CA3203208A1

CA3203208A1 - Multifunctional panax quinquefolius hydrolyzed peptide and preparation method and application thereof

Info

Publication number: CA3203208A1
Application number: CA3203208A
Authority: CA
Inventors: Xuanming ZHANG; Kechun LIU; Meng JIN; Xiaobin Li; Yun Zhang; Pengfei Tu; Shanshan Zhang; Qing Xia; Lizhen Wang; Wenlong SHENG; Peihai LI
Original assignee: Biology Institute of Shandong Academy of Sciences
Current assignee: Biology Institute of Shandong Academy of Sciences
Priority date: 2021-11-17
Filing date: 2022-10-28
Publication date: 2023-05-25
Also published as: WO2023088073A1; CN114032273A; CN114032273B

Abstract

The present disclosure relates to a multifunctional Panax quinquefolius hydrolyzed peptide and a preparation method and application thereof. The content of active peptides in the Panax quinquefolius hydrolyzed peptide of the present disclosure is greater than 85%, and the molecular weight of the active peptide is less than 10 kD. The present disclosure also provides a preparation method of a Panax quinquefolius hydrolyzed peptide, the Panax quinquefolius hydrolyzed peptide is extracted by an ionic liquid and pepsin-trypsin two-stage digestion process, and the process is green and safe, simple to operate, and suitable for mass production. The Panax quinquefoliushydrolyzed peptide of the present disclosure has significant functional effects of regulating immunity, lowering blood pressure, lowering blood sugar, resisting inflammation, and resisting oxidation. Moreover, the pharmacodynamic experiments show that the combined administration has a synergistic effect on some symptoms.

Description

MULTIFUNCTIONAL PANAX QUINQUEFOLIUS HYDROLYZED PEPTIDE
AND PREPARATION METHOD AND APPLICATION THEREOF
Field of the Invention The present disclosure relates to a multifunctional Panax quinquefolius hydrolyzed peptide and a preparation method and application thereof, and belongs to the field of pharmaceutical functional product processing.
Background of the Invention Organic solvents are commonly used in the extraction and separation of natural active ingredients, which not only have strong volatility or toxicity, but also cause environmental pollution during production. An ionic liquid is a liquid substance composed of larger asymmetrical organic cations and smaller inorganic/organic anions.
Compared with the conventional solvent, the ionic liquid has the characteristics of good heat stability, non-volatility, safety and environmental friendliness, reusability, and the like. Furthermore, due to high selectivity to targets, the ionic liquid can be used for effectively extracting active ingredients from a natural product, and has become a novel green solvent in the field of purification and separation.
The concept of ionic liquid aqueous two-phase system was first proposed by Gutowski in 2003. More studies have been focused on ionic liquid/inorganic salt systems, and study results show that a hydrophilic ionic liquid [Camim]Cl and can form an aqueous two-phase system in which an ionic liquid is enriched in an upper phase and potassium phosphate is enriched in a lower phase. Compared with a conventional aqueous two-phase system, the ionic liquid aqueous two-phase system not only creates a mild environment for extraction, but also avoids the use of organic solvent during extraction, which has the advantages of both the ionic liquid and the aqueous two-phase system, and has the advantages of short phase separation time, difficult emulsification, high extraction rate, easy reutilization of an ionic system, and the like. Therefore, the ionic liquid aqueous two-phase system has wide application prospect in separation of natural active substances.
Panax quinquefolius has the effects of boosting qi and nourishing yin, and removing heat and promoting salivation, and is a nourishing health care product with extremely high medicinal value. Panax quinquefolius contains a variety of active ingredients such as ginsenoside, polysaccharide, sterol, protein, and polypeptide.
Protein and polypeptide are important active ingredients in addition to ginsenoside in Panax quinquefolius, and studies have proved that Panax quinquefolius has the effects of regulating immunity, lowering blood pressure, lowering blood sugar, lowering blood lipid, resisting oxidation, and resisting radiation damage. Protein, as a biomacromolecule, is generally difficult to be directly absorbed by the human body, especially for patients and the elderly. Due to decreased physical function, the digestion-absorption capacity becomes poor, and it is more difficult for patients and the elderly to absorb protein from food. Peptide constituents, as a hydrolysate of protein, have physical and chemical properties superior to those of protein in many aspects, and may be directly absorbed in the gastrointestinal tract without digestion, and the absorption efficiency of the peptide constituents is even more significant than that of amino acids.
According to the preparation method of a Panax quinquefolius polypeptide in prior art, organic solvents or expensive extraction equipment are mainly used, and the preparation process is complicated and the cost is high, which is not conducive to the promotion and application of the Panax quinquefolius polypeptide in the market. Panax quinquefolius is a natural product with a complicated composition, the purity of the Panax quinquefolius polypeptide product in the prior art is low, and how to simplify the extraction process and effectively improve the purity of the Panax quinquefolius polypeptide is a technical problem faced by those skilled in the art.
Summary of the Invention In view of the deficiencies in the prior art, the present disclosure provides a multifunctional Panax quinquefolius hydrolyzed peptide and a preparation method and application thereof.

2 The present disclosure provides a multifunctional Panax quinquefolius hydrolyzed peptide in which the content of active peptides is greater than 85%.
Based on the advantages of absorption and utilization of peptide constituents by the human body, the present disclosure provides a preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide, the extraction efficiency is excellent, the operation process is green and safe, and the content of active peptides in a final product may be greater than 85%. High-quality Panax quinquefolius active peptide constituents are obtained to a great extent by the technology, and the technology has wide application prospect in development of antioxidant, immunity regulating, anti-inflammatory, blood pressure lowering, and blood sugar lowering functional products.
The technical solutions of the preset disclosure are as follows:
A multifunctional Panax quinquefolius hydrolyzed peptide is provided. The hydrolyzed peptide is prepared through extraction with an ionic liquid, purification with inorganic salt, and enzymatic hydrolysis by a pepsin-trypsin two-step digestion process.
The content of active peptides in the hydrolyzed peptide is greater than 85%
by mass fraction, and the molecular weight of the active peptide is less than 10 kD.
According to the present disclosure, preferably, the content of active peptides in the hydrolyzed peptide is greater than 90% by mass fraction, and the molecular weight of the active peptide is less than 10 kD.
Further preferably, the content of active peptides in the hydrolyzed peptide is greater than 92% by mass fraction, and the molecular weight of the active peptide is less than 3 kD.
A preparation method of the foregoing Panax quinquefolius hydrolyzed peptide includes the following steps:
(1) grinding Panax quinquefolius, adding to an ionic liquid according to a mass-to-volume ratio (g/rnL) of 1: (10-35), extracting at 40-70 C for 0.5-4 h, and performing solid-liquid separation to prepare Panax quinquefolius crude protein extract;

