Eclipta prostrata extract dye as well as preparation method and application thereof in cotton fabric dyeing

Abstract

The invention belongs to the field of natural medicine extracts and the field of light dyes, and particularly relates to a yerbadetajo herb extract dye, a preparation method thereof and application of the yerbadetajo herb extract dye in cotton fabric dyeing. The method comprises the following steps: taking dried eclipta leaves, adding 8-10 times of ethanol with the concentration of 70-85%, carrying out reflux extraction twice (2 hours each time), carrying out suction filtration, and combining filtrates; the preparation method comprises the following steps: adding a concentrated solution into a filtrate, filtering, recovering a solvent from the filtrate until the concentration of the concentrated solution is 0.3 g crude drug / mL, adding a chitosan acetic acid solution at the temperature of 55 DEG C for flocculation, uniformly stirring and mixing, standing for 12 hours, centrifuging, taking supernate, and freeze-drying to obtain freeze-dried powder, namely the eclipta extract dye which is used for dyeing cotton fabrics, so that the color of the fabrics is natural and stable, and meanwhile, the eclipta extract dye also has a good anti-oxidation function.

Description

Technical Field

[0001] The invention belongs to the field of natural medicine extracts and light chemical dyes, and particularly relates to an Eclipta prostrata extract dye, a preparation method thereof and application thereof in cotton fabric dyeing. Background Art

[0002] As people's requirements for quality of life continue to improve and they pay more and more attention to environmental protection, natural plant dyes are becoming more and more popular. Compared with traditional synthetic dyes, natural plant dyes have rich colors, no adverse effects on the body, and the preparation process is more environmentally friendly. In recent years, some plant dyes with additional functions have enriched the dye market.

[0003] However, most of the plant dyes currently have complex ingredients, some of which contain certain irritating ingredients; or, some plant dyes use a large amount of less safe organic solvents in the purification process, resulting in organic solvent residues. The plant dyes obtained by these processes, if used in the dyeing of household products and textiles, may cause skin discomfort or allergic reactions, and have potential effects on the human body.

[0004] Eclipta prostrata is the dried aerial part of the plant of the genus Channa in the Asteraceae family, also known as Eclipta prostrata. Its leaves and stems contain dark green juice, which has the medical effects of nourishing the liver and kidneys, cooling blood and stopping bleeding, relieving itching and anti-oxidation. Because it is a "medicine and food homology" substance, it can be used as both a medicine and a food. In addition to being used in clinical practice in the form of a drug, Eclipta prostrata is also used in other fields. For example, the patent with application number 202111036171.6 discloses a method of using Eclipta prostrata extract as a hair dye. However, it does not describe in detail the preparation process of Eclipta prostrata extract and the content of effective ingredients, and the dyeing effect of Eclipta prostrata extract as a hair dye alone is not ideal. Oxidative chemical dyes are also added to the process, which are used in combination with Eclipta prostrata extract to achieve the hair dyeing effect. Summary of the invention

[0005] The present invention provides a natural, green plant dye and an application method thereof. In order to achieve the above object, the preparation method of the Eclipta prostrata extract dye with antioxidant function provided by the present invention comprises the following steps:

[0006] The steps of extracting Eclipta prostrata are as follows:

[0007] (1) Raw material pretreatment: Take the dried Eclipta prostrata leaves, remove impurities, crush, and pass through a 20-mesh sieve;

[0008] (2) Extraction of dye from Eclipta prostrata: Add 8-10 times (V / W) ethanol with a concentration of 70%-85% (V / V) to the sieved Eclipta prostrata medicinal material, heat and reflux to extract for 2 hours, filter with suction, and take the filtrate for later use; continue to add 8-10 times (V / W) ethanol with a concentration of 70%-85% (V / V) to the filtered medicinal residue, heat and reflux to extract for 2 hours, filter with suction, and combine the filtrate with the filtrate from the first extraction.

[0009] The purification steps of Eclipta prostrata are as follows:

[0010] (1) taking the filtrate obtained by extracting Eclipta prostrata, placing it in a rotary evaporator, and recovering the solvent under reduced pressure until the concentration of the concentrated solution is 0.3 g crude drug / mL;

[0011] (2) Add 1% acetic acid to the concentrate to adjust the pH to 5-6.5, slowly add 1% (W% by volume) chitosan acetate solution at a temperature of 35-60°C, stir and mix, and let stand for 12 hours to flocculate; wherein the amount of chitosan acetate solution is 6%-10% (V / V) of the volume of the concentrate.

