1. A liquid chromatography-mass spectrometry analysis method for phenylpropane metabolites.

2. Analysis of phenylpropanoid compounds according to claim 1, characterized in that: the metabolites comprise 103 of phenylpropanoids, coumarins, flavonoids, isoflavones, flavanones, flavanonols, flavonols, flavanols and biflavonoids.

3. The LC-MS of claim 1, wherein: the liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry combined technology is used, the species of parent ions and daughter ions and the retention time of the parent ions and the daughter ions are used as qualitative basis, and the abundance of specific daughter ions is used as quantitative basis.

4. Use of a phenylpropanoid metabolite assay according to claim 1, wherein: analyzing the change trend of phenylpropane metabolites in organisms with phenylpropane metabolic pathways.

5. An example of an analytical use of phenylpropane metabolites according to claim 4, wherein: analyzing the content change trend of the phenylpropanoid metabolic pathway in the ginkgo leaves in one year.

6. An example of an analytical use of phenylpropane metabolites according to claim 4, wherein: analyzing the change trend of the phenylpropanoid metabolic pathways when the soybean leaves are stressed by salt and drought.

Background

Phenylpropanoids are a class of compounds containing one or more C' s₆-C₃The compounds as basic units include phenylpropene, phenylpropanoids, phenylpropanoic acid and its condensed esters, coumarins, lignans, flavonoids, lignin, etc. The compounds play an important role in the life processes of plant growth regulation, disease attack resistance and the like. Coumarin (coumarins) was first isolated from the leguminous plant coumarins and has an aromatic odor, hence the name coumarin. It is derived from phenylpropanoids in vivo, and structurally, the parent nucleus is formed by lactonization of cis-o-hydroxy cinnamic acid. Coumarins are widely distributed in the plant kingdom in free or glycosidic forms, and they act as phytohormones in the plant or as phytohormones when the plant is subjected to foreign insults. In a broad sense, flavonoids (flavanoids) belong to the class of phenylpropanoids, because of their C₆-C₃-C₆Skeleton derived from phenylpropanoids C₆-C₃And (3) a framework. It is a kind of secondary metabolite which is most widely distributed in plants, and has important effects on regulating the growth and development of the plants and resisting foreign matter invasion besides forming flower colors. C₆-C₃-C₆The skeleton is the basic nucleus of flavonoids, according to C₃The differences in the ring formation, oxidation and substitution patterns of the moieties can be classified into flavanones, flavonoids, flavanols, isoflavanols, flavanols, anthocyanidins, and biflavones, and the substitution of methyl, hydroxyl or methoxy groups on the backbone further enriches the structural diversity of the flavone substances. The metabolic pathways of phenylpropanoids exist in all terrestrial organisms, so that the research on the metabolic processes of the phenylpropanoids has important theoretical and application values.

The biosynthesis process of phenylpropanoid metabolites is currently known to originate from the cinnamic acid pathway (cinnamic acid pathway): phenylalanine and tyrosine formed from shikimic acid are produced by deaminizing and oxidizing reactionThe cinnamic acid is then converted into C by oxidation, methylation and reduction₆-C₃Phenylpropanoids and C of the skeleton₆-C₃-C₆Flavonoids of the skeleton (fig. 1). Therefore, flavonoids have close relationship with phenylpropanoids such as phenylacrylic acid, coumarin and the like in biosynthesis, and isotope tracing experiments prove that C in A ring in flavonoid molecules₆The structure is synthesized by three acetyl-CoA molecules connected end to end, and C of B ring and C ring₆-C₃The structure is derived from cinnamic acid formed by cinnamic acid pathway. Based on the experimental facts, the phenylpropane metabolites with the same hydroxyl, methoxy and the like substituents are likely to be derived from the same synthetic route, so that the content change has relevance.

The invention utilizes the theoretical basis to specifically detect different metabolites with the same substituent, monitors the metabolic trend of the phenylpropanoid metabolic pathway under specific conditions by comparing content difference, and provides basis for metabolic analysis. Because the phenylpropane compounds have similar structures and more isomers, the currently common detection method has low qualitative reliability and weaker detection sensitivity. The invention uses liquid chromatogram-electrospray ionization-mass spectrum combined technology to carry out qualitative and quantitative detection on metabolites: the specific son-mother ion pairing and the retention time of the specific son-mother ion pairing are used as parameters to carry out accurate qualitative identification on metabolites, particularly isomers with similar structural properties, the targeting property of detection is improved, and the defect that the analysis qualitative is not accurate by a common method is overcome; meanwhile, the metabolite is quantitatively detected according to the abundance of the specific ion, so that the detection sensitivity is greatly improved, and in addition, the method does not need isotope tracing to analyze the metabolic trend of the same metabolic pathway, and has the advantages of simple operation and wide applicability.