3 (2) adding the Panax quinquefolius crude protein extract prepared in step (1) to inorganic salt according to a volume-to-mass ratio (mL/g) of (5-15): 0.8, ultrasonically shaking for 0.5-2 h, centrifuging at 3,000-5,000 r/min for 5-15 min to separate the liquid, removing a lower liquid, adding polyethylene glycol to an upper liquid, placing for 12-48 h, centrifuging at 3,000-5,000 r/min for 15-30 min, and collecting the precipitate, that is, Panax quinquefolius protein extract; and (3) dissolving the protein extract prepared in step (2) in water with the volume 10-15 times that of the protein extract, obtaining a Panax quinquefolius protein hydrolysate by a pepsin-trypsin two-step digestion process, adding to a sulfosalicylic acid solution, placing at room temperature for 30-90 min, performing solid-liquid separation, redissolving the precipitate, performing ultrafiltration, and lyophilizing to prepare a Panax quinquefolius hydrolyzed peptide.
According to the present disclosure, preferably, in step (1), the ionic liquid is 1-buty1-3-methylimidazolium tetrafluoroborate, 1 -buty1-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium bistrifluoromethanesulfonimide, 1 -octy1-3 -methylimidazolium chloride Or 1 -hexy1-3-methylimidazolium hexafluorophosphate.
Further preferably, the selected ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate or 1-buty1-methylimidazolium bistrifluoromethanesulfonimide.
More preferably, the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate.
According to the present disclosure, preferably, in step (1), the final concentration of the ionic liquid is 0.001-0.01 mol/L.
Further preferably, the final concentration of the ionic liquid is 0.002-0.008 mol/L.
More preferably, the final concentration of the ionic liquid is 0.004 mol/L.

4 According to the present disclosure, preferably, in step (2), the inorganic salt is dipotassium phosphate, sodium citrate, potassium chloride, monosodium phosphate or ammonium sulfate.
Further preferably, the inorganic salt is dipotassium phosphate, sodium citrate or monosodium phosphate.
More preferably, the inorganic salt is dipotassium phosphate.
According to the present disclosure, preferably, in step (2), the type of the added polyethylene glycol is polyethylene glycol 200, 400, 600, 800 or 1000.
Further preferably, the type of the added polyethylene glycol is polyethylene glycol 400, 600 or 800.
More preferably, the type of the added polyethylene glycol is polyethylene glycol 600.
According to the present disclosure, preferably, in step (2), an addition amount of polyethylene glycol is 5-20% by mass fraction.
Further preferably, the addition amount of polyethylene glycol is 12-18% by mass fraction.
More preferably, the addition amount of polyethylene glycol is 15% by mass fraction.
According to the present disclosure, preferably, in step (2), the frequency of ultrasonic shaking is 40-100 KHz.
Further preferably, the frequency of ultrasonic shaking is 60-80 KHz.
More preferably, the frequency of ultrasonic shaking is 70 KHz.

5 According to the present disclosure, preferably, in step (3), the primary digestion process is that an addition amount of pepsin is 10-100 mg/mL, the pH value is 1.5-4, the final concentration of NaCl is 0.01-0.08 mol/L, and the enzymatic hydrolysis time is 0.5-4 h, the secondary digestion process is that an addition amount of trypsin is 4-20 mg/mL, the pH value is 7.5-9.5, the final concentration of KH2PO4 is 0.05-0.12 mol/L, and the enzymatic hydrolysis time is 1-6 h, sulfosalicylic acid is added according to a mass-to-volume ratio (g/mL) of 0.15: (8-25), and molecular weight cut-off of ultrafiltration is less than 10 kDa.
Further preferably, the primary digestion process is that the addition amount of pepsin is 30-80 mg/mL, the pH value is 2-3, the final concentration of NaCl is 0.025-0.06 mol/L, and the enzymatic hydrolysis time is 1-3 h, the secondary digestion process is that the addition amount of trypsin is 8-16 mg/mL, the pH value is 8-9, the final concentration of KH2PO4. is 0.07-0.10 mol/L, and the enzymatic hydrolysis time is 2-5 h, sulfosalicylic acid is added according to a mass-to-volume ratio (g/mL) of 0.15: (10-15), and the molecular weight cut-off of ultrafiltration is less than 6 kDa.
More preferably, the primary digestion process is that the addition amount of pepsin is 60 mg/mL, the pH value is 2.5, the final concentration of NaCl is 0.04 mol/L, and the enzymatic hydrolysis time is 2 h, the secondary digestion process is that the addition amount of trypsin is 12 mg/mL, the pH value is 8.5, the final concentration of KH2PO4 is 0.08 mol/L, and the enzymatic hydrolysis time is 3 h, sulfosalicylic acid is added according to a mass-to-volume ratio (g/rnL) of 0.15: 12, and the molecular weight cut-off of ultrafiltration is less than 3 kDa.
An application of the foregoing Panax quinquefolius hydrolyzed peptide as an active ingredient in preparation of functional food, health care food, a drug or a daily chemical product is provided.
According to the present disclosure, preferably, an application of the foregoing Panax quinquefolius hydrolyzed peptide as an active ingredient in preparation of an immunity regulating, blood pressure lowering, blood sugar lowering, anti-inflammatory, or antioxidant functional product is provided.