[0012] (3) The mixed liquid after flocculation and precipitation in step (2) is transferred to a centrifuge and centrifuged at a speed of 4000 rpm for 5 minutes. The supernatant is taken and freeze-dried to obtain freeze-dried powder of Eclipta prostrata extract.

[0013] The present invention also provides a method for dyeing cotton fabric with the Eclipta prostrata extract dye, comprising the following steps:

[0014] (1) cotton fabric is modified by cationic modifier REBACATH NT-2A, rinsed and dried;

[0015] (2) diluting the Eclipta extract dye with double distilled water to obtain an Eclipta dye solution; the ratio of the dye to double distilled water is 1:25-1:40 (W / V);

[0016] (2) Directly dyeing or pre-mordanting the cotton fabric with the Eclipta prostrata dye solution for 10 minutes, then heating to 70° C.-80° C. for dyeing, and controlling the dyeing time to be 20-30 minutes; washing the dyed fabric to remove the floating color, and drying.

[0017] The ratio of Eclipta dye solution to cotton fabric (V / W) is 1:10-1:25;

[0018] The pre-mordanting method is: using copper ion, ferrous ion and aluminum ion as mordants, adding mordant dosage of 2-3g / L, and controlling the mordant time at 20-30min. Among them, the copper ion mordant is copper sulfate, the ferrous ion mordant is ferrous sulfate, and the aluminum ion mordant is alum.

[0019] Beneficial Effects

[0020] Eclipta prostrata contains volatile oil, phenolic acid, flavonoids, coumarin and saponin components. Among them, phenolic acid, flavonoids and coumarin components all have certain antioxidant and antibacterial activities, but phenolic acid components do not contribute much to dyeing function, and because of the large difference in solubility between them and other components, the extraction process is complicated. The purpose of the extraction and purification of the present invention is to extract flavonoids and coumarin components from Eclipta prostrata leaves, and make the obtained products into plant dyes. The dyed fabrics have bright colors, have certain positive protective functions for the human body, and can better meet the needs of the high-end market. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram showing the dyeing effect of the dye on cotton fabric in Example 1;

[0022] Figure 2 This is a diagram showing the dyeing effect of cotton fabric using dyes from Example 3 (pH 5.5 of the concentrated solution, 6% chitosan dosage);

[0023] Figure 3 This is a diagram showing the dyeing effect of the dye on cotton fabric in Example 5;

[0024] Figure 4 This is a diagram showing the dyeing effect of the dye of Comparative Example 3 on cotton fabric. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with embodiments, but is not limited thereto.

[0026] Example 1

[0027] The steps of extracting Eclipta prostrata are as follows:

[0028] (1) Raw material pretreatment: Take the dried Eclipta prostrata leaves, remove impurities, crush, and pass through a 20-mesh sieve;

[0029] (2) Extraction of dye from Eclipta prostrata: Add 8 times the amount (V / W) of 80% (V / V) ethanol to dried Eclipta prostrata leaves, heat and reflux for extraction for 2 hours, filter with suction, and take the filtrate for later use; add 8 times the amount (V / W) of 80% (V / V) ethanol to the filtered residue, reflux for extraction for 2 hours, filter with suction, and combine the filtrate with the filtrate from the first extraction.

[0030] The purification steps of Eclipta prostrata are as follows:

[0031] (1) taking the filtrate obtained by extracting Eclipta prostrata, placing it on a rotary evaporator, and recovering the solvent under reduced pressure until the concentration of the concentrated solution is 0.3 g crude drug / mL;

[0032] (2) Add 1% acetic acid to the concentrate to adjust the pH to 5.5, slowly add 1% chitosan acetate solution at 55°C for flocculation, the amount of chitosan acetate solution added is 10% (V / V) of the concentrate volume, stir and mix, and let stand for 12 hours.

[0033] (3) The mixed liquid after flocculation and precipitation in step (2) is transferred to a centrifuge and centrifuged at a speed of 4000 rpm for 5 minutes. The supernatant is taken and freeze-dried to obtain freeze-dried powder of Eclipta prostrata extract, i.e., Eclipta prostrata extract dye.

