Method for extracting gynostemma pentaphyllum total saponins from gynostemma pentaphyllum

Abstract

The invention provides a method for extracting gynostemma pentaphyllum total saponins from gynostemma pentaphyllum, which can solve the problems that more inorganic salts are generated and the subsequent sewage treatment cost is higher due to the fact that the dosage of a coagulant is larger in the extraction process in the existing extraction method. The method comprises the following steps: crushing a gynostemma pentaphylla raw material, adding a low-methoxyl pectin aqueous solution or a low-methoxyl pectin weak acid solution with the mass being 1-3 times that of the gynostemma pentaphylla raw material and the mass fraction being 10%-20%, and uniformly stirring and mixing to obtain a mixture; wherein the low-ester pectin is pectin of which the esterification degree is lower than 50%; a multivalent cation solution with the mass being 0.2-0.5 time of the mass of the gynostemma pentaphyllum raw material and the mass fraction being 5%-10% is added into the mixture, stirring continues, and a gynostemma pentaphyllum-low ester pectin compound is obtained; carrying out alcohol extraction on the gynostemma pentaphyllum-low-methoxyl pectin compound to obtain a gynostemma pentaphyllum total saponin extracting solution; and concentrating the gynostemma pentaphyllum total saponin extracting solution, standing, carrying out suction filtration, collecting precipitate, and drying to obtain the gynostemma pentaphyllum total saponin.

Description

Technical Field

[0001] The invention relates to a method for extracting chemical substances from natural substances, and in particular to a method for extracting total saponins of Gynostemma pentaphyllum from Gynostemma pentaphyllum. Background Art

[0002] Gynostemma pentaphyum is a common subtropical plant. In China, Gynostemma pentaphyum is mostly planted in the southern part of Qinling Mountains. Gynostemma pentaphyum (Gynostemma Pentaphyum (Thunb.) Makino, GP), also known as seven-leaf gall and five-leaf ginseng, is a herbaceous climbing plant of the Cucurbitaceae family and the genus Gynostemma. The whole plant is generally used as medicine. The Compendium of Materia Medica records that "five-leaf vine treats sores, furuncles, insect bites, cools blood and detoxifies, and promotes urination". Gynostemma pentaphyum, as a medicinal plant used for both medicine and food, has the characteristics of wide pharmacological activity, small toxic and side effects, and good efficacy. The main chemical components in Gynostemma pentaphyum are total saponins of Gynostemma pentaphyum (GPS), amino acids, polysaccharides, flavonoids and various trace elements. Among them, total saponins of Gynostemma pentaphyum are the main active ingredients of Gynostemma pentaphyum, and its acid hydrolysis product has the same physical and chemical properties as the acid hydrolysis product of ginsenosides, ginsenodiol. Gynostemma total saponins have the same tetracyclic triterpene dammarane structure as ginsenosides, and have no side effects even if taken in excess. Therefore, they have great application prospects in the research and development of health foods and new drugs.

[0003] At present, there are many methods for extracting total saponins of gynostemma pentaphyllum, mainly including hot water extraction, ultrasound-assisted method and microwave-assisted method, wherein, hot water extraction is time-consuming, required temperature is high and impurity removal effect is poor, ultrasound-assisted method and microwave-assisted method cost are too large, commercial risk is too high, and are not suitable for the production mode of small and medium-sized enterprises. In order to solve the problems existing in the above method, the Chinese patent of publication number CN116098929A discloses a method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum, first adopts ethanol solution and coagulant to stir and extract, obtains gynostemma pentaphyllum extract, then concentrates gynostemma pentaphyllum extract, leaves and filters, collects precipitation and dries, obtains total saponins of gynostemma pentaphyllum. However, the problem existing in the method is: because the consumption of coagulant in the extraction process is large, causes to produce more inorganic salts, and subsequent sewage treatment cost is higher. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems that a large amount of coagulant is used in the extraction process of the existing extraction method, resulting in the production of more inorganic salts and higher subsequent sewage treatment costs, and to provide a method for extracting total saponins of Gynostemma pentaphyllum from Gynostemma pentaphyllum.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for extracting total saponins of Gynostemma pentaphyllum from Gynostemma pentaphyllum, which is special in that it comprises the following steps:

[0007] Step 1, crushing the raw material of Gynostemma pentaphyllum, adding a low-ester pectin aqueous solution or a weakly acidic solution of low-ester pectin with a mass fraction of 10% to 20% and a mass fraction of 1 to 3 times that of the raw material of Gynostemma pentaphyllum, stirring and mixing to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50%;

