Allelopathic essential oils

Cyperus brevifolius (Rottb.) Hassk. C. difformis L. C. glomeratus L. C. iria L. Sha Cao (rhizome) Allelopathic essential oils, terpenes, alpha-cyperone, beta-selinene, alpha-humulene.60197 198 A vermifuge, antidote, remedy for dysentery, alleviate stress, sedative. 

The bioassays showed the wide allelopathic potential of these plants as well as the phytotoxicity of some soils extracts and essential oils (Tables I, II, and III). 

The species with the higher allelopathic potentials were Piper auritum. Piper hispidum, Croton pyramidalis, and Siparuna nicaraguen-sis. The essential oils of the Piperaceae were highly inhibitory while that of Croton pyramidalis was less inhibitory and even produced stimulations (Table III). 

Studies on Helietta parvifolia. In the northern arid region of Mexico, Rovalo e al. (23) carried out a study of the potential uses of Helietta parvifolia. They demonstrated that the essential oil of Helietta acts as a fungicide upon Penicillium, Rhlzopus, Fusarlum, and Aspergillus and also acts as an insecticide upon Anastrepha ludens (fruit fly). The allelopathic potential of Helietta leaves was demonstrated upon a common weed Convolvulus arvense. 

Scrivanti, E. R., M. P. Zunino, and J. A. Zygadlo. 2003. Tagetes minuta and Schinus areira essential oils as allelopathic agents. 31 563-572. 

Cineole (Fig. 1) is a major constituent of these plant essential oils and is one of the most potent allelochemicals released by Artemisia spp. [37]. However, the potential allelopathic role of this monoterpene is not clearly established. Other factors such as competitiveness, reduced seed predation, and/or drought tolerance may be more important in the survival of the species [37]. 

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