A semi-biomimetic method for extracting antioxidant active products from hibiscus and its application

Abstract

This invention discloses a semi-biomimetic method for extracting antioxidant active products from roselle and its application. The method includes: ultrasonically extracting pulverized roselle calyx powder with lactic acid solution, collecting filtrate a and residue; ultrasonically extracting the residue with urea solution, filtering, and collecting filtrate b; combining filtrates a and b, concentrating under low temperature and reduced pressure to obtain a crude extract; soaking D101 resin in anhydrous ethanol to fully swell, packing the column using a wet method, and washing the resin with deionized water to remove ethanol; adding the crude extract, allowing it to stand for adsorption, and then eluting with 2 BV water, 30% ethanol, 70% ethanol, and anhydrous ethanol respectively, collecting the eluent to obtain fractions I, II, III, and IV sequentially; concentrating fraction II and freeze-drying to obtain the antioxidant active product. The extract of this invention exhibits excellent antioxidant activity under optimal process conditions, particularly showing a significant improvement in DPPH free radical scavenging rate.

Description

Technical Field

[0001] This invention belongs to the field of preparation of natural plant extracts, specifically relating to a method for semi-biomimetic extraction of antioxidant active products from roselle and its application. Background Technology

[0002] Hibiscus sabdariffa L. is a common medicinal plant. Its calyx contains abundant anthocyanins, polyphenols and other natural active substances, which have significant effects on lowering blood pressure, lowering blood lipids, anti-oxidation and inhibiting cardiovascular diseases.

[0003] However, traditional extraction methods often suffer from low extraction efficiency and significant loss of active ingredients, limiting their widespread application in pharmaceuticals and health foods. Therefore, developing an efficient, environmentally friendly extraction process that maximizes the retention of active ingredients is of paramount importance.

[0004] In recent years, ultrasound-assisted extraction technology has been widely used in the extraction of natural products due to its high efficiency, speed, and environmental friendliness. Furthermore, the use of appropriate extraction aids can further improve extraction efficiency and the solubility of target components. Traditional Chinese medicine often treats diseases not through a single substance, but through the combined effects of multiple components.

[0005] Currently, there are no reports on extraction processes that maximize the preservation of the active ingredients in hibiscus. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a semi-biomimetic method for extracting antioxidant active products from roselle.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for semi-bionic extraction of antioxidant active products from hibiscus, comprising,

[0010] The pulverized roselle calyx powder was mixed with lactic acid solution and extracted by ultrasonication. Filtrate a and filter residue were collected.

[0011] The filter residue was mixed with urea solution and extracted by ultrasonication. After filtration, filtrate b was collected.

[0012] Combine filtrates a and b, concentrate under low temperature and reduced pressure to obtain a crude extract containing antioxidant active ingredients;

[0013] The D101 resin was soaked in anhydrous ethanol to fully swell, then packed into a column using a wet method, and the ethanol in the resin was washed away with deionized water.

[0014] Add crude extract, allow to stand for adsorption, then elute with 2 BV of water, 2 BV of 30% ethanol, 2 BV of 70% ethanol and 2 BV of anhydrous ethanol respectively, collect the eluents to obtain fraction I, fraction II, fraction III and fraction IV in sequence.

[0015] Fraction II was concentrated and freeze-dried to obtain the antioxidant active product.

[0016] In a preferred embodiment of the method described in this invention, the mass concentration of the lactic acid solution is 30%.

[0017] As a preferred embodiment of the method described in this invention, the step of mixing the pulverized roselle calyx powder with a lactic acid solution and ultrasonically extracting the mixture is performed at an ultrasonic temperature of 40°C for 20 minutes.

[0018] In a preferred embodiment of the method described in this invention, the ratio of the pulverized roselle calyx powder to the lactic acid solution is 1:20 g / mL.

[0019] In a preferred embodiment of the method described in this invention, the mass concentration of the urea solution is 20%.

[0020] In a preferred embodiment of the method described in this invention, the filter residue is mixed with urea solution and ultrasonically extracted, wherein the ultrasonic temperature is 60°C and the extraction time is 50 min.

[0021] In a preferred embodiment of the method described in this invention, the ratio of the filter residue to the urea solution is 1:20 g / mL.

[0022] In a preferred embodiment of the method described in this invention, the deionized water is used to wash away ethanol from the resin, wherein the amount of deionized water used is 2 BV.

