Chemical composition and fumigant toxicity of three citrus essential oils against eggs, larvae and adults of Callosobruchus maculatus (Col.: Bruchidae)

The fumigant toxicity of volatile fractions of peel essential oils of the Rutaceae species of Citrus reticulata Blanco, C. limon L. and C. aurantium L. was studied against eggs, larvae and adults of Callosobruchus maculatus (F.) at 27 ± 1 ºC and 65 ± 5% RH in darkness. The oils were extracted from the fruit peels using water steam distillation. The essential oils were characterized by a combination of GC and GC/MS analyses. Limonene was the major constituent of the three essential oils. The effect of different concentrations of the essential oil vapors on egg hatchability as well as larval and adult mortality was found to be significant. Citrus reticulata and C. aurantium oils were more toxic on egg hatchability than C. limon extract and caused higher mortality on larvae as well. There was no significant difference between essential oils in terms of adult mortality. The adult beetles were also exposed to the concentrations of 18.5, 37, 55.5 and 74 μl/l air. At the highest concentration (74 μl/l air), C. aurantium oil caused 100% mortality after a 6 h exposure, but the oils from C. reticulata and C. limon caused 38% and 62% mortality, at the identical exposure time, respectively. The results suggest that citrus peel oils can be effectively used as botanical fumigants against various life stages of Ca. maculatus

Ferrous Ion Chelating, Superoxide Anion Radical Scavenging and Tyrosinase Inhibitory Properties of Pure and Commercial Essential Oils of Anetrhum Graveolens

Introduction: Despite slight toxicities of essential oils, they are not under strict control in many countries. Anethum graveolens is widely consumed and its essential oils are at public reach. This study was designed to study essential oils of Anethum graveolens. Methods: The biological properties of pure and commercial essential oils of Anethum graveolens were investigated. In fact, Ferrous ion chelating activity, superoxide anion radical scavenging property, tyrosinase inhibition and total flavonoids of the oils were determined. Results: Chelating activity of 7.8 µg of EDTA was equivalent to 2 µg of the pure oil. The oils had superoxide anion radical scavenging activities which may be related to their total phenol and flavonoid contents. IC50 of ferrous ion chelating, antityrosiase and superoxide anion radical scavenging activities of pure and commercial oils were 1.3, 1.4, 1 and (171.6, 589, 132) µg respectively. Antityrosiase activity of 6.4 µg pure oil was equal to 1000 µg of the commercial oil. Conclusion: Anethum possesses antioxidative and free radical scavenging properties. This oil chelates ferrous ions and superoxide radicals. It is effective in formation of reactive toxic products. Anethum has good potentials regarding its applications in food and drug industries