阅读说明：本技术 利用银杏叶提取物加工过程中的废液提取银杏酚酸的方法 (Method for extracting ginkgolic acid by using waste liquid in processing process of ginkgo leaf extract ) 是由 杨宪勇 张爱丽 花丽 于 2021-08-15 设计创作，主要内容包括：本发明公开的是一种利用银杏叶加工废液提取银杏酚酸的方法,该方法是将银杏叶加工废液分别经滤布过滤三次,再经精滤、浓缩至质量的1/10～20,得浓缩液,然后将浓缩液与硅胶按重量1：0.3～0.5比例混合,搅拌处理三次,再将三次滤取后的硅胶合并,用去离子水洗涤至无色,然后将硅胶分别用乙醇、甲醇和石油醚各浸提一次,分别回收溶媒,得提取物,经干燥、粉碎、混匀即得银杏酚酸提取物,经HPLC方法检测,银杏酚酸的含量＞60%。本发明方法获得的银杏酚酸可作为生物农药制剂、外用药品制剂和化妆品制品的用途。本发明方法可将大量的银杏叶加工废液进行有益利用,对扩大银杏酚酸原料的来源具有较大的实用价值。(The invention discloses a method for extracting ginkgolic acid from ginkgo leaf processing waste liquid, which is implemented by filtering the ginkgo leaf processing waste liquid for three times through filter cloth, then carrying out fine filtration and concentration to 1/10-20 of the mass of the ginkgo leaf processing waste liquid to obtain concentrated solution, and then mixing the concentrated solution and silica gel according to the weight ratio of 1: mixing the components in a ratio of 0.3-0.5, stirring for three times, merging the silica gels obtained after three times of filtration, washing the silica gels to be colorless by using deionized water, then respectively leaching the silica gels once by using ethanol, methanol and petroleum ether, respectively recovering solvents to obtain extracts, drying, crushing and uniformly mixing the extracts to obtain the ginkgolic acid extract, wherein the content of the ginkgolic acid is more than 60 percent through HPLC (high performance liquid chromatography) detection. The ginkgolic acid obtained by the method can be used as a biological pesticide preparation, an external medicine preparation and a cosmetic product. The method can make beneficial use of a large amount of ginkgo biloba processing waste liquid, and has great practical value for enlarging the source of the ginkgolic acid raw material.)

1. A method for extracting ginkgolic acid from ginkgo leaf processing waste liquid is characterized by comprising the following process steps:

(1) filtering the ginkgo leaf processing waste liquid for three times by using filter cloth respectively, then carrying out fine filtration to obtain filtrate, concentrating the filtrate to 1/10-20 of the weight of the solution, and obtaining concentrated solution;

(2) according to the weight ratio of the concentrated solution of 1: adding silica gel powder in a proportion of 0.3-0.5, stirring for 3-4 hours under the condition of 20-30 r/min, stopping stirring, standing for 1 hour, filtering out the silica gel, and adding a concentrated solution into the residual filtrate in a weight ratio of 1: 0.3-0.5 of silica gel powder, stirring for 3-4 hours under the condition of 15-25 r/min, stopping stirring, standing for 1 hour, filtering out the silica gel, and adding a concentrated solution into the residual filtrate in a weight ratio of 1: 0.3-0.5 of silica gel powder, stirring for 3-4 hours under the condition of 10-20 r/min, stopping stirring, standing for 1 hour, and filtering out the silica gel;

(3) combining the silica gels obtained by the three times of filtration, washing the silica gels with deionized water until the eluate is colorless, and obtaining soaked silica gels;

(4) the washed silica gel is soaked and extracted once by ethanol, methanol and petroleum ether respectively, and the specific method comprises the following steps:

ethanol with the volume content of 95 percent is used, and the mass ratio of silica gel to ethanol is 1: 10, carrying out reflux extraction at the temperature of 60-65 ℃ for 5 hours, and filtering to obtain an ethanol extract after the extraction is finished;

secondly, using 90 percent (volume) of methanol for the silica gel after ethanol extraction according to the mass ratio of the silica gel to the methanol of 1: 10, carrying out reflux extraction at the temperature of 55-60 ℃ for 4 hours, and filtering to obtain a methanol extracting solution after the extraction is finished;

thirdly, extracting the silica gel from the second step by using methanol according to the mass ratio of the silica gel to petroleum ether of 1: 10, reflux extracting for 3 hours at 50-55 ℃, and filtering to obtain petroleum ether extract after extraction is finished;

