Determination of 16 Phenolic Compounds in Prunella vulgaris and Analysis Their Correlation with Antioxidant Activity

Objective: To determine the content of 16 phenolic compounds in 24 batches of Prunella vulgaris by liquid chromatography- tandem mass spectrometry (LC-MS/MS) and to investigate the correlation between phenolic compounds and antioxidant activity by grey relational analysis (GRA) and partial least squares regression (PLSR) analysis. Methods: The sample was extracted with 80% methanol by the ultrasonic extraction. A method for the determination of 16 phenolic compounds in Prunella vulgaris was established by LC-MS/MS. The Waters ACQUITY UPLC BEH C18 column (2.1 mm×100 mm, 1.7 μm) was selected as the stationary phase. The gradient elution was performed with the mobile phase of 0.1% formic acid-acetonitrile at the flow rate of 0.4 mL/min. The eluted compounds were detected in the negative ion mode with multiple reaction monitoring technology. The antioxidant activities were evaluated by DPPH free radical scavenging capacity, ABTS free radical scavenging capacity and ferric reducing antioxidant power. Results: Ther