[0008] Step 2, adding a polyvalent cation solution having a mass fraction of 5% to 10% and a mass fraction of 0.2 to 0.5 times that of the Gynostemma pentaphyllum raw material to the mixture, and continuing stirring to obtain a Gynostemma pentaphyllum-low ester pectin complex;

[0009] Step 3, performing alcohol extraction on the Gynostemma pentaphyllum-low ester pectin complex to obtain a Gynostemma pentaphyllum total saponin extract;

[0010] Step 4: Concentrate the Gynostemma pentaphyllum total saponin extract, let it stand and filter it, collect the precipitate and dry it to obtain Gynostemma pentaphyllum total saponins.

[0011] Furthermore, since the underground roots of Gynostemma pentaphyllum are well developed, the total saponin content of the underground part is much higher than that of the aboveground stems and leaves, and the total saponin content of the thicker part of the rhizome is higher than that of the relatively thinner part. In step 1, the Gynostemma pentaphyllum raw material is the rhizome part of Gynostemma pentaphyllum.

[0012] Furthermore, step 3 specifically includes the following steps:

[0013] Step 3.1, adding an alcohol reagent in an amount of 7 to 10 times the mass of the Gynostemma pentaphyllum raw material to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 40° C. to 50° C. for 1 h to 3 h, filtering to obtain a filtrate and a filter residue, respectively;

[0014] Step 3.2, add an alcohol solution with a mass fraction of 70% to 80% and a mass fraction of 6 to 8 times that of the Gynostemma pentaphyllum raw material to the filter residue, stir and extract 2 to 3 times at a temperature of 40°C to 50°C, each extraction for 1h to 3h, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract.

[0015] Further, in step 3.1, the alcohol reagent is a methanol reagent or an ethanol reagent;

[0016] In step 3.2, the alcohol solution is a methanol solution or an ethanol solution.

[0017] Furthermore, in order to facilitate the recovery of methanol or ethanol, in step 3.1, the alcohol reagent is a methanol reagent; in step 3.2, the alcohol solution is a methanol solution;

[0018] Alternatively, in step 3.1, the alcohol reagent is an ethanol reagent; in step 3.2, the alcohol solution is an ethanol solution.

[0019] Further, in order to shorten the time for obtaining total saponins of Gynostemma pentaphyllum and effectively avoid the precipitation of other impurities, step 4 is specifically as follows:

[0020] The Gynostemma pentaphyllum total saponin extract is concentrated to a specific gravity of 1.010-1.030, and then allowed to stand for suction filtration, and the precipitate is collected and dried to obtain Gynostemma pentaphyllum total saponin.

[0021] Further, in step 2, the multivalent cation solution is a calcium hydroxide solution or a calcium chloride solution;

[0022] The stirring time is at least 30 min.

[0023] Furthermore, in step 1, the weakly acidic solution of low-ester pectin is a hydrochloric acid solution of low-ester pectin with a pH of 5 to 6, a sulfuric acid solution of low-ester pectin, or a glacial acetic acid solution of low-ester pectin.

[0024] Furthermore, in step 1, the stirring time is at least 1 hour.

[0025] Beneficial effects of the present invention:

[0026] 1. The present invention provides a method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum. After mixing an aqueous solution of low-ester pectin or a weakly acidic solution of low-ester pectin with a raw material of gynostemma pentaphyllum, non-covalent interactions occur between total saponins of gynostemma pentaphyllum, starch and some flavonoids in the raw material of gynostemma pentaphyllum and the low-ester pectin, and then adding a polyvalent cation solution to make the aqueous solution of low-ester pectin or the weakly acidic solution of low-ester pectin in a gel state. In the presence of polyvalent cations, the carboxyl groups of the dissociated galacturonic acid residues in the low-ester pectin molecules combine with the polyvalent cations to form ionic bonds, thereby forming a three-dimensional network structure similar to an "egg box" model. This structure can adsorb total saponins of gynostemma pentaphyllum, starch and some flavonoids in the raw material of gynostemma pentaphyllum, wherein the structure has good fixation for impurities such as starch and some flavonoids, and effectively avoids the dissolution of many impurity components in the subsequent alcohol extraction process, thereby reducing the content of impurities in the total saponins of gynostemma pentaphyllum extract and improving the quality of the total saponins of gynostemma pentaphyllum product.

