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.