6 A blood sugar lowering drug is provided, which contains the following active ingredients: acarbose and the foregoing Panax quinquefolius hydrolyzed peptide.
According to the present disclosure, preferably, in the blood sugar lowering drug, a mass ratio of acarbose to the Panax quinquefolius hydrolyzed peptide is 1:
1.
A blood pressure lowering drug is provided, which contains the following active ingredients: captopril and the foregoing Panax quinquefolius hydrolyzed peptide.
According to the present disclosure, preferably, in the blood pressure lowering drug, a mass ratio of captopril to the foregoing Panax quinquefolius hydrolyzed peptide is 1: 2.
The present disclosure has the following beneficial effects:
1. The present disclosure provides a highly pure Panax quinquefolius hydrolyzed peptide in which the content of active peptides is greater than 85% by mass fraction, the molecular weight of the active peptide is less than 10 kD, and the Panax quinquefolius hydrolyzed peptide of the present disclosure has a significant antioxidant effect.
2. The preparation method of a Panax quinquefolius hydrolyzed peptide of the present disclosure is easy to operate without requiring expensive equipment, and significantly reduces a usage amount of organic solvent, and the content of active peptides in a prepared Panax quinquefolius hydrolyzed peptide is greater than 85%.
3. The present disclosure provides combined administration of the Panax quinquefolius hydrolyzed peptide and acarbose, which has inhibitory effects on the a-glucosidase and a-amylase activities superior to those of both alone, and has a synergistic effect. The present disclosure provides combined administration of the Panax quinquefolius hydrolyzed peptide and captopril, which has an inhibitory effect on angiotensin-converting enzyme (ACE) superior to that of both alone, and has a synergistic effect. That is, combined use of the Panax quinquefolius hydrolyzed peptide of the present disclosure and typical drugs may exert a stronger blood pressure and

7 blood sugar regulating effect, which helps to improve the technological content of Panax quinquefolius resource processing and utilization technology in China, and has important economic and social benefits.
4. The Panax quinquefolius hydrolyzed peptide of the present disclosure has a significant anti-inflammatory effect, effectively inhibits nitric oxide (NO) release, with an inhibition rate of 33.5%, and may efficiently regulate the expression of lipopolysaccharide (LPS) induced relevant inflammatory mediators or inflammatory factors to exert an effective anti-inflammatory effect.
5. The Panax quinquefolius hydrolyzed peptide of the present disclosure has a significant immunity regulating effect, and may effectively stimulate macrophages, so that the phagocytic function of macrophages is significantly enhanced and the immune function is enhanced.
6. The Panax quinquefolius hydrolyzed peptide of the present disclosure may effectively block the production of angiotensin II having the effect of raising blood pressure, so as to treat hypertension symptoms, with an inhibition rate of 77.2%.
7. The Panax quinquefolius hydrolyzed peptide of the present disclosure has inhibitory effects on the a-glucosidase and a-amylase activities, with inhibition rates of 42.5% and 27.2%, respectively, and the inhibitory effect on the a-glucosidase activity is even superior to that of an acarbose positive group.
Brief Description of the Drawings Fig. 1 is a diagram of influences of a Panax quinquefolius hydrolyzed peptide on the NO level of LPS-induced RAW 264.7 cells; and Fig. 2 is a diagram of the ACE inhibitory activity of a Panax quinquefolius hydrolyzed peptide.
Detailed Description of the Embodiments

8 The present disclosure will be described in detail below with reference to specific implementation modes, the described implementation cases are provided to facilitate the understanding and implementation of the present disclosure and are not to be construed as limiting the present disclosure. The scope of protection of the present disclosure is not limited by the specific implementation modes, but by the claims.
For content not described in detail in the examples, refer to the prior art.
Material source Ionic liquid reagents, such as 1-butyl-3-methylimidazolium tetrafluoroborate, buty1-3-methylimidazolium hexafluorophosphate, and 1-octy1-3-methylimidazolium chloride, were purchased from Shanghai Chengjie Chemical Co., Ltd.; inorganic salt reagents, such as dipotassium phosphate, sodium citrate, and ammonium sulfate, were purchased from Sinopharm Chemical Reagent Co., Ltd.; polyethylene glycol was purchased from Beijing Solarbio Technology Co. Ltd.; and pepsin (1: 3000), trypsin (1:
250), and the like were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
Example 1 A preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide included the following specific steps:
(1) 1 kg of Panax quinquefolius was ground and added to a 0.004 mol/L 1-butyl-3-methylimidazolium tetrafluoroborate solution according to a mass-to-volume ratio (g/mL) of 1: 20, and the solution was extracted at 55 C for 2 h to prepare Panax quinquefolius crude protein extract;
(2) the Panax quinquefolius crude protein extract was added to dipotassium phosphate according to a volume-to-mass ratio (mL/g) of 12: 0.8, the solution was ultrasonically shaken at 70 KHz for 1 h and centrifuged at 4,000 r/min for 10 mm to separate the liquid, a lower liquid was removed, a supernatant was added to polyethylene glycol 600 at a final concentration of 15%, the solution was placed at 4 C