[0027] 2. The method provided by the present invention is easy to operate, fast and time-saving, shortens the production cycle, greatly reduces the impurity components in the production process, and there is almost no pollution in the production process, and the product quality is high.

[0028] 3. During the alcohol extraction process, when the mass fraction of the alcohol reagent is higher than 70%, the starch and some flavonoids in the Gynostemma pentaphyllum-low-ester pectin complex are almost insoluble in the alcohol solution; when the mass fraction of the alcohol reagent is higher than 80%, it is easy to cause incomplete extraction of total saponins of Gynostemma pentaphyllum. Therefore, in order to fully extract total saponins of Gynostemma pentaphyllum, it is necessary to ensure that the mass fraction of the alcohol reagent during the alcohol extraction process is 70% to 80%. The present invention first uses an alcohol reagent for extraction once to prevent the residual water in the mixed system obtained in the early stage from diluting the alcohol reagent to a mass fraction of less than 70%. In order to fully extract total saponins of Gynostemma pentaphyllum, an alcohol solution with a mass fraction of 70% to 80% is used for extraction multiple times.

[0029] 4. The present invention concentrates the total saponin extract of Gynostemma pentaphyllum to a specific gravity of 1.010 to 1.030, which can shorten the time for obtaining total saponin of Gynostemma pentaphyllum and effectively avoid the precipitation of other impurities. The total saponin product of Gynostemma pentaphyllum obtained by the method of the present invention is off-white, has a total saponin content of more than 98%, and a recovery rate of more than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The ultraviolet absorption value images of the sample solution and the reference solution in Example 1 and Example 3 of the method for extracting total saponins of Gynostemma pentaphyllum from Gynostemma pentaphyllum of the present invention are shown. DETAILED DESCRIPTION

[0031] Embodiment 1

[0032] A method for extracting total saponins from Gynostemma pentaphyllum comprises the following steps:

[0033] Step 1, crushing 500g of Gynostemma pentaphyllum raw material, adding an aqueous solution of low-ester pectin with a mass fraction of 20% and a mass fraction of 500g of the Gynostemma pentaphyllum raw material, stirring for 1h to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50% (DE < 50%), and the low-ester pectin is mainly derived from the peels of citrus, lemon, grapefruit, etc.;

[0034] Step 2, adding a 5% calcium chloride solution with a mass fraction of 0.2 times (100 g) of the Gynostemma pentaphyllum raw material to the mixture, and continuing stirring for 30 minutes to obtain a Gynostemma pentaphyllum-low ester pectin complex;

[0035] Step 3, extracting the Gynostemma pentaphyllum-low ester pectin complex with alcohol to obtain a Gynostemma pentaphyllum total saponin extract; specifically comprising the following steps:

[0036] Step 3.1, adding ethanol reagent in an amount 10 times the mass of the Gynostemma pentaphyllum raw material to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 40° C. for 2 h, filtering to obtain a filtrate and a filter residue, respectively;

[0037] Step 3.2, add 6 times the mass of the raw material of Gynostemma pentaphyllum and 80% ethanol solution to the filter residue, stir and extract twice at a temperature of 40°C, each time for 2 hours, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract;

[0038] Step 4, the total saponin extract of gynostemma pentaphyllum is concentrated to a specific gravity of 1.010, and the extract is allowed to stand for suction filtration, and the precipitate is collected and dried to obtain 37.3g of off-white total saponin of gynostemma pentaphyllum, wherein the total saponin content of gynostemma pentaphyllum is 98.90%. In the present embodiment, the gynostemma pentaphyllum raw material is the rhizome of gynostemma pentaphyllum, wherein the content of total saponin of gynostemma pentaphyllum is about 8%.

[0039] The calculation method of the content of total saponins of Gynostemma pentaphyllum in the Gynostemma pentaphyllum raw material and the content of total saponins of Gynostemma pentaphyllum obtained in step 4 is:

[0040] Accurately weigh 100ul of each of the reference solution of total saponins of Gynostemma pentaphyllum (add methanol reagent to make a solution containing about 2mg of total saponins of Gynostemma pentaphyllum per 1ml) and the product solution of total saponins of Gynostemma pentaphyllum (add methanol reagent to make a solution containing about 2mg of total saponins of Gynostemma pentaphyllum per 1ml), respectively, and place them in 15ml stoppered test tubes, and accurately add 2ml of the mixture of 5% vanillin glacial acetic acid solution and perchloric acid (2:8, V / V), shake well, seal the test tube with stoppers, place it in a 60℃ water bath and heat for 15min, take it out, immediately put it in ice water to cool for 2 minutes, accurately add 10ml of glacial acetic acid, shake well, obtain the reference solution and sample solution, use methanol reagent as blank, measure the absorbance at a wavelength of 555nm, and calculate by external standard method. The calculation formula is: Content (%) = (A1×Wo×V1×K)÷(Ao×Vo×W1)×100

