CN112691136A

CN112691136A - Swertia extract and application thereof in preparation of antidepressant drugs

Info

Publication number: CN112691136A
Application number: CN202110212224.9A
Authority: CN
Inventors: 师新伟; 孙洪发
Original assignee: Henan Bifu Pharmaceutical Co Ltd
Current assignee: Henan Bifu Pharmaceutical Co Ltd
Priority date: 2021-02-25
Filing date: 2021-02-25
Publication date: 2021-04-23

Abstract

The invention discloses a swertia herb extract, and a preparation method thereof comprises the following steps: s1: drying in the shade, cutting or pulverizing; s2: extracting; s3: concentrating, degreasing, separating by column chromatography, and collecting eluent; s4: concentrating, evaporating organic solvent, drying, and pulverizing to obtain herba Swertiae Bimaculatae extract. The results of in-vitro pharmacodynamic experiments show that the swertia extract provided by the invention has a good protection effect on SH-SY5Y cells, the survival rate of the cells reaches 84.7%, and the swertia extract is proved to have a remarkable anti-depression effect, and the results of animal experiments show that the swertia extract provided by the invention can remarkably relieve the behavior despair state of mice, reduce the suspension immobility times and shorten the suspension immobility time, and has a remarkable effect on relieving depression mood. The swertia extract provided by the invention has high anti-depression activity and can be applied to preparation of anti-depression drugs.

Description

Swertia extract and application thereof in preparation of antidepressant drugs

Technical Field

The invention relates to the technical field of biomedicine, in particular to a swertia extract and application thereof in preparation of antidepressant drugs.

Background

The swertia herb medicinal plant, Tibetan named as 'Dida', is an annual gentianaceae dwarf herbal medicinal plant, and is recorded in Tibetan medicine book 'four medical classics': has effects of clearing away heat and toxic materials, removing liver heat, and promoting function of gallbladder. Modern pharmacology proves that the Tibetan capillaris has various pharmacological activities, including liver injury resistance, depression resistance, tuberculosis resistance, tumor resistance, jaundice treatment, bile flow promotion, mutation resistance, inflammation resistance, virus resistance, oxidation resistance, diuresis, blood sugar reduction and heart strengthening. The swertia can also promote small intestine movement; regulating endocrine or affecting sexual function; promoting hair growth and improving skin function; can metabolize human intestinal bacteria; meanwhile, the medicine also has good curative effect on the red bara disease.

Depression is also called depressive disorder, a common mood disorder disease, and seriously harms the physical and mental health of people. The low mood is not matched with the situation in clinic, the depression of the mood can be from sultriness to sadness, and the self-declining depression and even the pessimism are taken away, and suicide attempts or behaviors can be caused; some patients may develop sleep disorders in a certain period, so effective prevention and treatment of sleep disorders is of great significance for alleviation and improvement of depressed mood. The pathogenesis of depression is complicated, the related causes are various, and fatigue, improper diet, mental factors and the like can all cause vegetative nerve functional disturbance, gastrointestinal motility disturbance, gastrointestinal hormone abnormality and primary and secondary functional intestinal diarrhea. Modern medicine mostly adopts gastrointestinal motility promoting medicines, the effect is not ideal, in recent years, traditional Chinese medicines obtain abundant experience and better curative effect on the aspect of treating the disease, and the traditional Chinese medicines become a new research direction and target for treating depression. SH-SY5Y cells (neuroblastoma cells) are widely applied to the research of treating nervous system diseases such as depression and Parkinson's disease, and SH-SY5Y cell oxidative damage models are commonly used for the screening research of antidepressant drugs.

