Guided isolation of enantiomeric lignans from Cimicifuga heracleifolia Kom. by antioxidant activity and molecular networking

Under the guidance of antioxidant evaluation combined with molecular networking, six pairs of enantiomeric lignans including seven undescribed ones (1a, 2a/2b-4a/4b), along with five known analogs (1b, 5a/5b-6a/6b) were isolated from Cimicifuga heracleifolia Kom. Their structures were determined by extensive spectroscopic data analysis, including HRESIMS, 1D and 2D NMR, experimental and calculated ECD. All the enantiomeric isolates were evaluated for antioxidation by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging tests. Compounds 1a and 3a/3b exhibited great DPPH and ABTS scavenging activities. The results are of great value for understanding structurally interesting enantiomeric lignans with antioxidant activity from C. heracleifolia in depth and providing its further development in functional evaluation and drug development.