[0041] Wherein, A1 is the absorbance value of the sample solution, Ao is the absorbance value of the reference solution, W1 is the sample weight (mg) of the total saponins product of Gynostemma pentaphyllum, Wo is the sample weight (mg) of the total saponins reference of Gynostemma pentaphyllum, V1 is the volume (ml) of the sample solution, Vo is the volume (ml) of the reference solution, and K is the purity of the total saponins reference of Gynostemma pentaphyllum.

[0042] Figure 1 In the above example, No. 8 is a sample solution obtained by using the total saponins of Gynostemma pentaphyllum obtained in step 4 of this embodiment, and the corresponding measured A1 is 0.5397; No. 12 is a sample solution obtained by using the raw material of Gynostemma pentaphyllum, and the corresponding measured A1 is 0.0649; No. 4 is a reference solution obtained, and the measured Ao is 0.3922. According to the above calculation method, it can be obtained:

[0043] The content of total saponins of Gynostemma pentaphyllum obtained in step 4 of this embodiment (%) = (0.5397 × 105.45 mg × 50 ml × 94%) ÷ (0.3922 × 50 ml × 137.92 mg) × 100 = 98.90%.

[0044] The content of total saponins of Gynostemma pentaphyllum in the Gynostemma pentaphyllum raw material (%) = (0.0649 × 105.45 mg × 50 ml × 94%) ÷ (0.3922 × 50 ml × 205.03 mg) × 100 = 8.00%.

[0045] Embodiment 2

[0046] A method for extracting total saponins from Gynostemma pentaphyllum comprises the following steps:

[0047] Step 1, crush 500g of Gynostemma pentaphyllum raw material, add an aqueous solution of low-ester pectin with a mass fraction of 10% and a mass fraction of 2 times (1000g) of the Gynostemma pentaphyllum raw material, stir for 1.5h to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50%;

[0048] Step 2, adding a 10% calcium hydroxide solution with a mass fraction of 0.2 times (100 g) of the Gynostemma pentaphyllum raw material to the mixture, and continuing stirring for 35 minutes to obtain a Gynostemma pentaphyllum-low ester pectin complex;

[0049] Step 3, extracting the Gynostemma pentaphyllum-low ester pectin complex with alcohol to obtain a Gynostemma pentaphyllum total saponin extract; specifically comprising the following steps:

[0050] Step 3.1, adding a methanol reagent of 7 times the mass of the Gynostemma pentaphyllum raw material to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 40° C. for 3 hours, filtering to obtain a filtrate and a filter residue respectively;

[0051] Step 3.2, add a methanol solution with a mass fraction of 70% and a mass fraction of 8 times that of the raw material of Gynostemma pentaphyllum to the filter residue, stir and extract 3 times at a temperature of 40°C, each time for 3 hours, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract;

[0052] Step 4: Concentrate the total saponin extract of Gynostemma pentaphyllum to a specific gravity of 1.030, let it stand and filter it, collect the precipitate and dry it to obtain 38.1 g of off-white total saponin of Gynostemma pentaphyllum, wherein the content of total saponin of Gynostemma pentaphyllum is 98.46%.

[0053] Embodiment 3

[0054] A method for extracting total saponins from Gynostemma pentaphyllum comprises the following steps:

[0055] Step 1, crush 500g of Gynostemma pentaphyllum raw material, add a hydrochloric acid solution of low-ester pectin with a mass fraction of 10% and a mass fraction of 3 times (1500g) of the Gynostemma pentaphyllum raw material, the pH of the hydrochloric acid solution of low-ester pectin is 5, stir for 1h to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50%;

[0056] Step 2, adding 0.5 times the mass (250 g) of the Gynostemma pentaphyllum raw material and 8% calcium chloride solution to the mixture, and continuing stirring for 30 minutes to obtain a Gynostemma pentaphyllum-low ester pectin complex;

[0057] Step 3, extracting the Gynostemma pentaphyllum-low ester pectin complex with alcohol to obtain a Gynostemma pentaphyllum total saponin extract; specifically comprising the following steps:

[0058] Step 3.1, adding 9 times the mass of ethanol reagent as the raw material of Gynostemma pentaphyllum to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 45° C. for 1 hour, filtering, and obtaining a filtrate and a filter residue respectively;

[0059] Step 3.2, add 75% ethanol solution with a mass fraction of 7 times that of the raw material of Gynostemma pentaphyllum to the filter residue, stir and extract 3 times at a temperature of 45°C, each extraction is 1 hour, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract;

[0060] Step 4, the total saponin extract of Gynostemma pentaphyllum was concentrated to a specific gravity of 1.021, and the extract was filtered and collected, and the precipitate was dried to obtain 36.6 g of off-white total saponin of Gynostemma pentaphyllum, wherein the total saponin content of Gynostemma pentaphyllum was 99.87%. The raw material of Gynostemma pentaphyllum in this embodiment is the same as that in the first embodiment.

[0061] Figure 1 In the example, No. 16 is the sample solution obtained by using the total saponins of Gynostemma pentaphyllum obtained in step 4 of this example, and the corresponding measured A1 is 0.4899; No. 4 is the reference solution obtained, and the measured Ao is 0.3922. According to the calculation method in Example 1, it can be obtained:

[0062] The content of total saponins of Gynostemma pentaphyllum obtained in step 4 of this embodiment (%) = (0.4899 × 105.45 mg × 50 ml × 94%) ÷ (0.3922 × 50 ml × 123.98 mg) × 100 = 99.87%.

[0063] Embodiment 4

[0064] A method for extracting total saponins from Gynostemma pentaphyllum comprises the following steps:

[0065] Step 1, crush 500g of Gynostemma pentaphyllum raw material, add a sulfuric acid solution of low-ester pectin with a mass fraction of 15% and a mass fraction of twice (1000g) of the Gynostemma pentaphyllum raw material, the pH of the sulfuric acid solution of low-ester pectin is 5, stir for 1h to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50%;

[0066] Step 2, adding a 9% calcium hydroxide solution with a mass fraction of 0.25 times (125 g) of the Gynostemma pentaphyllum raw material to the mixture, and continuing stirring for 30 minutes to obtain a Gynostemma pentaphyllum-low ester pectin complex;

[0067] Step 3, extracting the Gynostemma pentaphyllum-low ester pectin complex with alcohol to obtain a Gynostemma pentaphyllum total saponin extract; specifically comprising the following steps:

[0068] Step 3.1, adding methanol reagent in an amount 8 times the mass of the Gynostemma pentaphyllum raw material to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 40° C. for 2 h, filtering to obtain a filtrate and a filter residue, respectively;

[0069] Step 3.2, add 80% methanol solution with a mass fraction of 7 times that of the raw material of Gynostemma pentaphyllum to the filter residue, stir and extract twice at a temperature of 40°C, each time for 2 hours, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract;

[0070] Step 4: Concentrate the total saponin extract of Gynostemma pentaphyllum to a specific gravity of 1.025, let it stand and filter it, collect the precipitate and dry it to obtain 36.9 g of off-white total saponin of Gynostemma pentaphyllum, wherein the content of total saponin of Gynostemma pentaphyllum is 99.27%.

[0071] Embodiment 5

[0072] A method for extracting total saponins from Gynostemma pentaphyllum comprises the following steps:

[0073] Step 1, crush 500g of Gynostemma pentaphyllum raw material, add 18% low-ester pectin glacial acetic acid solution with a mass of 1 times (500g) of the Gynostemma pentaphyllum raw material, the pH of the low-ester pectin glacial acetic acid solution is 6, stir for 1h to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50%;

[0074] Step 2, adding a 5% calcium hydroxide solution with a mass fraction of 0.2 times (100 g) of the Gynostemma pentaphyllum raw material to the mixture, and continuing stirring for 30 minutes to obtain a Gynostemma pentaphyllum-low ester pectin complex;

[0075] Step 3, extracting the Gynostemma pentaphyllum-low ester pectin complex with alcohol to obtain a Gynostemma pentaphyllum total saponin extract; specifically comprising the following steps:

[0076] Step 3.1, adding ethanol reagent in an amount 10 times the mass of the Gynostemma pentaphyllum raw material to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 50° C. for 2 h, filtering to obtain a filtrate and a filter residue, respectively;

[0077] Step 3.2, add 6 times the mass of the raw material of Gynostemma pentaphyllum and 70% ethanol solution to the filter residue, stir and extract twice at a temperature of 50°C, each time for 2 hours, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract;

[0078] Step 4: Concentrate the total saponin extract of Gynostemma pentaphyllum to a specific gravity of 1.016, let it stand and filter it, collect the precipitate and dry it to obtain 37.0 g of off-white total saponin of Gynostemma pentaphyllum, wherein the content of total saponin of Gynostemma pentaphyllum is 99.01%.