[0023] Another objective of this invention is to overcome the shortcomings of the prior art and provide a roselle antioxidant product.

[0024] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of hibiscus antioxidant active products in food, health products, and cosmetics.

[0025] Beneficial effects of this invention:

[0026] (1) High-efficiency extraction: This invention significantly improves the extraction efficiency of antioxidant active ingredients in roselle by optimizing the mass concentration of lactic acid and urea, ultrasonic temperature and extraction time.

[0027] (2) High antioxidant activity: The extract exhibits excellent antioxidant activity under optimal processing conditions, especially with a significant improvement in DPPH free radical scavenging rate.

[0028] (3) Environmentally friendly: The extraction aids used in this invention are naturally occurring organic acids and organic bases, which are environmentally friendly.

[0029] (4) Wide range of applications: The extract has strong antioxidant activity and can be widely used in food, health products, cosmetics and other fields. It has high economic value and market potential. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0031] Figure 1 This is a graph showing the effect of different mass concentrations of lactic acid on the DPPH free radical scavenging rate in this invention.

[0032] Figure 2 This is a graph showing the effect of extraction time on DPPH free radical scavenging rate during lactic acid extraction in this invention.

[0033] Figure 3 This figure shows the effect of ultrasonic temperature on DPPH free radical scavenging rate during lactic acid extraction in this invention.

[0034] Figure 4 This is a graph showing the effect of different mass concentrations of urea on the DPPH free radical scavenging rate in this invention.

[0035] Figure 5 This is a graph showing the effect of extraction time on DPPH free radical scavenging rate during urea extraction in this invention.

[0036] Figure 6 This is a graph showing the effect of ultrasonic temperature on DPPH free radical scavenging rate during urea extraction in this invention. Detailed Implementation

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments. All raw materials used in this invention are common commercially available products.

[0040] Example 1

[0041] Lactic acid was used as an extraction aid to extract antioxidants from hibiscus.

[0042] (1) Crush 15g of dried roselle calyx and pass it through a 40-mesh sieve. Add 300mL of 30% lactic acid solution and mix well.

[0043] (2) Place the mixture in an ultrasonic-assisted extractor and extract it ultrasonically at 40°C for 20 min.

[0044] (3) After extraction, the extract was filtered to obtain crude extract, which was then concentrated to a concentration of 0.1 g crude drug / mL.

[0045] (4) Immerse D101 resin in anhydrous ethanol for 12 hours to allow it to swell fully;

[0046] For wet packing, wash with ethanol until no white turbidity appears when deionized water is added to the effluent. Then wash with two column volumes (2 BV) of 5% HCl solution, deionized water, and 2% NaOH solution in sequence. Finally, wash with deionized water until the effluent is neutral.

[0047] According to the ratio of crude drug to resin of 1:30, 20 mL of crude extract (0.1 g crude drug / mL) was added to the top of a D101 macroporous resin (60 g) column. After static adsorption for 1.5 h, it was eluted sequentially with 2 BV of water, 2 BV of 30% (v / v) ethanol, 2 BV of 70% ethanol and 2 BV of anhydrous ethanol. The eluents were collected to obtain fraction I, fraction II, fraction III and fraction IV, which were concentrated to a concentration of 0.1 g crude drug / mL.

[0048] (5) Determine the DPPH radical scavenging rate of fraction II.

[0049] Weigh 8.0±0.1 mg of DPPH solid, add anhydrous ethanol to a 250 mL brown volumetric flask and dilute to volume. Store at -4℃ in the dark. Because the roselle extract is dark in color, it needs to be diluted 200 times with water before it can be used for antioxidant activity testing. At this point, the concentration of the crude extract used in the antioxidant activity test is 0.1 mg / mL.

[0050] Prepare the extract by mixing Tris buffer and anhydrous ethanol at a volume ratio of 1:1, and dilute it by mixing Tris buffer, anhydrous ethanol, and DPPH solution at a volume ratio of 1:1:2. Dilute the extract with the corresponding extraction solvents used for the roselle extract by the appropriate factor.

[0051] The DPPH radical scavenging experiment was performed in 96-well plates, and the samples added to the 96-well plates are shown in Table 1.