(5) recovering ethanol from the ethanol extracting solution obtained in the step (4) to obtain a concentrated material, and drying the concentrated material in vacuum to obtain an ethanol extract; recovering methanol from the methanol extracting solution of the second step to obtain concentrated material, and vacuum drying the concentrated material to obtain methanol extract; recovering petroleum ether from the petroleum ether extracting solution of the third step to obtain a concentrated material, and drying the concentrated material in vacuum to obtain a petroleum ether extract;

(6) respectively pulverizing the ethanol extract, the methanol extract and the petroleum ether extract in the step (5) and uniformly mixing to obtain ginkgolic acid; the detection shows that the content of the ginkgolic acid is more than 60 percent.

2. The method as claimed in claim 1, wherein the filtering is performed three times by using 100 mesh, 300 mesh and 500 mesh filter cloths respectively; and the fine filtration is carried out by adopting a ceramic membrane with the thickness of 0.15-0.3 mu m.

3. The method of claim 1, wherein the concentrating is performed by using a rotary evaporator; the concentration conditions are that the temperature is 85-90 ℃ and the pressure is-0.065 to-0.09 MPa.

4. The method of claim 1, wherein the petroleum ether is reagent grade petroleum ether having a boiling range of 60 ℃ to 90 ℃; and conforms to the GB/T15894-2008 regulation.

5. The use of a ginkgolic acid as claimed in claim 1 as a biopesticide, a pharmaceutical preparation for external use and a cosmetic preparation.

Technical Field

The invention belongs to the field of processing of raw materials of medicines and biological pesticides, and relates to a method for processing a ginkgolic acid extract contained in a medicine external preparation and a biological pesticide. In particular to a method for extracting ginkgolic acid by using waste liquid in the processing process of a Ginkgo Biloba Extract (GBE).

Background

The waste liquid flowing out after being adsorbed by macroporous adsorption resin in the processing process of the ginkgo leaf extract (GBE) refers to the waste liquid generated after the ginkgo leaf decoction in the process of extracting the ginkgo leaf extract from ginkgo leaves is adsorbed by the macroporous adsorption resin. In the current process of preparing Ginkgo Biloba Extract (GBE), the juice of the ginkgo biloba extract after extracting the total flavonoids is discharged as waste. According to the existing production method, folium Ginkgo extract is prepared by pulverizing folium Ginkgo, extracting with ethanol under reflux, mixing extractive solutions, recovering ethanol, concentrating to appropriate amount, loading onto treated macroporous adsorbent resin column, sequentially eluting with water and ethanol of different concentrations, collecting corresponding eluates, recovering ethanol, and spray drying; or recovering ethanol, concentrating into soft extract, vacuum drying, and pulverizing to obtain the final product (pharmacopoeia of the national pharmacopoeia committee, China and China people's republic of China, 2015 edition, one part, page 466). However, some manufacturers optimize the production of ginkgo biloba extract, and mostly adopt dry ginkgo biloba leaves directly or after being crushed, add water for decoction, extract, combine extract solutions, add the extract solutions to a treated macroporous resin column for adsorption, and then sequentially elute with water and ethanol with different concentrations. No matter the process method of pharmacopoeia or the optimization process of enterprises, the extraction amount of the ginkgo leaf total flavone extract is only 0.2-0.425% (calculated on dry products), although the pharmacopoeia stipulates that the ginkgo leaves contain not less than 0.40% of total flavonol glycosides and not less than 0.25% of terpene lactones according to dry products, the content difference of the ginkgo leaf total flavone is larger according to different harvesting seasons, different growth environments and different processing and storage conditions of the ginkgo leaves, but the maximum content extraction amount is less than 0.50% no matter the extraction rate of the extract is large. However, in the processing enterprises of ginkgo biloba extract, a large amount of extract is discharged as waste liquid in the process of extracting flavonol glycosides. Ginkgolic acid belongs to alkylphenol and alkylphenol acid compounds, and ginkgolic acid at present mainly refers to such compounds, including ginkgolic acid (ginkgolic acid), hydroginkgolic acid (hydroginkgolic acid), ginkgol (bilobol) and ginkgol (ginkgol), which have strong allergy and contact dermatitis on human bodies and are toxic and side effects in a ginkgo leaf extracting solution, and the content of ginkgolic acid in ginkgo leaves is 500-2000 mug/g. The content of the Ginkgo Biloba Extract (GBE) is required to be controlled below 10 mug/g, the content of the Ginkgo Biloba Extract (GBE) can be less than 5 mug/g by adopting the modern separation means at present, and some advanced processes can be controlled to be 2-3 mug/g. Therefore, in the preparation process of the Ginkgo Biloba Extract (GBE), most ginkgolic acid components are still remained in the waste liquid in the processing process, and the ginkgolic acid serving as a novel biopesticide resource has a satisfactory application effect in the aspects of preventing and treating plant diseases and insect pests. According to the existing processing method of ginkgo leaf extract (GBE), the dosage ratio of ginkgo leaf (dry) to water (or alcohol) is 1: 10-20, removing the residual ginkgolic acid and partial loss in the ginkgo biloba extract (GEB), wherein the residual quantity of the ginkgolic acid in the waste liquid is 40-190 mu g/g-20-95 mu g/g, which seems that the content of the ginkgolic acid in the processing waste liquid is very low, and the ginkgo biloba has considerable value in development and utilization as the source of the ginkgolic acid raw material due to huge processing amount of the ginkgo biloba production place if the adopted process is proper.