9 for 24 h and centrifuged at 4,000 r/min for 20 min, and the precipitate, that is, Panax quinquefolius protein extract, was collected; and (3) the protein extract was dissolved in water with the volume 12 times that of the protein extract, the solution was subjected to primary digestion under the following conditions: an addition amount of pepsin was 60 mg/mL, the pH value was 2.5, the final concentration of NaC1 was 0.04 mol/L, and the enzymatic hydrolysis time was 2 h, subjected to secondary digestion under the following conditions: an addition amount of trypsin was 12 mg/mL, the pH value was 8.5, the final concentration of KH2PO4 was 0.08 mol/L, and the enzymatic hydrolysis time was 3 h, and added to sulfosalicylic acid according to a mass-to-volume ratio (g/mL) of 0.15: 12, the solution was placed at room temperature for 60 min and subjected to solid-liquid separation, the precipitate was redissolved, and the solution was subjected to ultrafiltration with molecular weight cut-off less than 3 kDa and lyophilized to prepare 184 g of extract stored in the form of powder.
Example 2 A preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide included the following specific steps:
(1) 1 kg of Panax quinquefolius was ground and added to a 0.01 mol/L 1-buty1-3-methylimidazolium tetrafluoroborate solution according to a mass-to-volume ratio (g/mL) of 1: 35, and the solution was extracted at 70 C for 0.5 h to prepare Panax quinquefolius crude protein extract;
(2) the Panax quinquefolius crude protein extract was added to dipotassium phosphate according to a volume-to-mass ratio (mL/g) of 15: 0.8, the solution was ultrasonically shaken at 100 KHz for 0.5 h and centrifuged at 5,000 r/min for 5 min to separate the liquid, a lower liquid was removed, a supernatant was added to polyethylene glycol 200 at a final concentration of 20%, the solution was placed at 4 C
for 48 h and centrifuged at 5,000 r/min for 15 min, and the precipitate, that is, Panax quinquefolius protein extract, was collected; and (3) the protein extract was dissolved in water with the volume 10 times that of the protein extract, the solution was subjected to primary digestion under the following conditions: an addition amount of pepsin was 20 mg,/mL, the pH value was 4, the final concentration of NaCl was 0.08 mol/L, and the enzymatic hydrolysis time was 4 h, subjected to secondary digestion under the following conditions: an addition amount of trypsin was 4 mg/mL, the pH value was 9, the final concentration of KH2PO4 was 0.12 mol/L, and the enzymatic hydrolysis time was 6 h, and added to sulfosalicylic acid according to a mass-to-volume ratio (g/mL) of 0.15: 25, the solution was placed at room temperature for 90 min and subjected to solid-liquid separation, the precipitate was redissolved, and the solution was subjected to ultrafiltration with molecular weight cut-off less than 6 kDa and lyophilized to prepare 171 g of extract stored in the form of powder.
Example 3 A preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide included the following specific steps:
(1) 1 kg of Panax quinquefolius was ground and added to a 0.001 mol/L 1-butyl-3-methylimidazolium tetrafluoroborate solution according to a mass-to-volume ratio (g/mL) of 1: 10, and the solution was extracted at 40 C for 4 h to prepare Panax quinquefolius crude protein extract;
(2) the Panax quinquefolius crude protein extract was added to dipotassium phosphate according to a volume-to-mass ratio (mL/g) of 5: 0.8, the solution was ultrasonically shaken at 40 KHz for 2 h and centrifuged at 3,000 r/min for 15 min to separate the liquid, a lower liquid was removed, a supernatant was added to polyethylene glycol 1000 at a final concentration of 5%, the solution was placed at 4 C
for 12 h and centrifuged at 3,000 r/min for 30 min, and the precipitate, that is, Panax quinquefolius protein extract, was collected; and (3) the protein extract was dissolved in water with the volume 15 times that of the protein extract, the solution was subjected to primary digestion under the following conditions: an addition amount of pepsin was 100 mg/mL, the pH value was 1.5, the final concentration of NaCl was 0.01 mol/L, and the enzymatic hydrolysis time was 0.5 h, subjected to secondary digestion under the following conditions: an addition amount of trypsin was 20 mg/mL, the pH value was 7.5, the final concentration of KH2PO4 was 0.05 mol/L, and the enzymatic hydrolysis time was 1 h, and added to sulfosalicylic acid according to a mass-to-volume ratio (g/mL) of 0.15: 8, the solution was placed at room temperature for 30 min and subjected to solid-liquid separation, the precipitate was redissolved, and the solution was subjected to ultrafiltration with molecular weight cut-off less than 10 kDa and lyophilized to prepare 176 g of extract stored in the form of powder.
Example 4 Differences between a preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide of this example and that of Example 1 were as follows:
(1) the ionic liquid was a 1-butyl-3-methylimidazolium hexafluorophosphate solution;
(2) the inorganic salt was sodium citrate; and (3) all others were the same as those in Example 1, and 166 g of extract stored in the form of powder was prepared.
Example 5 Differences between a preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide of this example and that of Example 1 were as follows:
(1) the ionic liquid was a 1-octy1-3-methylimidazolium chloride solution;
(2) the inorganic salt was ammonium sulfate; and (3) all others were the same as those in Example 1, and 163 g of extract stored in the form of powder was prepared.

Contrast 1 A difference between a preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide of this contrast and that of Example 1 was as follows:
the inorganic salt was anhydrous sodium carbonate, all others were the same, and 158 g of extract stored in the form of powder was prepared.
Contrast 2 A difference between a preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide of this contrast and that of Example 1 was as follows:
the ionic liquid was a 1-hepty1-3-methylimidazolium chloride solution, all others were the same, and 160 g of extract stored in the form of powder was prepared.
Contrast 3 A preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide included the following specific steps:
1 kg of Panax quinquefolius was ground and added to 10 mmol/L Tris-HC1 (pH=7.4) with the volume 15 times that of Panax quinquefolius, the solution was extracted at 45 C for 2 h and centrifuged at 5,000 r/min for 30 min, a supernatant was collected and added with acetone with the volume 1.5 times that of the supernatant, the solution was placed at 4 C for 24 h, and the precipitate was collected and subjected to enzymatic digestion under the conditions the same as those in the preparation steps in Example 1 to prepare 155 g of extract stored in the form of powder.
Contrast 4 A preparation method of a multifunctional Panax quinquefolius hydrolyzed peptide included the following specific steps:
1 kg of Panax quinquefolius was ground and added to a complex enzyme solution (trypsin: papain = 1: 1 w/w, 500 U/L) with the volume 20 times that of Panax quinquefolius, the solution was hydrolyzed at 37 C for 4 h and centrifuged at 5,000 r/min for 15 min, and a supernatant was subjected to ultrafiltration with molecular weight cut-off less than 10 kDa and lyophilized to prepare 161 g of extract stored in the form of powder.
Application Test Example 1 Determination of Panax quinquefolius active peptide content (1) A biuret solution was prepared: 0.6 g of CuSO4=5H20 was weighed and dissolved in 100 mL of distilled water, 1.8 g of potassium sodium tartrate was added, 1 g of K1 was added, after the added reagents were completely dissolved, 20 mL
of 6 mol/L NaOH solution was added while the solution was stirred, distilled water was added to dilute the solution to 200 mL, and the solution was uniformly mixed for later use.
(2) A standard curve was drawn: the reduced glutathione (GSH) concentration was taken as the x-axis, the absorbance was taken as the y-axis, and the operation was as follows: 1 mL of GSH standard solution at concentrations of 0.05, 0.1,0.2, 0.3, 0.4, and 0.5 mg,/mL, respectively, was added to 6 graduated colorimetric tubes, 4 mL of biuret solution was added, the color was developed at 50 C for 20 min, and the absorbance was measured at 540 rim and recorded.
Linear regression equation: Y=0.617x+0.253, R2=0.9961, and a linear range was 0.05-0.5 mg/mL.
(3) The active peptide content was determined: 5 mg of extract powder was weighed and diluted to 10 mL for later use. 1 mL of sample solution was pipetted and placed into a graduated colorimetric tube, 4 mL of biuret reagent was added, the solution was uniformly mixed, the color was developed according to the item "standard curve", the absorbance was measured at 540 nm, the mass (mg) of active peptides in the sample solution was calculated with reference to the standard curve, and the content (%) of active peptides in the extract (see Table 1) was calculated.