[0052] The sample group was prepared by adding 40 μL of the sample solution diluted 200 times and 160 μL of LPPH diluent; the blank group was prepared by adding 40 μL of the diluted extract and 160 μL of Tris diluent; the control group was prepared by adding 40 μL of the corresponding extract solvent diluted 100 times and 160 μL of LPPH diluent; each group was to be performed in triplicate.

[0053] After adding the sample using a pipette, allow it to react at room temperature in the dark for 30 minutes. Once the reaction is complete, place the 96-well plate in an ELISA reader at a wavelength of 517 nm to measure the absorbance.

[0054] Table 196 Sample Dosage for Plates

[0055]

[0056]

[0057] The formula for calculating DPPH free radical scavenging rate is as follows:

[0058] DPPH free radical scavenging rate = (1-(A) S -A B ) / A C )*100;

[0059] Among them, A S - Absorbance after the sample solution reacts with DPPH diluent; A B - Absorbance of the sample solution after reaction with Tris dilution solution; A C - The absorbance of the sample after the corresponding extraction solvent reacts with DPPH dilution solution.

[0060] The results showed that, at a concentration of 0.1 mg / mL based on the crude drug, fraction II had a DPPH free radical scavenging rate of 40.2%.

[0061] Transfer 10 mL of the concentrated fraction II solution (0.1 g crude drug / mL) to a small volume, concentrate, dry, and weigh. The yield of fraction II is 40.7%.

[0062] Example 2

[0063] Urea was used as an extraction aid to extract antioxidants from roselle.

[0064] (1) Crush 15g of dried roselle calyx and pass it through a 40-mesh sieve. Add 300mL of 20% urea solution and mix well.

[0065] (2) Place the mixture in an ultrasonic-assisted extractor and extract it ultrasonically at 60°C for 50 min.

[0066] (3) After extraction, the extract was filtered to obtain crude extract, which was then concentrated to a concentration of 0.1 g crude drug / mL.

[0067] (4) Pass the crude extract through a D101 macroporous resin column, elute with 30% ethanol, and collect fraction II. The specific process is the same as in Example 1.

[0068] (5) The DPPH free radical scavenging rate of fraction II was determined to be 33.9%, and the yield was 45.5%. The test method was the same as in Example 1.

[0069] Example 3: Optimization of extraction process using single-factor experimental method

[0070] ① Effects of lactic acid and urea solution concentrations on the antioxidant activity of roselle extract

[0071] Prepare aqueous solutions of lactic acid and urea with mass fractions of 1%, 10%, 20%, 30%, and 50%, respectively.

[0072] Weigh 1 ± 0.005 g of hibiscus powder (passed through a 40-mesh sieve) into a 50 mL centrifuge tube, add different concentrations of lactic acid and urea extraction solvents at a material-to-liquid ratio of 1:20 g / mL, and extract by ultrasonication at 40 °C for 40 min with an ultrasonic power of 100%.

[0073] After extraction, the system was cooled to room temperature, and the extract was obtained by vacuum filtration. The extract was then stored at room temperature away from light.

[0074] The extract was diluted with water and its DPPH free radical scavenging rate was tested. The concentration of the crude drug in the diluted roselle extract was 0.1 mg / mL.

[0075] ② Effect of extraction time on the antioxidant activity of hibiscus extract

[0076] The extraction solvent was prepared according to the optimal mass concentrations of lactic acid and urea in experiment ①.

[0077] Weigh 1 ± 0.005 g of hibiscus powder into a 50 mL centrifuge tube, add extraction solvent at a material-to-liquid ratio of 1:20 g / mL, and ultrasonically extract at 40℃ for 20, 30, 40, 50, and 60 min with an ultrasonic power of 100%.

[0078] After extraction, the system was cooled to room temperature, and the extract was obtained by vacuum filtration. The extract was then stored at room temperature away from light.

[0079] ③ Effect of extraction temperature on the antioxidant activity of hibiscus extract

[0080] The extraction solvent was prepared according to the optimal mass concentrations of lactic acid and urea in experiment ①.

[0081] Weigh 1 ± 0.005 g of hibiscus powder into a 50 mL centrifuge tube. Add extraction solvent at a solid-liquid ratio of 1:20 g / mL. Perform ultrasonic extraction at room temperature, 30, 40, 50, and 60 °C, respectively, according to the optimal extraction times for the lactic acid and urea groups in experiment ②, with an ultrasonic power of 100%. After extraction, allow the system to cool to room temperature and then filter under vacuum to obtain the extract. Store the extract at room temperature, protected from light.

