Method for extracting selenium-containing moringa oleifera tannin from selenium-rich moringa oleifera leaves

Abstract

The invention provides a method for extracting selenium-containing moringa oleifera tannin from selenium-rich moringa oleifera leaves, and relates to the technical field of natural product extraction, the method comprises the following steps: (1) pretreatment of moringa oleifera leaves, (2) soaking in an alcoholic solution, (3) extraction, and (4) adsorption and elution. According to the method, the selenium-containing moringa oleifera tannin is extracted from the selenium-rich moringa oleifera leaves, the method has the advantages of being simple in process, easy to operate, high in extraction purity and the like, and the selenium-containing moringa oleifera tannin substance in which selenium and moringa oleifera tannin coexist can be extracted through the method.

Description

[Technical field]

[0001] The invention relates to the technical field of natural products, and in particular to a method for extracting selenium-containing Moringa tannins from selenium-enriched Moringa leaves. [Background technology]

[0002] Moringa is a perennial plant of the genus Moringa in the family Moringaceae. It is a fast-growing tree native to the southern foothills of the Himalayas in northern India. It is drought-resistant and prefers to grow in sandy loam. The roots, stems, leaves, flowers, seeds, branches and bark of Moringa are rich in nutrients and medicinal ingredients. Moringa is also rich in moringa flavonoids, polysaccharide compounds, proteins, amino acids and vitamins.

[0003] Tannins are bitter and astringent compounds that exist in large quantities in nature. They are found in the wood, bark, leaves and fruits of plants. Although tannins taste bitter, they are widely used, including sterilization, beauty, anti-aging, heavy metal absorption, and liquid clarification.

[0004] Selenium is one of the essential trace elements for humans and animals. It can improve immunity and accelerate the production of immunoglobulins and antibodies. It protects the cardiovascular system and myocardium and reduces the incidence of cardiovascular disease and angina pectoris. It has multiple effects in anti-oxidation, anti-aging, anti-cancer and cancer prevention, and has special physiological functions such as reducing heavy metal poisoning. It is praised by scientists at home and abroad as the "king of anti-cancer, longevity element, fire of life, natural detoxifier, and heart guardian".

[0005] At present, the technology of extracting tannin from Moringa leaves is still vacant, and there is no method for simultaneously extracting selenium and Moringa tannin from Moringa leaves. The present invention comes into being. [Summary of the invention]

[0006] In view of this, the purpose of the present invention is to provide a method for extracting selenium-containing Moringa tannins from selenium-rich Moringa leaves, which has the advantages of simple process, easy operation, high extraction purity, etc. The method of the present application can extract selenium-containing Moringa tannin substances in which selenium and Moringa tannins coexist.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for extracting selenium-containing Moringa tannins from selenium-rich Moringa leaves comprises the following steps:

[0009] (1) Pretreatment of Moringa leaves: taking selenium-rich Moringa leaves, removing impurities and washing them, then drying them, and crushing them to obtain Moringa leaf powder for later use;

[0010] (2) Soaking in alcohol solution: Soaking the Moringa leaf powder obtained in step (1) in an ethanol solution and letting it stand to obtain a mixed solution;

[0011] (3) Extraction: subjecting the mixed solution to microwave reflux extraction, centrifuging the extract, taking the supernatant, and separating the supernatant through a vacuum concentration distillation device to obtain an extract for later use;

[0012] (4) Adsorption and elution: The macroporous resin is placed in a beaker, and the extract is added for ultrasonic vibration treatment. Then, the macroporous resin is washed with purified water for 2-3 times, filtered and dried, and ethanol is used as an eluent. The eluate is filtered and concentrated under reduced pressure to obtain the selenium-containing Moringa tannin.

[0013] In the present invention, further, the concentration of the ethanol solution in step (2) is 55%.

[0014] In the present invention, further, in the step (2), the solid-to-liquid ratio of the ethanol solution to the Moringa leaf powder is 1g:50-55mL.

[0015] In the present invention, further, the temperature of the microwave heat reflux extraction in step (3) is 45-55°C.

[0016] In the present invention, further, the temperature of the ultrasonic oscillation treatment in step (4) is 28-35° C., and the treatment time is 25-30 min.

