Quantification and antioxidant and anti-HCV activities of the constituents from the inflorescences of Scabiosa comosa and S. tschilliensis

To investigate the bioactive constituents of the inflorescences of Scabiosa comosa and S. tschilliensis, which are used traditionally for liver diseases, we tested the antioxidant activity using 2,2'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), ferric reducing antioxidant potential (FRAP), and DPPH-ultra high performance liquid chromatography-mass spectrometer (UPLC-MS) assay. In addition, cell-based anti-HCV activity of the major compounds were evaluated. The plant extracts showed strong antioxidant activity. For the first time, 3,4-dicaffeoylquinic acid (DCQA), 3,5-DCQA and 4,5-DCQA were identified from genus Scabiosa. A UPLC-MS method in multiple reaction monitoring (MRM) mode was established to quantify 18 constituents in the inflorescences of Scabiosa. The 3,5-DCQA, chlorogenic acid and some glycosides of luteolin or apigenin were found to be the most abundant constituents. Chlorogenic acid and 3,5-DCQA showed excellent radical scavenging activity and demonstrated anti-HCV activity. These findings provided scientific evidences for the clinic use of this herbal medicine for liver diseases.