Selective fractionation of supercritical extracts from leaves of Baccharis dracunculifolia

Baccharis dracunculifolia is a plant native to Brazil, rich in phenolic compounds such as 3,5-dipreny1-4hydroxycinnamic acid (artepillin C), a derivative of cinnamic acid, and 4-methoxy-3,5,7-trihydroxyflavone (kaempferide), a flavonoid. This study evaluated the performance of supercritical carbon dioxide (scCO(2)) as solvent for selective fractionation by precipitation from a supercritical extract of B. dracunculifolia using scCO(2) pressure reduction in a sequence of separators to obtain different extract fractions in relation to its composition. The extracts and fractions were analyzed in terms of overall yield, antioxidant activity and concentration of protocatechuic acid, caffeic acid, sinapic acid, chrysin, p-coumaric acid, kaempferide and artepillin C. High concentrations were observed of the two major compounds (kaempferide and artepillin C) in the extract fractions of the first two separators. However, the aqueous extract obtained in the third step presented better antioxidant activity when compared the other fractions. Also obtained was a volatile fraction composed mainly of sesquiterpenes.