The prior patent in China also adopts a process method for extracting ginkgolic acid from ginkgo industrial waste liquid, for example, (CN 110354153A) the ginkgo industrial waste liquid is firstly filtered by a 0.45 mu membrane, filtrate is subjected to vacuum rotary evaporation, organic solvent is recovered, 95% ethanol is added into the residual liquid, the concentration is adjusted to 80%, reflux is carried out for 4h at 60 ℃, extraction is carried out for 3 times, extracting solutions are combined and filtered by a 0.45 mu membrane, then the filtrate is proportionally added onto a pretreated macroporous resin column and washed by distilled water until eluate is clear and no visible solid is produced, then 90% ethanol is used for elution until the eluate is colorless, the ethanol eluate is subjected to rotary evaporation at the temperature of below 60 ℃, ethanol is recovered, and the remainder is subjected to vacuum drying at the temperature of 60 ℃ to obtain the total phenolic acid. It can be seen that the process of extracting the ginkgolic acid from the industrial waste liquid extracted from the ginkgo leaves, concentrating, extracting with alcohol, adsorbing by macroporous resin, eluting and the like is complicated and huge, and the extraction of the ginkgolic acid from the waste liquid extracted from the ginkgo leaves is time-consuming, labor-consuming and high in processing cost.

Disclosure of Invention

Aiming at the problems existing in the extraction of ginkgolic acid by using waste liquid in the processing process of a Ginkgo Biloba Extract (GBE), the invention aims to improve the technical process of extracting ginkgolic acid by using waste liquid in the processing process of the ginkgo biloba extract so as to realize the purposes of low cost, simple and feasible operation process and high content of extracted ginkgolic acid. The invention aims to extract ginkgolic acid by using waste liquid in the processing process of a Ginkgo Biloba Extract (GBE).

In order to realize the invention, the following technical scheme is adopted:

a method for extracting ginkgolic acid from waste liquid in the processing process of a ginkgo leaf extract (hereinafter referred to as ginkgo leaf processing waste liquid) is characterized by comprising the following process steps:

(1) filtering the ginkgo leaf processing waste liquid for three times by using filter cloth respectively, then carrying out fine filtration to obtain filtrate, concentrating the filtrate to 1/10-20 of the weight of the solution, and obtaining concentrated solution;

(2) according to the weight ratio of the concentrated solution of 1: adding silica gel powder in a proportion of 0.3-0.5, stirring for 3-4 hours under the condition of 20-30 r/min, stopping stirring, standing for 1 hour, filtering out the silica gel, and adding a concentrated solution into the residual filtrate in a weight ratio of 1: 0.3-0.5 of silica gel powder, stirring for 3-4 hours under the condition of 15-25 r/min, stopping stirring, standing for 1 hour, filtering out the silica gel, and adding a concentrated solution into the residual filtrate in a weight ratio of 1: 0.3-0.5 of silica gel powder, stirring for 3-4 hours under the condition of 10-20 r/min, stopping stirring, standing for 1 hour, and filtering out the silica gel;

(3) combining the silica gels obtained by the three times of filtration, washing the silica gels with deionized water until the eluate is colorless, and obtaining soaked silica gels;

