Method for screening surfactant for extracting allium macrostemon polysaccharide based on molecular docking simulation

Abstract

The invention discloses a method for screening a surfactant for extracting allium macrostemon polysaccharide based on molecular docking simulation. The method comprises the following steps: (1) treating an allium macrostemon raw material; (2) constructing a surfactant model; (3) constructing an allium macrostemon polysaccharide monosaccharide model; (4) simulating and screening molecular docking; and (5) carrying out experimental verification on the candidate surfactant. According to the method, the surfactant is screened in advance through molecular docking simulation, the number of candidate agents is reduced to 3-5, the screening period is shortened to 1-2 weeks, and the problem that a traditional trial and error method consumes time and labor is thoroughly solved; the optimal extraction rate of the surfactant reaches 26.18-26.52%, and is improved by 51.91-77.87% compared with the traditional hot water extraction under the same extraction time; based on intermolecular structure complementarity and interaction energy quantification screening, the randomness of a traditional trial and error method is avoided, the docking fraction is directly associated with the surfactant-polysaccharide binding capacity, and the screened optimal surfactant is stably bound with allium macrostemon polysaccharide.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of computer simulation and natural product extraction, and relates to a method for extracting polysaccharides from Allii macrostemonis Bulbus, in particular to a method for screening surfactants for extracting polysaccharides from Allii macrostemonis Bulbus based on molecular docking simulation. BACKGROUND

[0002] Allii macrostemonis Bulbus is a homologous medicinal and edible material recorded in Chinese Pharmacopoeia, which is defined as the dried bulb of Allium macrostemon Bge. or Allium chinense G. Don in Liliaceae and has the effects of dispersing stagnation and promoting blood circulation, and is often used for treating abdominal distension and pain, and post-dysentery heaviness. Existing studies have confirmed that polysaccharides in Allii macrostemonis Bulbus are the core bioactive components and have the effects of anti-atherosclerosis, antioxidant, and hypoglycemic, but the efficient extraction is still a key bottleneck for industrial application.

[0003] At present, there are significant technical defects in the extraction of polysaccharides from Allii macrostemonis Bulbus. On the one hand, the extraction method is single, and only internal boiling method (using different concentrations of alcohol solution as solvent) is reported by Xu Yingwei et al., but this method requires special equipment and is difficult to scale up, and the rest of the studies rely on hot water extraction, which is low in extraction rate and time-consuming. On the other hand, surfactants have become important auxiliary reagents for polysaccharide extraction because they can reduce the surface tension of the solvent and destroy the cell wall structure.

[0004] However, in the existing technology, the screening of surfactants suitable for the extraction of polysaccharides from Allii macrostemonis Bulbus generally adopts the "trial and error method", which requires the extraction experiment of dozens or even hundreds of surfactants one by one, consumes a large amount of Allii macrostemonis Bulbus raw materials and chemical reagents, and has the problems of long screening period and inability to accurately match the molecular structure characteristics of Allii macrostemonis Bulbus polysaccharides, resulting in unstable extraction effect. Moreover, the existing technology does not combine computer simulation screening technology with extraction process optimization, lacks a precise extraction scheme for the characteristics of Allii macrostemonis Bulbus polysaccharides, and long-time high temperature easily causes the breakage of polysaccharide glycosidic bond, resulting in the loss of biological activity.

[0005] Through the above analysis, the problems and defects of the existing technology are as follows: (1) the screening efficiency of surfactants for the extraction of Allii macrostemonis Bulbus polysaccharides is low and the cost is high, the "trial and error method" leads to serious waste of raw materials and reagents, and cannot match the molecular structure of Allii macrostemonis Bulbus polysaccharides, resulting in unstable extraction effect; (2) the computer simulation screening technology is not combined with the extraction process optimization, lacks a precise extraction scheme for the characteristics of Allii macrostemonis Bulbus polysaccharides, and the extraction rate is low and the polysaccharide structure and activity are easily damaged; (3) the existing extraction process does not form a whole-chain control system, and the parameters of each link are isolated, which is difficult to meet the requirements of industrial production on efficiency, stability and product quality. SUMMARY

