Anti-trypanosomal activity of flavones and chlorogenic acids from Moquiniastrum floribundum (Asteraceae)

Asteraceae is one the largest families of Eudicots comprising several species used for economic and medicinal purposes, and characterized by the production of various bioactive metabolites¹. Among the 1700 genera of the family, Moquiniastrum (Cabrera) G. Sancho is restricted to South America and comprises 21 species, 12 of them endemic to Brazil¹. The aim of this work is to report the phytochemical study of polar phases from Moquiniastrum floribundum and the phytotoxic activities of their isolated compounds. Aerial parts (421.7 g) of M. floribundum were extracted with hexane and subsequently with methanol. Methanol extract was partitioned successively with hexane, dichloromethane, ethyl acetate and butanol. The partition phases were subjected to silica gel and preparative HPLC, respectively, furnishing the compounds 1 – 8. The structures were elucidated by ¹H and ¹³C NMR, gHMBC and comparison with literature data. Thus, the compounds were identified as three flavones: genkwanin (1), hispidulin (2) and cirsimaritin (3), and five chlorogenic acid derivatives: 4,5-(4), 3,5-(5) and 3,4-(6) dicaffeoylquinic acids, and 3,5-dicaffeoylquinic acid methyl ester (7) and 3,4,5-tricaffeoylquinic acid methyl ester (8). The anti-trypanosomal activity of compounds was tested against trypomastigotes of Trypanosoma cruzi. Compound 1 and 8 showed significant activity exhibiting 50% inhibitory concentration (IC₅₀) values of 72.6µM and 40.6µM, respectively. Additionally, the compounds were evaluated for cytotoxicity against NCTC cells and they did not display cytotoxicity (CC₅₀ superior to 200µM).

Fig. 1: Steroidal alkaloids and steroidal non-alkaloid isolated from the leaves (1 – 6) and stem bark (7 – 18) of Holarrhena africana

[1] Sancho G, Funk VA, Roque N. Phytotaxa 2013; 147: 26 – 34