Caffeoylquinic Acids: Separation Method, Antiradical Properties and Cytotoxicity.

Twelve chlorogenic acid derivatives and two flavones were isolated from Moquiniastrum floribundum (Asteraceae, other name: Gochnatia floribunda). Compounds were evaluated in relation to their cytotoxicity and antiradical properties. Cytotoxicity was not observed for compounds, however, chlorogenic acid derivatives showed antiradical activity and were more active than the Trolox standard. Quinic acid esterified with caffeoyl group at C-4 position showed higher antiradical activity compared to acylation at C-3 or C-5 positions. Additional caffeoyl groups esterified in quinic acid increase the antiradical activity observed for 4-caffeoylquinic acid. Excepted to 3,4-dicaffeoylquinic acid methyl ester, methyl ester derivatives show higher capacity of trapping radicals than their respective acids. Consequently, the presence of caffeoyl group at C-4 position of quinic acid is suggested as fundamental to obtain the highest antiradical activity.