Medicinal plants used in Rondônia, Western Amazon, Brazil

This study refers to the use of medicinal plants by populations in the Western Amazon and provides information that can be used in phytochemical studies. It draws upon the traditional knowledge regarding the use of medicinal plants in five regions of the state of Rondônia, in the Brazilian Amazon, focusing on native species. The field research was carried out in five municipalities of the state of Rondônia: Ariquemes, Buritis, Candeias do Jamari, Cujubim and Itapoa do Oeste, characterized by primary economic sectors: agriculture, cattle farming, plant extraction and mineral exploration. Structured interviews were applied to 227 persons chosen because of their prestige in the communities in relation to the knowledge and use of medicinal plants, identifying the therapeutic purpose, parts of the plant used and methods of preparation. The species were taxonomically identified. The ethnobotanic knowledge (inferred by the number of uses of medicinal plants per person) was correlated with the Brazilian region of origin, age, and gender of the interviewees. According to the collected data, 34 botanical families and 53 native species were identified. Of the 53 species, only 7 occur exclusively in the Amazon Forest: Theobroma grandiflorum (Willd. ex Spreng.) K. Schum., Psidium densicomum Mart. ex DC, Piper cavalcantei Yunck., Pilocarpus microphyllus Stapf ex Wardlew., Euterpe oleracea Mart., Croton cajucara Benth., Baccharis altimontana G. Heiden. The most common disorders treated with the plants were kidney problems, influenza, generalized infections and inflammations, malaria and high blood pressure. Leaves were the most used parts in preparations. Barks, fruits, roots, flowers, stems, seeds, oils, buds, tubercles, and rhizomes were also mentioned. Thirteen forms of preparations were recorded, and infusion and decoction were the most used. Syrups, juices, flour, sap, oil and parts of the plant blended with milk, honey and coffee or flamed, macerated and in the form of poultice, were also found. Persons from the Southeast region had more information compared with persons from the other regions; persons in the age groups between 50-59, 60-69 and 70-79 had more information in comparison with the other age groups; and the female interviewees mentioned significantly more uses of medicinal plants than the male ones. The relatively small number of native Amazon species identified can be the result of the loss of knowledge about medicinal plants in the Amazon because of i