Chemical Composition and Phytotoxicity of Volatile Essential Oil from Intact and Fallen Leaves of Eucalyptus citriodora

Abstract

A total of 23 volatile constituents was identified and characterized by GC and GC-MS in the volatile essential oil extracted from intact (juvenile and adult) and fallen (senescent and leaf litter) leaves of lemon-scented eucalyptus (Eucalyptus citriodora Hook.). The leaves differed in their pigment, water and protein content, and C/N ratio. The oils were, in general, monoterpenoid in nature with 18 monoterpenes and 5 sesquiterpenes. However, a great variability in the amount of essential oils and their individual constituents was observed in different leaf tissues. The amount was maximum in the senescent leaves collected from the floor of the tree closely followed by that from juvenile leaves. In all, 19 constituents were identified in oil from juvenile and senescent leaves compared to 23 in adult leaves and 20 in leaf litter, respectively. Citronellal, a characteristic monoterpene of the oil reported hitherto was found to be more (77Ð78%) in the juvenile and senescent leaves compared to 48 and 54%, respectively, in the adult leaves and leaf litter. In the adult leaves, however, the content of citronellol Ð another important monoterpene Ð was very high (21.9%) compared to other leaf types (7.8Ð12.2%). Essential oil and its two major monoterpenes viz. citronellal and citronellol were tested for their phytotoxicity against two weeds (Amaranthus viridis and Echinochloa crus-galli) and two crops (Triticum aestivum and Oryza sativa) under laboratory conditions. A difference in the phytotoxicity, measured in terms of seedling length and dry weight, of oil from different leaves and major monoterpenes was observed. Oil from adult leaves was found to be most phytotoxic although it occurs in smaller amount (on unit weight basis). The different toxicity of different oil types was due to the relative amount of individual monoterpenes present in the oil, their solubility and interactive action. The study concludes that oil from senescent and juvenile leaves being rich in citronellal could be used as commercial source of citronellal whereas that from adult leaves for weed management programmes as it was the most phytotoxic.

The halophytic model plant Thellungiella salsuginea exhibited increased tolerance to phenanthrene-induced stress in comparison with the glycophitic one Arabidopsis thaliana: Application for phytoremediation

“…Although Arabidopsis thaliana is sensitive to PAHs, it was shown to be a model plant for the understanding of phytoremediation process. However, this criterion is not sufficient as phytoremediation of a PAH-polluted site requires species showing, among other criteria, a high tolerance to PAH stress and to the PAH-induced oxidant stress (Batish et al, 2006;Herbinger et al 2002;Selote et al, 2004). Indeed, ROS production and subsequent oxidative damage may be an important mechanism of toxicity in plants exposed to xenobiotics (Livingstone, 2001).…”

Fitotoxicidad De Aceites Esenciales Y Extractos Acuosos De Plantas Mediterráneas Para El Control De Arvenses

“…El aceite esencial de E. camaldulensis de diferentes lugares: Cerdeña (Barra et al, 2010), Grecia (Tsiri et al, 2003), Etiopía (Dagne et al, 2000), Mozambique (Pagula et al, 2000), Nigeria (Oyedeji et al, 2000), sur de Florida (Pappas y Sheppard-Hanger, 2000), ha sido estudiado, habiendo grandes diferencias en cuanto a su composición tanto cualitativa como cuantitativa, que varía dependiendo del origen y el estado vegetativo, la estación, el clima y la edad (Tsiri et al, 2003;Batish et al, 2006b, Barra et al, 2010.…”

Extraction of Eucalyptus Oil as Reduction of Bacterial Growth in Drinking Water

“…Due to its disinfectant action, the essential oil is used externally, applied to cuts and skin infections but it has deleterious effect on the body in high doses [17,18]. Beside antimicrobial activity, the essential oil and its constituents have also been used for their herbicidal [19,20], insecticidal [21,22] antihelmintic [23], anti-tumour [24] and anti-leech [25,26] properties, as well as in integrated disease management against phytopathogenic fungi nonspecific skin infections and mastitis in animals [27,28].…”