Antioxidant activities of coumarins from Korean medicinal plants and their structure-activity relationships.
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.
Thuong
Phuong Thien
PT
College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
Hung
Tran Manh
TM
Ngoc
Tran Minh
TM
Ha
Do Thi
do T
Min
Byung Sun
BS
Kwack
Seung Jun
SJ
Kang
Tae Suk
TS
Choi
Jae Sue
JS
Bae
KiHwan
K
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
D003374:Coumarins; D016166:Free Radical Scavengers