[0034] Determination of total flavonoids in Eclipta prostrata extract

[0035] The spectrophotometric method using AlCl3-NaAc as the color development system is as follows:

[0036] Accurately weigh AlCl3 powder and dissolve it in 50mL of distilled water to prepare a 0.1moL / L AlCl3 solution. Accurately weigh CH3COONa powder and dissolve it in 50mL of distilled water, add glacial acetic acid to adjust the pH to 5.5. Accurately weigh the rutin standard and add anhydrous methanol solution to prepare a standard solution with a concentration of 50μg / mL. Take 0, 6, 7, 8, 9, and 10mL of rutin standard solution respectively and place them in a 25mL volumetric flask, add 32mL of AlCl3 solution and 1mL of CH3COONa solution, add 70% ethanol solution to make the volume to 25mL, and prepare rutin standard solutions with mass concentrations of 12, 14, 16, 18, and 20μg / mL, respectively. Ultrasonicate at 23℃ for 20min, measure the absorbance at 410nm, and draw a standard curve. Take another 1 mg of Eclipta prostrata extract powder and place it in a 25 mL volumetric flask, dissolve it with 2 mL of 70% ethanol solution, add 32 mL of AlCl3 solution and 1 mL of CH3COONa solution, and then add 70% ethanol solution to make the volume to 25 mL. Ultrasonicate at 23°C for 20 min, measure the absorbance at 410 nm, substitute it into the standard curve equation, and calculate the total flavonoids content.

[0037] Determination of total coumarin content in extracts of Eclipta prostrata

[0038] The total content of coumarin was determined by high performance liquid chromatography. The instrument used was an Agilent 1200 high performance liquid chromatograph, which included a diode array detector (DAD), an automatic sampler, a quaternary pump, a column heater-cooler and an Agilent CSCATSO software. The analysis conditions were as follows: Agilent ZOBAX 5TC-C18 (250 mm×4.6 mm, 5 μm), column temperature: 30°C, detection wavelength: 350 nm; flow rate: 1 mL / min; injection volume: 20 μL. The mobile phase consisted of acetonitrile (A) and 0.1% acetic acid aqueous solution (B). Gradient elution conditions: 0-15 minutes, 13-18% A; 15-20 minutes, 18-32% A; 20-30 minutes, 32-80% A. Isodemethylwedeholide and wedeholide were selected as mixed reference substances, and the contents of the two indicator components in the samples were calculated using the standard curve method. The sum of the contents of the two components was taken as the total content of the coumarin component.

[0039] Dyeing method of Eclipta prostrata extract dye:

[0040] (1) cotton fabric is modified by a cationic modifier REBACATH NT-2A, rinsed, and dried; a dye of Eclipta prostrata extract is dispersed in double distilled water to obtain an Eclipta prostrata dye solution, wherein the ratio of the dye to the double distilled water is 1:30 (W / V);

[0041] (2) The cotton fabric was directly dyed with Eclipta dye solution, the ratio of Eclipta dye solution to cotton fabric (V / W) was 1:15, and the dyeing time was controlled within 25 min;

[0042] (3) Wash the dyed fabric to remove the floating color and dry it.

[0043] Example 2

[0044] The preparation method of this embodiment is the same as that of Example 1, except that the concentration and volume of the ethanol solvent used in the extraction of the Eclipta prostrata dye are different. The contents of total flavonoids and coumarin in the obtained Eclipta prostrata extract are shown in Table 1.

[0045] Table 1

[0046]

[0047] As can be seen from Table 1, when different solid-liquid ratios of solvents are used to extract Eclipta prostrata, the ratios are different, and the total flavonoids and coumarin obtained are also different. When the solid-liquid ratio (W / V) is 1:7, the total flavonoids and coumarin obtained are relatively low in content. As the solvent ratio increases, the content of the two types of effective components continues to increase. When the solid-liquid ratio (W / V) is 1:11, the content increase is not obvious, and the use of a large amount of solvents has a certain impact on the operation and cost. Therefore, the present invention determines the solid-liquid ratio (W / V) during extraction to be 1:8-1:10.

[0048] Similarly, when the solvent concentration (V / V) is 65% ethanol, the contents of the two target components are not high. When the solvent concentration is increased, the contents of the two components continue to increase. When the solvent concentration reaches 90%, the increase in the content of the two components is not obvious. Considering the cost in actual operation, the extraction solvent concentration is determined to be 70%-85% ethanol.