[0006] To address the shortcomings of existing methods for surfactant selection in Allium macrostemon polysaccharide extraction, which rely on trial and error and are time-consuming and labor-intensive, this invention provides a method for screening surfactants for Allium macrostemon polysaccharide extraction based on molecular docking simulation. This method constructs three-dimensional structural models of surfactants and Allium macrostemon polysaccharide monosaccharides, performs multiple rounds of docking calculations using AutoDock software, screens candidate surfactants based on interaction energies, and determines the optimal reagent through experimental verification, achieving efficient extraction of Allium macrostemon polysaccharide. This invention is both scientifically sound and economically viable, and is applicable to the industrial production of Allium macrostemon polysaccharide in the food, health product, and pharmaceutical fields.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for screening surfactants for extracting polysaccharides from Allium macrostemon based on molecular docking simulation includes the following steps:

[0009] Step (1) Processing of raw materials of Allium macrostemon: The raw materials of Allium macrostemon are crushed and pretreated with ethanol. The specific steps are as follows: Crush the dried Allium macrostemon and pass it through a 20-200 mesh sieve. Take Allium macrostemon powder and add 2-10 times the volume of 80-95% (v / v) ethanol. Reflux and extract 1-5 times at 60-90℃ for 1-5 hours each time. After degreasing and removing impurities, dry the residue for later use.

[0010] Step (2) Surfactant (ligand) model construction: Collect 20-30 kinds of green surfactants, obtain two-dimensional structures through PubChem or ChemSpider databases, convert them into three-dimensional structures using AutoDock Tools software, and construct ligand models through hydrogenation and Gasteiger charge partitioning. Among them, green surfactants include, but are not limited to, alkyl glycoside surfactants (APG1214, APG0810, APG0610), betaine surfactants (cocamidopropyl betaine CAPB, lauroamide propyl betaine LAPB), and Tween surfactants (Tween 80, Tween 60, Tween 20), and exclude strong acid / alkaline surfactants with pH < 2 or pH > 11.

[0011] Step (3) Construction of the Allium macrostemon polysaccharide monosaccharide (receptor) model: Galactose was selected as the core monosaccharide representative of Allium macrostemon polysaccharide. The two-dimensional structure was obtained through the PubChem database and converted into a three-dimensional structure using AutoDock Tools software. Density functional theory (DFT) was used to optimize the model at the B3LYP / 6-31G++(d,p) level. The hydroxyl regions at C1 and C3 were defined as docking pockets to construct the receptor model. Among them, the optimized galactose model needs to be verified by vibrational frequency analysis to ensure that there are no imaginary frequencies (frequency range 50~3500cm). - ¹), the docking pocket size is 8×8×8Å;

[0012] Step (4) Molecular docking simulation and screening: AutoDock Vina software was used to perform semi-flexible docking, and candidate surfactants were screened based on relative binding energy as the core indicator. The specific steps are as follows: AutoDock Vina software was used to perform semi-flexible docking, and the grid center was set as the geometric center of the docking pocket (X=1.25Å, Y=0.92Å, Z=0.61Å), the grid size was 20×20×20Å, and the grid spacing was 0.375Å. Docking calculations were performed, and candidate surfactants were screened based on relative binding energy. Among them, the docking screening is based on relative binding energy as the core indicator. The smaller the relative binding energy value (the larger the absolute value of the negative value), the tighter the surfactant is bound to galactose. Surfactants with relative binding energy ≤-4.5kcal / mol were selected as candidates.

