CHEMICAL STUDY AND EVALUATION OF INSECTICAL PROPERTIES OF AFRICAN LIPPIA CITRIODORA ESSENTIAL OIL

Abstract

The main objective of this study is to highlight the chemical composition, the insecticidal and the antibacterial activities of essential oil of Lippia citriodora growing spontaneously in central Morocco, particularly in Beni Mellal. After extracting the essential oil by a clevenger type distiller from the aerial parts, all constituents were analyzed by gas chromatography coupled with mass spectrometry (GC/MS). Their chemical composition of chemotype revealed the presence of 45 compounds in the essential oil, which has Geranial as the major constituent with a content of approximately (35.45%), followed by Neral (26.11%) and Limonene (14.06%), with a total percentage of (75.62%). The insecticidal activities were carried out against three weevils:Sitophilus granarius, Sitophilus oryzae and Sitophilus zeamais, the results of this test to show a very important activity during 24 hours of the treatments confirmed by the values of LD50 and LD90 which tend towards 0, or this activity was probably due to the major constituents. The bacterial power was studied in vitro against gram-positive bacteria: Bacillus cereus (CECT 193) and Listeria monocytogenes (CECT 4032), gram-negative bacteria: Yersinia enterocolitica (CECT 9144), Pseudomonas aeruginosa (CECT 116) and Staphylococcus aureus (CECT 239), the results of this tests made it possible to quantitatively assess the bacterial power by looking for minimum MIC inhibitory concentrations and minimum MBC bactericidal concentrations, which have a varying activity depending on the strain tested.