[0079] It should be noted that the raw material of Gynostemma pentaphyllum in Example 2, Example 4 and Example 5 is the same as that in Example 1. In Example 2, Example 4 and Example 5, the calculation method of the total saponin content of Gynostemma pentaphyllum is the same as that in Example 1.

[0080] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for extracting total saponins from Gynostemma pentaphyllum, characterized in that: The following steps are involved: Step 1, crushing the raw material of Gynostemma pentaphyllum, adding a low-ester pectin aqueous solution or a weakly acidic solution of low-ester pectin with a mass fraction of 10% to 20% and a mass fraction of 1 to 3 times that of the raw material of Gynostemma pentaphyllum, stirring and mixing to obtain a mixture; wherein the low-ester pectin refers to pectin with an esterification degree of less than 50%; Step 2, adding a polyvalent cation solution having a mass fraction of 5% to 10% and a mass fraction of 0.2 to 0.5 times that of the Gynostemma pentaphyllum raw material to the mixture, and continuing stirring to obtain a Gynostemma pentaphyllum-low ester pectin complex; Step 3, performing alcohol extraction on the Gynostemma pentaphyllum-low ester pectin complex to obtain a Gynostemma pentaphyllum total saponin extract; Step 4: Concentrate the Gynostemma pentaphyllum total saponin extract, let it stand and filter it, collect the precipitate and dry it to obtain Gynostemma pentaphyllum total saponins.

2. The method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum according to claim 1, characterized in that: In step 1, the Gynostemma pentaphyllum raw material is the rhizome part of Gynostemma pentaphyllum.

3. The method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum according to claim 1 or 2, characterized in that: Step 3 specifically includes the following steps: Step 3.1, adding an alcohol reagent in an amount of 7 to 10 times the mass of the Gynostemma pentaphyllum raw material to the Gynostemma pentaphyllum-low ester pectin complex, stirring and extracting once at a temperature of 40° C. to 50° C. for 1 h to 3 h, filtering to obtain a filtrate and a filter residue, respectively; Step 3.2, add an alcohol solution with a mass fraction of 70% to 80% and a mass fraction of 6 to 8 times that of the Gynostemma pentaphyllum raw material to the filter residue, stir and extract 2 to 3 times at a temperature of 40°C to 50°C, each extraction for 1h to 3h, filter, and combine the filtrate with the filtrate obtained in step 3.1 to obtain a Gynostemma pentaphyllum total saponin extract.

4. The method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum according to claim 3, characterized in that: In step 3.1, the alcohol reagent is a methanol reagent or an ethanol reagent; In step 3.2, the alcohol solution is a methanol solution or an ethanol solution.

5. The method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum according to claim 4, characterized in that: In step 3.1, the alcohol reagent is a methanol reagent; in step 3.2, the alcohol solution is a methanol solution; Alternatively, in step 3.1, the alcohol reagent is an ethanol reagent; in step 3.2, the alcohol solution is an ethanol solution.

6. The method for extracting total saponins of Gynostemma pentaphyllum from Gynostemma pentaphyllum according to claim 5, characterized in that: Step 4 is as follows: The Gynostemma pentaphyllum total saponin extract is concentrated to a specific gravity of 1.010-1.030, and then allowed to stand for suction filtration, and the precipitate is collected and dried to obtain Gynostemma pentaphyllum total saponin.

7. The method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum according to claim 1, characterized in that: In step 2, the multivalent cation solution is a calcium hydroxide solution or a calcium chloride solution; The stirring time is at least 30 min.

8. The method for extracting total saponins of gynostemma pentaphyllum from gynostemma pentaphyllum according to claim 1, characterized in that: In step 1, the weakly acidic solution of low-ester pectin is a low-ester pectin hydrochloric acid solution with a pH of 5 to 6, a low-ester pectin sulfuric acid solution or a low-ester pectin glacial acetic acid solution.

9. The method for extracting total saponins of Gynostemma pentaphyllum from Gynostemma pentaphyllum according to claim 8, characterized in that: In step 1, the stirring time is at least 1 hour.

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