[0013] Step (5) Experimental verification of candidate surfactants: The extraction rate was determined by the phenol-sulfuric acid method to identify the optimal surfactant. The specific steps are as follows: Mix the Allium macrostemon powder with the aqueous solution of the candidate surfactant at a solid-liquid ratio of 1:20~1:50, extract by stirring in a water bath at 80~140℃ for 15~150 min, centrifuge at 3000~12000 rpm for 5~20 min, take the supernatant and determine the extraction rate by the phenol-sulfuric acid method to screen the optimal surfactant. The surfactant aqueous solution concentration is 0.5~10%, preferably 1~3%; the extraction temperature is preferably 90℃, the extraction time is preferably 30 min, the solid-liquid ratio is preferably 1:20 g / mL; the centrifugation parameters are preferably 8000 rpm for 10 min, and the centrifugation temperature is controlled at 4℃. The specific operation of the phenol-sulfuric acid method to determine the extraction rate is as follows: Take 0.5 mL of supernatant, add 0.25 mL of 6% phenol solution, mix well, add 1.25 mL of concentrated sulfuric acid, react in a water bath at 40℃ for 30 min, and measure the absorbance at 490 nm. The optimal surfactant is Genapol. X-080 or APG1214 had relative binding energies of -19.7067 kcal / mol and -17.5023 kcal / mol, respectively, and polysaccharide extraction rates of Allium macrostemon were 26.52% and 26.18%, respectively. Meanwhile, with pure water as a blank control, the polysaccharide extraction rate of Allium macrostemon was 14.91%.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. Significantly improved screening efficiency: By pre-screening surfactants through molecular docking simulation, the number of candidates that can be tested one by one in the traditional method is reduced from 20 to 30 to 3 to 5. The screening cycle is shortened from 2 to 3 months to 1 to 2 weeks, reducing experimental costs (raw materials, reagents, and labor costs) by more than 70%, and completely solving the problem of time-consuming and labor-intensive traditional trial-and-error methods. The optimal surfactant extraction rate reaches 26.18 to 26.52%, which is 51.91 to 77.87% higher than that of traditional hot water extraction (14.91%) under the same extraction time.

[0016] 2. Highly scientific screening: Based on the quantification screening of intermolecular structural complementarity and interaction, it avoids the randomness of traditional trial and error methods. The docking score is directly related to the binding ability of surfactant-polysaccharide. The optimal surfactant screened binds stably with Allium macrostemon polysaccharide.

[0017] 3. Excellent economic and environmental performance: The selected surfactants do not need to be dissolved in advance and the amount used is low, which significantly reduces solvent costs; and green biodegradable surfactants are preferred, which are non-toxic and have good biocompatibility, avoiding the pollution of the environment by traditional organic solvents and conforming to the concept of green extraction. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0019] Example 1:

[0020] This embodiment provides a method for extracting polysaccharides from Allium macrostemon by molecular docking simulation screening of surfactants, the method comprising the following steps:

[0021] Step 1: Processing of raw materials for Allium macrostemon:

[0022] Pulverize the dried Allium macrostemon and pass it through an 80-100 mesh sieve. Add 5 times the volume of 95% (v / v) ethanol to the Allium macrostemon powder and reflux extract it 3 times at 85℃ for 2 hours each time. After defatting and removing impurities, dry the residue at 60℃ for 4 hours for later use.

[0023] Step 2: Construction of the Allium macrostemon polysaccharide core monomer (receptor) model:

[0024] The two-dimensional molecular structure of galactose (CAS No.: 59-23-4) was obtained from the PubChem database and converted into a three-dimensional structure using AutoDockTools 1.5.6 software. Structural optimization was performed at the density functional theory (DFT) B3LYP / 6-31G++(d,p) level, eliminating redundant conformations to ensure the lowest energy in the final configuration. Surface charge analysis identified the C1 (O1-H bond) and C3 (O3-H bond) hydroxyl groups as the main binding sites, defining this region as a docking pocket (8×8×8 Å) and saving it as a gjf format file as the docking "acceptor".

[0025] Step 3: Surfactant (ligand) model construction:

[0026] The two-dimensional structure of lauryl glucoside (APG1214) was obtained from the ChemSpider database and converted into a three-dimensional structure using AutoDockTools 1.5.6 software. Hydrogenation (to supplement missing hydrogen atoms) and Gasteiger charge distribution were performed sequentially (to ensure that the molecular charge conforms to the actual chemical properties). The structure was saved as a gjf file as a docking "ligand".