Table 1 Measurement results of active peptide content Panax Polypeptide Molecular weight Active peptide quinquefolius mass/g content hydrolyzed peptide Example 1 184 <3 kDa 92.2%
Example 2 171 <6 kDa 90.1%
Example 3 176 <10 kDa 90.5%
Example 4 166 <3 kDa 88.3%
Example 5 163 <3 kDa 86.6%
Contrast 1 158 <3 kDa 72.4%
Contrast 2 160 <3 kDa 70.5%
Contrast 3 155 <3 kDa 75.8%
Contrast 4 161 <10 kDa 66.4%
It can be seen from Table 1 that the preparation method of the present disclosure has the double advantages of high preparation rate and high enrichment rate for active peptide target constituents, and the content of active peptides in the Panax quinquefolius hydrolyzed peptide of the present disclosure is greater than 85%.
Compared with Example 1, only the types of ionic liquid and inorganic salt were changed in Contrast 1 and Contrast 2, resulting in a significant decrease in the content of Panax quinquefolius peptides in the product. The results indicate that the efficient preparation of a Panax quinquefolius peptide is only achieved under the conditions of specific ionic liquid and inorganic salt.
Although the enzymatic digestion preparation process is the same as that of the present disclosure, total protein is prepared by a conventional organic solvent precipitation method in Contrast 3, resulting in a great decrease in the yield and content of active peptide constituents. The Panax quinquefolius active peptide is prepared by a single composite enzymatic hydrolysis process only in Contrast 4, and the purity of active peptide constituents in the final product is low. The results indicate that compared with the conventional technology, the yield and purity of the Panax quinquefolius hydrolyzed peptide prepared by the ionic liquid-two-stage enzymatic hydrolysis technology established in the present disclosure are high, and the content of active peptides in the Panax quinquefolius hydrolyzed peptide is greater than 85%.
Application Test Example 2 Antioxidant activity of Panax quinquefolius hydrolyzed peptide (1) DPPH free radical scavenging assay The Panax quinquefolius hydrolyzed peptide was diluted to different concentrations for later use. 1 mL of each of the diluted solutions at different concentrations was placed into a test tube, 1 mL of 1 mmol/mL DPPH solution was added, anhydrous ethanol was added to 4 mL, the solution was uniformly shaken and placed in a dark place for reaction for 30 min, the absorbance was measured at 517 nm, and the DPPH free radical scavenging rate was calculated.
DPPH scavenging rate (%) = (1-A/Ao) * 100%
(Aj = absorbance of sample + DPPH, Ao = absorbance of DPPH + ethanol) (2) = OH free radical scavenging assay The Panax quinquefolius hydrolyzed peptide was diluted to different concentrations for later use. 1 mL of each of the diluted solutions at different concentrations was placed into a test tube, 2 mL of 6 mmol/L FeSO4. solution, 2 mL of 6 mmol/L salicylic acid, and 2 mL of 6 mmol/L H202 solution were added in sequence, the solution was uniformly mixed and placed for 30 min, the absorbance was measured at 510 nm, and the =OH free radical scavenging rate was calculated.
=OH scavenging rate (%) = [1-(Ai-Ai)/Ao] * 100%
(Aj = absorbance after addition of sample, Ao = absorbance of blank control, Ai =

absorbance of sample without H202) (3) Test results are shown in Table 2.
Table 2 Antioxidant activity of Panczx quinquefolius hydrolyzed peptide Active Active = OH
peptide DPPH ICso peptide scavengin IC5c) Group concentrat scavengin (mg/m Group concentrati g rate (mg/rnL) ion g rate (%) L) on (%) (mg/mL) (mg/mL) 0.5 77.6 0.6 66.5 0.4 56.3 0.5 45.7 Example 1 Example 1 0.3 39.1 0.3519 0.4 38.2 0.4993 group group 0.2 22.4 0.3 21.4 0.1 11.5 0.2 13.5 0.5 68.5 1.0 61.9 0.4 45.3 0.8 50.5 Contrast 3 Contrast 3 0.3 37.4 0.3961 0.6 36.1 0.8186 group group 0.2 20.9 0.4 15.7 0.1 8.8 0.2 9.4 0.5 47.1 1.0 50.6 0.4 33.8 0.8 44.1 Contrast 4 Contrast 4 0.3 23.6 0.5563 0.6 30.5 0.9653 group group 0.2 14.2 0.4 16.8 0.1 9.3 0.2 11.3 It can be seen from Table 2 that the IC50 values of Example 1 in the two experiments are 0.3519 mg/rnL and 0.4993 mg/mL, respectively, which indicates that Example 1 has higher free radical scavenging activity compared with Contrast 3 and Contrast 4. Especially, the difference in the = OH free radical scavenging assay is more significant. The foregoing experimental results indicate that compared with the conventional process, the ionic liquid-two-stage enzymatic hydrolysis process of the present disclosure may prepare the Panax quinquefolius hydrolyzed peptide with higher antioxidant activity, which may be related to the higher purity of target constituents in the final product.
Application Test Example 3 Anti-inflammatory activity of Panax quinquefolius hydrolyzed peptide (1) RAW264.7 cells were inoculated into a 96-well plate (1 x105 cells/mL), experimental groups were as follows: a blank control group (Dulbecco's Modified Eagle Medium (DMEM)), a model group (1 Iag/mL LPS), low-, medium-, and high-concentration Example 1 administration groups (25, 50, and 100 [ig/mL + 1 [tg/mL
LPS), a Contrast 3 administration group (100 pg/mL + 1 iag/mL LPS), and a Contrast 4 administration group (100 lig/mL + 1 g/mL LPS), and 3 duplicate wells were set for each group.
(2) After each group was cultured in a constant temperature incubator with 5%
CO2 at 37 C for 24 h, 100 1.LL of culture supernatant was pipetted and transferred to a microplate, the optical density (OD) was measured at 540 nm by using a microplate reader according to the instructions for use of an NO kit, and the inhibition rate of the Panax quinquefolius hydrolyzed peptide on NO release was calculated.
(3) Experimental results are shown in Fig. 1, nitric oxide (NO), as an important intercellular communication substance with various biological activities, plays an important role in regulating other pathophysiological processes such as vasodilation and inflammatory immune response. When inflammation occurs in the body, the protein expression level of nitric oxide synthase (iNOS) may be significantly up-regulated, and then production of a large amount of NO may be induced to trigger subsequent relevant pathological reactions. Therefore, how to effectively block the pathway of NO
synthesis is one of the important methods for regulating inflammatory response.
The high-concentration Example 1 group (100 pg/mL) shows the strongest inhibitory effect on NO release, with an inhibition rate of 33.5%. The inhibition rates of the Contrast 3 and Contrast 4 administration groups at the concentration of pg/mL on NO release are only 16.8% and 17.9%, respectively. Therefore, the Panax quinquefolius hydrolyzed peptide of the present disclosure may efficiently regulate the expression of LPS-induced relevant inflammatory mediators or inflammatory factors, so as to exert an anti-inflammatory effect on mouse macrophages RAW 264.7.

