2) Preliminary activity test The candidate compounds were co-cultured with enriched SRB bacterial communities; 3.3) Effect Evaluation By measuring the pH value, sulfate consumption, and the yield of metabolites such as hydrogen sulfide / methanethiol after culture, the inhibitory effect of the compound on the activity of the entire SRB community was preliminarily evaluated.

[0011] 4) Compound-based single-strain rescreening of desulfurized Vibrio. A purified single colony of *Desulfovibrio vulgaris* was isolated from the enriched bacterial community, and its growth curve was determined. The same specificity activity test and effect evaluation were then performed. This invention also provides the application of an aloe-emodin composition in the preparation of a product that inhibits the growth of *Desulfovibrio vulgaris* and the generation of hydrogen sulfide.

[0012] The beneficial effects of this invention are as follows: This invention relates to an aloe-emodin composition that inhibits the growth of desulfurizing Vibrio and hydrogen sulfide production. The raw material mixture is prepared by blending aloe-emodin, flavonoids, sea buckthorn extract, sappanwood extract, and *Erigeron breviscapus* extract. The resulting composition is a pale yellow powder and exhibits excellent effects in inhibiting the growth of sulfate-reducing bacteria and desulfurizing Vibrio, and reducing hydrogen sulfide production. It is particularly suitable for addressing hydrogen sulfide emissions caused by sulfate-reducing bacteria such as desulfurizing Vibrio. Furthermore, this invention provides a novel method for virtual screening of natural compounds that inhibit the growth of sulfate-reducing bacteria and desulfurizing Vibrio, and reduce hydrogen sulfide production. The screening method is novel, and the composition preparation method is simple to operate, uses readily available raw materials, is low in cost, and is easily reproducible. This is of great significance for preparing products that inhibit the growth of desulfurizing Vibrio and hydrogen sulfide production. Attached Figure Description

[0013] Figure 1 The results show the homology comparison of three different polypeptide subunits of Dsr. Figure 2 The crystal structure diagram of the Dsr enzyme protein and the structure diagrams of its binding with the cofactor Siroheme-[4Fe4S] and Sirohydrochlorins, respectively; Figure 3 Schematic diagram of the binding site of DsrA subunit to [4Fe4S] and substrate binding site, and the binding site of DsrB subunit to Siroheme-[4Fe4S] coupling cofactor; Figure 4 A schematic diagram of a screening strategy for compounds that target and inhibit Desulfovibrio vulgaris Dsr; Figure 5 This is a structural diagram of aloin combined with the Siroheme-[4Fe4S] coupling cofactor; Figure 6 To demonstrate the inhibition of SRB growth and hydrogen sulfide generation by the aloin composition, (A) enriched culture medium, (B) SRB growth curve, (C) SRB before and after culturing with the aloin composition, and (D) OD. 600 Values, (E) pH, (F) sulfate content, (G) H2S content dissolved in the culture system, (H) H2S content released from the culture system, and (I) methanethiol content released from the culture system. Data are expressed as mean ± standard deviation (n=6) and analyzed using one-way ANOVA. Significant differences are expressed as follows: * p<0.05, ** p<0.01, *** p<0.001; Figure 7 To show the inhibition of D. vulgaris growth and hydrogen sulfide production by the aloin composition, (A) D. vulgaris growth curve, (B) D. vulgaris growth before and after cultivation with the aloin composition, (C) OD 600 (D) pH, (E) sulfate content, (F) H2S content dissolved in the culture system, (G) H2S content released from the culture system, and (H) methanethiol content released from the culture system. Data are expressed as mean ± standard deviation (n=6) and analyzed using one-way ANOVA. Significant differences are expressed as follows: * p<0.05, ** p<0.01, *** p<0.001. Detailed Implementation

[0014] The present invention will be further described in detail below through specific implementation examples and accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope of the appended claims.

[0015] Unless otherwise specified, all raw materials and reagents used in this invention are from the conventional market.

[0016] Example 1 A method for screening natural compounds that inhibit the growth of sulfate-reducing bacteria and desulfurizing Vibrio, and reduce the formation of hydrogen sulfide. 1) Phylogenetic analysis and sequence alignment of homologous proteins of the target protein dissimilatory sulfite reductase (Dsr) The amino acid sequence and protein crystal structure of dissimilatory sulfite reductase (Dsr) produced by *Desulfovibrio vulgaris* were downloaded from the Uniprot and PDB databases (PDB ID: 2V4J). A phylogenetic tree of Dsr was generated using MEGA X (neighbor-join method). The crystal protein structure was aligned using Pairwise Structure Alignment in the RCSB PDB. The amino acid residues involved in the substrate binding pocket were identified using the Site Finder module of MOE v2015.10011 software, and multiple alignments of Dsr homologous protein sequences were performed using Clustal Omega. The sequence alignments were edited, visualized, and analyzed using Jalview.

