Free radical Scavengers and Antioxidants from Baccharis grisebachii.

ALEJANDRO TAPIA; JAIME RODRIGUEZ; CRISTINA THEODULOZ; SUSANA LOPEZ; GABRIELA EGLY FERESIN; GUILLERMO SCHMEDA-HIRSCHMANN.

JOURNAL OF ETHNOPHARMACOLOGY

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2004 vol. 95 p. 155 - 161

0378-8741

The exudate and seriated extracts from the aerial parts of Baccharis grisebachii (Asteraceae) which is recommended as a digestive and to relieve gastric ulcers in Argentina, showed activity as free radical scavengers and inhibited lipoperoxidation in erythrocytes. Assay guided isolation led to seven p-coumaric acid derivatives and six flavonoids as the main active constituents of the crude drug. The activity towards the superoxide anion was mainly due to the flavonoid constituents. 5,7,4-Trihydroxy-6-methoxyflavone and quercetin presented high activity (64 and 79%) even at 12.5 g/ml. The xanthine oxidase inhibitory effect of the extracts can be related with the p-coumaric acid derivatives drupanin, 4-acetyl-3,5-diprenylcinnamic acid and trans-ferulic acid O-hexan-3-onyl-ether which showed IC50 values in therange 28?40 g/ml. Both p-coumaric acid derivatives and flavonoids inhibited lipoperoxidation in erythrocytes. The highest activity was found for the p-coumaric acid derivatives 4-acetyl-3-prenyl-ethoxycinnamate, 3-prenyl-4-(4-hydroxydihydrocinnamoyloxy)-cinnamate and trans-ferulic acid O-hexan-3-onyl-ether (69?82%) and the flavonoids 5,7,4-trihydroxy-6-methoxyflavone, quercetin, 5,7,4-trihydroxy-6,3-dimethoxyflavone and 5,7,4-trihydroxy-6,8-dimethoxyflavone (64?84%) at 100 g/ml. The most active free radical scavengers measured by the DPPH decoloration assay were the p-coumaric acid derivatives drupanin and trans-ferulic acid O-hexan-3-onyl-ether (27?35% at 10 g/ml) and the flavonoid quercetin (97 and 23% at 10 and 1 g/ml, respectively). The results support the use of Baccharis grisebachii in Argentinian traditional medicine