Application Test Example 4 Immunoregulatory activity of Panax quinquefolius hydrolyzed peptide (1) 42 Kunming mice (half male and half female) weighing 18-22 g were randomly divided into 7 groups, 6 mice per group, which were a blank control group, a model group, low-, medium-, and high-dose Example 1 groups, a Contrast 3 administration group, and a Contrast 4 administration group, respectively. The test animals in each group were administered intragastrically for 7 days, once a day, 0.2 mL/10 g each time.
The mice in the blank control group and the model group were administered with an equal volume of normal saline, doses for the mice in the low-, medium-, and high-dose Example 1 groups were 50 mg/10 g, 100 mg/10 g, and 250 mg/10 g, respectively, and doses for the mice in the Contrast 3 administration group and the Contrast 4 administration group were both 250 mg/10 g. On day 4, each mouse in the groups other than the blank group was injected intraperitoneally with cyclophosphamide.
(2) On day 4 of the experiment, each mouse was injected intraperitoneally with mL of starch broth, after the administration was finished, each mouse was injected intraperitoneally with 1 mL of 1% chicken red blood cells, injected intraperitoneally with 1 mL of normal saline after 30 min, and then killed by cervical dislocation, the peritoneal fluid was drawn, dripped on a glass slide and fixed with a mixture of methanol and acetone (1: 1 V: V) for 5 min, and stained with Giemsa, 50 macrophages were observed under an oil immersion lens, and the phagocytosis rate and phagocytic index were calculated according to the following formulas (one macrophage may phagocytose several chicken red blood cells).
Phagocytosis rate / 100% = (number of macrophages phagocytosing chicken red blood cells / 50 macrophages) X 100%
Phagocytic index / 100% = (total number of phagocytosed chicken red blood cells / 50 macrophages) X 1 00%
(3) Experimental results are shown in Table 3.

Table 3 Influences of Panax quinquefolius hydrolyzed peptide on phagocytosis of chicken red blood cells in the abdominal cavity of a mouse Group Dose Phagocytic index Phagocytosis rate (mg/10 g) (%) (%) Normal control group - 119.3+6.4 42.1+2.6 Model group - 103.5+3.2 36.3+2.4 Example 1 group 50 126.1+5.8 44.7+3.3 Example 1 group 100 143.6+7.1**
56.3+3.5*
Example 1 group 250 158.7+6.6**
70.2+4.4**
Contrast 3 group 250 134.4+3.5*
53.5+3.8*
Contrast 4 group 250 126.9+4.3 57.2+3.0*
* (p< 0.05) and ** (p< 0.01) compared to the model group Macrophages are activated after being stimulated, and their phagocytic function is significantly enhanced. Macrophages have an active phagocytic function, may scavenge antigenic substances and denatured cells in the body, and play an important role in both specific and non-specific immunity. Compared with the normal control group, the phagocytic indexes of peritoneal macrophages in the mice in the medium-dose and high-dose Example 1 groups are extremely significant (P<0.01), with a statistical difference, the phagocytosis rate of peritoneal macrophages in the mice in the medium-dose Example 1 group is significant (P<0.05), and the phagocytosis rate of peritoneal macrophages in the mice in the high-dose Example 1 group is extremely significant (P<0.01), both with a statistical difference. Compared with the experimental results of Contrast 3 and Contrast 4, continuous administration of Example 1 for 7 d may better enhance the phagocytic function of peritoneal macrophages in the mouse.
Application Test Example 5 ACE inhibitory activity of Panax quinquefolius hydrolyzed peptide (1) The sample of Example 1 was diluted to 0.25 mg/mL, 0.5 mg/mL, and 1.25 mg/mL, respectively, with a 50 mmol/L Tris-HC1buffer (containing 300 mmol/L
NaCl, pH=7.5) and the samples of Contrast 3 and Contrast 4 were respectively diluted to 1.25 mg/mL. 40 [iL of angiotensin-converting enzyme (ACE solution, 0.25 units/mL) and ilL of sample solution were added to each well of a 96-well plate and reacted at 37 C
for 10 min. Then, 150 1AL of N[3-acryloyli-L-phenylalanyl-glycyl-glycine solution (FAPGG-Tris-HC1, 0.88 mmol/L) was added for detection. 10 [LL of Tris-HC1 buffer 5 was added instead of the sample solution to prepare a blank control, and the concentration of captopril in a positive control group was 50 pg/mL. In addition, an Example 1 + captopril administration group, a Contrast 3 + captopril administration group, and a Contrast 4+ captopril administration group (50 g/mL sample +25 [ig/mL
captopril) were set.
(2) The absorbance decay due to degradation of FAPGG by ACE was monitored at a wavelength of 340 nm, ACE activity was represented as the slope of the decrease in this absorbance, and the inhibition performance of the active peptide within 40 min was recorded. The inhibition rate was calculated according to the following formula:
ACE inhibition rate (%) = (1 -AAsample/AAblank) x 100%.
(3) Experimental results are shown in Fig. 2. The ACE inhibitory effects of the Example 1 administration groups at the test concentrations show a dose-effect relationship, and the ACE inhibitory effect is the strongest at the reaction concentration of 250 [ig/mL, with an inhibition rate of 77.2%, which is equivalent to that of the captopril positive control group. However, at this concentration, the ACE
inhibition indexes of Contrast 3 and Contrast 4 are both weaker than that of Example 1, and the inhibition rates are only 60.3% and 55.6%, respectively. The ACE inhibitory effect of the combined administration of low-dose captopril and the sample of Example 1 is also excellent, with an inhibition rate of 86.1%, which is significantly higher than that of the combined administration of captopril and the same dose of Contrast 3 and Contrast 4, and even higher than that of the administration of captopril or high-concentration sample of Example 1 alone. Therefore, the ionic liquid-two-stage enzymatic hydrolysis preparation technology of the present disclosure may prepare the Panax quinquefolius hydrolyzed peptide with a more significant ACE inhibitory effect, which may have a synergistic effect with conventional ACE antihypertensive drugs. Vascular pressure is regulated by the renin-angiotensin system, and renin promotes the production of angiotensin I, which is converted into angiotensin II under the action of angiotensin-converting enzyme (ACE). The Panax quinquefolius active peptide sample of the present disclosure may block the production of angiotensin II having the effect of raising blood pressure, so as to treat hypertension symptoms.
Application Test Example 6 Blood sugar lowering effect of Panax quinquefolius hydrolyzed peptide (1) 101AL of each of Panax quinquefolius hydrolyzed peptide sample solutions at different concentrations and 45 1AL of 5 U/mL a-glucosidase phosphate solution (0.2 mol/L, pH=5.0) are uniformly mixed by shaking and placed in an incubator at 55 C for reaction for 10 min. Then, 35 [IL of 5 mmol/L 4-nitrophenyl-a-D-glucopyranoside (PNPG) was added to initiate a reaction, and the solution was incubated in an incubator at 55 C for 30 min. 100 1AL of 0.2 mol/L Na2CO3 solution was added to terminate the reaction, and the absorbance was measured at 405 nm. PBS was added instead of the a-glucosidase solution to measure a sample blank, and PBS was added instead of the sample to measure an enzyme solution blank. The inhibition rate was calculated according to the following formula:
a-glucosidase inhibition rate (%) = [1-(c¨d)/(a¨b)] x 100%
where, a is the absorbance of the a-glucosidase solution, b is the absorbance of the blank, c is the absorbance of the reaction mixture, d is the absorbance of the sample.
(2) 100 pi, of each of Panax quinquefolius hydrolyzed peptide sample solutions at different concentrations was premixed with 200 pL of a-amylase solution (16.67 nkat/mL) at 37 C for 10 min, 400 tit of 1 g/mL soluble starch solution was added to react at 37 C for 15 min, after the reaction was completed, 400 [LI, of DNS
reagent was added to terminate the reaction, the mixture was heated in a boiling water bath for 5 min, and cooled in an ice-water bath for 30 min, and the absorbance was measured at 540 nm. An equal volume of phosphate buffer (0.1 mol/L, pH=6.8) was added instead of the a-amylase solution to prepare a control group, and the inhibition rate was calculated according to the following formula:
a-amylase inhibition rate (%) = (1-Ao/A) X 100%

