Abstract

This study aimed to investigate the phenolic content and antioxidant capacity of four species ofCnidoscolus (C. infestus Pax & K. Hoffm., C. pubescens Pohl, C. quercifolius Pohl and C. urens [L.] Arthur) used as ethnopharmacologicals in the Caatinga. The total phenolic content (TPC), total tannin content (TTC) and total flavonoid content (TFC) were analyzed by spectrophotometric method. The antioxidant activity (AOA) was measured using the qualitativeantioxidant assay (QAA), the free-radical scavenging assay (DPPH assay) and the ferrous-ion chelating (FIC) assay. The extract of the leaves of C. pubescens had the highest levels of TPC, TFC and TTC. Extracts from the roots of C. infestus showed the highest antioxidant activity, while extracts from the roots of C. pubescens showed the highest level of chelating activity. The AOA was correlated with TPC, TFC and TTC, but these were not statistical. The parties cited by the population had on average high levels of TPC, TTC, TFC and AOA, while the parties non-cited had high levels of FIC. The results show that the antioxidant activity of plants of the genus Cnidoscolus, specifically of the Caatinga, appears to be associated with levels of phenolic compounds and these may explain its popular use.

Key words: 2,2-diphenyl 1-2-picryl-hydrazyl (DPPH), FIC, flavonoids, Folin-Ciocalteu, polyphenols, tannins.