Chemical composition of the volatile oil of Croton glandulosus Linnaeus and its allelopathic activity

Several essential oils have allelochemicals with phytotoxic effects. Croton species are producers of secondary metabolites with biological potential. In the present study, chemical composition of the essential oil extracted from aerial parts of Croton glandulosus Linnaeus was evaluated by gas chromatography and the phytotoxicity of the oil on Lactuca sativa seeds was evaluated for the first time. The yield of the essential oil was 0.12% (v/w). Chromatographic analysis allowed the identification of 97.49% of the total compounds present in the oil. Sesquiterpenes were found to be the predominant constituents of the volatile oil, with β-caryophyllene (53.24%) being the major compound. Treatment with 0.1%-1% (v/v) of the essential oil inhibited the development of the hypocotyl and radicle of L. sativa to a greater extent compared to the inhibition of seed germination, demonstrating the phytotoxic effect of the oil.