Chemical Composition and Phytotoxic Activity of Rosmarinus officinalis Essential Oil

In this study we determined the chemical composition of R. officinalis essential oil and evaluated its possible phytotoxic activity. The chemical composition of the essential oil was studied by GC and GC-MS analyses. A total of 57 compounds were identified and the main components are alpha-pinene (24.9%), verbenol (8.5%), verbenone (8.5%), 1,8-cineol (8.2%) and isobomeol (8.1%). Moreover, the essential oil and its main constituents, alpha-pinene and 1,8-cineol,were evaluated for their possible in vitro phytotoxic activity against germination and initial radical growth of radish (Raphanus sativus L.), rue (Ruta graveolens L.), lettuce (Lactuca sativa L.) and tomato (Solanum lycopersicum L.). The results showed thatboth germination and radical elongation were sensitive to the oil but not in the same way to alpha-pinene and 1,8-cineol. The oil influences in different ways radical elongation of R. sativus, R. graveolens, and L. sativa and the germination of S. lycopersicum. Instead alpha-pinene influenced only radical elongation of lettuce.