Estudo dos óleos voláteis de plantas medicinais da família Asteraceae do Rio Grande do Sul: Baccharidastrum triplinervium, Baccharis pentodonta, Pluchea sagittalis e Eupatorium buniifolium

Abstract

In this study four species were studied: Baccharidastrum triplinervium, Baccharis pentodonta, Pluchea sagittalis and Eupatorium buniifolium, all species belong to Asteraceae family. The essential oils of these four species of medicinal plants of the Rio Grande Do Sul were obtained by hydrodestillation in a modified Clevenger apparatus and submitted to GC-MS analysis for determination of its chemical compositions. The essential oils had been submitted to in vitro and in vivo tests to determine its antimicrobial, cytotoxic and antioxidant activities The volatile oils from the leaves of Baccharidastrum triplinervium, which were collected in spring and summer, showed sesquiterpenic composition, as well as Baccharis pentodonta leaves that were collected in spring and winter. The essential oils of the flowers and leaves of Baccharis pentodonta, that were extracted on summer, showed a larger portion of monoterpenics compounds. Pluchea sagittalis also had a large portion of monoterpenes in the essential oils of its leaves and flowers, as well as the essential oils of the leaves of Eupatorium buniifolium that has as majority component α-thujene, on the samples collected in summer and winter. The antimicrobial activities showed by these plants were analysed by bioautography test, disc difusion and microdilution in broth. All samples showed activity against to the tested microorganisms, except by the disc difusion that only showed activity against B. triplinervium. The in vivo toxicity of these essential oils were tested by the letal test with brine shrimp, that showed medium insecticide activity (LC50 between 29,63 e 116,44μg/mL). The majorority of these plants shows antioxidant activity by the free-radical test DPPH.