[0027] Step 4: Molecular docking simulation and screening:

[0028] Semi-flexible docking was performed using AutoDock Vina software with the following parameters set: grid center coordinates (X=1.25Å, Y=0.92Å, Z=0.61Å), grid size 20×20×20 Å, and grid spacing 0.375 Å. The relative binding energy calculated by AutoDock Vina reflects the tightness of the binding between the surfactant and galactose. The smaller the relative binding energy value (the larger the absolute value of the negative value), the stronger the binding ability.

[0029] Step 5: Experimental verification of candidate surfactants:

[0030] 1g of Allium macrostemon powder was mixed with 2% APG1214 aqueous solution at a solid-liquid ratio of 1:20 and extracted for 30 min at 90℃ with stirring at 100 rpm. The resulting extract was centrifuged at 8000 rpm for 10 min, and the upper layer was the Allium macrostemon polysaccharide extract. The extract was diluted 800 times, and 0.5 mL of the diluted solution was mixed with 0.25 mL of phenol solution (6%). Then, 1.25 mL of concentrated sulfuric acid was added. After the reaction was completed, the diluted solution was replaced with pure water (blank control), and the absorbance was measured at 490 nm. The extraction rate of Allium macrostemon polysaccharide was determined by the phenol-sulfuric acid method. Under these conditions, the relative binding energy between APG1214 and Allium macrostemon polysaccharide was -17.5023 kcal / mol, and the extraction rate of Allium macrostemon polysaccharide was 26.18%.

[0031] Example 2:

[0032] This embodiment provides a method for extracting polysaccharides from Allium macrostemon by molecular docking simulation screening of surfactants, the method comprising the following steps:

[0033] Step 1: Processing of raw materials for Allium macrostemon:

[0034] Pulverize the dried Allium macrostemon and pass it through an 80-100 mesh sieve. Add 5 times the volume of 95% (v / v) ethanol to the Allium macrostemon powder and reflux extract it 3 times at 85℃ for 2 hours each time. After defatting and removing impurities, dry the residue at 60℃ for 4 hours for later use.

[0035] Step 2: Construction of the Allium macrostemon polysaccharide core monomer (receptor) model:

[0036] The two-dimensional molecular structure of galactose (CAS No.: 59-23-4) was obtained from the PubChem database and converted into a three-dimensional structure using AutoDockTools 1.5.6 software. Structural optimization was performed at the density functional theory (DFT) B3LYP / 6-31G++(d,p) level, eliminating redundant conformations to ensure the lowest energy in the final configuration. Surface charge analysis identified the C1 (O1-H bond) and C3 (O3-H bond) hydroxyl groups as the main binding sites, defining this region as a docking pocket (8×8×8 Å) and saving it as a gjf format file as the docking "acceptor".

[0037] Step 3: Surfactant (ligand) model construction:

[0038] The two-dimensional structure of sodium dodecyl sulfate (SDS) was obtained from the ChemSpider database and converted into a three-dimensional structure using AutoDockTools 1.5.6 software. Hydrogenation (to supplement missing hydrogen atoms) and Gasteiger charge distribution (to ensure that the molecular charge conforms to the actual chemical properties) were then performed sequentially. The structure was saved as a gjf format file as a docking "ligand".

[0039] Step 4: Molecular docking simulation and screening:

[0040] Semi-flexible docking was performed using AutoDock Vina software with the following parameters set: grid center coordinates (X=1.25Å, Y=0.92Å, Z=0.61Å), grid size 20×20×20 Å, and grid spacing 0.375 Å. The relative binding energy calculated by AutoDock Vina reflects the tightness of the binding between the surfactant and galactose. The smaller the relative binding energy value (the larger the absolute value of the negative value), the stronger the binding ability.