At present, a plurality of chemical medicaments with good curative effect, high safety and convenient use are available for treating the depression, but the chemical medicaments generally have the defects of narrow antidepressant spectrum, large adverse reaction, easy relapse and the like in the aspect of treating the depression, such as dry mouth, mydriasis, blurred vision, constipation, dysuria, tachycardia, even orthostatic hypotension and other side effects of a tricyclic antidepressant classical representative medicament, namely the mepacrine medicament. Thus, antidepressant drugs derived from natural plants have attracted attention. At present, Chinese patent CN 110772564A discloses a traditional Chinese medicine extract composition with the function of regulating depressed mood, a preparation method thereof and a traditional Chinese medicine preparation. The composition comprises the following traditional Chinese medicine extracts in parts by weight: the traditional Chinese medicine extract composition has an obvious effect of relieving depression mood and is a safe and effective dietary supplement, and the traditional Chinese medicine extract composition comprises 40-80 parts of hypericum perforatum extract, 10-40 parts of acanthopanax extract and 2-20 parts of moutan bark extract. Meanwhile, the pillow also has the functions of helping sleep and the like. Chinese patent CN1381242A discloses a Chinese medicine for treating depression, which comprises herba Hyperici perforati and radix Acanthopanacis Senticosi. Chinese patent CN102670752A discloses an application of moutan bark extract in preparing a medicament for treating depression. At present, the report of using a Tibetan medicine 'swertia herb' extract for resisting depression is not seen.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a swertia extract and application thereof in preparing antidepressant drugs.

The purpose of the invention is realized by the following technical scheme:

the invention provides a swertia herb extract, and a preparation method thereof comprises the following steps:

s1, drying the swertia herb in the shade, chopping or crushing to obtain swertia herb small segments or coarse powder;

s2, extracting the obtained herba Swertiae Bimaculatae by ethanol immersion extraction or acidic ethanol immersion extraction or by one of the three methods of immersion with dilute hydrochloric acid solution and immersion extraction with ethanol to obtain extractive solution;

s3, concentrating the extracting solution, degreasing the extracting solution by using an organic solvent, performing column chromatography separation, and collecting eluent;

s4, concentrating the eluent, evaporating the organic solvent to dryness, drying and crushing to obtain the swertia extract.

Further, the specific operations of the ethanol immersion extraction in step S2 are as follows: soaking herba Swertiae Bimaculatae or coarse powder in ethanol, refluxing the solution for several times, and mixing extractive solutions; wherein the volume of the used ethanol is 6-12 times of the solid volume, the volume concentration is 70%, and the impregnation time is 1-6 h; refluxing the ethanol immersion liquid at the temperature of 80 ℃, wherein the extraction times are 1-3 times, and the extraction time is 1-4 h each time;

further, the specific operation of the acidic ethanol immersion extraction in step S2 is as follows: soaking herba Swertiae Bimaculatae in acidic ethanol, refluxing for several times, mixing extractive solutions, and adjusting to neutral with alkali; wherein the pH value of the used acidic ethanol is 1-2, the volume of the acidic ethanol is 6-12 times of the solid volume, the volume concentration of the acidic ethanol is 50%, and the impregnation time is 1-6 h; refluxing the acidic ethanol immersion liquid at the temperature of 80 ℃, wherein the extraction times are 1-3 times, and the extraction time is 1-4 h each time;

further, the specific operations of impregnating with dilute hydrochloric acid solution and then impregnating and extracting with ethanol in step S2 are as follows: soaking herba Swertiae Bimaculatae in dilute hydrochloric acid solution, refluxing for several times, discarding the extractive solution of dilute hydrochloric acid solution, soaking in ethanol, refluxing for several times, and mixing extractive solutions; wherein the pH value of the used dilute hydrochloric acid solution is 1-2, the volume of the dilute hydrochloric acid solution is 6-12 times of the solid volume, the concentration of the dilute hydrochloric acid solution is 3-4 wt%, and the dipping time is 1-6 h; the reflux temperature of the dilute hydrochloric acid immersion liquid is 80-100 ℃, the extraction times are 1-3 times, and the extraction time is 1-4 h each time; the volume of the used ethanol is 6-12 times of the solid volume, the volume concentration is 70%, and the impregnation time is 1-6 h; the reflux temperature of the ethanol impregnation liquid is 80 ℃, the extraction times are 1-3 times, and the extraction time is 1-4 hours each time.

Further, in the specific operation of the impregnation extraction with acidic ethanol in step S2, the alkali is saturated caustic soda or soda solution.

Further, one specific operation of step S3 is: concentrating the extracting solution to liquid medicine with the concentration of 0.5-3.5 g/mL, selecting macroporous adsorption resin as a filler selected by column chromatography, selecting a wet method for loading on a column, washing 1-6 BV of column volume with water to remove impurities during elution, eluting 1-12 BV of column volume with an ethanol solution with the volume concentration of 30-90%, and collecting eluent.