[0017] The results of the Desulfovibrio spp. Dsr enzyme homology comparison are as follows: Figure 1 As shown, Dsr is a hexamer composed of three different polypeptide subunits in an α2β2γ2 structure (DsrA, DsrB, and DsrC subunits). Dsr from different Desulfovibrio strains showed high amino acid sequence homology with Dsr from Desufovibrio vulgaris that was biochemically identified (DsrA: 70-96%; DsrB: 71-96%; DsrC: 80-97%).

[0018] Depend on Figure 2 It is evident that Dsr contains two Siroheme-[4Fe4S] coupling cofactors (catalytically active sites) bound to DsrB, two Sirohydrochlorins bound to DsrA, and two [4Fe4S] (non-catalytically active) substrates, SO3. 2- The S atom in the middle coordinates with the iron atom in the Siroheme, and the oxygen atom forms hydrogen bonds with Arg-101, Arg-172, Lys-213 and Lys-215 of the DsrA subunit.

[0019] Depend on Figure 3 It is evident that the DsrA subunit forms a strictly conserved CX5CXnCX3C motif with four Cys residues (Cys-177, Cya-183, Cys-221, Cys-225) bound to the [4Fe4S] group near the Sirohydrochlorin group; and with the substrate SO3 2-The four bound residues (Arg-101, Arg-172, Lys-213, Lys-215) are strictly conserved. The four Cys residues (Cys-151, Cys-188, Cys-189, Cys-193) bound to the DsrB subunit and the catalytic coupling cofactor form a strictly conserved motif of CXnCCX3C.

[0020] 2) Virtual screening based on Dsr enzyme structure 320,000 molecules were randomly selected from the ChemBridge compound database as a virtual screening database. These 320,000 molecules were compared with inhibitor molecules whose Dsr structures are known, and the similarity scores were calculated. The top 10,000 molecules with the highest similarity scores (minimum similarity value 0.53) were selected and filtered using the opera's lead-like filter in MOE. Molecules that did not meet the following criteria were removed: a) Number of N or O atoms acting as hydrogen bond donors ≤ 5; b) Number of N and O atoms acting as hydrogen bond acceptors ≤ 8; c) Molecular weight ≤ 450; d) LogP value in the range of [-3.5-4.5]; e) Number of tricyclic to octagonal rings ≤ 4; f) Number of rotatable bonds ≤ 10.

[0021] The obtained molecules were filtered and further processed using the Wash module in MOE. Molecular docking was then performed using Dsr as the acceptor. The binding pocket in the protein was determined using the Site Finder module in MOE. Before docking, the AMBER10:EHT force field and R-field implicit solvent model were selected, and docking was performed in induced fit mode. After importing the acceptor into MOE software, the protonation state and hydrogen atom positions of the protein were determined using the LigX module in MOE software, with pH=7 and temperature set to 300K. First, the binding modes of the ligand and acceptor were ranked using the London dG scoring function, and then the top 10 conformations were re-evaluated using the GBVI / WSAdG method to obtain the final conformation. After docking, the 100 compounds with the lowest docking scores were selected for molecular fingerprint clustering analysis, and a diverse subset with 20 matching compounds was finally identified.

[0022] Depend on Figure 4 It is evident that by competing with the substrate sulfite for binding sites, the binding of sulfite to the Siroheme-[4Fe4S] coupling cofactor at the catalytic center can be inhibited, thus enabling the screening of potential target compounds from a known compound library.

[0023] Depend on Figure 5As can be seen, a total of five compounds were screened: flavonoids, aloin, isorhamnetin, rutin, and baicalin. The binding energies of these compounds with the catalytically active center of sulfite, Siroheme-[4Fe4S], were -7.6, -8.3, -7.7, -7.9, and -8.0 kcal / mol, respectively. Among them, aloin had the lowest binding energy. Therefore, aloin was selected as the best potential screening compound for further experimental verification.

[0024] Example 2 Aloe-glycoside Compositions and Their Applications 1) Preparation of aloin composition Accurately weigh 200-250 parts of aloin, 100-120 parts of flavonoids, 30-40 parts of sea buckthorn extract, 20-30 parts of sappanwood extract, and 10-20 parts of scutellaria baicalensis extract, and mix them well to obtain an aloin composition.