(4) the washed silica gel is soaked and extracted once by ethanol, methanol and petroleum ether respectively, and the specific method comprises the following steps:

ethanol with the volume content of 95 percent is used, and the mass ratio of silica gel to ethanol is 1: 10, carrying out reflux extraction at the temperature of 60-65 ℃ for 5 hours, and filtering to obtain an ethanol extract after the extraction is finished;

secondly, using 90 percent (volume) of methanol for the silica gel after ethanol extraction according to the mass ratio of the silica gel to the methanol of 1: 10, carrying out reflux extraction at the temperature of 55-60 ℃ for 4 hours, and filtering to obtain a methanol extracting solution after the extraction is finished;

thirdly, extracting the silica gel from the second step by using methanol according to the mass ratio of the silica gel to petroleum ether of 1: 10, reflux extracting for 3 hours at 50-55 ℃, and filtering to obtain petroleum ether extract after extraction is finished;

(5) recovering ethanol from the ethanol extracting solution obtained in the step (4) to obtain a concentrated material, and drying the concentrated material in vacuum to obtain an ethanol extract; recovering methanol from the methanol extracting solution of the second step to obtain concentrated material, and vacuum drying the concentrated material to obtain methanol extract; recovering petroleum ether from the petroleum ether extracting solution of the third step to obtain a concentrated material, and drying the concentrated material in vacuum to obtain a petroleum ether extract;

(6) respectively pulverizing the ethanol extract, the methanol extract and the petroleum ether extract in the step (5) and uniformly mixing to obtain ginkgolic acid; the detection shows that the content of the ginkgolic acid is more than 60 percent.

The detection adopts a known High Performance Liquid Chromatography (HPLC) detection method, and references are made to published detection technical conditions, such as Chinese patent (CN 102727538A), Chinese patent (CN 111359260A) and the like.

Filtering for three times by using 100-mesh, 300-mesh and 500-mesh filter cloth respectively; and the fine filtration is carried out by adopting a ceramic membrane with the thickness of 0.15-0.3 mu m.

The concentration conditions are that the temperature is 85-90 ℃ and the pressure is-0.065 to-0.09 MPa; a rotary evaporator is used.

The method can realize the extraction of the high-purity ginkgolic acid by filtering, concentrating and adsorbing and extracting the ginkgo leaf processing waste liquid in the preparation process of the ginkgo leaf extract, and then carrying out the steps of ethanol leaching elution, methanol leaching elution, petroleum ether leaching elution and the like, wherein the step filtration can greatly reduce impurities in the ginkgo leaf processing waste liquid, avoid the influence of impurities with large particle size in the solution on the subsequent steps, simultaneously avoid the influence on the adsorption process of the silica gel, simultaneously reduce the using amount of the elution solution, reduce the attachment of pigments and have good beneficial effects on improving the yield and the quality of products.

The method adopts the ginkgo leaf processing waste liquid as the raw material, the content of the ginkgolic acid in the waste liquid is low, if the ginkgo leaf processing waste liquid is directly extracted, the consumption of an organic solvent is large, the labor force is greatly increased in the operation process, and the energy consumption is relatively increased, so that the filtration and concentration of the ginkgo leaf processing waste liquid are one of the most economic operations, the considerable and high content of the ginkgolic acid can be extracted from the ginkgo leaf processing waste liquid according to the embodiment of the invention, and the scheme of the invention still has great practical value in order to expand the source of the ginkgolic acid raw material.

The method can adopt leaching tanks, jars, tanks and the like according to production conditions, does not need to be provided with silica gel columns, can select leaching facilities for production units according to self conditions, facilitates production selection and avoids the limitation of the production conditions. The method is better than the method of mixing organic solvents, can respectively recover the solvents, is convenient for the recovery process, is beneficial to the complete recovery of the solvents, and is beneficial to saving the cost of raw materials.

According to the invention, the adsorbate is extracted by ethanol, methanol and petroleum ether step by step, so that acid group substances of ginkgolic acids can be fully extracted, the uncertainty of a single solvent to the extract is avoided, and the purification effect of the adsorbate is greatly improved compared with the purification effect of the single solvent.

For the process steps of the invention, no waste such as solvent and the like is lost in the operation process, and no environmental pollution is caused.

