Phenolic acid derivatives from Ligusticum chuanxiong

Four new phenolic acid derivatives, namely, 2,3-bis(4-hydroxy-3-methoxyphenyl)cyclopent-2-enone (1), 4,5-di-O-caffeoyldaucic acid methyl ester (2), (+)-ligusticumtone (3a), and (‒)-ligusticumtone (3b), and two known compounds were isolated from the rhizome of Ligusticum chuanxiong Hort. Among of them, compound 1 is an unusual norlignan. Additionally, compounds 3a and 3b are enantiomers that were obtained by chiral separation. Their structures were established using UV, IR, HRESIMS, NMR analysis. The absolute configurations of 3a and 3b were determined via quantum ECD calculations. All the isolates were evaluated for their hepatoprotective activity against N-acetyl-p-aminophenol-induced HepG2 cell injury. Compound 1 showed moderate hepatoprotective activity at a concentration of 10 μM (p