[0049] Example 3

[0050] The preparation method of this embodiment is the same as that of Example 1, except that when purifying the Eclipta prostrata extract, the pH of the concentrated solution is adjusted and the amount of chitosan acetic acid solution is different. The contents of total flavonoids and coumarin in the obtained Eclipta prostrata extract are shown in Table 2.

[0051] Table 2

[0052]

[0053] As can be seen from Table 2, when the pH of the concentrated solution is adjusted to 4.5, chitosan is added for flocculation and sedimentation, and the total flavonoids and coumarin content obtained by extraction are low. When the pH is continuously increased, the total flavonoids and coumarin content obtained are continuously increasing, but when the pH is 6.5, the content of the two components is on a downward trend, so the present invention determines the pH of the concentrated solution to be 5-6.5 during chitosan flocculation and sedimentation. When the amount of chitosan acetic acid solution is 5% of the volume of the concentrated solution, the content of the two types of components obtained is not high, and when the amount of chitosan acetic acid solution reaches 11%, the total flavonoids and coumarin content are not much increased, so the amount of chitosan acetic acid solution is determined to be 6%-10% of the volume of the concentrated solution.

[0054] Example 4

[0055] The preparation method of this embodiment is the same as that of Example 1, except that when purifying the Eclipta prostrata extract, the temperature when the chitosan acetic acid solution is added to the concentrate for flocculation is different. The contents of total flavonoids and coumarin in the obtained Eclipta prostrata extract are shown in Table 3.

[0056] Table 3

[0057]

[0058] As can be seen from Table 3, when chitosan is added for flocculation and sedimentation, the temperature of the concentrated solution is different, and the total flavonoids and coumarin content in the obtained extract is also different. When the temperature is low, the total flavonoids and coumarin content are both low. As the temperature increases, the content of the two index components in the extract also increases. When the temperature reaches 60°C, the content of the two components begins to decrease, and the solution is relatively viscous at this time, which is not conducive to subsequent operations. Therefore, the present invention sets the optimal solution temperature when chitosan is added for flocculation and sedimentation to 55°C.

[0059] Example 5

[0060] The preparation method of this embodiment is the same as that of embodiment 1, except that when the Eclipta extract dye is used to dye the fabric, the dyeing method selected is pre-mordanting. Specifically, copper sulfate is used as the mordant, the added mordant dosage is 2.5 g / L, and the mordant time is controlled at 20 min.

[0061] Comparative Example 1

[0062] The preparation method of this embodiment is the same as that of embodiment 1, except that in the first step of the Eclipta prostrata extraction process, the extraction solvent used is distilled water.

[0063] Comparative Example 2

[0064] The preparation method of this embodiment is the same as that of embodiment 1, except that chitosan is not added for flocculation and precipitation in the second step of the Eclipta prostrata purification process.

[0065] Comparative Example 3

[0066] The preparation method of this embodiment is the same as that of embodiment 1, except that in the first step of the Eclipta prostrata extraction process, the raw material used is the whole herb of the aerial part of Eclipta prostrata.

[0067] The total flavonoids content and coumarin content in the Eclipta prostrata extracts prepared in Comparative Examples 1-3 are shown in Table 4.

[0068] Table 4

[0069] Total flavonoids content (mg / g extract) Coumarin content (mg / g extract) Comparative Example 1 16.94 20.73 Comparative Example 2 23.17 29.35 Comparative Example 3 24.28 30.11

[0070] As can be seen from Table 4, in Comparative Examples 1-3, both the content of total flavonoids and the content of coumarin are relatively low.

[0071] Color fastness performance test

[0072] The fastness performance test was performed on textiles dyed with the Eclipta dye provided in Example 1, Example 2 (solid-liquid ratio 1:8, ethanol concentration 85%), Example 3 (concentrated solution pH 5.5, chitosan dosage 6%), Example 5 and Comparative Examples 1-3; wherein the color fastness to rubbing, color fastness to soaping, and color fastness to sunlight refer to the Chinese national textile dyeing standards GB / T 3920-2008 and GB / T 3921-2008 series. The three types of color fastness indicators of qualified products need to be level 3 or above.