[0025] In the following experiment, the median values ​​of each component were weighed for testing: 225 parts of aloin, 110 parts of flavonoids, 35 parts of sea buckthorn extract, 25 parts of sappanwood extract, and 15 parts of gentian extract.

[0026] 2) Enrichment of sulfate-reducing bacteria and cultivation of desulfurizing Vibrio Take 0.1 g of fresh piglet feces, add 5 mL of sterile physiological saline, and vortex for 10 min to form a turbid and homogenous slurry. Centrifuge at 300 rpm / min at room temperature for 10 min to remove insoluble residue. Then, inoculate the diluted feces solution into 30 mL of liquid Postgate medium at a 10% inoculation rate. Incubate anaerobically at 37℃ for 4-5 days, and subculture 3-4 times. After 5 days of culture in Postgate medium, compared with the blank medium, the enriched solution of piglet feces samples showed a large amount of black precipitate (FeS), accompanied by a rotten egg odor. H2S was detected at the mouth of the culture bottle using lead acetate test paper, indicating that SRB in the feces was enriched by Postgate medium. Figure 6 A in the formula can be used for further isolation of Desulfovibrio (DSV).

[0027] The enriched SRB bacterial culture was serially diluted with sterile physiological saline, and 10 μL of each diluted solution was taken. -4 10 -5 and 10 -6Three gradient dilutions of bacterial culture, 100 μL each, were spread onto Postgate agar plates and incubated anaerobically at 37°C for 5–7 days. Using appropriately gradient plates, different colonies were selected and streaked according to their morphology and size until uniformity in colony morphology and size was achieved. Finally, single colonies with different morphologies and sizes were inoculated into Postgate agar plates and incubated anaerobically at 37°C.

[0028] 3) Determination of growth curves of SRB and Desulfovibrio vulgaris OD of SRB and D. vulgaris seed culture 600 The pH was adjusted to 0.4, and the culture was inoculated into Postgate medium at a 10% inoculum size and incubated anaerobically at 37°C. The OD values ​​of the culture were measured at 0, 1, 2, 4, 8, 12, 24, 36, 48, 72, 96, 120, and 144 h post-inoculation. 600 Values ​​are used to plot growth curves.

[0029] The enriched bacterial community SRB was in a slow growth phase from 0 to 12 hours, entered a logarithmic growth phase after 12 hours, reached its peak at 48 hours, and then entered a plateau phase. Figure 6 (B in the text). Therefore, 48 h was selected as the co-culture time with the aloin composition.

[0030] 4) Co-culture of sulfate-reducing bacteria, desulfurizing Vibrio, and aloe-emodin combination SRB and DSV were cultured to the logarithmic plateau phase and used as seed cultures. Co-culture fermentation was performed using fermentation tubes. 10 mL of liquid Postgate medium, 1 mL of SRB or DSV seed culture, and 100 μL of different concentrations of aloin combinations (see Table 1) were added to each fermentation tube, resulting in final concentrations of 0.4624 g / L (concentration 1, total weight 5.13 mg), 1.8489 g / L (concentration 2, total weight 20.52 mg), and 3.6978 g / L (concentration 3, total weight 41.05 mg). Anaerobic culture was performed at 37°C for 48 h for SRB and 24 h for DSV. 100 μL of liquid Postgate medium was added as a blank control.

[0031] Table 1 Dosage of each component in the aloe-emodin composition

[0032] After co-culturing with the aloin composition for 48 h, compared with the control group, the aloin composition significantly reduced the OD of SRB in a dose-dependent manner. 600 value( Figure 6 (D) indicates that the growth of SRB was significantly inhibited, and Figure 6The C value in the figure shows that the black FeS precipitate in the aloin composition group decreases with increasing concentration of the aloin composition.

[0033] 5) Determination of pH value and sulfate level After co-cultivation, the culture medium was centrifuged at 10,000 rpm / min and 4℃ for 10 min. The supernatant was used for pH, sulfate, and hydrogen sulfide determination. The pH value of the supernatant was measured using a pH meter. The sulfate content in the culture supernatant was determined using a turbidimetric method, based on the relationship between sodium-barium mixed stabilizer and SO42-. 2- The absorbance curve of the reaction yields the SO4 in the solution. 2- The content of.

[0034] Compared with the control group, the pH of the culture system also decreased with increasing concentration of the aloin composition. Figure 6 (E in the text).

