NL2026582B1 - Treatment method for improving saponin from aerial part of panax notoginseng - Google Patents

Abstract

The present invention discloses a treatment method for improving saponins from the aerial part of Panax nologmseng. The treatment method includes the following steps: (l) coarsely grinding dried aerial parts of P. nologl'nseng, mixing into water, ethanol or a solvent in which water and ethanol are mixed in any proportion, and filtering after heat reflux extraction for 0.5-4 h at 40-100°C, to obtain filter residues; (2) extracting the filter residues 1-3 times under the same conditions of the heat reflux extraction in step (1), where each extraction lasts for 1-3 h, to obtain an extract; filtering the extract, and concentrating to 1/5-1/20 of the original volume of the combined solution under reduced pressure, to obtain a concentrated solution, (3) adding alumina into the concentrated solution for reaction for 8-24 h at 60-100°C, and filtering to obtain a supernatant and alumina precipitates, (4) eluting the alumina precipitates with a solvent to obtain an eluent, where the solvent is an ethanol solution, an acid solution of ethanol or an alkali solution of ethanol, and (5) combining the supernatant with the eluent, concentrating to dryness under reduced pressure, and adding water until the volume is equal to that of the concentrated solution in step (2).

Description

-1-

TREATMENT METHOD FOR IMPROVING SAPONIN FROM AERIAL PART OF PANAX NOTOGINSENG

TECHNICAL FIELD The present invention relates to the technical field of agricultural products processing, and in particular to a treatment method for improving saponins from the aerial part of Panax notoginseng.

BACKGROUND Radix Notoginseng is the dried root and stem of Pariax notoginseng (Burk.) FH. Chen (Fam. Araliaceae). P. notoginseng is mainly distributed in Yunnan, Guangxi, Jiangxi, Sichuan, etc. Traditionally, Radix Notoginseng plays roles in promoting blood circulation, arresting bleeding and eliminating stasis to subdue swelling. It has been found that Radix Notoginseng has multiple physiological effects on cardio- cerebrovascular, nervous, immune systems, and the like. With the increasing use of P. notoginseng, planting area thereof is increasing, but growth cycle thereof is mostly around three years. Therefore, a large number of leaves of P. notoginseng are produced every year. Notoginseng triterpenes are active pharmaceutical ingredients (APIs) of Folium Notoginseng (leaves of P. notoginseng), which shorten sleep latency, reduce wake-time after sleep onset (WASO), and improve headache, dizziness, palpitation, hypodynamia, and neurasthenia; notoginseng triterpenes have significantly better total response rate of treating neurasthenia and alleviating migraine than gastrodin. So far, such Chinese patent medicine as Qiye Shen’an Pian with notoginseng leaf triterpenes as APIs has been widely used. Modern pharmacological research has indicated that Folium Notoginseng (leaves of P. notoginseng) have similar APIs to Flos Notoginseng (flowers of P. notoginseng), which mainly include ginsenosides Rb3, Re, Rc, Fc, Rb2, Rb3, etc; in addition, there are trace amounts of ginsenosides XVII, Fe, Rd2, Fd, etc. So far, methods for extracting and preparing high-purity notoginseng leaf triterpenes from Folium Notoginseng include: (1) water-ethanol extraction — alcohol precipitation — decolorization by macroporous adsorption resin (Chinese Patent Application No. CN 106727806A); (ii) ultrasonic extraction — adding a clarifying agent — centrifugation — alcohol precipitation — desugaring by resin — decolorization by

-2- anion exchange resin — concentration — microwave drying (Chinese Patent Application No. 103948659A); (iii) Zhao et al. removed macromolecules and impurities with large polarity using macroporous adsorption resin, and then removed flavonoids by alumina column chromatography. All these methods use steps of clarification, decolorization by column chromatography, or impurity removal. Alumina column chromatography achieves the purifying purpose by means of adsorption characteristics of the alumina and adsorbability of different substances in alumina. However, dead adsorption occurs during adsorption, which leads to a loss of APIs. The purity increases, but the yield of notoginsenosides decreases. In general, disadvantages of the alumina column chromatography are as follows: (i) The separation effect of the column chromatography is related to the diameter-length ratio, and the height of the chromatography column is limited by the plant height, thereby limiting the sample volume of the column chromatography. (ii) The consumption of the packing materials and solvents of the column chromatography is large, and energy consumption is relatively large during solvent recovery, resulting in large production costs. (iii) Samples are lost during separation because alumina causes dead adsorption of substances to be separated. Larger consumption of alumina results in larger material loss rate. In addition, alumina column has a significantly higher production cost. It was reported that: 4.0 g of Radix Notoginseng extract was dissolved in 25 mL of water; 9.7 g of alumina was used; columns were rinsed with 215 ml of water, followed by 86 ml of water, 86 ml of 30% ethanol, and 86 ml of 60% ethanol (Teng Chen, et al. J. Sep. Sci. 2015). In brief, the prior art increases the purity of notoginseng leaf triterpenes, but operation steps are tedious. Moreover, some APIs will be lost in each operation step, resulting in decreased yield of notoginsenosides; wide use of such methods as column chromatography also substantially increases production costs. Therefore, it is of particular importance to seek an economical and practical method for improving raw material utilization ratio, reducing production costs, and increasing notoginsenoside content.