[0082] In this embodiment, when the material-to-liquid ratio is 1:20 g / mL, the ultrasonic temperature is 40℃, and the extraction time is 40 min, the effect of the mass concentration of lactic acid extraction solvent on the antioxidant activity of roselle extract is as follows: Figure 1 As shown, the DPPH free radical scavenging rate of the hibiscus extract first increases and then decreases, reaching its peak at a concentration of 20%. This trend may be due to the polarity of the lactic acid solution, which facilitates the release of effective components from the hibiscus calyx; however, as the concentration increases, the acidity of the system increases, leading to the inactivation of effective components and a decrease in antioxidant activity.

[0083] When the lactic acid extraction solvent concentration is 20%, the solid-liquid ratio is 1:20 g / mL, and the ultrasonic temperature is 40℃, the effect of lactic acid extraction time on the antioxidant activity of roselle extract is as follows: Figure 2 The DPPH free radical scavenging rate showed a trend of first increasing and then decreasing, reaching its peak when the extraction time was 20 minutes. This trend may be because an appropriate extraction time allows for the full extraction of effective components from the hibiscus calyx; however, as the extraction time continues to extend, the acidity of the system increases due to the high content of organic acids in hibiscus, causing the effective components to lose their activity under strongly acidic conditions, thus reducing the DPPH free radical scavenging rate.

[0084] When the lactic acid extraction solvent concentration was 20%, the solid-liquid ratio was 1:20 g / mL, and the extraction time was 20 min, the effect of ultrasonic temperature on the antioxidant activity of hibiscus extract in the lactic acid group was as follows: Figure 3Similarly, the DPPH free radical scavenging rate of hibiscus extract showed a trend of first increasing and then decreasing, reaching its peak when the ultrasonic temperature was 30℃. This trend may be because an appropriate increase in ultrasonic temperature helps to accelerate the molecular motion rate, allowing the raw material to fully contact the extraction solvent and facilitating the extraction of effective components; however, when the temperature exceeds a certain range, excessively high temperatures deactivate the heat-sensitive components in hibiscus, reducing its antioxidant activity.

[0085] In this embodiment, when the material-to-liquid ratio is 1:20 g / mL, the ultrasonic temperature is 40°C, and the extraction time is 40 min, the effect of the mass concentration of the lactic acid extraction solvent on the antioxidant activity of the hibiscus extract is as follows: Figure 4 The concentration of DPPH free radical scavenging in the hibiscus extract initially increased and then decreased, reaching its peak at a concentration of 10%. This trend may be due to the alkalinity of the urea solution. At lower concentrations, it promotes the precipitation of acidic substances from the hibiscus calyx; however, when the urea solution concentration is too high, the acidic substances in the system may react with the urea, reducing the actual concentration of the extraction solvent. Consequently, this leads to a decrease in the precipitation of effective components from the hibiscus and a reduction in its antioxidant activity.

[0086] When the urea extraction solvent concentration is 10%, the solid-liquid ratio is 1:20 g / mL, and the ultrasonic temperature is 40℃, the effect of urea extraction time on the antioxidant activity of roselle extract is as follows: Figure 5 The DPPH free radical scavenging rate of the hibiscus extract showed a trend of first increasing and then decreasing, reaching its peak at an extraction time of 40 minutes. This trend may be because an appropriate extraction time allows for the full extraction of effective components from the hibiscus calyx; however, as the extraction time continues to extend, the acidity of the system increases due to the high content of organic acids in hibiscus. More acidic substances may react with urea, not only reducing the urea content but also consuming the acidic components in the system, thus decreasing the overall antioxidant activity.

[0087] When the urea extraction solvent concentration was 10%, the extraction time was 30 min, and the solid-liquid ratio was 1:20 g / mL, the effect of ultrasonic temperature on the antioxidant activity of roselle extract was as follows: Figure 6 Similarly, the DPPH free radical scavenging rate of hibiscus extract showed a trend of first increasing and then decreasing, reaching its peak when the ultrasonic temperature was 50℃. This trend may be because an appropriate increase in ultrasonic temperature helps to accelerate the molecular motion rate, allowing the raw material and extraction solvent to come into full contact, thus facilitating the extraction of effective components; however, when the temperature exceeds a certain range, excessively high temperatures deactivate the heat-sensitive components in hibiscus, reducing its antioxidant activity.

