Chemical composition and biological activities of the essential oils from two Pereskia species grown in Brazil.

The chemical composition of the essential oils of Pereskia aculeata Mill. and P. grandifolia Haw. (Cactaceae), grown in Brazil, was studied by means of GC and GC-MS. In all, 37 compounds were identified, 30 for P. aculeata and 15 for P. grandifolia. Oxygenated diterpenes are the main constituents, both in the oil ofP. grandifolia (55.5%) and in that ofP. aculeata (29.4%). The essential oils were evaluated for their in vitro phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Sinapis arvensis L., and Phalaris canariensis L. seeds. The essential oil of P. grandifolia, at all doses tested, significantly inhibited the radicle elongation of R. sativus. Moreover, the antimicrobial activity of the essential oils was assayed against ten bacterial strains. The essential oils showed weak inhibitory activity against the Gram-positive pathogens.