Antioxidant activity of coumarins and flavonols from the resinous exudate of Haplopappus multifolius.
The antioxidant activity of eight coumarins and two flavonols isolated from Haplopappus multifolius was studied with the DPPH radical method. Results show that a high concentration of phenolic coumarins and the presence of quercetin and rhamnetin in the exudates could account for the protection of the plant against oxidative stress. Structures for the coumarins 6-hydroxy-7-[(E,E)-3',7'-dimethyl-2',4',7'-octatrienyloxy] coumarin and 7-[(E)-3'-methyl-4'-hydroxy-2'-butenyloxy] coumarin are proposed on the basis of spectroscopic evidence.
Torres
René
R
Departamento de Ciencias del Ambiente, Fascultad de Química y Biología, Universidad de Santiago de Chile, Avda. Bernardo O'Higgins 3363, Santiago, Chile. rtorres@lauca.usach.cl
Faini
Francesca
F
Modak
Brenda
B
Urbina
Francisco
F
Labbé
Cecilia
C
Guerrero
Juan
J