SUMMARY In view of practical problems of low yield of notoginseng leaf triterpenes and high

-3- production costs when increasing the content of notoginseng leaf triterpenes in extracts of aerial parts of P. notoginseng, the present invention is intended to provide a treatment method for improving saponins from the aerial part of £. notoginseng.

To achieve the above objective, the present invention provides the following technical solution: A treatment method for improving saponins from the aerial part of P notoginseng includes the following steps: (1) coarsely grinding dried aerial parts of P. notoginseng, mixing into water, ethanol or a solvent in which water and ethanol are mixed in any proportion, and filtering after heat reflux extraction for 0.5-4 h at 40-100°C, to obtain filter residues; where the extraction is performed at a solid-liquid ratio of (1:5)-(1:12), and the unit of the solid- liquid ratio during the heat reflux extraction is kg/L; (2) extracting the filter residues 1-3 times under the same conditions of the heat reflux extraction in step (1), where each extraction lasts for 1-3 h, to obtain an extract; after filtering, combining the extract with a filtrate obtained in step (1) to obtain a combined solution, and concentrating the combined solution to 1/5-1/20 of the original volume of the combined solution under reduced pressure, to obtain a concentrated solution for use, where the heat reflux extraction is performed at a solid-liquid ratio of (1:5)-(1:12), and the unit of the solid-liquid ratio is kg/L; (3) adding alumina into the concentrated solution for reaction for 8-24 h at 60-100°C (transformation reaction does not occur when the temperature is too low, and notoginsenosides content does not increase; short reaction time results in insufficient reaction; as the reaction time prolongs and transformation rate increases, the notoginsenosides content will not increase any more substantially), and filtering to obtain a supernatant and alumina precipitates, where the mass-to-volume ratio of the alumina to the concentrated solution is (1:1)-(1:10), and the unit of the mass-to-volume ratio is g/mL; (4) eluting the alumina precipitates with a solvent to obtain an eluent, where the solvent is an ethanol solution, an acid solution of ethanol or an alkali solution of ethanol; and (5) combining a supernatant obtained in step (3) with an eluent obtained in step (4), concentrating to dryness under reduced pressure, and adding water until the volume is

-4- equal to that of the concentrated solution in step (2), where notoginseng triterpenes content increases by 6-17% compared with that by the existing method for extracting notoginseng triterpenes.

Preferably, the alumina in step (3) is acidic alumina, neutral alumina, or basic alumina. Acidic alumina is soaked in 1% hydrochloric acid, and a resulting alumina suspension is washed with distilled water to pH 4, which is used to separate acidic substances; Neutral alumina suspension is at pH 7.5, which 1s used to separate neutral substances, Basic alumina suspension is at pH 10, which 1s used to separate amines or other alkaline substances.

Definitions and preparation of the acidic alumina, the neutral alumina, and the basic alumina are well known in the art.

Preferably, in step (4), the content of the ethanol in the ethanol solution is 80-100% by volume, and the content of the ethanol in the acid solution of ethanol or the alkali solution of ethanol is 95% by volume.

Preferably, in step (4), the acid in the acid solution of ethanol is at least one of formic acid, acetic acid, sulfuric acid, hydrochloric acid, and phosphoric acid; the alkali in the alkali solution of ethanol is at least one of trimethylamine, sodium hydroxide, and potassium hydroxide.

Preferably, in step (4), the mass-to-volume ratio of the alumina precipitates to the solvent is (1:1)-(1:10), and more preferably 1:6; the unit of the mass-to-volume ratio is g/mL.

Compared with the prior art, the present invention has the following advantageous effects:

1. Through experiment, it is remarkably effective that the alumina (acidic, neutral, or

-5- basic) is used to improve notoginseng leaf triterpenes content.

