ETNOFARMACOLOGIA DAS PLANTAS MEDICINAIS DE CÉU AZUL E COMPOSIÇÃO QUÍMICA DO ÓLEO ESSENCIAL DE Plectranthus neochilus Schltr.

Abstract

The aim of the present work was to carry out an ethnopharmacological survey of the vegetal species used by the inhabitants of the municipality of Céu Azul (located in the extreme west of the State of Paraná, Brazil). A specific questionnaire was used to get the referring data to the uses and ways of preparation of the species used as medicinal. During the interviews, the plant material (exsiccate) was collected in duplicate with the aid of the informers for posterior identification and deposit in the Museu Botânico Municipal de Curitiba. The uses of 47 species pertaining to 12 botanical families were surveyed in this field research. One of the main objectives of the present work was to evaluate the possible use of forest medicinal species in Céu Azul, especially because an extensive area of the municipality belongs to the National Park of the Iguaçu. However, th 47 plants cited by the population can be divided in a group with 42 exotic species and another one with only 6 Brazilian plants, and none of which is being removed from the reserve. The data base of The International Plant Names Index was used to prevent inappropriate botanical names and to verify the current use of synonyms. A survey of the scientific information on the chemical composition and bioactivity was carried out for each cited species. The main source of scientific information for this work was the data base of the Institute of Scientific Information and the Chemical Abstracts on-line. In general, the Céu Azul population makes use of medicinal plants sufficiently known in the scientific sense, but there is also the use of little studied species. For four of the cited species (Alternanthera bettzickiana, Alternanthera dentata, Plectranthus neochilus, Tradescantia pallida), we could not find any scientific reference on its bioactivity. The results of this survey have been concomitantly interpreted as indicative for the election of one of these species, sufficiently known for the Céu Azul population, for deepening of study in the chemistry area. The chemical composition of the essential oil of Plectranthus neochilus was determined using gas chromatography techniques coupled to mass spectrometry. The main components were the monoterpenes α-pinene (9.7), thujene (9.0), terpin-4-ol (4.8) and sabinene (4.7); the sesquiterpenes caryophyllene (19.9) and caryophyllene oxide (15.5); and the diterpene methyl communate (4.4). The presence of pinene and caryophyllene as principal components of the essential oil could be related to the traditional use of Plectranthus against stomach ache. Keywords: medicinal plants, Céu Azul, ethnopharmacology, Plectranthus neochilus, essential oil, GC-MS.