[0041] Step 5: Experimental verification of candidate surfactants:

[0042] 1g of Allium macrostemon powder was mixed with SDS aqueous solution (2% concentration) at a solid-liquid ratio of 1:20 and extracted for 30 min under stirring in a 90℃ water bath at 100 rpm. The resulting extract was centrifuged at 8000 rpm for 10 min, and the upper layer was the Allium macrostemon polysaccharide extract. The extract was diluted 800 times, and 0.5 mL of the diluted solution was mixed with 0.25 mL of phenol solution (6%). Then, 1.25 mL of concentrated sulfuric acid was added. After the reaction was completed, the diluted solution was replaced with pure water (blank control), and the absorbance was measured at 490 nm. The extraction rate of Allium macrostemon polysaccharide was determined by the phenol-sulfuric acid method. Under these conditions, the relative binding energy between SDS and Allium macrostemon polysaccharide was -9.2160 kcal / mol, and the extraction rate of Allium macrostemon polysaccharide was 22.65%.

[0043] Example 3:

[0044] This embodiment provides a method for extracting polysaccharides from Allium macrostemon by molecular docking simulation screening of surfactants, the method comprising the following steps:

[0045] Step 1: Processing of raw materials for Allium macrostemon:

[0046] Pulverize the dried Allium macrostemon and pass it through an 80-100 mesh sieve. Add 5 times the volume of 95% (v / v) ethanol to the Allium macrostemon powder and reflux extract it 3 times at 85℃ for 2 hours each time. After defatting and removing impurities, dry the residue at 60℃ for 4 hours for later use.

[0047] Step 2: Construction of the Allium macrostemon polysaccharide core monomer (receptor) model:

[0048] The two-dimensional molecular structure of galactose (CAS No.: 59-23-4) was obtained from the PubChem database and converted into a three-dimensional structure using AutoDockTools 1.5.6 software. Structural optimization was performed at the density functional theory (DFT) B3LYP / 6-31G++(d,p) level, eliminating redundant conformations to ensure the lowest energy in the final configuration. Surface charge analysis identified the C1 (O1-H bond) and C3 (O3-H bond) hydroxyl groups as the main binding sites, defining this region as a docking pocket (8×8×8 Å) and saving it as a gjf format file as the docking "acceptor".

[0049] Step 3: Surfactant (ligand) model construction:

[0050] The two-dimensional structure of polyoxyethylene fatty alcohol ether (Genapol X-080) was obtained from the ChemSpider database and converted into a three-dimensional structure using AutoDock Tools 1.5.6 software. Hydrogenation (to supplement missing hydrogen atoms) and Gasteiger charge distribution were performed sequentially (to ensure that the molecular charge conforms to the actual chemical properties). The structure was saved as a gjf file as a docking "ligand".

[0051] Step 4: Molecular docking simulation and screening:

[0052] Semi-flexible docking was performed using AutoDock Vina software with the following parameters set: grid center coordinates (X=1.25Å, Y=0.92Å, Z=0.61Å), grid size 20×20×20 Å, and grid spacing 0.375 Å. The relative binding energy calculated by AutoDock Vina reflects the tightness of the binding between the surfactant and galactose. The smaller the relative binding energy value (the larger the absolute value of the negative value), the stronger the binding ability.

[0053] Step 5: Experimental verification of candidate surfactants:

[0054] 1g of Allium macrostemon powder was mixed with a 2% Genapol X-080 aqueous solution at a solid-liquid ratio of 1:20 and extracted for 30 min at 90℃ with stirring at 100 rpm. The resulting extract was centrifuged at 8000 rpm for 10 min, and the upper layer was the Allium macrostemon polysaccharide extract. The extract was diluted 800 times, and 0.5 mL of the diluted solution was mixed with 0.25 mL of phenol solution (6%). Then, 1.25 mL of concentrated sulfuric acid was added. After the reaction was complete, the diluted solution was replaced with pure water (blank control), and the absorbance was measured at 490 nm. The extraction rate of Allium macrostemon polysaccharide was determined by the phenol-sulfuric acid method. Under these conditions, the relative binding energy between Genapol X-080 and Allium macrostemon polysaccharide was -19.7067 kcal / mol, and the extraction rate of Allium macrostemon polysaccharide was 26.52%.

