During a large-scale isolation of the cancer chemopreventive mammalian lignan precursor secoisolariciresinol diglucoside (SDG, 6) from the defatted meal of flaxseed (Linum usitatissimum L.), a new flavonoid, herbacetin 3,8-O-diglucopynanoside (1) was obtained along with two known flavonoids, herbacetin 3,7-O-dimethyl ether (3) and kaempferol 3,7-O-diglucopyranoside (4), and the known lignan (-)-pinoresinol diglucoside (5). The structure of herbacetin 3,8-O-β-D-diglucopynanoside (1) was determined by a combination of NMR techniques. Further the absolute configuration of the stereogenic center of secoisolari-ciresinol diglucoside (SDG, 6) was assigned by spectroscopic methods. Herbacetin 3,7-O-dimethyl ether (3) and herbacetin (2), the aglycone of 1, were shown to mediate antioxidant activity which may contribute to the chemopreventive activity of flaxseed.
structure elucidation, Antioxidant activity, NMR assignments, lignan glucosides, flaxseed, Linum usitatissimum L., flavonoid glucosides, cancer chemoprevention
Publication DOI: 10.1076/phbi.37.1.1.6320Journal NLM ID: 9812552Publisher: Lisse, the Netherlands: Swets & Zeitlinger
Institutions: Program for Collaborative Research in the Pharmaceutical Sciences, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA, Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada
Methods: 13C NMR, 1H NMR, EI-MS, IR, FAB-MS, TLC, MS, UV, optical rotation measurement, DEPT, antioxidant activity assay, HCl hydrolysis, sulfuric acid hydrolysis
Found