[0088] Example 4

[0089] Orthogonal experimental design for optimizing extraction process:

[0090] Based on single-factor experiments, orthogonal experiments were conducted on the mass concentration of lactic acid and urea extraction aids, extraction time, and ultrasonic temperature. Therefore, the orthogonal experiments examined the effects of ultrasonic temperature (A), extraction time (B), and mass concentration (C) on the DPPH free radical scavenging rate. Three levels were selected for each factor, and the orthogonal experimental method was used for investigation.

[0091] As shown in Table 2, when lactic acid is used as the extraction agent, the order of influence of each factor on the DPPH free radical scavenging rate of roselle extract is temperature > concentration > time. The extraction process is optimal when the lactic acid mass concentration is 30%, the extraction time is 20 min, and the extraction temperature is 40℃, at which time the DPPH free radical scavenging rate is 55.59%.

[0092] Table 2 Results of the orthogonal experiment on lactate

[0093]

[0094] As shown in Table 3, when urea is used as the extraction agent, the order of influence of each factor on the DPPH free radical scavenging rate of roselle extract is temperature > concentration > time. The extraction process is optimal when the lactic acid mass concentration is 20%, the extraction time is 50 min, and the extraction temperature is 60℃, at which time the DPPH free radical scavenging rate is 50.84%.

[0095] Table 3 Results of the orthogonal experiment on urea

[0096]

[0097] The orthogonal experiment showed that when lactic acid was used as the extraction agent, the order of influence of each factor on the DPPH free radical scavenging rate of roselle extract was temperature > concentration > time. The extraction process was optimal when the lactic acid mass concentration was 30%, the extraction time was 20 min, and the extraction temperature was 40℃.

[0098] When urea is used as the extraction agent, the order of influence of various factors on the DPPH free radical scavenging rate of roselle extract is temperature > concentration > time. The extraction process is optimal when the urea mass concentration is 20%, the extraction time is 50 min, and the extraction temperature is 60℃.

[0099] Example 5

[0100] Separation and purification of extract from hibiscus semi-bionic extraction process:

[0101] (1) Mix roselle calyx powder with 30% lactic acid solution at a mass ratio of 1:20, place in an ultrasonic-assisted extractor, and ultrasonically extract at 40℃ for 20 min. Filter and collect the filtrate (a) and residue respectively.

[0102] (2) Mix the above filter residue with 20% urea solution at a mass ratio of 1:20, place it in an ultrasonic-assisted extractor, and ultrasonically extract at 60°C for 50 min. Filter and collect the filtrate (b).

[0103] (3) Combine filtrates a and b, and concentrate them under low temperature and reduced pressure to a concentration of 0.1 g crude drug / mL to obtain a crude extract containing antioxidant active ingredients.

[0104] (4) Take 1 mL of crude extract and make up to 200 mL to test its ability to scavenge DPPH free radicals.

[0105] (5) Immerse D101 resin in anhydrous ethanol for 12 hours to allow it to swell fully. Pack the column using a wet method and wash away the ethanol from the resin with 2 BV of deionized water;

[0106] Add 10 mL of the optimized roselle crude extract and allow it to stand for 1.5 h for adsorption. Then elute with 2 BV of water, 2 BV of 30% (v / v) ethanol, 2 BV of 70% ethanol and 2 BV of anhydrous ethanol, respectively. Collect the eluent and make up to 250 mL to obtain fraction I, fraction II, fraction III and fraction IV in sequence.

[0107] To maintain the concentration of the crude drug consistent with that in Example 1 above, the four eluents after being brought to a fixed volume need to be diluted before being used for DPPH free radical antioxidant activity testing.

[0108] Take another 100 mL of 30% ethanol eluent (fraction II), and evaporate it under vacuum at 50℃ to obtain the separated solid. Weigh the solid and calculate the extraction rate.

[0109] It can be clearly observed that fraction II, eluted with 30% ethanol, is red, fraction III, eluted with 70% ethanol, is light purple, while fractions I and IV are colorless and transparent.

[0110] The antioxidant activities of fractions I, II, III, and IV were detected by DPPH free radical scavenging assay, and their DPPH free radical scavenging rates were 14.50%, 44.20%, 19.52%, and 2.50%, respectively.