[0017] In the present invention, further, the macroporous resin in step (4) is ADS-21 macroporous resin.

[0018] In the present invention, further, the ethanol used as the washing machine in step (4) is 75% ethanol.

[0019] The present invention also proposes a selenium-containing Moringa tannin extracted from selenium-rich Moringa leaves by the above method, which has a very broad application prospect.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. The present invention proposes to extract selenium-containing Moringa tannins from selenium-rich Moringa leaves, and realizes the extraction of tannin components containing selenium from Moringa leaves for the first time, which has a very positive significance; specifically, the Moringa leaves are crushed and then the selenium-containing Moringa tannins are extracted therefrom. The method has a simple process, the devices used are easy to obtain, and the operation is simple, the production cost is low, and it is easy to promote.

[0022] 2. The method for extracting selenium-containing Moringa tannin from selenium-rich Moringa leaves of the present invention, in a specific extraction process, the present invention obtains Moringa leaf powder by crushing Moringa leaves, and then soaks the Moringa leaf powder in an alcohol organic solvent, and effectively extracts tannic acid from the Moringa leaf powder by utilizing the polarity of the alcohol organic solvent and the binding property of the phenolic hydroxyl group of tannic acid and the hydrogen group of the alcohol solvent. However, in the specific extraction process, it is found that the concentration of ethanol affects the extraction rate, and the extraction rate of tannin is not ideal when the ethanol concentration is too low or too high. It is considered that when the ethanol concentration is too high, other alcohol-soluble substances, such as pigments and certain lipophilic components, dissolve more, resulting in a decrease in the extraction rate of tannic acid. Therefore, it is appropriate to select an ethanol concentration of 55%. However, the applicant further finds that at a concentration of 55%, the selenium content of Moringa tannin is not ideal. The applicant has solved this problem through a number of experimental studies by a process of adsorption and elution, and adopts a combination of dynamic adsorption and static elution, and finally can obtain a tannin component with high extraction rate and high selenium content, thereby improving the application prospect of tannin. [Specific implementation method]

[0023] The following embodiments may help those skilled in the art to more fully understand the present invention, but shall not limit the present invention in any way.

[0024] Example 1

[0025] The present embodiment provides a method for extracting selenium-containing Moringa tannins from selenium-rich Moringa leaves, which specifically comprises the following steps:

[0026] (1) Pretreatment of Moringa leaves: taking selenium-rich Moringa leaves, removing impurities and washing them, then drying them, and crushing them to obtain Moringa leaf powder for later use;

[0027] (2) Soaking in alcohol solution: Soak the Moringa leaf powder obtained in step (1) in a 55% ethanol solution, and let it stand to obtain a mixed solution; the solid-liquid ratio of the ethanol solution to the Moringa leaf powder is 1 g:50 mL;

[0028] (3) Extraction: subjecting the mixed solution to microwave reflux extraction at a temperature of 45° C., subjecting the extract to centrifugation, taking the supernatant, and separating the supernatant through a vacuum concentration distillation device to obtain an extract for later use;

[0029] (4) Adsorption and elution: ADS-21 macroporous resin is placed in a beaker, and the extract is added for ultrasonic vibration treatment. The temperature of the ultrasonic vibration treatment is 28°C and the treatment time is 25 min. Then, the macroporous resin is washed twice with purified water, filtered and dried, and 75% ethanol is used as an eluent. The eluate is filtered and concentrated under reduced pressure to obtain the selenium-containing Moringa tannin.

[0030] Example 2

[0031] The present embodiment provides a method for extracting selenium-containing Moringa tannins from selenium-rich Moringa leaves, which specifically comprises the following steps:

[0032] (1) Pretreatment of Moringa leaves: taking selenium-rich Moringa leaves, removing impurities and washing them, then drying them, and crushing them to obtain Moringa leaf powder for later use;

[0033] (2) Soaking in alcohol solution: Soak the Moringa leaf powder obtained in step (1) in a 55% ethanol solution, and let it stand to obtain a mixed solution; the solid-liquid ratio of the ethanol solution to the Moringa leaf powder is 1 g:52 mL;