Further, another specific operation of step S3 is: concentrating the extracting solution to liquid medicine with the concentration of 0.5-3.5 g/mL, selecting silica gel as a filler for column chromatography, selecting a dry method for loading on a column, eluting by using petroleum ether, dichloromethane, ethyl acetate, acetone, ethanol and water or preparing a mixed solvent with gradually increased polarity according to the polarity of the solvent in sequence, and collecting dichloromethane, ethyl acetate and acetone eluting parts or mixed solvent eluting parts.

Further, the organic solvent used for degreasing in step S3 is any one of petroleum ether, ethyl acetate, and dichloromethane.

The invention provides application of a swertia extract in the aspect of preparing antidepressant drugs.

The invention also provides an antidepressant pharmaceutical preparation which comprises the swertia herb extract and a pharmaceutically acceptable pharmaceutical carrier or auxiliary material.

Further, the pharmaceutically acceptable carriers include, but are not limited to: aluminum oxide, aluminum stearate, lecithin, serum protein, glycerol, sorbate, potassium sorbate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinylpyrrolidone, cellulose, polyethylene glycol, sodium carboxymethylcellulose, polyacrylate, beeswax, and lanolin.

Furthermore, the dosage form of the medicinal preparation is not limited, and the medicinal preparation can be liquid dosage form, solid dosage form and external preparation, and is administrated in unit dosage form, and the weight content of the swertia extract in the medicinal preparation is not less than 50%.

Furthermore, the pharmaceutical dosage forms include, but are not limited to, tablets, capsules, dripping pills, aerosols, pills, powders, solutions, suspensions, emulsions, granules, suppositories, freeze-dried powder injections, clathrates, landfill agents, patches and liniments.

The swertia pseudochinensis Benth is an annual medicinal plant of swertia genus of Gentianaceae family, namely swertia pseudochinensis Benth (swertia pseudochinensis Benth.) (S．franchetiana) Swertia mussotii Franch (swertia mussotii Franch.) (S．mussotii) Swertia pseudochinensis, (b) and (c)S.kingii) Four swertia herb (swertia davidi Franch. (Sw.) MakinoS． tetraptera) India swertia (S．cliralyita) Swertia Przewalskii, swertia Przewalskii (Sw.) MakinoS．purpurascens) Swertia mussotii Franch (swertia davidi Franch.) (S． racemosa) Swertia chiretta (swertia davidi Franch.) (S．erythrosticta) Swertia przewalskii (Swertia przewalskii Franch.) (S．przewalskii) Swertia herb for manifesting Yao (swertia davidi Franch. (A. potasifera and B. potasifera)S． nervosa) Large and largeSeed swertia herb (S．macrosperma) Swertia angustifolia (swertia angustifolia Vahl.), (S．angustifolin) Swertia pseudochinensis Franch (swertia pseudochinensis Franch. (A. potasifera Franch.))S． angustifolia) Swertia japonica Makino (swertia japonica Makino) (iii)S. verticillifolia) Swertia bimaculata（S. bifalia) Swertia Maoensis Makino (swertia Makino, swertia Makino (sweS. purprascens) When used in combination with other drugsS．diluta) And the like.

Compared with the prior art, the invention has the following beneficial effects:

(1) the preparation method of the swertia japonica extract provided by the invention is simple in steps, the toxicity of the used solvent is lower, the content of effective components in the obtained extract is higher through a mode of dipping and refluxing, the extract is subjected to degreasing operation and then column chromatography separation, and part of non-target products can be directly separated and removed through degreasing, so that the subsequent operation is facilitated.

(2) The swertia japonica extract provided by the invention is proved to have a good protection effect on SH-SY5Y cells through in-vitro efficacy experiments, the cell survival rate reaches 84.7%, and the swertia japonica extract provided by the invention is proved to have a remarkable anti-depression effect, so that a foundation is laid for the development of new drugs in the aspect of anti-depression.

(3) The swertia japonica extract provided by the invention can obviously relieve the behavior despair state of a mouse, reduce the suspension immobility times and shorten the suspension immobility time; compared with the prior art, the swertia extract or the preparation has obvious effect of relieving depression; in addition, the extract and the preparation thereof also have the effects of soothing the liver and benefiting the gallbladder, have small side effect, no dependence and small administration dosage, can be prepared into various dosage forms and are suitable for wide popularization.

