Caffeoylquinic acid derivatives from the roots of Arctium lappa L. (burdock) and their structure-activity relationships (SARs) of free radical scavenging activities - Jiang, X W; Bai, J P; Zhang, Q; Hu, X L; Tian, X; Zhu, J; Liu, J; Meng, W H; Zhao, Q C (Phytochem Lett, 2016)