[0035] The initial sulfate concentration was kept consistent across all culture systems; therefore, the amount of sulfate consumed indirectly reflects the growth of SRB and the generation of H2S. Figure 6 As shown in F, the sulfate concentration was lowest in the control group. With increasing concentration of the aloin composition, the sulfate content in the culture system gradually increased, indicating a gradual decrease in sulfate consumption. Of the H2S produced by SRB metabolism, some dissolves in the culture system, while the rest escapes into the air as a gas.

[0036] 6) Determination of hydrogen sulfide and methanethiol The concentrations of gaseous hydrogen sulfide and methanethiol in the co-culture system were determined using a Fuli F80 gas chromatograph (Zhejiang Fuli Analytical Instrument Co., Ltd.; model: F80). The concentrations of sulfur in the culture medium... 2- Hydrogen sulfide was detected using a detection kit (Nanjing Jiancheng Bioengineering Institute; catalog number: A146-1-1).

[0037] In the control group, the concentration of H2S dissolved in the culture system was the highest. The 0.4624 g / L aloin composition reduced the H2S concentration by 37.03%, while the 1.8489 and 3.6978 g / L aloin compositions reduced the H2S concentration by 63.56% and 67.39%, respectively. Figure 6 Similarly, the H2S content escaping from the culture system decreased by 48.51%, 80.84%, and 83.74% in the 0.4624, 1.8489, and 3.6978 g / L aloe-glycoside combination groups, respectively. Figure 6 The H in the methanethiol content decreased by 42.66%, 64.32%, and 68.16%, respectively. Figure 6 (I in the middle).

[0038] The enriched SRB bacterial suspension was subjected to initial plate screening and multiple secondary screenings, ultimately identifying one strain of *D. vulgaris*, and its growth curve was plotted. *D. vulgaris* exhibited a slow growth phase from 0 to 4 hours, entered a logarithmic growth phase after 4 hours, reached its peak at 24 hours, and then entered a plateau phase. Figure 7 (A in the text). Therefore, 24 hours was selected as the co-culture time with the aloin composition.

[0039] After co-culturing with the aloin composition for 24 h, compared with the control group, the aloin composition significantly reduced the OD of D. vulgaris in a dose-dependent manner. 600 value( Figure 7 The C in the figure indicates that the growth of D. vulgaris was significantly inhibited, and Figure 7 Figure B shows that the black FeS precipitate in the aloin composition group decreased with increasing aloin composition concentration. Compared with the control group, the pH of the culture system also decreased with increasing aloin composition concentration. Figure 7 (D) in the middle. Figure 7 As shown in Figure E, the sulfate concentration was lowest in the control group. With increasing concentration of the aloin composition, the sulfate content in the culture system gradually increased, indicating a gradual decrease in sulfate consumption. In the control group, the H2S concentration dissolved in the culture system was highest, while the 0.4624 g / L aloin composition reduced the H2S concentration by 36.76%. In the 1.8489 and 3.6978 g / L aloin composition groups, the H2S concentration decreased by 54.91% and 60.24%, respectively. Figure 7 Similarly, the H2S content escaping from the culture system decreased by 32.60%, 40.94%, and 43.94% in the 0.4624, 1.8489, and 3.6978 g / L aloe-glycoside combination groups, respectively. Figure 7 In the G group, methanethiol decreased by 31.32%, 43.20%, and 47.44%, respectively. Figure 7 (H in the text).

Claims

1. An aloe-emodin composition for inhibiting the growth of *Vibrio desulfurans* and the generation of hydrogen sulfide, characterized in that, The aloe-glycoside composition includes aloe-glycoside, flavonoids, sea buckthorn extract, sappanwood extract, and scutellaria baicalensis extract.

2. The aloin composition according to claim 1, characterized in that, by weight, it comprises 200-250 parts aloin, 100-120 parts flavonoids, 30-40 parts sea buckthorn extract, 20-30 parts sappanwood extract, and 10-20 parts scutellaria baicalensis extract.

