Chemical composition and insecticidal activity of the essential oil of the aerial parts of Ostericum grosseserratum (maxim) Kitag (Umbelliferae)

Abstract

Purpose: To investigate the chemical composition and insecticidal activity of the essential oil of the aerial parts of Ostericum grosseserratum against the maize weevil, Sitophilus zeamais. Methods: Steam distillation of the aerial parts of O. grosseserratum during the flowering stage was carried out using a Clavenger apparatus in order to obtain its volatile oil content. Gas chromatography/mass spectrometric (GC/MS) analyses (HP-5MS column) of the essential oil were performed and its contact and fumigant activity determined. Results: A total of 43 components of the essential oil were identified. The principal compounds were (d)-limonene (16.2 %), 4-terpineol (13.5 %), myristicin (11.3 %), γ-terpineol (8.3 %), β-pinene (5.1 %), β- caryophyllene (4.6 %) and linalool (4.1 %). The oil exhibited contact toxicity against adult S. zeamais with lethal concentration (LC50) value of 17.97 μg/adult. The essential oils also possessed fumigant toxicity against S. zeamais with LC50 value of 13.70 mg/L air. Conclusion: The study indicates that the essential oil of O. grosseserratum has a potential to be developed into a natural fumigant/insecticide for the control of grain storage insects. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. All rights reserved.