title: Antioxidant activities of coumarins from Korean medicinal plants and their structure-activity relationships.
abstract: The aim of this work was to study the structure-activity relationships of the antioxidant activity of natural coumarins isolated from four Korean medicinal plants (1-17) and four purchased coumarins (18-21). The free radical scavenging and lipid peroxidation assays revealed that five phenolic coumarins, scopoletin (1), aesculetin (2), fraxetin (3), umbelliferone (18) and daphnetin (19), possessed considerable antioxidant activities. The coumarins having a catechol group, 2, 3 and 19, showed significant free radical scavenging activity and inhibitory effects on lipid peroxidation, indicating that the catechol group significantly contributed to the antioxidant activities of coumarins. In contrast, the sugar moiety markedly reduced the activities of coumarin glycosides. The results also demonstrate that the alpha-pyrone ring of coumarins significantly enhanced the capacity of inhibiting oxidative reactions of coumarins.
authors.affiliation: College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Phuong Thien
authors.initials: PT
authors.lastname: Thuong
authors.forename: Tran Manh
authors.initials: TM
authors.lastname: Hung
authors.forename: Tran Minh
authors.initials: TM
authors.lastname: Ngoc
authors.forename: Do Thi
authors.initials: do T
authors.lastname: Ha
authors.forename: Byung Sun
authors.initials: BS
authors.lastname: Min
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Kwack
authors.forename: Tae Suk
authors.initials: TS
authors.lastname: Kang
authors.forename: Jae Sue
authors.initials: JS
authors.lastname: Choi
authors.forename: KiHwan
authors.initials: K
authors.lastname: Bae
mesh_terms: D000818:Animals; D003374:Coumarins / Q000302:isolation & purification / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000302:isolation & purification / Q000494:pharmacology*; D015227:Lipid Peroxidation; D055670:Medicine, Korean Traditional; D008930:Mitochondria, Liver / Q000187:drug effects; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D013329:Structure-Activity Relationship
chemical_list: D003374:Coumarins; D016166:Free Radical Scavengers