| Currently,with the progress of society and the improvement of living standards,people have started to prioritize health and enhancing their quality of life.There is a growing trend towards "returning to nature" and "green consumption," shifting the focus from mere disease treatment to prevention.In this overarching context,active and functional herbal extracts have gained significant popularity..In this paper,we selected two typical Chinese herbal medicines with homology of medicine and food,dandelion and Ganoderma lucidum.Flavonoids are one of the main activities of dandelion,which are closely related to the pharmacological effects of dandelion.For example,dandelion has anti-cancer,anti-tumor,anti-aging,liver-protecting,cholagogic,anti-stomach injury and bacteriostasis,all of which are directly or indirectly related to the activities of flavonoids.Ganoderma triterpenes is one of the main active components of Ganoderma lucidum,and it is an important index to measure the quality of Ganoderma lucidum.The content of triterpenes is the key work to study Ganoderma lucidum.At present,the quantitative detection of triterpenes in Ganoderma lucidum mainly includes colorimetry and high performance liquid chromatography,which is not only time-consuming and labor-intensive,but also difficult to quantify the total terpenes content,and requires high equipment conditions.Therefore,the accurate and rapid quantification of total terpenoids in Ganoderma lucidum is still a problem to be solved.Infrared spectroscopy is a powerful tool used for the analysis of active substances.The fundamental vibrations of molecules lead to infrared absorption,while the near-infrared region reflects the overtones and combination frequencies of hydrogen groups,such as O-H,N-H,C-H,and S-H.Mid-infrared spectroscopy offers the advantages of simplicity,speed,sensitivity,high resolution in sample preparation,and enables simultaneous multi-component analysis,making it commonly employed for qualitative analysis of substances.By utilizing techniques like 2D correlation spectroscopy,we can identify the characteristic spectral regions of flavonoids and triterpenes,facilitating their qualitative and quantitative analysis.This underscores the pressing need and significant importance of employing infrared spectroscopy for the analysis of active substances.The main results of this paper are as follows:1.Flavonoids from dandelion were extracted by Box-Behnken design response surface optimization experiment based on single factor.The extraction time was 50 min,the ratio of liquid to material was 52.56:1(mL/g),and the extraction temperature was 70℃,UPLC-MSMS and NMR were used to identify the purified flavonoids from dandelion.The results showed that seven flavonoids were purified from dandelion,and the content of hesperidin-7-neohesperidin was obtained from dandelion for the first time,and the relative content was relatively high.The antioxidant activities of flavonoids were evaluated by DPPH free radical scavenging assay.The IC50 values of seven flavonoids were quercetin(8.07±0.67 mg/L)<hesperidin-7-neohesperidin(8.72 ±0.88 mg/L)<kaempfer-3-glucoside(13.49±1.02 mg/L)<baicalein(15.5±0.98 mg/L)<hesperidin-7-glucoside(22.11 ± 0.76 mg/L)<Hyperoside(31.39 ± 0.65 mg/L)<rutin(31.54±0.79 mg/L).In addition,the antioxidant activities of flavonoids were compared by density functional theory,and the calculated results were in good agreement with the experimental results,which indicated that the frontier molecular orbital energy level difference could be used as a reliable theoretical parameter to predict the free radical scavenging activity of flavonoids in the same type of molecules.2.Specific spectral intervals of flavonoids were selected by 2D correlation of infrared spectra(near infrared combined with mid infrared),which were concentrated in three regions(4200～5200 cm-1,5800～6200 cm-1,6400～7000 cm-1).Near infrared spectroscopy combined with chemometrics was used to quantify the content of hesperidin-7-neohesperidin,and the prediction ability of the model based on full spectrum and characteristic spectrum was compared.The results showed that the prediction ability of the model increased by 3.2%under the selected spectrum conditions.After that,the generalization ability of the model is further verified,and the prediction performance is R2C=0.9965,RMSEC=0.0015.Therefore,it can be concluded that the quantitative model based on characteristic spectrum can effectively improve the performance of iPLS model based on full spectrum.In addition,we studied the application of NIRS in recognition of dandelion origin,and established four pattern recognition models,namely LDA,KNN,RF and SVM.Compared with LDA,SVM and RF,the recognition accuracy of KNN increased by 57.32%,11.97%and 14.39%respectively.The overall results show that NIR spectroscopy has great potential in rapid evaluation of dandelion quality.3.Twelve triterpenes of Ganoderma lucidum were purified from Ganoderma lucidum,Coriolus versicolor and Ganoderma lucidum,which were Ganoderic Acid I,Ganoderic Acid A,Oleanolic acid,Ganoderic Acid B,Ganoderenic acid C,Ganoderic Acid C2,Ganoderma lucidum alcohol B,Ganoderic Acid LM2,Ganoderic Acid C6,Ganoderic Acid G,Ganoderic Acid D and Ganoderenic acid D.Among them,Ganoderic Acid G/B/C6/C2/I has a common parent structure 1;Ganoderic Acid A/D/LM2 has a common parent structure 2;The difference between the two parent structures is mainly caused by the substituent hydroxyl and carboxyl groups at the third position of the ring.Structural information Except oleanolic acid is pentacyclic triterpenes,the other 11 species are tetracyclic triterpenes.The characteristic recognition region of triterpenoids in Ganoderma lucidum was determined by mid-infrared spectra combined with DFT theory.The results showed that the infrared spectra of triterpenoids were mainly in two regions:A(1692～1355 cm-1)and B(1330～1245 cm-1),and tetracyclic triterpenoids had an absorption band in A and B regions respectively.4.The correlation between the selected band and the structure of Ganoderma lucidum triterpenoids was verified by mid-infrared-near-infrared correlation analysis,and the characteristic spectra of these two segments(6102～5446.3 cm-1)and(5280～4212.8 cm-1)were modeled and predicted.The quantitative correction model of Ganoderma lucidum triterpenoids was established by different methods,which was based on most of Ganoderma lucidum Under the assumption that the near-infrared spectrum of senoic acid is similar to that of ganoderic acid A,the total triterpenoids of ganoderma lucidum were simulated by ganoderma lucidum acid A and compared with conventional Ganoderma lucidum total triterpenoid quantitative model for validation.The results showed,Spirit The prediction value of total triterpene content by the quantitative model of semolic acid A was 73%～158%,and the average value was 110%,the predicted value is greater than the average true value;Routinely modeled triterpene quantification models for multiple alcohol extraction samples contained The predicted result of the quantity shows R2cal of 89.60%,RMSEc of 0.7,and R2pre of 87.64%.The RMSEP is 0.5656,which fully indicates that a quantitative model of ganoderic acid A can advance the total triterpenoids in the reishinol extract Rough quantification provides a new focus for rapid quantification of Ganoderma lucidum total terpenes by near-infrared spectroscopy.To sum up,this paper focuses on the research of active components in Chinese herbal medicine:from extraction,purification,structure identification and qualitative and quantitative development of infrared spectroscopy,combining infrared spectroscopy with chromatography,spectroscopy and other technologies,organically combining traditional Chinese medicine,mathematics and analytical chemistry,realizing modern analytical means with complementary advantages,and promoting the development and application of infrared spectroscopy in the utilization of Chinese herbal medicine. |
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