[0034] (3) Extraction: subjecting the mixed solution to microwave reflux extraction at a temperature of 50° C., subjecting the extract to centrifugation, taking the supernatant, and separating the supernatant through a vacuum concentration distillation device to obtain an extract for later use;

[0035] (4) Adsorption and elution: ADS-21 macroporous resin is placed in a beaker, and the extract is added for ultrasonic vibration treatment. The temperature of the ultrasonic vibration treatment is 30°C and the treatment time is 28 minutes. Then, the macroporous resin is washed 3 times with purified water, filtered and dried, and 75% ethanol is used as an eluent. The eluate is filtered and concentrated under reduced pressure to obtain the selenium-containing Moringa tannin.

[0036] Example 3

[0037] The present embodiment provides a method for extracting selenium-containing Moringa tannins from selenium-rich Moringa leaves, which specifically comprises the following steps:

[0038] (1) Pretreatment of Moringa leaves: taking selenium-rich Moringa leaves, removing impurities and washing them, then drying them, and crushing them to obtain Moringa leaf powder for later use;

[0039] (2) Soaking in alcohol solution: Soak the Moringa leaf powder obtained in step (1) in a 55% ethanol solution, and let it stand to obtain a mixed solution; the solid-liquid ratio of the ethanol solution to the Moringa leaf powder is 1 g:55 mL;

[0040] (3) Extraction: subjecting the mixed solution to microwave reflux extraction at a temperature of 55° C., subjecting the extract to centrifugation, taking the supernatant, and separating the supernatant through a vacuum concentration distillation device to obtain an extract for later use;

[0041] (4) Adsorption and elution: ADS-21 macroporous resin is placed in a beaker, and the extract is added for ultrasonic vibration treatment. The temperature of the ultrasonic vibration treatment is 35°C and the treatment time is 30 min. Then, the macroporous resin is washed 3 times with purified water, filtered and dried, and 75% ethanol is used as an eluent. The eluate is filtered and concentrated under reduced pressure to obtain the selenium-containing Moringa tannin.

[0042] Test example

[0043] In order to illustrate the practical value of this application, the applicant divided several groups into several groups to conduct the following comparative tests:

[0044] The first group: selenium-containing Moringa tannin prepared by the method described in Example 2;

[0045] Group 2: The concentration of the ethanol solution used for soaking in step (2) was 25%, and the other methods were strictly carried out in accordance with Example 2;

[0046] Group 3: The concentration of the ethanol solution used for soaking in step (2) was 35%, and the other methods were strictly carried out in accordance with Example 2;

[0047] Group 4: The concentration of the ethanol solution used for soaking in step (2) was 45%, and the other methods were strictly carried out according to Example 2;

[0048] Group 5: The concentration of the ethanol solution used for soaking in step (2) was 50%, and the other methods were strictly carried out in accordance with Example 2;

[0049] Group 6: The concentration of the ethanol solution used for soaking in step (2) was 65%, and the other methods were strictly carried out in accordance with Example 2;

[0050] The seventh group: the concentration of the ethanol solution used for soaking in step (2) is 55%, and the steps of adsorption and elution are: putting the macroporous resin into a beaker, adding the extract for static adsorption, then washing the macroporous resin with purified water for 2-3 times, filtering and drying, using ethanol as an eluent, filtering the obtained eluate, and concentrating under reduced pressure to obtain the selenium-containing Moringa tannin, and the other methods are strictly carried out according to Example 2;

[0051] Group 8: The concentration of the ethanol solution used for soaking in step (2) is 55%, and the steps of adsorption and elution are as follows: the macroporous resin is placed in a beaker, the extract is added for ultrasonic vibration treatment, 75% ethanol is used as the eluent to elute the tannin in the resin, and the eluate is collected by a fully automatic partial collector (3 min / tube, constant flow pump flow rate 60 mL / min), the eluate flowing out of each tube is collected, and reduced pressure concentration is performed to obtain the selenium-containing Moringa tannin, and the other methods are strictly carried out in accordance with Example 2;