The petroleum ether adopted in the invention is the petroleum ether used as a reagent and with a boiling range of 60-90 ℃, and the specification is as follows: GB/T15894-2008, practice proves that the reagent grade petroleum ether is easy to remove the petroleum ether in the extracted ginkgolic acid completely without residue.

The ginkgolic acid is well known to have important pharmacological action, has good killing effect on agricultural plant diseases and insect pests, fungal diseases and the like, and is widely used as a production raw material of pharmaceutical preparations, cosmetics and biopesticide preparations.

Detailed Description

Example 1

(1) Taking 100kg of ginkgo leaf processing waste liquid, sequentially filtering the ginkgo leaf processing waste liquid through 100-mesh, 300-mesh and 500-mesh filter cloth for three times to obtain filtrate, finely filtering the filtrate by using a 0.15 mu m ceramic membrane to obtain fine filtered liquid, then concentrating by using a rotary evaporator under the conditions that the temperature is 85 ℃ and the vacuum degree is-0.09 MPa, and concentrating to 1/10 of the mass of the ginkgo leaf processing waste liquid to obtain 10kg of concentrated liquid for later use;

(2) taking 10kg of the concentrated solution obtained in the step (1), adding 5kg of silica gel powder, stirring for 4h under the condition of 30r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 4kg of silica gel powder into the residual filtrate, stirring for 3.5h under the condition of 25r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 3kg of silica gel powder into the residual filtrate, stirring for 3h under the condition of 20r/min, stopping stirring, standing for 1h, and filtering out the silica gel;

(3) combining the silica gels filtered for three times in the step (2), and washing with deionized water until the eluate is colorless to obtain washed silica gels;

(4) soaking and extracting the washed silica gel obtained in the step (3) with ethanol, methanol and petroleum ether respectively for one time, wherein the specific method comprises the following steps:

carrying out reflux extraction on 12kg of the silica gel washed in the step (3) by 120kg of ethanol with the volume content of 95% at the temperature of 65 ℃ for 5h, and filtering to obtain an ethanol extract after the extraction is finished;

secondly, refluxing and extracting the silica gel extracted by ethanol in 120kg of methanol with the volume content of 90 percent for 4 hours at the temperature of 55 ℃, and filtering the methanol extract after the extraction is finished;

thirdly, adding 120kg of petroleum ether into the silica gel extracted by the methanol in the step two, performing reflux extraction at the temperature of 55 ℃ for 3 hours, and filtering to obtain petroleum ether extract after the extraction is finished;

(5) recovering ethanol from the ethanol extracting solution obtained in the step (4) to obtain a concentrated material, and drying the concentrated material in vacuum to obtain an ethanol extract; recovering methanol from the methanol extracting solution of the second step to obtain concentrated material, and vacuum drying the concentrated material to obtain methanol extract; recovering petroleum ether from the petroleum ether extracting solution of the third step to obtain a concentrated material, and drying the concentrated material in vacuum to obtain a petroleum ether extract;

(6) respectively crushing and uniformly mixing the ethanol extract, the methanol extract and the petroleum ether extract obtained in the step (5) to obtain 108.64g of ginkgolic acid; the content of ginkgolic acid is 61.83% by HPLC detection.

The invention is directed to example 1, a comparative experiment was carried out using a single solvent of ethanol, methanol and petroleum ether as leaching solvents:

comparative example:

in the comparative example, 3 parts of concentrated solution is prepared by the method in the step (1) in the example 1, the filtered silica gel is prepared by the method in the step (2), then the washed silica gel is obtained by the method in the step (3), and then 3 parts of the washed silica gel are leached by single ethanol, methanol and petroleum ether respectively according to the comparative examples 1, 2 and 3; the specific method comprises the following steps:

comparative example 1

(1) Taking 100kg of ginkgo leaf processing waste liquid, sequentially filtering the ginkgo leaf processing waste liquid through 100-mesh, 300-mesh and 500-mesh filter cloth for three times to obtain filtrate, finely filtering the filtrate by using a 0.15 mu m ceramic membrane to obtain fine filtered liquid, then concentrating by using a rotary evaporator under the conditions that the temperature is 85 ℃ and the vacuum degree is-0.09 MPa, and concentrating until the mass of the ginkgo leaf processing waste liquid is 1/10 to obtain 10kg of concentrated liquid for later use;