[0111] Therefore, 30% ethanol can effectively separate antioxidant active substances from roselle extract;

[0112] The fraction II was subjected to rotary evaporation, with a yield of 50.6%.

[0113] Comparative Example 1

[0114] Ultrasonic-assisted extraction of antioxidants from hibiscus using water as a solvent:

[0115] Powder the dried roselle calyx and pass it through a 40-mesh sieve;

[0116] Weigh 2g of powder, add 20 times the amount of deionized water, extract at 60℃ using an ultrasonic-assisted extractor for 50 minutes, cool to room temperature, and filter.

[0117] Take the filtrate, dilute it to a certain volume, so that the mass concentration of the resulting extract is 0.5 mg crude drug / mL, and test its ability to scavenge DPPH free radicals.

[0118] Comparative Example 2

[0119] Antioxidant components in hibiscus were extracted using a semi-biomimetic extraction method with traditional acid-base auxiliaries.

[0120] Roselle calyx powder was mixed with 1% hydrochloric acid solution at a ratio of 1:20, placed in an ultrasonic-assisted extractor, and ultrasonically extracted at 40℃ for 20 min. The filtrate (a) and the residue were collected separately after filtration.

[0121] The above filter residue was mixed with 1% NaOH solution at a ratio of 1:20, placed in an ultrasonic-assisted extractor, and ultrasonically extracted at 60℃ for 50 min. After filtration, the filtrate (b) was collected.

[0122] Filtrates a and b were combined and brought to a certain volume to obtain an extract with a mass concentration of 0.5 mg crude drug / mL, thus obtaining a crude extract containing antioxidant active ingredients. Its ability to scavenge DPPH free radicals was then tested.

[0123] Comparative Example 3

[0124] The "urea first, then lactic acid" extraction method is used to extract antioxidants from roselle.

[0125] Roselle calyx powder was mixed with 30% lactic acid solution at a ratio of 1:20, placed in an ultrasonic-assisted extractor, and ultrasonically extracted at 40℃ for 20 min. The filtrate (a) and the residue were collected separately after filtration.

[0126] The above filter residue was mixed with 20% urea solution at a ratio of 1:20, placed in an ultrasonic-assisted extractor, and ultrasonically extracted at 60°C for 50 min. The mixture was then filtered and the filtrate (b) was collected.

[0127] Filtrates a and b were combined and brought to a certain volume to obtain a crude extract containing antioxidant active ingredients (mass concentration of 0.5 mg crude drug / mL). Its ability to scavenge DPPH free radicals was then tested.

[0128] Table 4. Roselle extracts obtained by different extraction methods

[0129]

[0130]

[0131] As shown in Table 4, the extract obtained in Example 5 had the highest antioxidant activity.

[0132] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for semi-bionic extraction of antioxidant active products from hibiscus, characterized in that: include, The pulverized roselle calyx powder was mixed with lactic acid solution and ultrasonically extracted. Filtrate a and filter residue were collected. The mass concentration of the lactic acid solution was 30%. The ultrasonic temperature was 40℃ and the extraction time was 20 min. The material-liquid ratio of the pulverized roselle calyx powder to the lactic acid solution was 1:20 g / mL. The filter residue was mixed with urea solution and ultrasonically extracted. After filtration, filtrate b was collected. The mass concentration of the urea solution was 20%. The ultrasonic temperature was 60℃ and the extraction time was 50 min. The material-to-liquid ratio of the filter residue to the urea solution was 1:20 g / mL. Combine filtrates a and b, concentrate under low temperature and reduced pressure to obtain a crude extract containing antioxidant active ingredients; The D101 resin was soaked in anhydrous ethanol to fully swell, then packed into a column using a wet method, and the ethanol in the resin was washed away with deionized water. Add crude extract, allow to stand for adsorption, then elute with 2 BV of water, 2 BV of 30% ethanol, 2 BV of 70% ethanol and 2 BV of anhydrous ethanol respectively, collect the eluents to obtain fraction I, fraction II, fraction III and fraction IV in sequence. Fraction II was concentrated and freeze-dried to obtain the antioxidant active product.

2. The method as described in claim 1, characterized in that: The deionized water is used to wash away the ethanol from the resin, wherein the amount of deionized water used is 2 BV.

3. The hibiscus antioxidant product obtained by the method of claim 1 or 2.

4. The use of the hibiscus antioxidant active product according to claim 3 in the preparation of food, health products, and cosmetics.

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