Rapid Screening of Antioxidant Active Constituents from Puerariae Lobatae Radix Based on the Investigation of Quantitative Patteren-Activity Relationship

Screening bioactive constituents from herbal medicines or traditional Chinese medicines according to traditional phytochemical approach is time-consuming and laborious. The objective of the present study is to provide a strategy for rapid screening of active candidates from plant extract based on the Quantitative Patteren-Activity Relationship. The chromatographic fingerprint (Patteren) data sets were obtained by our previous proposed method and the antioxidant activity was measured by Ferric Reduction Ability Power assay. The correlation model was built by partial least squares and bioactive components were screened out by target projection. Variable selection and model evaluation were performed by 4-fold cross validation. The optimal model required 5 PLS components. The calibration and prediction multiple correlation coefficients were 0.990 and 0.975, respectively. And the calibration and prediction errors were 23.2 and 36.4, respectively. The projection result showed that the antioxidant activity was highly correlated to some variables/peaks, indicating that they are main antioxidants. 3'-Hydroxypuerarin, puerarin, 3'-methoxypuerarin and 6 ''-O-(D)-xylosylpuerarin were identified to be four main antioxidants by comparing their TOF MS patterns and retention times. Moreover, the model was found to predict accurately the antioxidant capacity of the Radix puerariae samples through their chromatographic fingerprint only. The results obtained in this work show clearly how simple and effective our proposed method is in bioactive constituent screening as well as drug lead compound discovery from herbal medicines.