Chemical Pattern Recognition and Antioxidant Spectrum-Effect Relationship Development of Coreopsis Tinctoria from Different Origins and Harvesting Periods Based on High Performance Liquid Chromatography Fingerprint

Ten batches of samples of Coreopsis tinctoria from different origins and harvesting periods were dried and crushed, and an aliquot (0.2 g) was taken, extracted with 50 mL of 60% (volume fraction) methanol solution for 30 min by ultrasound, and passed through a 0.45 μm filter membrane. The solution (mass concentration of 4 000 mg·L^-1) obtained was introduced into high performance liquid chromatograph. Separation was performed on an Agilent HC-C₁₈ column by gradient elution with mixed solutions composed of 0.4% (volume fraction) acetic acid solution and acetonitrile at different volume ratios, and targets were detected at 285 nm. The fingerprints were established by the chromatographic fingerprint similarity evaluation system of traditional Chinese medicine, and the common components were screened and used for similarity evaluation. Chlorogenic acid was investigated methodologically, and the content of each common component was calculated using chlorogenic acid as reference. The samples from different origins and harvesting periods were classified by chemical pattern recognition methods such as cluster analysis and principal component analysis. The antioxidant activities of the 10 batches of samples were determined by 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and 2,2-benzo-bis(3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging methods, and the spectrum-effect relationships between the peak area data of common components and the antioxidant activity were established by gray correlation analysis. It was shown that the similarity between fingerprints of the 10 batches of samples and them together with control fingerprint was greater than 0.900, and 24 common components were found. Two chemical pattern recognition methods classified the samples into 4 categories, and it was assumed that the classification results were related to the origin and harvesting period. The 5 components with the correlation degree greater than 0.800 were obtained from each of the 2 free radical scavenging methods, which could be used as the pharmacodynamic control points of Coreopsis tinctoria.