Disclosure of Invention

The invention aims to establish a method for researching the metabolism trend of phenylpropanoids and application by detecting the content change of metabolites with synthetic relations in the phenylpropanoid metabolism pathway.

In order to achieve the purpose, the invention adopts the technical scheme that:

(1) the metabolites with synthetic relation in the phenylpropane metabolic pathway are characterized in that: comprises 18 phenylpropenoic acids and phenylpropanoic acids; the structural characteristics of the total 103 of 85 coumarins, flavanones, flavones, isoflavones, flavanonols, flavonols, flavanols, biflavones and the like comprise 62 isomers, hydroxyl or methoxyl substituent groups on benzene rings are used as longitudinal classification standards, the compound types formed by the framework connection characteristics are used as transverse classification standards, and a phenylpropane metabolite structural periodic table (shown in figure 2) is established.

(2) The qualitative and quantitative detection of the metabolites in the phenylpropane metabolic pathway is characterized in that: using a liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry coupled technique, the instrument is configured to: ultra-high performance liquid chromatography as a separation system; an electrospray ionization system is used as an ion source; a triple quadrupole mass spectrometer was used as the detector.

(3) The qualitative and quantitative detection of the metabolites such as 85 coumarins, flavanones, flavones, isoflavones, flavanonols, flavonols, flavanols, biflavonoids and the like is characterized in that: specific parameters for the use of the liquid chromatography separation system are as follows: the model of the chromatographic column isBEH C182.5 μm 3.0X 150mm XP; ② the mobile phase is methanol (A) containing 0.01 percent of formic acid and aqueous solution (B) containing 0.01 percent of formic acid; ② 1 gradient elution procedure 10% A (0min), 30% A (5min), 30% A (8min), 50% A (18min), 50% A (25min), 70% A (29min), 100% A (33min), 10% A (34min), 10% A (37min) stop; the flow rate is 0.4 ml/min; 2, the sample amount is 1-5 mu l; ② 3 the column temperature is 40 ℃. (II) the specific parameters of the electrospray ionization system are as follows: firstly, the nitrogen temperature (Gas Temp) is 350 ℃; 0 Gas Flow rate (Gas Flow) 10L/min; ③ 40psi of spraying air pressure (Nebulizer); capillary voltage (Capillary) + 4000V. (III) establishing detection parameters for each metabolite by using a multi-reaction detection mode (MRM) of a triple quadrupole mass spectrometry detection system as follows: (ii) Retention Time (Retention Time); (iii) Precursor Ion (Precursor Ion), Production Ion (Production Ion), ionization voltage (fragmentation), collision (V)Voltage (Collision Energy), Polarity (Polarity), and residence time (Dwell). The specific parameter values are shown in table 1 and fig. 3.

(4) The qualitative and quantitative detection of the metabolites such as 85 coumarins, flavanones, flavones, isoflavones, flavanonols, flavonols, flavanols, biflavonoids and the like is characterized in that: the specific parameters of the liquid chromatographic separation system are as follows: the model of the chromatographic column isBEH C182.5 μm 3.0X 150mm XP; ② the mobile phase is acetonitrile (A) and aqueous solution (B) containing 0.01 percent formic acid; ② 1 gradient elution procedure 10% A (0min), 30% A (5min), 30% A (8min), 50% A (18min), 50% A (25min), 70% A (29min), 100% A (30min), 10% A (32min), 10% A (35.5min) stop; the flow rate is 0.4 ml/min; 2, the sample amount is 1-5 mu l; ② 3 the column temperature is 40 ℃. (II) the specific parameters of the electrospray ionization system are as follows: firstly, the nitrogen temperature (Gas Temp) is 350 ℃; 0 Gas Flow rate (Gas Flow) 10L/min; ③ 45psi of spraying air pressure (Nebulizer); capillary voltage (Capillary) + 4000V. (III) establishing detection parameters for each metabolite by using a multi-reaction detection mode (MRM) of a triple quadrupole mass spectrometry detection system as follows: (ii) Retention Time (Retention Time); (ii) parent Ion (Precursor Ion), Ion (Production Ion), driving voltage (fragment), Collision voltage (Collision Energy), Polarity detection (Polarity) 4, and specific parameter values of Dwell time (Dwell) 5 are shown in table 2 and fig. 4.