[0055] Comparative Example 1:

[0056] This comparative example provides a method for extracting polysaccharides from Allium macrostemon by molecular docking simulation screening of surfactants, including the following steps:

[0057] Step 1: Processing of raw materials for Allium macrostemon:

[0058] Pulverize the dried Allium macrostemon and pass it through an 80-100 mesh sieve. Add 5 times the volume of 95% (v / v) ethanol to the Allium macrostemon powder and reflux extract it 3 times at 85℃ for 2 hours each time. After defatting and removing impurities, dry the residue at 60℃ for 4 hours for later use.

[0059] Step 2: Hot water extraction experiment of Allium macrostemon polysaccharide:

[0060] 1g of Allium macrostemon powder was mixed with an aqueous solution at a solid-liquid ratio of 1:20 and extracted for 120 minutes at 90℃ with stirring at 100 rpm. The resulting extract was centrifuged to obtain Allium macrostemon polysaccharide extract. The extract was diluted 800 times, and 0.5mL of the diluted solution was mixed with 0.25mL of phenol solution (6%). Then, 1.25mL of concentrated sulfuric acid was added. After the reaction was complete, the diluted solution was replaced with pure water (blank control), and the absorbance was measured at 490nm. The extraction rate of Allium macrostemon polysaccharide was determined by the phenol-sulfuric acid method. Under these conditions, the extraction rate of Allium macrostemon polysaccharide was 22.16%.

[0061] Comparative Example 2:

[0062] This comparative example provides a method for extracting polysaccharides from Allium macrostemon by molecular docking simulation screening of surfactants, including the following steps:

[0063] Step 1: Processing of raw materials for Allium macrostemon:

[0064] Pulverize the dried Allium macrostemon and pass it through an 80-100 mesh sieve. Add 5 times the volume of 95% (v / v) ethanol to the Allium macrostemon powder and reflux extract it 3 times at 85℃ for 2 hours each time. After defatting and removing impurities, dry the residue at 60℃ for 4 hours for later use.

[0065] Step 2: Hot water extraction experiment of Allium macrostemon polysaccharide:

[0066] 1g of Allium macrostemon powder was mixed with an aqueous solution at a solid-liquid ratio of 1:20 and extracted for 120 minutes at 90℃ with stirring at 100 rpm. The resulting extract was centrifuged to obtain Allium macrostemon polysaccharide extract. The extract was diluted 800 times, and 0.5mL of the diluted solution was mixed with 0.25mL of phenol solution (6%). Then, 1.25mL of concentrated sulfuric acid was added. After the reaction was complete, the diluted solution was replaced with pure water (blank control). The absorbance was measured at 490nm, and the extraction rate of Allium macrostemon polysaccharide was determined by the phenol-sulfuric acid method. Under these conditions, the extraction rate of Allium macrostemon polysaccharide was 14.91%.

[0067] Based on Examples 1, 2, and 3, it can be concluded that the absolute values ​​of the relative binding energies of the three surfactants to Allium macrostemon polysaccharide are in the following order: Genapol X-080 > APG1214 > SDS. The extraction rates of Allium macrostemon polysaccharide extracted by the three surfactants are in the following order: Genapol X-080 > APG1214 > SDS. This indicates that the method of molecular docking simulation screening of surfactants for extracting Allium macrostemon polysaccharide is effective and feasible.

[0068] Based on Example 3 and Comparative Example 1, it can be concluded that aqueous solutions based on surfactants are superior to hot water extraction, with a polysaccharide extraction rate 1.2 times higher, while reducing the extraction time by 75%.

[0069] Based on Example 3 and Comparative Example 2, it can be concluded that, under the same extraction time, aqueous solution based on surfactant is superior to hot water extraction, and the polysaccharide extraction rate is 1.8 times higher.