Drawings

FIG. 1 shows the effect of swertia extract on the number of immobility suspensions in forced swimming experiments of mice.

FIG. 2 shows the effect of swertia extract on the immobility time of dangtail in mouse dangtail experiment.

Detailed Description

To further illustrate the technical means adopted by the present invention and the effects thereof, the following detailed description is given with reference to the preferred embodiments of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The reagents or starting materials used in the present invention can be purchased from conventional sources, and unless otherwise specified, the reagents or starting materials used in the present invention can be used in a conventional manner in the art or in accordance with the product specifications.

Example 1

Drying herba Swertiae Bimaculatae in the shade, and chopping to obtain herba Swertiae Bimaculatae herba radix; accurately weighing herba Swertiae Bimaculatae herba radix Dipsaci 10g, adding into 100 mL ethanol (volume concentration 70%) for soaking for 4h, refluxing the soaking solution at 80 deg.C for 4h, refluxing for 3 times, and mixing extractive solutions; concentrating the extracting solution to obtain a liquid medicine with the concentration of 1.5 g/mL, degreasing the concentrated solution by using petroleum ether, performing column chromatography separation by using macroporous adsorption resin, loading the liquid medicine on a column by a wet method, washing the column by 1-6 BV by using water to remove impurities during elution, eluting the column by 1-12 BV by using an ethanol solution with the volume concentration of 30-90%, and collecting eluent; concentrating the eluate, evaporating to remove organic solvent, drying, and pulverizing to obtain total 1.1 g of herba Swertiae Bimaculatae extract.

Example 2

Drying a swertia medicinal material in the shade, and crushing to obtain swertia coarse powder (40-60 meshes); accurately weighing 10g of coarse powder of swertia japonica Makino, adding the coarse powder into 100 mL of ethanol (volume concentration is 70%) for soaking for 6 h, refluxing the soaking solution at 100 ℃ for 2h after soaking is finished, refluxing for 3 times totally, and then combining the extracting solutions; concentrating the extractive solution to obtain medicinal liquid with concentration of 1.0 g/mL, defatting the concentrated solution with ethyl acetate, separating by silica gel column chromatography, loading onto column by dry method, eluting with petroleum ether, dichloromethane, ethyl acetate, acetone, ethanol and water, and collecting eluate of dichloromethane, ethyl acetate and acetone; concentrating the eluate, evaporating to remove organic solvent, drying, and pulverizing to obtain herba Swertiae Bimaculatae extract 2.3 g.

Example 3

Drying a swertia medicinal material in the shade, and crushing to obtain swertia coarse powder (40-60 meshes); accurately weighing 10g of coarse powder of swertia japonica Makino, adding the coarse powder into 100 mL of ethanol (volume concentration is 70%), soaking for 2h, refluxing the soaking solution at 120 ℃ for 1h for 3 times, and then combining the extracting solutions; concentrating the extracting solution to obtain a liquid medicine with the concentration of 0.5 g/mL, degreasing the concentrated solution by using ethyl acetate, performing column chromatography separation by using macroporous adsorption resin, loading the liquid medicine on a column by a wet method, washing the column by using water for 1-6 BV to remove impurities during elution, eluting the column by using an ethanol solution with the volume concentration of 30-90% for 1-12 BV, and collecting eluent; concentrating the eluate, evaporating to remove organic solvent, drying, and pulverizing to obtain herba Swertiae Bimaculatae extract 0.68 g.

Example 4

Drying herba Swertiae Bimaculatae in the shade, chopping to obtain herba Swertiae Bimaculatae coarse powder; accurately weighing 10g of coarse powder of the swertia japonica thunb, adding the coarse powder into 100 mL of dilute hydrochloric acid (the concentration is 3-4 wt%) for soaking for 4 hours, refluxing the soaking solution at 80 ℃ for 4 hours after the soaking is finished, refluxing for 3 times, and discarding the dilute hydrochloric acid extracting solution; adding 100 mL of ethanol (volume concentration 70%) for soaking for 2h, refluxing the soaking solution at 120 deg.C for 1h for 3 times, and mixing extractive solutions; concentrating the extracting solution to obtain a liquid medicine with the concentration of 2.5g/mL, degreasing the concentrated solution by using ethyl acetate, performing column chromatography separation by using macroporous adsorption resin, loading the liquid medicine on a column by a wet method, washing the column by using water for 1-6 BV to remove impurities during elution, eluting the column by using an ethanol solution with the volume concentration of 30-90% for 1-12 BV, and collecting eluent; concentrating the eluate, evaporating to remove organic solvent, drying, and pulverizing to obtain total 1.3 g of herba Swertiae Bimaculatae extract.

