Fenóis totais e atividade antioxidante de cinco plantas medicinais

<abstract language="eng">This paper describes total phenolics content and antioxidant activity in the ethanolic extract of leaves, bark and roots of five medicinal plants: Terminalia brasiliensis Camb., Terminalia fagifolia Mart. & Zucc., Copernicia cerifera (Miller) H.E. Moore, Cenostigma macrophyllum Tul. var. acuminata Teles Freire and Qualea grandiflora Mart. The total phenolics content of the plant extracts, determined by the Folin-Ciocalteu method, varied from 250.0 &plusmn;8,2 to 763,63 &plusmn; 13.03 mg of gallic acid equivalent/g dry EtOH extract. The antioxidant activity of extracts was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay system. Extract of bark from T. brasiliensis, the most active, with an EC50 value of 27.59 &plusmn; 0.82 µg/mL, was comparable to rutin (EC50 = 27.80 &plusmn; 1.38) and gallic acid (EC50 = 24.27 &plusmn; 0.31), used as positive controls. The relationship between total phenolic content and antioxidant activity was positive and significant for T. brasiliensis, C. macrophyllum and C. cerifera.