[0070]

Claims

1. A method for screening surfactants for extracting polysaccharides from Allium bakeri based on molecular docking simulation, characterized in that The method comprises the following steps: Step (1) processing of raw materials: the raw materials are crushed and pretreated with ethanol; Step (2) surfactant model construction: the two-dimensional structure of the surfactant is obtained from the PubChem or ChemSpider database, and is converted into a three-dimensional structure using AutoDock Tools software, and is treated by hydrogenation and Gasteiger charge distribution to construct a surfactant model; Step (3) construction of a single sugar model of the polysaccharide in Allium macrostemon Bunge: galactose is selected as a representative of the core single sugar of the polysaccharide, the two-dimensional structure is obtained from the PubChem database, and is converted into a three-dimensional structure using AutoDock Tools software, and is optimized at the B3LYP / 6-31G++(d,p) level using density functional theory, and the C1 and C3 hydroxyl regions are defined as the docking pocket to construct a single sugar model of the polysaccharide in Allium macrostemon Bunge; Step (4) molecular docking simulation and screening: semi-flexible docking is performed using AutoDock Vina software, and the relative binding energy is used as the core index to screen candidate surfactants; Step (5) experimental verification of the candidate surfactants: the extraction rate is determined by the phenol-sulfuric acid method to determine the optimal surfactant.

2. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 1, characterized in that The specific steps of step (1) are as follows: dry Allium macrostemon Bunge is crushed and passed through a 20-200 mesh sieve, 2-10 times the volume of 80-95% (v / v) ethanol is added to the Allium macrostemon Bunge powder, and reflux extraction is performed at 60-90°C for 1-5 times, each time for 1-5 hours, and after defatting and impurity removal, the residue is dried for use.

3. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 1, characterized in that In step (2), the green surfactant includes alkyl glycoside surfactants, betaine surfactants, and Tween surfactants, and strong acid / alkaline surfactants with pH<2 or pH>11 are excluded.

4. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 1, characterized in that In step (3), the galactose model after optimization needs to be verified by vibration frequency analysis to ensure that there is no virtual frequency, and the docking pocket size is 8×8×8Å.

5. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 1, characterized in that The specific steps of step (4) are as follows: semi-flexible docking is performed using AutoDock Vina software, the grid center is set to the geometric center of the docking pocket X=1.25Å, Y=0.92Å, Z=0.61Å, the grid size is 20×20×20Å, the grid spacing is 0.375Å, docking calculation is performed, and candidate surfactants are screened according to the relative binding energy.

6. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 5, characterized in that Surfactants with a relative binding energy of ≤-4.5 kcal / mol are selected as candidate agents.

7. The method for extracting surface active agent from Allium bakeri polysaccharide based on molecular docking simulation screening according to claim 1, characterized in that The specific steps of step (5) are as follows: Allium macrostemon Bunge powder is mixed with a candidate surfactant aqueous solution at a solid-liquid ratio of 1:20-1:50, and extraction is performed at 80-140°C in a water bath for 15-150 minutes, centrifugation is performed at 3000-12000 rpm for 5-20 minutes, the supernatant is taken and the extraction rate is determined by the phenol-sulfuric acid method, and the optimal surfactant is selected.

8. The method for extracting the surfactant of the polygonatum sibiricum polysaccharide based on the molecular docking simulation screening according to claim 7, characterized in that The concentration of the surfactant aqueous solution is 0.5-10%, preferably 1-3%; the extraction temperature is preferably 90°C, the extraction time is preferably 30 minutes, the solid-liquid ratio is preferably 1:20 g / mL; the centrifugation parameters are preferably 8000 rpm for 10 minutes, and the centrifugation temperature is controlled at 4°C.

9. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 7, characterized in that The specific operation of the phenol-sulfuric acid method for determining the extraction rate is as follows: 0.5 mL of supernatant is taken, 0.25 mL of 6% phenol solution is added, after mixing, 1.25 mL of concentrated sulfuric acid is added, and the reaction is carried out in a 40 ℃ water bath for 30 min, and the absorbance is determined at 490 nm.

10. The method for screening surfactants for extracting polysaccharides from Allium bakeri according to claim 7, characterized in that The optimal surfactant is Genapol X-080 or APG1214, and the corresponding relative binding energy is-19.7067 kcal / mol and-17.5023 kcal / mol, respectively.

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