Ethnopharmacological study of medicinal plants and their possible drug interactions in two cities of the South of Brazil / Estudo etnofarmacológico de plantas medicinais e suas possíveis interações medicamentosas em duas cidades do Sul do Brasil

Medicinal plants have been used by the population for several years for treatment and prevention of diseases. Folk knowledge of plants can serve as information on efficacy and toxicity of these vegetables. Many people think that because they are natural, plants are free of side effects and interactions with the medicines that they used. The present study had as objective to conduct an ethnopharmacological survey of medicinal plants in the Brazilian cities of Manoel Viana, RS, and São Francisco de Assis, RS, and to evaluate their possible drug interactions. The present work was carried out through interviews, where individuals were questioned about the use of plants and of medicines. Of the 205 participants interviewed, most were women (79%), approximately 98% used medicinal plants, and approximately 82% reported the presence of chronic diseases in their communities and the use of pharmaceuticals to treat them. The medicinal plants cited most often were Achyrocline satureioides, Peumus boldus Molina, Chamomilla recutita, Cymbopogon citratus (DC), and Melissa officinalis L, while the most frequent chronic diseases mentioned were arterial hypertension, depression, dyslipidemia, and diabetes mellitus. The drugs cited most often were hydrochlorothiazide, losartan, simvastatin, and metformin, and the results of the study revealed numerous plant–drug interactions. Results of the study indicate a profile of the use of medicinal plants and synthetic drugs used by the population of Manoel Viana, RS, and São Francisco de Assis, RS, Brazil.