Coreopsis tinctoria Nutt
Coreopsis tinctoria Nutt, also known as “blood chrysanthemum” or “Guliqal” in Uyghur language, is currently the only alpine wild plant in Xinjiang that has the same name as snow lotus and has unique effects.
It has extremely high medicinal value. Coreopsis tinctoria Nutt contains polyphenols, flavonoids, saponins, and is also rich in volatile oils. It has many physiological activities such as lowering blood lipids, lowering blood pressure, lowering blood sugar, protecting cells, and anti-oxidation and antibacterial. It has received extensive attention in recent years.
Supercritical CO2 extraction
Supercritical CO2 extraction technology has been widely used in the extraction of volatile components from plants at the beginning of its development. It has the characteristics of completely retaining the natural flavor of plants, safe and solvent-free, and is recognized as a green chemical high-tech. As a safe extraction solvent, subcritical water is also used in the extraction of plant volatile components.
Accurately weighed 300.0g of the crushed Coreopsis tinctoria Nutt raw material into the extraction kettle of the supercritical CO2 extraction device, and closed the device.
Select the set extraction temperature and pressure, pass CO2 into the extractor, and the components in the Coreopsis tinctoria Nutt that can be dissolved in supercritical CO2 will dissolve in the CO2 fluid;
When the CO2 fluid passes through the separator, under the set separation temperature and pressure, the active ingredients of snow chrysanthemum dissolved in supercritical CO2 will be resolved due to the decrease in solubility under the conditions of reduced pressure and elevated temperature.
The separator is separated from CO2, and the extracted snow chrysanthemum active components remain in the separator, while the CO2 is separated from the separator in gaseous form, and the separated CO2 gas is condensed by the condenser and recycled.
After 2 hours of extraction at a temperature of 45°C and an extraction pressure of 25Mpa, the equipment stops running and the snow chrysanthemum extract is taken out from the separator.
Subcritical water extraction (SW)
Weigh 20 g of dry Coreopsis tinctoria Nutt (Qitai area), use PPL lined stainless steel reactor (250 mL), extract 1 h at 150°C, use ether to extract the volatile oil, and then use Drying with anhydrous Na2SO4, the steam distillation essential oil of Tianshan Snow Chrysanthemum is obtained.
Steam distillation (SD)
Weigh 100 g of dry Coreopsis tinctoria Nutt (Qitai area), and use steam distillation to extract for 3 hours. After the extraction is complete, use ether to extract the volatile oil, and then dry it with anhydrous Na2SO4. The resulting volatile oil is kept in the refrigerator for later use .
Analysis of Volatile Components
Extract from CO2 extraction
A total of 50 components were identified in the supercritical CO2 extract of Coreopsis tinctoria Nutt, and the relative content accounted for 96.58% of the total.
Among them, olefin compounds (including terpenes) have a total of 9 components, the content of which is only 7.74% of the total mass fraction, which is significantly lower than our previous analysis of headspace solid-phase microextraction-GC-MS in flowers. Proportion (above 85%); but limonene is still the highest content component in its olefins.
The total mass fraction of the seven alcohol compounds is 27.12%, second only to the higher alkane compound (28.59%) with the highest content.
Higher alkane compounds
Higher alkane compounds generally exist in the waxy components of plant stratum corneum, and the high content can reach more than 50% of the plant waxy components.
The coreopsis tinctoria Nutt extract obtained by supercritical extraction method extracts a large amount of waxy components during the extraction process, and during the headspace analysis process, the waxy components are not easy to volatilize, so the detection of such higher alkane components is not To.
It can be seen from the experimental data that the higher alkanes in Coreopsis tinctoria Nutt are alkanes between C21 and C40, with C31 accounting for the highest proportion (10.99%), which is similar to the composition of plant alkanes reported in many literature, followed by C28 And C35.
Free fatty acids
In addition, the free fatty acids from C12 to C18 also account for a considerable proportion (a total of eight components are 18.98%), and these components are also the main components of vegetable waxes.
In addition, the extract also contains 8.81% of aldehydes and ketones, 5.72% of lipid compounds and 0.47% of terpene oxides. These components are also metabolites during plant growth.
Steam distillation extract
Steam distillation products are mainly composed of hydrocarbons (including terpenes), accounting for 71.42% of the total content. In the volatile oil of steam distillation, in addition to the compounds listed in Table 2, the main hydrocarbons are Compounds (including terpenes) and α-pinene (3.31%), α-myrcene (1.89%), morocene-13 (2.15%), trans caryophyllene (1.16%) and trans Farnesene (1.39%).