(5) The qualitative and quantitative detection of the metabolites such as 18 phenylpropenoic acids, phenylpropanoic acids and the like is characterized in that: the specific parameters of the liquid chromatographic separation system are as follows: the model of the chromatographic column isBEH C182.5 μm 3.0X 150mm XP; ② the mobile phase is methanol (A) and aqueous solution (B) containing 5mM ammonium formate and 0.05% formic acid; ③ gradient elution procedure 5% A (0min), 5% A (1min), 30% A (5min), 30% A (6min), 100% A (9min), 100% A (12min), 5% A (12.5 min)) 5% A (15.5min) stopped; the flow rate is 0.4 ml/min; fourthly, the sample volume is 1 to 5 mul; column temperature 40 ℃. (II) the specific parameters of the electrospray ionization system are as follows: nitrogen temperature (Gas Temp)350 ℃; gas Flow rate (Gas Flow) 10L/min; spray air pressure (Nebulizer)40 psi; capillary voltage (Capillary) -4000V. (III) establishing detection parameters for each metabolite by using a multi-reaction detection mode (MRM) of a triple quadrupole mass spectrometry detection system as follows: (ii) Retention Time (Retention Time); specific parameter values of the Precursor Ion (Precursor Ion), the product Ion (Production Ion), the driving voltage (fragment), the Collision voltage (Collision Energy), the Polarity detection (Polarity), and the residence time (Dwell) are shown in Table 3 and FIG. 5.

The invention has the advantages that:

the phenylpropane metabolites with the same hydroxyl, methoxy and other substituents are likely to be derived from the same synthetic route, so that the content change is relevant. The invention utilizes the theoretical basis to specifically detect different metabolites with the same substituent, monitors the metabolic trend of the phenylpropanoid metabolic pathway under specific conditions by comparing content difference, and provides basis for metabolic analysis. Because the phenylpropane compounds have similar structures and more isomers, the currently common detection method has low qualitative reliability and weaker detection sensitivity. The invention uses liquid chromatogram-electrospray ionization-mass spectrum combined technology to carry out qualitative and quantitative detection on metabolites: the specific son-mother ion pairing and the retention time of the specific son-mother ion pairing are used as parameters to carry out accurate qualitative identification on metabolites, particularly isomers with similar structural properties, the targeting property of detection is improved, and the defect that the analysis qualitative is not accurate by a common method is overcome; meanwhile, the metabolite is quantitatively detected according to the abundance of the specific ion, so that the detection sensitivity is greatly improved, isotope tracing is not needed, the operation is simple, and the applicability is wide.

Description of the figures (tables)

FIG. 1 is a schematic diagram of the biosynthesis of phenylpropanoid and flavonoid metabolites in the cinnamic acid pathway

FIG. 2 is a diagram showing the structural period of phenylpropanoids to be analyzed

FIG. 3 shows the mass spectra of 85 metabolites in the technical scheme (3) under the condition of MRM positive ion mode detection in a mobile phase of methanol (0.01% formic acid)/water (0.01% formic acid). Wherein A represents 58 isomeric physique spectra, and B represents 27 non-isomeric physique spectra.

FIG. 4 shows the mass spectra of 85 metabolites in the technical scheme (4) under the condition of MRM positive ion mode detection in acetonitrile/water (0.01% formic acid) as the mobile phase. Wherein A represents 58 isomeric physique spectra, and B represents 27 non-isomeric physique spectra.

FIG. 5 shows the mass spectra of 18 metabolites in the technical scheme (5) under the detection condition of MRM anion mode by using methanol/water (5mM ammonium formate, 0.05% formic acid) as a mobile phase.

FIG. 6 is a chart showing the trend of the content of phenylpropane metabolic pathway in ginkgo leaf over one year.

FIG. 7 is a trend heat map of changes in phenylpropanoid metabolic pathways when soybean leaves are subjected to salt and drought stress.

Table 1 multiple reaction detection mode analysis of parameter values for 85 metabolites in technical scheme (3).

Table 2 multiple reaction detection mode analysis of parameter values for 85 metabolites in technical scheme (4).

Table 3 multiple reaction detection mode analysis of parameter values for 18 metabolites in technical scheme (5).

Detailed Description

The present invention will be described in further detail with reference to the drawings (tables) and examples.

The present invention is to analyze the metabolites described in claim 2 with the aim of improving the analysis accuracy, but since the research on natural products is continuously updated and new compounds having the characteristics described in the claims are continuously discovered, the present invention retains the right to continuously increase the new metabolites meeting the requirements. The methods used in the examples of the present invention are conventional methods unless otherwise specified.

Example 1 establishment of a LC-MS analysis method for phenylpropane metabolites:

1. according to the synthetic sequence of the phenylpropanoid metabolic pathways, determining the metabolite classes with the front-back correspondence to be analyzed: in order to determine the types of metabolites to be analyzed, a hydroxyl group or a methoxyl group substituted group on a benzene ring in the synthesis process is used as a longitudinal classification standard, the types of compounds formed by the connection characteristics of a skeleton are used as a transverse classification standard, a phenylpropane metabolite structure periodic table (figure 2) is established, and 103 metabolites are found for analysis.