(2) taking 10kg of the concentrated solution obtained in the step (1), adding 5kg of silica gel powder, stirring for 3h under the condition of 30r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 4kg of silica gel powder into the residual filtrate, stirring for 3.5h under the condition of 25r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 3kg of silica gel powder into the residual filtrate, stirring for 3h under the condition of 20r/min, stopping stirring, standing for 1h, and filtering out the silica gel;

(3) combining the silica gels filtered for three times in the step (2), and washing with deionized water until the eluate is colorless to obtain washed silica gels;

(4) soaking and extracting the washed silica gel obtained in the step (3) with ethanol for three times, wherein the specific method comprises the following steps:

carrying out reflux extraction on 12kg of the silica gel washed in the step (3) by using 120kg of ethanol with the volume content of 95 percent at the temperature of 65 ℃ for 5 hours, and filtering to obtain an ethanol extracting solution after the extraction is finished;

secondly, refluxing and extracting the silica gel extracted by ethanol in an amount of 120kg with 95 percent (volume) of ethanol at the temperature of 60 ℃ for 5 hours, and filtering to obtain an ethanol extracting solution after the extraction is finished;

thirdly, refluxing and extracting the silica gel extracted by the ethanol in the second step for 5 hours at 63 ℃ by using 120kg of ethanol with the volume content of 95 percent, and filtering to obtain ethanol extract after the extraction is finished;

(5) mixing the ethanol extract obtained in the step (4), recovering ethanol to obtain a concentrated material, and vacuum drying the concentrated material to obtain 93.17g of ethanol extract; the content of ginkgolic acid is 60.05% by HPLC detection.

Comparative example 2

(1) Taking 100kg of ginkgo leaf processing waste liquid, sequentially filtering the ginkgo leaf processing waste liquid through 100-mesh, 300-mesh and 500-mesh filter cloth for three times to obtain filtrate, finely filtering the filtrate by using a 0.15 mu m ceramic membrane to obtain fine filtered liquid, then concentrating by using a rotary evaporator under the conditions that the temperature is 85 ℃ and the vacuum degree is-0.09 MPa, and concentrating until the mass of the ginkgo leaf processing waste liquid is 1/10 to obtain 10kg of concentrated liquid for later use;

(2) taking 10kg of the concentrated solution obtained in the step (1), adding 5kg of silica gel powder, stirring for 3h under the condition of 30r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 4kg of silica gel powder into the residual filtrate, stirring for 3.5h under the condition of 25r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 3kg of silica gel powder into the residual filtrate, stirring for 3h under the condition of 20r/min, stopping stirring, standing for 1h, and filtering out the silica gel;

(3) combining the silica gels filtered for three times in the step (2), and washing with deionized water until the eluate is colorless to obtain washed silica gels;

(4) soaking and extracting the washed silica gel obtained in the step (3) with methanol for three times, wherein the specific method comprises the following steps:

carrying out reflux extraction on 12kg of silica gel washed in the step (3) by using 120kg of methanol with the volume content of 90 percent at the temperature of 55 ℃ for 4 hours, and filtering to obtain a methanol extracting solution after the extraction is finished;

secondly, refluxing and extracting the silica gel extracted by the methanol in the step one by 120kg of methanol with the volume content of 90 percent at the temperature of 60 ℃ for 4 hours, and filtering the methanol extract after the extraction is finished;

thirdly, refluxing and extracting the silica gel extracted by the methanol in the second step for 4 hours at the temperature of 58 ℃ by using 120kg of methanol with the volume content of 90 percent, and filtering the methanol extract after the extraction is finished;

(5) combining the methanol extracting solutions respectively obtained in the step (4), recovering methanol to obtain a concentrated material, and vacuum drying the concentrated material to obtain 94.22g of methanol extract; the content of ginkgolic acid is 61.07% by HPLC detection.