A total of 18 alcohol compounds were obtained in the steam distillation products. There are trans-p-menthol-2,8-dienol (0.51 %), tau-cadinol (0.38%), (-)-spartol (0.35%), 2,5-dimethyl-1,5-hexadiene-3,4-diol (1.34% ), trans-p-2,8-menthadien-1-ol (1.02%), verbenaol (0.37%), 1,2,5,6-tetramethyl-bicyclo[3.3.0] Octan-3-ol (0.58%), p-menthol-1(7), 8(10)-diene-9-ol (0.35%), 6-isopropenyl-4,8a-diyl-1 ,2,3,5,6,7,8,8a-octahydro-naphthalene-2-ol (0.65%), cumyl alcohol (0.33%), (Z)-2-nonen-1-ol (0.27% ) And p-santalol (0.35%);
The 8 ketones and aldehyde compounds identified are: L-carvone, garlic-4(14)-en-1-one, cis-dihydrocarvone (0.29%), 6,10,14-trimethyl-2-pentadecanone (0.48%), p-menth-1-en-9-aldehyde (0.35%), geranyl acetone (0.41%) and β-ionone (0.41%), only one ester compound (linalyl acetate (1.39%)) was identified, and 7 terpene oxides (4.19%), caryophyllene oxide (1.28%) Is the most important ingredient. In addition, other compounds identified are n-palmitic acid (1.00%), myristic acid (0.37%), lauric acid (0.77%), acetic acid (0.70%), caproic acid (0.63%).
Subcritical water extract
In the volatile oil extracted by subcritical water, the content of hydrocarbons (including terpenes) is relatively low. Only 8 hydrocarbons have been identified, as well as verbena (0.33%) and behenyl (0.45%), (E)-2,6-dimethyl-1,3,5,7-octatetraene (0.39%), 1,3,8-p-menthtriene (0.34%).
The ester compound in the volatile oil extracted by subcritical water is the main component, and the content accounts for 49.82% of the total.
This may be due to the high temperature of the extraction process which caused the oxidation and further esterification of the hydrocarbon compounds in the Tianshan snow chrysanthemum .
(Z)-9-octadecenoic acid methyl ester (16.01%), hexadecanoic acid methyl ester (10.39%), 3-(4-hydroxyphenyl)-2-acrylic acid Methyl (2.28%) (Z)-9-hexadecenoic acid methyl ester (5.68%), methyl octadecanoate (2.35%), (Z,Z)-9,12-octadecadiene Methyl tetradecanoate (4.03%), methyl tetradecanoate (1.57%), (Z,Z,Z)-9,12,15-octadecatrienoate (2.13%) and (E)-10 -Methyl unadecenoate (1.79%).
In addition to the 14 alcohol compounds (21.61%) identified, the content of ethanol is relatively high.
In addition to those listed in Table 2, there are 2,5-dimethyl-1,5-hexadiene-3,4-diol (2.25%), (R)-2-butanol (0.31%), cis-authaltanol (0.38%), p-menthol-1(7), 8(10)-diene-9-ol (0.35 %), cumyl alcohol (0.70%), verbenaol (0.55%), 1,8-1-monadien-4-ol (0.67%) and terpineol (0.49%); 4 aldehydes and ketones Among the compounds (3.81%), L-carvone (2.48%) is the main component, and only one terpene oxide α-phellandrene epoxy compound (1.36%) was identified.
Among the other components, 1 , 2-Benzenediol (6.03%) is its main component.
The content of hydrocarbons in supercritical extracts is lower than steam distillation but higher than subcritical water extraction.
Many oxygen-containing compounds were also identified in the two essential oils.
The volatile components of the Coreopsis tinctoria Nutt extract obtained by supercritical CO2 and subcritical water extraction were compared, and compared with the traditional steam distillation method.
The results showed that the extract obtained by the traditional steam distillation method was based on hydrocarbons. Mainly, due to the high temperature used in the extraction process of subcritical water, most of the hydrocarbons in the extract have been oxidized or esterified, and esters are the main components.
The products obtained by this method are more suitable for use in flavor formulations.
In addition to terpenoids, the supercritical CO2 extract retains more waxy components (higher alkanes) of the Coreopsis tinctoria Nutt plant. In particular, the content of behenyl alcohol is relatively high and has higher The antibacterial and antiviral activity. If used as an essential oil, it still needs further refinement.
Pulverization degree:50 mesh
Extraction pressure: 25 MPa
Extraction temperature: 45°C
Separation pressure I: 12 MPa
Separation I temperature: 50°C
Separation pressure II: 8 MPa
Separation II temperature: 40°C
Extraction time: 120 min