2. Steps of clarification, decolorization by column chromatography, or impurity removal are mostly used in conventional methods for improving the content of total saponins from the aerial part of P. notoginseng, and there are problems of tedious operation steps, low yield of notoginsenosides, and high production costs. Treatment with alumina can effectively improve the content of notoginseng leaf triterpenes in the concentrated solution. Operation steps are simpler, and production costs are lower. In brief, with the catalysis of alumina, the present invention achieves the objective of increasing the content/purity of notoginsenosides by converting some substances in Radix Notoginseng extract into notoginsenosides to improve the yield of notoginsenosides. With the development of the process of alumina treatment, the present invention realizes one-step treatment, simplifies the operation process, and enables the use of alumina in the improvement of the content of notoginseng leaf triterpenes.

DETAILED DESCRIPTION Example 1 2 kg of coarse powders of dried aerial part of P. notoginseng were mixed with 20 L of water, heated in a water bath at 80°C, extracted under reflux for 2 h, and filtered to obtain a filtrate and filter residues; the filter residues were extracted twice to obtain extracts. The extracts and the filtrate were combined and concentrated to 1/10 of the original volume of the combined solution under reduced pressure, to obtain a concentrated solution. Neutral alumina was added into the concentrated solution in a 1:6 mass-to-volume ratio of the neutral alumina (g) to the concentrated solution (mL); the mixture was reacted for 24 h at 80°C, and filtered to obtain a supernatant and alumina precipitates.

The alumina precipitates were eluted with 95% ethanol solution; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 15.58%.

-6- The alumina precipitates were eluted with formic acid in 95% ethanol; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 12.72%. The alumina precipitates were soaked in and eluted with trimethylamine in 95% ethanol; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 11.52%. Table 1 Changes of saponins from the aerial part of I> notoginseng in the concentrated solution in the presence of neutral alumina © Content of saponins from the aerial part of P nofoginseng, mg/mL Rc Fc Rb2 Rb3 XVII Fe Rd2 Fd Total “Stock solution ~~ 147 209 076 3.72 0.75 258 1.78 623 1938 Rinsing with ethanol in the presence of neutral 1.78 2.01 1.10 499 09 294 148 7.14 2240 alumina Rinsing with acid in the presence of neutral 1.71 1.89 1.13 505 094 298 140 7.13 22.23 alumina Rinsing with alkali in the presence of neutral 1.75 1.92 1.11 490 095 290 141 7.00 21.94 alumina Example 2 2 kg of coarse powders of dried aerial part of P. notoginseng were mixed with 20 L of water, heated in a water bath at 80°C, extracted under reflux for 2 h, and filtered to obtain a filtrate and filter residues; the filter residues were extracted twice to obtain extracts.

The extracts and the filtrate were combined and concentrated to 1/10 of the original volume of the combined solution under reduced pressure, to obtain a

-7- concentrated solution. Acidic alumina was added into the concentrated solution in a 1:6 mass-to-volume ratio of the acidic alumina (g) to the concentrated solution (mL); the mixture was reacted for 24 h at 80°C, and filtered to obtain a supernatant and alumina precipitates.

The alumina precipitates were eluted with 95% ethanol solution; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 6.50%.

The alumina precipitates were eluted with formic acid in 95% ethanol; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 6.25%.

The alumina precipitates were soaked in and eluted with trimethylamine in 95% ethanol; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 6.68%.

Table 2 Changes of saponins from the aerial part of P. notoginseng in the concentrated solution in the presence of acidic alumina Content of saponins from the aerial part of P. nofoginseng, mg/mL Rc Fc Rb2 Rb3 XVII Fe Rd2 Fd Total Stock solution 1.47 209 0.76 3.72 0.75 258 1.78 6.23 19.38 Rinsing with ethanol 1.53 1.69 1.03 459 087 278 142 6.73 20.64 in the presence of acidic alumina Rinsing with acidin 151 1.63 0.99 456 091 285 143 679 20.67 the presence of acidic alumina

-8- Rinsing with alkali 1.48 1.67 1.06 452 0901 289 157 667 20.76 in the presence of acidic alumina Example 3 2 kg of coarse powders of dried aerial part of P. nofoginseng were mixed with 20 L of water, heated in a water bath at 80°C, extracted under reflux for 2 h, and filtered to obtain a filtrate and filter residues; the filter residues were extracted twice to obtain extracts.

The extracts and the filtrate were combined and concentrated to 1/10 of the original volume of the combined solution under reduced pressure, to obtain a concentrated solution.