Comparative example 3

(1) Taking 100kg of ginkgo leaf processing waste liquid, sequentially filtering the ginkgo leaf processing waste liquid through 100-mesh, 300-mesh and 500-mesh filter cloth for three times to obtain filtrate, finely filtering the filtrate by using a 0.15 mu m ceramic membrane to obtain fine filtered liquid, then concentrating by using a rotary evaporator under the conditions that the temperature is 85 ℃ and the vacuum degree is-0.09 MPa, and concentrating until the mass of the ginkgo leaf processing waste liquid is 1/10 to obtain 10kg of concentrated liquid for later use;

(2) taking 10kg of the concentrated solution obtained in the step (1), adding 5kg of silica gel powder, stirring for 3h under the condition of 30r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 4kg of silica gel powder into the residual filtrate, stirring for 3.5h under the condition of 25r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 3kg of silica gel powder into the residual filtrate, stirring for 3h under the condition of 20r/min, stopping stirring, standing for 1h, and filtering out the silica gel;

(3) combining the silica gels filtered for three times in the step (2), and washing with deionized water until the eluate is colorless to obtain washed silica gels;

(4) soaking and extracting the washed silica gel obtained in the step (3) with petroleum ether for three times, wherein the specific method comprises the following steps:

carrying out reflux extraction on 12kg of silica gel washed in the step (3) with 120kg of petroleum ether at the temperature of 50 ℃ for 3h, and filtering to obtain a petroleum ether extracting solution after extraction is finished;

secondly, refluxing and extracting the silica gel extracted by the petroleum ether for 3 hours at the temperature of 55 ℃ by using 120kg of petroleum ether, and filtering to obtain petroleum ether extract after the extraction is finished;

thirdly, refluxing and extracting the silica gel extracted by petroleum ether in 120kg at 52 ℃ for 3h, and filtering to obtain petroleum ether extract after extraction is finished;

(5) mixing the petroleum ether extract solutions respectively obtained in the step (4), recovering petroleum ether to obtain a concentrated material, and vacuum drying the concentrated material to obtain 100.7g of petroleum ether extract; the content of ginkgolic acid is 61.03% by HPLC detection.

Comparative examples were conducted by extracting with ethanol, methanol and petroleum ether respectively under the same conditions as in the above-described methods, and the procedure was the same as in the above-described steps (1), (2) and (3) of example 1, except that the combined silica gel was washed with deionized water until the eluate was colorless, the silica gel was extracted with ethanol 3 times under the conditions of the first step of step (4), the ethanol extract was combined, the ethanol was recovered to obtain a concentrated material, and the concentrated material was vacuum-dried to obtain 93.17g of an ethanol extract; detecting the content of ginkgolic acid by HPLC method to be 60.05%;

the steps are the same as the steps (1), (2) and (3) in the previous embodiment 1, except that the combined silica gel is washed by deionized water until eluate is colorless, the silica gel is leached by methanol for 3 times respectively according to the conditions in the step (4) and the second step, methanol leaching liquor is combined, methanol is recycled to prepare concentrated material, and then the concentrated material is dried in vacuum to obtain 94.22g of methanol extract; detecting ginkgolic acid content by HPLC to be 61.07%;

the steps are the same as the steps (1), (2) and (3) in the previous embodiment 1, except that the combined silica gel is washed by deionized water until eluate is colorless, the silica gel is leached by petroleum ether for 3 times respectively according to the conditions in the step (4), petroleum ether leaching liquor is combined, the petroleum ether is recovered to prepare concentrated material, and then the concentrated material is dried in vacuum to obtain 100.7g of petroleum ether extract; the content of ginkgolic acid is 60.03 percent by HPLC detection.

The results show that the yield of the silica gel subjected to leaching by using ethanol, methanol and petroleum ether in a gradient leaching way is higher than that of the silica gel subjected to leaching repeated for 3 times by using a single solvent, and the content of phenolic acid is greatly improved.

Example 2

(1) Taking 100kg of ginkgo leaf processing waste liquid, sequentially filtering the ginkgo leaf processing waste liquid through 100-mesh, 300-mesh and 500-mesh filter cloth for three times to obtain filtrate, finely filtering the filtrate by using a 0.22 mu m ceramic membrane to obtain fine filtered liquid, then concentrating by using a rotary evaporator under the conditions that the temperature is 90 ℃ and the vacuum degree is-0.065 MPa, and concentrating to 1/20 which is equal to the mass of the ginkgo leaf processing waste liquid to obtain 5kg of concentrated liquid for later use;

(2) taking 5kg of the concentrated solution obtained in the step (1), adding 2.5kg of silica gel powder, stirring for 4h under the condition of 25r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 2kg of silica gel powder into the residual filtrate, stirring for 3.5h under the condition of 20r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 1.5kg of silica gel powder into the residual filtrate, stirring for 3h under the condition of 15r/min, stopping stirring, standing for 1h, and filtering out the silica gel;

(3) combining the silica gels filtered for three times in the step (2), and washing with deionized water until the eluate is colorless to obtain washed silica gels;