[0073] The results are shown in Table 5. After testing, the color fastness to soap washing of Example 1, Example 2 (solid-liquid ratio 1:8, ethanol concentration 85%), Example 3 (concentrated solution pH 5.5, chitosan dosage 6%), and Example 5 are all above 4, which can meet the requirements. The sunlight resistance and friction resistance are all above 3, which can meet the basic requirements. However, the color fastness to sunlight, color fastness to soap washing and color fastness to friction of Comparative Example 1, Comparative Example 2 and Comparative Example 3 are all poor and do not meet the basic requirements. The color fastness to soap washing and friction (wet) of Comparative Example 3 is relatively better, but the sunlight resistance still does not meet the basic requirements.

[0074] Table 5

[0075]

[0076] Antioxidant capacity determination:

[0077] The DPPH method was used to measure the antioxidant properties of the dyes obtained in each embodiment and comparative example.

[0078] Weigh 200 mg of dyed cotton fabric and undyed fabric respectively, add 50% ethanol solution, shake thoroughly in the dark, add 0.1 mmol / L DPPH·ethanol solution, shake again and seal, place in a 37°C constant temperature water bath and shake for 30 minutes before taking out. Take anhydrous ethanol as the reference solution and measure the absorbance of the sample solution at 517 nm. The dyed fabric is recorded as A sample, and the absorbance of the undyed fabric is recorded as A blank. The formula for calculating the ability to scavenge DPPH free radicals is: Scavenging rate (%) = (1-A 样品 / A 空白 )×100

[0079] The free radical scavenging rates of different fabrics are shown in Table 6.

[0080] Table 6

[0081]

[0082] It can be seen that the Eclipta prostrata extract in the embodiment has good antioxidant properties after being dyed on fabrics.

Claims

1. A method for preparing a dye from an extract of Eclipta prostrata, characterized in that: The preparation method of the Eclipta prostrata extract dye has the following steps: (1) Extraction: Take dried Eclipta prostrata leaves, remove impurities, add ethanol, reflux and extract twice, each time for 2 hours, filter and combine the filtrates; (2) Purification: The filtrate of step (1) is placed on a rotary evaporator, and the solvent is recovered under reduced pressure until the concentration of the concentrate is 0.3 g crude drug / mL, 1% chitosan acetic acid solution is added, stirred and mixed, and allowed to stand for 12 hours for flocculation, centrifuged, and the supernatant is taken and freeze-dried to obtain a freeze-dried powder of Eclipta prostrata extract, which is an Eclipta prostrata extract dye.

2. The method for preparing the dye from the Eclipta prostrata extract according to claim 1, characterized in that: In step (1), the concentration of ethanol is 70%-85%, and the amount of ethanol added is 8-10 times the amount of dry Eclipta prostrata leaves.

3. The method for preparing the dye from Eclipta prostrata extract according to claim 1, characterized in that: In step (2), the amount of chitosan acetic acid solution added is 6%-12% of the volume of the concentrated solution. Before adding the chitosan acetic acid solution for flocculation, the concentrated solution needs to be adjusted to pH 5-6.5 with 1% acetic acid; the flocculation temperature is 35-60°C.

4. The method for preparing the dye from the Eclipta prostrata extract as claimed in claim 2, characterized in that: In step (2), the centrifugation parameters are: rotation speed 4000 rpm, centrifugation time 5 minutes.

5. A dye made from an extract of Eclipta prostrata prepared by the method according to any one of claims 1 to 4.

6. An application of the Eclipta prostrata extract dye prepared by the method according to any one of claims 1 to 4, characterized in that: The dye is used for dyeing cotton fabrics.

7. The use of the Eclipta prostrata extract dye according to claim 6, characterized in that: The application method of the dye is as follows: (1) modifying cotton fabric, rinsing, and drying; diluting the Eclipta extract dye with double distilled water to obtain an Eclipta dye solution; (2) directly dyeing or pre-mordanting the modified cotton fabric with the Eclipta dye solution for 10 minutes, then heating the temperature to a dyeing temperature of 70° C.-80° C. and dyeing for 20-30 minutes; (3) Wash off the floating color of the fabric and dry it.

8. The use of the Eclipta prostrata extract dye according to claim 7, characterized in that: The cotton fabric is modified by using cationic modifier REBACATH NT-2A to modify the cotton fabric; in the Eclipta prostrata dye solution, the mass volume ratio of the dye to double distilled water is 1:25-1:

40.

9. The use of the Eclipta prostrata extract dye according to claim 1, characterized in that: The pre-mordanting method is: using copper ions, ferrous ions and aluminum ions as mordants, and the mordanting time is 20-30 minutes.

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