Basic alumina was added into the concentrated solution in a 1:6 mass-to-volume ratio of the basic alumina (g) to the concentrated solution (mL); the mixture was reacted for 24 h at 80°C, and filtered to obtain a supernatant and alumina precipitates.

The alumina precipitates were eluted with 95% ethanol solution; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 13.98%. The alumina precipitates were eluted with formic acid in 95% ethanol; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 15.07%. The alumina precipitates were soaked in and eluted with trimethylamine in 95% ethanol; eluents were combined and concentrated to dryness under reduced pressure; the precipitates were redissolved with water to the volume of the original concentrated solution; the content of notoginseng triterpenes in the solution increased by 13.52%. Table 3 Changes of saponins from the aerial part of P. nofoginseng in the concentrated solution in the presence of basic alumina

-9- © Content of saponins from the aerial part of P notoginseng, mg/mL Rc Fc Rb2 Rb3 XVII Fe Rd2 Fd Total “Stock solution ~~ 147 209 0.76 3.72 075 258 178 623 1938 Rinsing with ethanol 168 1.79 1.12 501 097 294 150 7.08 22.09 in the presence of basic alumina Rinsing with acidin 1.69 1.82 1.25 5.13 0972 3.11 160 7.14 2271 the presence of basic alumina Rinsing with alkali 22.45 in the presence of 1.67 1.81 1.27 511 0694 3.03 152 7.10 basic alumina Example 4 2 kg of coarse powders of dried aerial part of P. notoginseng were mixed with 20 L of water, heated in a water bath at 80°C, extracted under reflux for 2 h, and filtered to obtain a filtrate and filter residues; the filter residues were extracted twice to obtain extracts.

The extracts and the filtrate were combined and concentrated to 1/10 of the volume of the combined solution under reduced pressure, to obtain a concentrated solution.

Formic acid was added into the concentrated solution; the mixture was reacted for 24 h at 80°C, and filtered to obtain a supernatant; the supernatant was concentrated to dryness under reduced pressure and redissolved with water to the original volume of the supernatant; the content of notoginseng triterpenes in the solution decreased by 5.42%. It is indicated that high temperature treatment will break down notoginsenosides and reduce content thereof; in Examples 1, 2, and 3, increased notoginsenosides are principally attributable to the catalysis or transformation of (acidic, neutral, or basic) alumina, rather than high temperature condition.

Table 4 Changes of saponins from the aerial part of P. notoginseng in the concentrated solution at high temperature

-10- © Content of saponins from the aerial part of 2 notoginseng, mg/mL Rc Fe Rb2 Rb3 XVII Fe Rd2 Fd Total “Stock solution 1.47 2.09 0.76 3.72 0.753 2.583 1783 623 1938 High temperature 149 190 0.71 3.77 074 242 148 582 treatment 18.33 Example 5 2 kg of coarse powders of dried aerial part of P. notoginseng were mixed with 20 L of water, heated in a water bath at 80°C, extracted under reflux for 2 h, and filtered to obtain a filtrate and filter residues; the filter residues were extracted twice to obtain extracts. The extracts and the filtrate were combined and concentrated to 1/10 of the volume of the combined solution under reduced pressure, to obtain a concentrated solution. Formic acid was added into the concentrated solution; the mixture was reacted for 24 h at 80°C, and filtered to obtain a supernatant; the supernatant was concentrated to dryness under reduced pressure and redissolved with water to the original volume of the supernatant; the content of notoginseng triterpenes in the solution increased by 1.62%. It is indicated that acid treatment has a promoting effect on notoginsenosides consent, but notoginsenosides merely increase by 1.62% under acidic conditions; in Example 2, increased notoginsenosides are principally attributable to the catalysis or transformation of acidic alumina, rather than acidic conditions. Table 5 Changes of saponins from the aerial part of P. noftoginseng in the concentrated solution under acid treatment "Content of saponins from the aerial part of P notoginseng, mg/mL, Rc Fc Rb2 Rb3 XVII Fe Rd2 Fd Total Stok sedation 1.95 217 1.00 482 0.98 2.59 1.31 6.18 21.00 Acid