(4) soaking and extracting the washed silica gel obtained in the step (3) with ethanol, methanol and petroleum ether respectively once, wherein the specific method comprises the following steps:

carrying out reflux extraction on 6kg of the washed silica gel in the step (3) by 60kg of ethanol with the volume content of 95% at the temperature of 60 ℃ for 5h, and filtering to obtain an ethanol extract after the extraction is finished;

secondly, refluxing and extracting 60kg of silica gel extracted by ethanol with 90 percent of methanol by volume at the temperature of 60 ℃ for 4 hours, and filtering the methanol extract after the extraction is finished;

thirdly, adding 60kg of petroleum ether into the silica gel extracted by the methanol in the step two, performing reflux extraction at the temperature of 50 ℃ for 3 hours, and filtering to obtain petroleum ether extract after the extraction is finished;

(5) recovering ethanol from the ethanol extracting solution obtained in the step (4) to obtain a concentrated material, and drying the concentrated material in vacuum to obtain an ethanol extract; recovering methanol from the methanol extracting solution of the second step to obtain concentrated material, and vacuum drying the concentrated material to obtain methanol extract; recovering petroleum ether from the petroleum ether extracting solution of the third step to obtain a concentrated material, and drying the concentrated material in vacuum to obtain a petroleum ether extract;

(6) respectively crushing the ethanol extract, the methanol extract and the petroleum ether extract obtained in the step (5), and uniformly mixing to obtain 112.46 g of ginkgolic acid; the content of ginkgolic acid is 62.93 percent by HPLC detection.

Example 3

(1) Taking 100kg of ginkgo leaf processing waste liquid, sequentially filtering the ginkgo leaf processing waste liquid through 100-mesh, 300-mesh and 500-mesh filter cloth for three times to obtain filtrate, finely filtering the filtrate by using a 0.30 mu m ceramic membrane to obtain fine filtrate, then concentrating by using a rotary evaporator under the conditions that the temperature is 88 ℃ and the vacuum degree is-0.08 MPa, and concentrating until the mass of the ginkgo leaf processing waste liquid is 1/16 to obtain 6.25kg of concentrated liquid for later use;

(2) taking 6.25kg of the concentrated solution obtained in the step (1), adding 3.125kg of silica gel powder, stirring for 4h under the condition of 20r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 2.5kg of silica gel powder into the residual filtrate, stirring for 3h under the condition of 20r/min, stopping stirring, standing for 1h, filtering out the silica gel, adding 1.875kg of silica gel powder into the residual filtrate, stirring for 3.5h under the condition of 10r/min, stopping stirring, standing for 1h, and filtering out the silica gel;

(3) combining the silica gels filtered for three times in the step (2), and washing with deionized water until the eluate is colorless to obtain washed silica gels;

(4) soaking and extracting the washed silica gel obtained in the step (3) with ethanol, methanol and petroleum ether respectively once, wherein the specific method comprises the following steps:

carrying out reflux extraction on 7.5kg of the silica gel washed in the step (3) by using 75kg of ethanol with the volume content of 95 percent at the temperature of 63 ℃ for 5 hours, and filtering to obtain an ethanol extracting solution after the extraction is finished;

secondly, refluxing and extracting the silica gel extracted by ethanol in 75kg of methanol with the volume content of 90 percent for 4 hours at the temperature of 58 ℃, and filtering the methanol extract after the extraction is finished;

thirdly, adding 75kg of petroleum ether into the silica gel extracted by the methanol in the step two, performing reflux extraction at the temperature of 53 ℃ for 3 hours, and filtering to obtain petroleum ether extract after the extraction is finished;

(5) recovering ethanol from the ethanol extracting solution obtained in the step (4) to obtain a concentrated material, and drying the concentrated material in vacuum to obtain an ethanol extract; recovering methanol from the methanol extracting solution of the second step to obtain concentrated material, and vacuum drying the concentrated material to obtain methanol extract; recovering petroleum ether from the petroleum ether extracting solution of the third step to obtain a concentrated material, and drying the concentrated material in vacuum to obtain a petroleum ether extract;

(6) respectively crushing the ethanol extract, the methanol extract and the petroleum ether extract obtained in the step (5), and uniformly mixing to obtain 110.87g of ginkgolic acid; the content of ginkgolic acid is 62.09% by HPLC detection.