Radical scavenging activity and cytotoxicity of active quinic acid derivatives from Scorzonera divaricata roots

Abstract Five new quinic acid derivatives and two known 3- O -feruloylquinic acids were isolated from the roots of Scorzonera divaricata Turcz. The new compounds were elucidated as (–)–1,4-di- O -feruloyl-3- O -dihydrocaffeoylquinic acid, (–)–1- O -feruloyl-4- O - dihydrocaffeoylquinic acid, (–)–3,5-di- O -feruloylquinic acid, (–)–1- O -feruloyl-3- O -dihydro- caffeoylquinic acid, and (–)–1- O -feruloyl-5- O -dihydrocaffeoylquinic acid based on extensive spectroscopic studies, including one- and two-dimensional NMR, HRESIMS, UV, and IR results. Five compounds were assessed for antioxidant activity by ABTS and DPPH radical-scavenging assays and for their cytotoxicity against HL-60 and Hep-G2 cell lines by the MTT assay. Three quinic acid derivatives exhibited strong antioxidant activity, with IC 50 values of 3.95, 5.87, and 7.45 μg/mL against ABTS + and 11.7, 13.6, and 50.1 μg/mL against DPPH . (–)–1,4-Di- O -feruloyl-3- O -dihydrocaffeoylquinic acid also exhibited moderate activity against Hep-G2 cell lines with an IC 50 value of 14.6 μg/mL.