Example 5

Drying a swertia medicinal material in the shade, and crushing to obtain swertia coarse powder (40-60 meshes); accurately weighing 10g of coarse powder of swertia japonica Makino, adding the coarse powder into 100 mL of acidic ethanol (pH =1, volume concentration is 50%) for soaking for 6 h, refluxing the soaking solution at 80 ℃ for 2h for 3 times, and then combining the extracting solutions; regulating the pH value of the extracting solution to be neutral by using saturated caustic soda or soda ash solution, concentrating the extracting solution into liquid medicine with the concentration of 3.0g/mL, degreasing the concentrated solution by using petroleum ether, performing column chromatography by using silica gel, selecting wet column chromatography, selecting dry column chromatography, eluting by using petroleum ether, dichloromethane, ethyl acetate, acetone, ethanol and water in sequence, and collecting the eluent of the dichloromethane, ethyl acetate and acetone elution parts; concentrating the eluate, evaporating to remove organic solvent, drying, and pulverizing to obtain herba Swertiae Bimaculatae extract 2.5 g.

Example 6

Drying a swertia medicinal material in the shade, chopping or crushing to obtain swertia coarse powder (40-60 meshes); accurately weighing 10g of coarse powder of the swertia japonica thunb, adding the coarse powder into 100 mL of dilute hydrochloric acid (the concentration is 3-4 wt%) for soaking for 2 hours, refluxing the soaking solution at 100 ℃ for 1 hour after the soaking is finished, refluxing for 3 times, and discarding the dilute hydrochloric acid extracting solution; adding into 100 mL ethanol (volume concentration 70%), soaking for 2h, refluxing the soaking solution at 120 deg.C for 1h for 3 times, and mixing extractive solutions; concentrating the extracting solution to obtain a liquid medicine with the concentration of 2.5g/mL, degreasing the concentrated solution by using dichloromethane, performing column chromatography separation by using macroporous adsorption resin, performing wet column chromatography, selecting wet column chromatography, washing 1-6 BV of column volume by using water to remove impurities during elution, eluting 1-12 BV of column volume by using an ethanol solution with the volume concentration of 30-90%, and collecting the eluent; concentrating the eluate, evaporating to remove organic solvent, drying, and pulverizing to obtain total 1.79 g of herba Swertiae Bimaculatae extract.

In vitro assay

SH-SY5Y cells with good logarithmic growth phase and growth state are taken, washed by PBS, digested by 0.25% trypsin, flushed and blown by DMEM culture solution containing 15% imported fetal calf serum when the cells tend to become round, and then single cell suspension is prepared. At 1X 10 per ml⁵Inoculating 100 muL of each cell in a 96-well culture plate (except for blank zero setting holes), and placing the culture plate in CO₂Continuing culturing in incubator, adding H-containing solution after 24 hr₂O₂(final concentration is 100 mu mol as L^-1) The PBS solution is used for constructing an oxidative damage depression model, and a blank control group is added with H-free solution₂O₂Adding 100 muL culture medium of 10% serum into the blank control group and the model group after 2h of model building for culture, and adding 100 muL drug-containing culture medium of 10% serum into each administration group. Setting a blank toneA zero group (only adding culture medium for zero setting of a microplate reader), a blank control group, a model group (only adding cells) and an administration group (swertia pseudochinensis extract 40 mg/mL), and 5 multiple wells are arranged. At 37 deg.C, 5% CO₂After the culture is continued for 24 hours in the incubator, 50 muL of cell supernatant is sucked from each hole, the cell supernatant is stored at the temperature of minus 20 ℃, the cell supernatant is reserved for a test kit, 50 muL of culture solution is supplemented to each hole, the culture is continued for 3 hours, 20 muL (5 mg/mL) MTT is added to each hole, the supernatant in each hole is sucked completely after the culture is continued for 4 hours, 150 muL of DMSO is added to each hole, the DMSO is oscillated for 10 minutes by using an enzyme labeling instrument, the purple crystals are completely dissolved, and the absorbance (OD) value is measured at 492 nm. The results are shown in Table 1. Wherein cell viability = OD assay/OD blank control x 100%.