2.15 2.19 106 479 0.97 2.66 1.34 618 2134 treatment Example

-11- 2 kg of coarse powders of dried aerial part of P notoginseng were mixed with 20 L of water, heated in a water bath at 80°C, extracted under reflux for 2 h, and filtered to obtain a filtrate and filter residues; the filter residues were extracted twice to obtain extracts. The extracts and the filtrate were combined and concentrated to 1/10 of the volume of the combined solution under reduced pressure, to obtain a concentrated solution. Triethylamine was added into the concentrated solution; the mixture was reacted for 24 h at 80°C, and filtered to obtain a supernatant; the supernatant was concentrated to dryness under reduced pressure and redissolved with water to the original volume of the supernatant; the content of notoginseng triterpenes in the solution increased by 2.33%. It is indicated that alkali treatment has a promoting effect on notoginsenosides consent, but notoginsenosides merely increase by 2.33% under alkaline conditions; in Example 3, increased notoginsenosides are principally attributable to the catalysis or transformation of basic alumina, rather than alkaline conditions. Table 6 Changes of saponins from the aerial part of I> notoginseng in the concentrated solution under alkali treatment Content of saponins from the aerial part of P notoginseng, mg/mL Rc Fc Rb2 Rb3 XVII Fe Rd2 Fd Total “Stock

1.95 217 100 482 0098 2.59 1.31 6.18 21.00 solution Alkali 222 231 1.08 479 0.97 2.64 1.36 612 2149 treatment In view of increased notoginsenosides content, the optimum process of the present invention is compared with the prior art, where total amounts of reagents and materials used in the process are shown in Table 7. It is shown that the present invention shows extremely low solvent consumption and the consumption of chromatography packing materials is reduced. Compared with the prior art, the present invention overcomes a phenomenon of decreased yield of notoginseng leaf triterpenes caused by dead adsorption, and the catalysis produced by the integrated effect of high temperature and alumina increases the yield of notoginseng leaf triterpenes. The method of the present

-12- invention obtains different results by using different types of alumina and eluting with different solvents, as summarized in Table 8. Table 7 CNI1611510A | Prior art (Teng, Present

RT Yield of notoginsenosides | 75.86% 87.81% 115.63% wm Table8 Rieste JE Ramen Jo

Claims (6)

-13 - NL2026582 Conclusions A treatment method for improving saponins of the aerial part of Panax notoginseng, the method comprising the following steps: (1) coarsely grinding dried aerial parts of P. notoginseng, mixing in water, ethanol or a solvent containing water and ethanol are mixed in any proportion, and filtering after heat reflux extraction for 0.5-4 hours at 40-100°C, to obtain filter residues; wherein the extraction is performed at a solid-liquid ratio of (1:5) - (1:12), and the unit of the solid-liquid ratio during the heat reflux reaction is kg/L; (2) extracting the filter residues 1 - 3 times under the same conditions as the heat reflux extraction in step (1), each extraction lasting 1 - 3 hours, to obtain an extract; after filtering, combining the extract with a filtrate obtained in step (1) to obtain a combined solution, and concentrating the combined solution to 1/5 — 1/20 of the original volume of the combined solution under reduced pressure, to obtain a concentrated solution for use; wherein the heat reflux extraction is performed at a solid-liquid ratio of (1:5) - (1:12), and the unit of the solid-liquid ratio is kg/L; (3) adding alumina into the concentrated solution for reaction at 60-100°C for 8-24 hours, and filtering to obtain a supernatant and alumina precipitates; wherein the mass-to-volume ratio of the alumina to the concentrated solution is (1:1) - (1:10), and the unit of mass-to-volume ratio is g/mL; (4) eluting the alumina precipitates with a solvent to obtain an eluent, the solvent being an ethanol solution, an acid solution of ethanol or an alkali solution of ethanol; and (5) combining a supernatant obtained in step (3) with an eluent obtained in step (4), concentrating to dryness under reduced pressure and adding water until the volume equals that of the concentrated solution in step (2). -14 - NL2026582 The method of claim 1, wherein the alumina in step (3) is acidic alumina, neutral alumina or basic alumina. The method according to claim 1, wherein in step (4) the content of the ethanol in the ethanol solution is 80-100 % by volume, and the content of the ethanol in the acid solution of ethanol or the alkali solution of ethanol is 95 % by volume . The method of claim 3, wherein in step (4) the acid in the acid solution of ethanol is at least one of formic acid, acetic acid, sulfuric acid, hydrochloric acid and phosphoric acid; the alkali in the alkali solution of ethanol is at least one of trimethylamine, sodium hydroxide and potassium hydroxide. The method of claim 1, wherein in step (4) the mass-to-volume ratio of the alumina precipitates to the solvent is (1:1) - (1:10), and the unit of mass-to-volume ratio is g/ ml. The method of claim 1, wherein in step (4) the mass-to-volume ratio of the alumina precipitates to the solvent is 1:6, and the unit of the mass-to-volume ratio is g/mL.