3. A method for screening natural compounds that inhibit the growth of desulfurization vibrio and the generation of hydrogen sulfide, characterized by comprising the following steps: 1) Identification of protein target - phylogenetic analysis and sequence alignment of homologous proteins of the target protein dissimilatory sulfite reductase 1.1) Obtain the sequence and crystal structure of the target enzyme Dsr from the Uniprot and PDB databases: Download the amino acid sequence and protein crystal structure of the dissimilatory sulfite reductase produced by Desulfovibrio vulgaris from the Uniprot and PDB databases, respectively. 1.2) Perform phylogenetic analysis and sequence multiple alignment: The Dsr phylogenetic tree was generated using MEGA X (neighbor-join method). The crystal protein structure was aligned using the Pairwise Structure Alignment in the RCSB PDB. 1.3) Use structural analysis software to determine the enzyme's active pocket and key amino acid residues: The different active sites recommended by the Site Finder module of MOE v2015.10011 software were used to determine the amino acid residues involved in the substrate binding pocket. Multiple alignment of Dsr homologous protein sequences was performed using Clustal Omega, and the sequence alignment was edited, visualized and analyzed using Jalview. 2) Virtual screening based on Dsr enzyme structure to identify potential compounds. 2.1) Establish a preliminary screening compound library and perform similarity screening with known inhibitors: Randomly select 320,000 molecules from the ChemBridge compound database as a virtual screening database, compare the two-dimensional structural similarity of the 320,000 molecules with inhibitor molecules with known Dsr structures, and calculate the similarity value. 2.2) Applying drug-likeness rules for molecular filtering: Select the top 10,000 molecules by similarity value and filter them using opera's lead-like filter in MOE. Molecules that do not meet the requirements will be removed. The molecules obtained by filtration are further processed using the Wash module in MOE. 2.3) Molecular docking calculations were performed using the Dsr protein as the acceptor: Then, molecular docking was performed, using Dsr as the acceptor; The binding pocket in the protein was determined using the Site Finder module in MOE; Before docking, the AMBER10:EHT force field and R-field implicit solvent model were selected, and docking was performed using the induced fit mode. After the receptor is imported into the MOE software, the protonation state of the protein and the position of the hydrogen atom are determined by the LigX module in the MOE software. 2.4) Based on docking scoring and cluster analysis, 20 diverse candidate compounds were finally selected: the binding modes of the ligand and the receptor were ranked by the London dG scoring function, and then the top 10 conformations were evaluated again by the GBVI / WSA dG method to obtain the final conformations. After docking is completed, the 100 compounds with the lowest docking scores are selected for molecular fingerprint clustering analysis, and finally a diverse subset with 20 matching compounds is identified. Five compounds were screened out: flavonoids, aloin, isorhamnetin, rutin, and baicalin. The best potential compound screened was aloin. 3) Preliminary screening of sulfate-reducing bacteria enrichment communities using compounds. 3.1) Microbial enrichment and culture: Enrichment of SRB mixed microbiota from fecal samples Poultry and livestock manure was cultured. When black precipitate appeared in the culture system and a rotten egg smell was emitted, it indicated that sulfate-reducing bacteria in the manure had accumulated. Then, desulfurization Vibrio was isolated. The enriched SRB bacterial solution was serially diluted with sterile physiological saline and spread on Postgate solid medium. Appropriate gradient plates were selected, and different colonies were streaked according to different colony morphology, size and other indicators until the colony morphology and size were uniform. Finally, single colonies with different morphology, size and other indicators were selected and inoculated into Postgate medium for anaerobic culture. 3.2) Preliminary activity test The candidate compounds were co-cultured with enriched SRB bacterial communities; 3.3) Effect Evaluation By measuring the pH value, sulfate consumption, and the yield of metabolites such as hydrogen sulfide and methanethiol after culture, the inhibitory effect of the compound on the activity of the entire SRB community was preliminarily evaluated. 4) Compound-based single-strain rescreening of desulfurized Vibrio. A purified single colony of *D. vulgaris* was isolated from the enriched bacterial community, and its growth curve was determined. The same specific activity test and effect evaluation were then performed.

4. The screening method according to claim 3, characterized in that, The minimum similarity value is 0.

53.

5. The screening method according to claim 3, characterized in that, The non-compliant molecules will be removed under the following conditions: a) the number of N or O atoms acting as hydrogen bond donors ≤ 5; b) the number of N and O atoms acting as hydrogen bond acceptors ≤ 8; c) molecular weight ≤ 450; d) logP value in the range of [-3.5-4.5]; e) the number of tricyclic to octagonal rings ≤ 4; f) the number of rotatable bonds ≤ 10.

6. The screening method according to claim 3, characterized in that, The LigX module is set to pH=7 and temperature=300K.

7. The screening method according to claim 3, characterized in that, Five natural compounds were ultimately screened out: flavonoids, aloin, isorhamnetin, rutin, and baicalin.

8. The screening method according to claim 7, characterized in that, The final natural compound screened was aloe-emodin.

9. The use of an aloe-emodin composition according to claim 1 or 2, or a natural compound according to claim 7 or 9, in the preparation of a product that inhibits the growth of Vibrio desulfurans and the generation of hydrogen sulfide.

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