TABLE 1 cell viability in each group

Group of	OD₄₉₂	Cell survival rate (%)
			Blank control group	1.37	-
Model set	0.61	44.5
			Experimental group	1.16	84.7

Animal testing

The test method comprises the following steps: 60 mice are taken, 6 mice are taken in one cage, free diet and drinking water are fed in a light and temperature and humidity control room: the temperature is 21 +/-2 ℃, the humidity is 50 +/-10 percent, the light and shade period is 12h/12h, and all animal experiment operations are carried out according to the welfare of experimental animals issued by NIH and the use guiding principle. The mice were adapted for one week and entered the experiment, 12 mice in each group, and divided into 5 groups according to the random block design method: a normal Control group (Control), a fluoxetine group (FXT), a small-dose group (TUW-L) of a swertia extract, a medium-dose group (TUW-M) of a swertia extract and a high-dose group (TUW-H) of a swertia extract. The pure water with the same volume as the normal group is used for intragastric administration, the intragastric administration dosage of other groups is shown in the part of the result table, the intragastric administration is carried out on the mouse at a fixed time every morning, and the intragastric administration volume is 0.1mL and is 10g^-1The administration was continued for one month and the behavioral determination was performed 1h after the last gavage.

(1) Forced swimming experiment of mouse

When forced swimming, all animals are respectively placed into a plexiglass cylinder containing deep water of 23 +/-1 ℃ and 20cm, after 15min, the animals are transferred to a drying environment of 30 ℃ for 30min (preliminary experiment), after 24h, the mice are placed into the plexiglass cylinder again for 5min (formal experiment), during the period, the record is carried out by a video camera, after one mouse is made, water is changed, and the cylinder is cleaned. The number of times of immobility of suspension and the incubation period of immobility of suspension were recorded using SMART3.0 software (Table 2), and the results are shown in FIG. 1.

TABLE 2 influence of swertia extract on the number of immobility suspensions in forced swimming experiments in mice (x. + -. S.D.)

Group of	Dosage (mg/kg)	Number of times of suspension
			Control group
	0	71.27±2.16
			Fluoxetine group	20	57.48±1.15
Extract low dose group	20	64.13±1.24
			Extract medium dose group	40	60.25±0.83
High dose group of extracts	80	58.56±0.79

(2) Tail suspension experiment

During tail suspension experiments, the mouse tail tip part 1/3 is suspended on the tail suspension device by using a medical adhesive tape, the suspension is in a vertical state, the head of the suspension device is opposite to a lens and is about 30 cm away from the ground, the motionless time of each group of mice in the tail suspension experiments is recorded by shooting and lasts for 6 min, and the motionless time of the mice in the tail suspension experiments is calculated after 4 min. The immobility time was judged as the time when the mice stopped struggling, were in an inverted suspension state, and were still (table 3), and the results are shown in fig. 2.

TABLE 3 influence of swertia extract on the immobility time of dangtail in mouse dangtail experiment (x + -S.D.)

Group of	Dosage (mg/kg)	Time of suspension of tail
			Control group
	0	80.73±1.62
			Fluoxetine group	20	61.28±1.33
Extract low dose group	20	64.47±2.28
			Extract medium dose group	40	63.86±1.42
High dose group of extracts	80	60.62±0.95

The above description is only for the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and other modifications or equivalent substitutions made by the technical solution of the present invention by the ordinary skilled in the art should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. The preparation method of the swertia japonica extract is characterized by comprising the following steps of:

s2, carrying out inch breaking or coarse powder extraction on the obtained swertia japonica Makino by adopting ethanol immersion extraction or acidic ethanol immersion extraction or one of the three methods of firstly immersing by using dilute hydrochloric acid and then immersing and extracting by using ethanol to obtain an extracting solution;