where, Ao is the absorbance of the control group, and A is the absorbance of the sample group.
(3) Experimental results are shown in Table 4.
Table 4 Inhibitory effects of Panax quinquefolius hydrolyzed peptide on the a-glucosidase and a-amylase activities Sample a-glucosidase activity a-amylase activity Group concentration inhibition rate inhibition rate (jlgimL) (%) (%) Acarbose 50 30.4 1.1 33.6 0.8 Example 1 group 50 15.3 0.6 12.0 0.5 Example 1 group 100 28.7 0.3 19.4 1.3 Example 1 group 150 42.5 2.4 27.2 0.6 Contrast 3 group 150 26.6 1.5 20.4 1.8 Contrast 4 group 150 25.3 0.4 22.1 1.4 Acarbose + 50+50 63.2 2.6*
55.7 2.1*
Example 1 Acarbose + 50+50 38.6 2.2 35.3 1.6 Contrast 3 Acarbose + 50+50 36.1 1.8 38.4 1.5 Contrast 4 * (p<0.05) compared to the acarbose group a-glucosidase and a-amylase are the key digestive enzymes in the body, which play a very important role in the catabolism of carbohydrates. Glucose enters the blood through the small intestine under the catalysis of enzyme, and has an important correlation with postprandial blood glucose levels of diabetic patients. It can be seen from Table 4 that the inhibition rates of the Example 1 group on the a-glucosidase and a-amylase activities significantly increase as the concentration increases, and are respectively 42.5% and 27.2% at the concentration of 150 gg/mL. The comparison of the experimental results shows that the inhibitory effects of Example 1 on the two glycosidases are significantly better than those of Contrast 3 and Contrast 4, and the inhibitory effect of the high-concentration Example 1 group on the a-glucosidase activity is even better than that of the acarbose positive group. The inhibitory effect (with an inhibitory rate of 63.2%) of the acarbose + Example 1 administration group on a-glucosidase is significantly better than the inhibitory effect (with an inhibitor rate of 38.6%) of the acarbose + Contrast 3 administration group and the inhibitory effect (with an inhibition rate of 36.1%) of the acarbose +Contrast 4 administration group.
The inhibitory effect (with an inhibitory rate of 55.7%) of the acarbose + Example administration group on a-amylase is significantly better than the inhibitory effect (with an inhibitor rate of 35.3%) of the acarbose + Contrast 3 administration group and the inhibitory effect (with an inhibition rate of 38.4%) of the acarbose +Contrast administration group. Moreover, the acarbose + Example 1 administration group is significantly different (p<0.05) from the acarbose administration group, and has a synergistic effect. The Panax quinquefolius active peptide of the present disclosure may exert a blood sugar lowering effect through efficient a-glucosidase and a-amylase inhibitory activity, and may be clinically used as an auxiliary dietary supplement due to its characteristics of natural active ingredient source, with broad development prospect.
Based on the above, the present disclosure has established the ionic liquid enrichment-two-stage biomimetic enzymatic hydrolysis preparation technology of a Panax quinquefolius hydrolyzed peptide. The technology has double advantages of high preparation rate and high enrichment rate for target constituents, and the active peptide content is greater than 85%. The process is green and safe, simple to operate, and suitable for mass production. In addition, compared with the conventional preparation process, the Panax quinquefolius hydrolyzed peptide product prepared by the process of the present disclosure has better functional effects of regulating immunity, lowering blood pressure, lowering blood sugar, resisting inflammation, and resisting oxidation. Moreover, the pharmacodynamic experiments show that the combined administration has a synergistic effect on some symptoms. Therefore, the Panax quinquefolius hydrolyzed peptide may be applied as an active ingredient in preparation of functional food, a health care product, and even a drug, is applicable to a variety of conventional dosage forms, and is easy to be accepted by consumers.
The embodiments described above are some but not all embodiments of the present disclosure. The detailed description of the embodiments of the present disclosure is not intended to limit the scope of protection of the present disclosure, and is merely representative of selected embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without involving any inventive effort shall fall within the scope of protection of the present disclosure.

Claims

1. A multifunctional Panax quinquefolius hydrolyzed peptide, the hydrolyzed peptide being prepared through extraction with an ionic liquid, purification with inorganic salt, and enzymatic hydrolysis by a pepsin-trypsin two-step digestion process, the content of active peptides in the hydrolyzed peptide being greater than 85% by mass fraction, and the molecular weight of the active peptide being less than 10 kD.