[0052] The ninth group: the concentration of the ethanol solution used for soaking in step (2) is 45%, and the steps of adsorption and elution are as follows: the macroporous resin is placed in a beaker, the extract is added for ultrasonic vibration treatment, 75% ethanol is used as the eluent to elute the tannin in the resin, and the eluate is collected by a fully automatic partial collector (3 min / tube, constant flow pump flow rate 60 mL / min), the eluate flowing out of each tube is collected, and the eluate is concentrated under reduced pressure to obtain the selenium-containing Moringa tannin, and the other methods are strictly carried out in accordance with Example 2;

[0053] The tenth group: the concentration of the ethanol solution used for soaking in step (2) is 45%, and the steps of adsorption and elution are as follows: the macroporous resin is placed in a beaker, and the extract is added for static adsorption, and then the macroporous resin is washed with purified water for 3 times, filtered and dried, and ethanol is used as an eluent, and the eluate is filtered and concentrated under reduced pressure to obtain the selenium-containing Moringa tannin. The other methods are strictly carried out according to Example 2;

[0054] Group 11: The macroporous resin is AB-8 type macroporous resin, and other methods are strictly carried out according to Example 2.

[0055] Compare the Moringa tannins prepared by the methods described in the above groups, record the extraction rate and detect the selenium content in Moringa tannins, and the recorded data are shown in Table 1:

[0056] Table 1 Comparison of extraction effects of Moringa tannin containing selenium

[0057]

[0058]

[0059] As can be seen from Table 1, the extraction rate of selenium-containing Moringa tannins extracted from selenium-rich Moringa leaves by the method of the present application is the highest, and the selenium content of the obtained Moringa tannins is the highest. From the results of the second to the sixth groups, it is known that in the process of increasing ethanol concentration, the extraction of Moringa tannins first increases and then decreases, and 55% is taken as the optimal concentration. However, at this concentration, in order to ensure the content of selenium, it is necessary to explore suitable adsorption and elution processes. According to the experiments of the seventh to the tenth groups, it can be seen that the 45% concentration of ethanol in the ninth group can obtain a higher selenium content under the combination of dynamic adsorption and dynamic elution. However, the tannin extraction rate at this concentration is not ideal. The ethanol at a concentration of 55% has unsatisfactory selenium content under the conditions of dynamic adsorption and dynamic elution, or static adsorption combined with static elution. The applicant combined a large number of experiments and used a 55% ethanol solution concentration combined with suitable adsorption and elution operations to finally obtain Moringa tannins with high extraction rate and high selenium content.

[0060] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for extracting selenium-containing Moringa tannins from selenium-rich Moringa leaves, characterized in that: The following steps are involved: (1) Pretreatment of Moringa leaves: taking selenium-rich Moringa leaves, removing impurities and washing them, then drying them, and crushing them to obtain Moringa leaf powder for later use; (2) Soaking in alcohol solution: Soaking the Moringa leaf powder obtained in step (1) in an ethanol solution and letting it stand to obtain a mixed solution; (3) Extraction: subjecting the mixed solution to microwave reflux extraction, centrifuging the extract, taking the supernatant, and separating the supernatant through a vacuum concentration distillation device to obtain an extract for later use; (4) Adsorption and elution: The macroporous resin is placed in a beaker, and the extract is added for ultrasonic vibration treatment. Then, the macroporous resin is washed with purified water for 2-3 times, filtered and dried, and ethanol is used as an eluent. The eluate is filtered and concentrated under reduced pressure to obtain the selenium-containing Moringa tannin.

2. The method according to claim 1, characterized in that The concentration of the ethanol solution in step (2) is 55%.

3. The method according to claim 1, characterized in that In the step (2), the solid-to-liquid ratio of the ethanol solution to the Moringa leaf powder is 1 g:50-55 mL.

4. The method according to claim 1, characterized in that The temperature of the microwave reflux extraction in step (3) is 45-55°C.

5. The method according to claim 1, characterized in that The temperature of the ultrasonic oscillation treatment in step (4) is 28-35° C., and the treatment time is 25-30 min.

6. The method according to claim 1, characterized in that The macroporous resin in step (4) is ADS-21 macroporous resin.

7. The method according to claim 1, characterized in that The ethanol used as the washing machine in step (4) is 75% ethanol.

8. A selenium-containing Moringa tannin extracted by the method according to any one of claims 1 to 7.

Images