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 ±8,2 to 763,63 ± 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 ± 0.82 µg/mL, was comparable to rutin (EC50 = 27.80 ± 1.38) and gallic acid (EC50 = 24.27 ± 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

This investigation evaluated the role of capsaicin-sensitive afferent neurons in the gastroprotective effect of α- and β-amyrin, a triterpenoid mixture isolated from Protium heptaphyllum resin. Gastric mucosal damage was induced in mice by intragastric ethanol and assessed by planimetry. Mice pretreated orally with the amyrin mixture (50 and 100 mg/kg) or capsaicin (2.5 and 5 mg/kg), the pungent principle from red hot peppers, showed a significantly lower intensity of ethanol-associated gastric mucosal damage, in relation to vehicle-treated controls. At higher doses both these agents produced either a diminished protection or no significant effect. The maximal gastroprotection that was observed at the dose of 100 mg/kg amyrin mixture was almost abolished in mice with their sensory afferents chemically ablated by a neurotoxic dose of capsaicin, suggesting that the gastroprotective mechanism of α- and β-amyrin mixture involves at least in part the activation of capsaicin-sensitive primary afferent neurons.