2. The Panax quinquefolius hydrolyzed peptide according to claim 1, wherein the content of active peptides in the hydrolyzed peptide is greater than 90% by mass fraction, and the molecular weight of the active peptide is less than 10 kD;
and preferably, the content of active peptides in the hydrolyzed peptide is greater than 92% by mass fraction, and the molecular weight of the active peptide is less than 3 kD.

3. A preparation method of a Panax quinquefolius hydrolyzed peptide, comprising the following steps:
(1) grinding Panax quinquefolius, adding to an ionic liquid according to a mass-to-volume ratio (g/mL) of 1: (10-35), extracting at 40-70 C for 0.5-4 h, and performing solid-liquid separation to prepare Panax quinquefolius crude protein extract;
(2) adding the Panax quinquefolius crude protein extract prepared in step (1) to inorganic salt according to a volume-to-mass ratio (mL/g) of (5-15): 0.8, ultrasonically shaking for 0.5-2 h, centrifuging at 3,000-5,000 r/min for 5-15 min to separate the liquid, removing a lower liquid, adding polyethylene glycol to an upper liquid, standing for 12-48 h, centrifuging at 3,000-5,000 r/min for 15-30 min, and collecting the precipitate to obtain Panax quinquefolius protein extract; and (3) dissolving the protein extract prepared in step (2) in water with the volume 10-15 times that of the protein extract, obtaining a Panax quinquefolius protein hydrolysate by a pepsin-trypsin two-step digestion process, adding a sulfosalicylic acid solution, placing at room temperature for 30-90 min, performing solid-liquid separation, redissolving the precipitate, performing ultrafiltration, and lyophilizing to prepare a Panax quinquefolius hydrolyzed peptide.

4. The method according to claim 3, wherein in step (1), the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate, 1 -buty1-3-methylimidazolium hexafluorophosphate, 1-buty1-3-methylimidazolium bistrifluoromethanesulfonimide, 1 -octy1-3 -methylimidazolium chloride, or 1 -hexy1-3-methylimidazolium hexafluorophosphate;
preferably, the selected ionic liquid is 1 -buty1-3-methylimidazolium tetrafluoroborate, 1-buty1-3-methylimidazolium hexafluorophosphate, or 1-buty1-methylimidazolium bistrifluoromethanesulfonimide; and preferably, the ionic liquid is 1-buty1-3-methylimidazolium tetrafluoroborate.

5. The method according to claim 3, wherein in step (1), the final concentration of the ionic liquid is 0.001-0.01 mol/L;
preferably, the final concentration of the ionic liquid is 0.002-0.008 mol/L;
and preferably, the final concentration of the ionic liquid is 0.004 mol/L.

6. The method according to claim 3, wherein in step (2), the inorganic salt is dipotassium phosphate, sodium citrate, potassium chloride, monosodium phosphate or ammonium sulfate;
preferably, the inorganic salt is dipotassium phosphate, sodium citrate or monosodium phosphate; and preferably, the inorganic salt is dipotassium phosphate;
in step (2), the type of the added polyethylene glycol is polyethylene glycol 200, 400, 600, 800, or 1000;
preferably, the type of the added polyethylene glycol is polyethylene glycol 400, 600 or 800; and preferably, the type of the added polyethylene glycol is polyethylene glycol 600;
preferably, in step (2), an addition amount of polyethylene glycol is 5-20% by mass fraction;
preferably, the addition amount of polyethylene glycol is 12-18% by mass fraction;
and preferably, the addition amount of polyethylene glycol is 15% by mass fraction;
and preferably, in step (2), the frequency of ultrasonic shaking is 40-100 KHz;
preferably, the frequency of ultrasonic shaking is 60-80 KHz; and preferably, the frequency of ultrasonic shaking is 70 KHz.

7. The method according to claim 3, wherein in step (3), the primary digestion process is that an addition amount of pepsin is 10-100 mg/mL, the pH value is 1.5-4, the final concentration of NaC1 is 0.01-0.08 mol/L, and the enzymatic hydrolysis time is 0.5-4 h, the secondary digestion process is that an addition amount of trypsin is 4-20 mg/mL, the pH value is 7.5-9.5, the final concentration of KH2PO4 is 0.05-0.12 mol/L, and the enzymatic hydrolysis time is 1-6 h, sulfosalicylic acid is added according to a mass-to-volume ratio (g/mL) of 0.15: (8-25), and molecular weight cut-off of ultrafiltration is less than 10 kDa;
preferably, the primary digestion process is that the addition amount of pepsin is 30-80 mg/mL, the pH value is 2-3, the final concentration of NaC1 is 0.025-0.06 mol/L, and the enzymatic hydrolysis time is 1-3 h, the secondary digestion process is that the addition amount of trypsin is 8-16 mg/mL, the pH value is 8-9, the final concentration of KH2PO4 is 0.07-0.10 mol/L, and the enzymatic hydrolysis time is 2-5 h, sulfosalicylic acid is added according to a mass-to-volume ratio (g/mL) of 0.15: (10-15), and the molecular weight cut-off of ultrafiltration is less than 6 kDa;
and preferably, the primary digestion process is that the addition amount of pepsin is 60 mg/mL, the pH value is 2.5, the final concentration of NaC1 is 0.04 mol/L, and the enzymatic hydrolysis time is 2 h, the secondary digestion process is that the addition amount of trypsin is 12 mg/mL, the pH value is 8.5, the final concentration of is 0.08 mol/L, and the enzymatic hydrolysis time is 3 h, sulfosalicylic acid is added according to a mass-to-volume ratio (g/mL) of 0.15: 12, and the molecular weight cut-off of ultrafiltration is less than 3 kDa.

8. An application of the Panax quinquefolius hydrolyzed peptide according to claim 1 as an active ingredient in preparation of functional food, health care food, a drug, or a daily chemical product; and preferably, an application of the foregoing Panax quinquefolius hydrolyzed peptide as an active ingredient in preparation of an immunity regulating, blood pressure lowering, blood sugar lowering, anti-inflammatory, or antioxidant functional product.

9. A blood sugar lowering drug, active ingredients comprising acarbose and the Panax quinquefolius hydrolyzed peptide according to any one of claims 1-2; and preferably, in the blood sugar lowering drug, a mass ratio of acarbose to the Panax quinquefolius hydrolyzed peptide being 1: 1.

10. A blood pressure lowering drug, active ingredients comprising captopril and the Panax quinquefolius hydrolyzed peptide according to any one of claims 1-2;
and preferably, in the blood pressure lowering drug, a mass ratio of captopril to the Panax quinquefolius hydrolyzed peptide being 1: 2.