2. The swertia herb extract according to claim 1, wherein the specific operations of the ethanol immersion extraction in the step S2 of the preparation method are as follows: soaking herba Swertiae Bimaculatae or coarse powder in ethanol, refluxing the solution for several times, and mixing extractive solutions; wherein the volume of the used ethanol is 6-12 times of the solid volume, the volume concentration is 70%, and the impregnation time is 1-6 h; refluxing the ethanol immersion liquid at the temperature of 80 ℃, wherein the extraction times are 1-3 times, and the extraction time is 1-4 h each time;

the preparation method comprises the following specific operations of soaking and extracting by using acidic ethanol in the step S2: soaking herba Swertiae Bimaculatae in acidic ethanol, refluxing for several times, mixing extractive solutions, and adjusting to neutral with alkali; wherein the pH value of the used acidic ethanol is 1-2, the volume of the acidic ethanol is 6-12 times of the solid volume, the volume concentration of the acidic ethanol is 50%, and the impregnation time is 1-6 h; refluxing the acidic ethanol immersion liquid at the temperature of 80 ℃, wherein the extraction times are 1-3 times, and the extraction time is 1-4 h each time;

the preparation method comprises the following specific operations of firstly soaking with dilute hydrochloric acid and then soaking and extracting with ethanol in step S2: soaking herba Swertiae Bimaculatae in dilute hydrochloric acid, refluxing for several times, discarding dilute hydrochloric acid extractive solution, adding ethanol for soaking, refluxing for several times, and mixing extractive solutions; wherein the pH value of the used dilute hydrochloric acid is 1-2, the volume of the dilute hydrochloric acid is 6-12 times of the solid volume, the concentration of the dilute hydrochloric acid is 3-4 wt%, and the impregnation time is 1-6 h; the reflux temperature of the dilute hydrochloric acid immersion liquid is 80-100 ℃, the extraction times are 1-3 times, and the extraction time is 1-4 h each time; the volume of the used ethanol is 6-12 times of the solid volume, the volume concentration is 70%, and the impregnation time is 1-6 h; the reflux temperature of the ethanol impregnation liquid is 80 ℃, the extraction times are 1-3 times, and the extraction time is 1-4 hours each time.

3. The swertia herb extract of claim 2, wherein the alkali in the step S2 of the preparation method is saturated caustic soda or soda solution in the specific operation of soaking and extracting with acidic ethanol.

4. The swertia herb extract of claim 1, wherein the preparation method step S3 is implemented by the following steps: concentrating the extracting solution to liquid medicine with the concentration of 0.5-3.5 g/mL, selecting macroporous adsorption resin as a filler selected by column chromatography, selecting a wet method for loading on a column, washing 1-6 BV of column volume with water to remove impurities during elution, eluting 1-12 BV of column volume with an ethanol solution with the volume concentration of 30-90%, and collecting eluent.

5. The swertia herb extract of claim 1, wherein the preparation method step S3 is implemented by the following steps: concentrating the extracting solution to liquid medicine with the concentration of 0.5-3.5 g/mL, selecting silica gel as a filler for column chromatography, selecting a dry method for loading on a column, eluting by using petroleum ether, dichloromethane, ethyl acetate, acetone, ethanol and water or preparing a mixed solvent with gradually increased polarity according to the polarity of the solvent in sequence, and collecting dichloromethane, ethyl acetate and acetone eluting parts or mixed solvent eluting parts.

6. The swertia herb extract of claim 1, wherein the organic solvent for degreasing in the step S3 is any one of petroleum ether, ethyl acetate and dichloromethane.

7. The use of a swertia herb extract of any one of claims 1 to 6 in the preparation of an antidepressant medicament.

8. An antidepressant pharmaceutical preparation, which comprises the swertia herb extract of any one of claims 1 to 6 and a pharmaceutically acceptable pharmaceutical carrier or adjuvant.

9. The antidepressant pharmaceutical formulation of claim 8, characterized in that said pharmaceutical carrier includes, but is not limited to: aluminum oxide, aluminum stearate, lecithin, serum protein, glycerol, sorbate, potassium sorbate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinylpyrrolidone, cellulose, polyethylene glycol, sodium carboxymethylcellulose, polyacrylate, beeswax, and lanolin.

10. The antidepressant pharmaceutical formulation of claim 8, wherein said pharmaceutical formulation is in unlimited dosage forms and is administered in unit dosage form, said swertia herb extract being present in said pharmaceutical formulation in an amount not less than 50% by weight.