2. According to the structural characteristics of the metabolites, their analytical parameters are determined using the multi-reaction detection mode of the liquid mass analysis method:

the invention uses Agilent 1290 Infinity as a liquid phase separation system, Agilent 6430A as a mass spectrum detector,BEH C182.5 μm 3.0X 150mm XP was used as a chromatographic column and the analytical parameters for each compound were determined using standards, the values of which are shown in tables 1, 2 and 3. 85 of the 103 metabolites were analyzed using positive ion detection mode (see technical schemes 3 and 4 for table 1 and 2, respectively, using different mobile phases and elution procedures), and 18 were analyzed using negative ion detection mode (see technical scheme 5 for table 3).

Example 2 analysis of the trend of the content change of the phenylpropane metabolic pathway in ginkgo leaves in one year:

1. preparation of analytical samples

(1) Taking 200mg of ginkgo leaves to be detected in different months (preserved at minus 80 ℃), and fully grinding the ginkgo leaves under the condition of liquid nitrogen; (2) adding 1ml of 80% methanol, and performing ultrasonic-assisted extraction at 45 deg.C for 15 min; (3) centrifuging at 12000g for 5min, and collecting supernatant; (4) adding 1ml of 80% methanol into the precipitate, and repeating the operation twice; (5) mixing the three extractive solutions, and concentrating and volatilizing the extractive solution with nitrogen blowing instrument or vacuum centrifuge until no obvious liquid exists; (6) adding 80% methanol to a constant volume of 1ml, and filtering with 0.22 μm organic filter membrane to remove impurities.

2. The sample is analyzed on the computer to obtain the analysis data

The sample is analyzed in two times: positive ion mode analysis of 85 metabolites; negative ion mode analysis 18 metabolites. (1) First, data on the content of 85 metabolites in the sample are obtained: firstly, preparing corresponding mobile phases according to the technical scheme (3) and setting detection parameters; preparing standard products with different concentrations and analyzing the same products; (2) next, data on the content of 18 metabolites in the sample were obtained: firstly, preparing a mobile phase according to a technical scheme (5) and setting detection parameters; preparing standard products with different concentrations and analyzing the same products together.

3. Sample data analysis

Data files for standards and samples were analyzed using MassHunter Workstation software: determining the sample mass spectrum peak according to the retention time and the sub-ion species of the standard substance; quantifying the metabolites detected by the sample according to the quantitative ion abundance of the standard; making a heat map of metabolite content changing in time sequence; assemble the different metabolite change heatmaps together according to the structure in fig. 2; the change rule of the phenylpropanoid metabolic pathway in the ginkgo leaf within one year is observed according to the transverse trend and the longitudinal trend (figure 6).

Example 3 analysis of the trend of changes in the phenylpropanoid metabolic pathways when soybean leaves are subjected to abiotic stress:

1. preparation of analytical samples

(1) Taking 200mg of soybean leaves to be detected after salt treatment and drought treatment, preserving at (-80 ℃) and fully grinding under the condition of liquid nitrogen; (2) adding 1ml of 80% methanol, and performing ultrasonic-assisted extraction at 45 deg.C for 15 min; (3) centrifuging at 12000g for 5min, and collecting supernatant; (4) adding 1ml of 80% methanol into the precipitate, and repeating the operation twice; (5) mixing the three extractive solutions, and concentrating and volatilizing the extractive solution with nitrogen blowing instrument or vacuum centrifuge until no obvious liquid exists; (6) adding 80% methanol to a constant volume of 1ml, and filtering with 0.22 μm organic filter membrane to remove impurities.

2. The sample is analyzed on the computer to obtain the analysis data

The sample is analyzed in two times: positive ion mode analysis of 85 metabolites; negative ion mode analysis 18 metabolites. (1) First, data on the content of 85 metabolites in the sample are obtained: firstly, preparing corresponding mobile phases according to the technical scheme (3) and setting detection parameters; preparing standard products with different concentrations and analyzing the same products; (2) next, data on the content of 18 metabolites in the sample were obtained: firstly, preparing a mobile phase according to a technical scheme (5) and setting detection parameters; preparing standard products with different concentrations and analyzing the same products together.

3. Sample data analysis

Data files for standards and samples were analyzed using MassHunter Workstation software: determining the sample mass spectrum peak according to the retention time and the sub-ion species of the standard substance; quantifying the metabolites detected by the sample according to the quantitative ion abundance of the standard; making a heat map of metabolite content according to different treatment changes; assemble the different metabolite change heatmaps together according to the structure in fig. 2; the change rule of the phenylpropanoid metabolic pathways in the soybean leaves after salt stress and drought stress is observed according to the transverse trend and the longitudinal trend (figure 7).

TABLE 1 values of the positive ion multiple reaction detection mode analysis parameters for 85 metabolites in scheme (3)

TABLE 2 values of the positive ion multiple reaction detection mode analysis parameters for 85 metabolites in scheme (4)

TABLE 3 analysis of the values of the parameters for the anion multiple reaction detection mode of the 18 metabolites in solution (5)