Abstract

This study aims to determine the phytochemical characteristics, structural determination of bioactive component from the leaf extract  using GCMs and experimentally investigation of the antibacterial activity of essential oil from Persea americana and Citrus sinensis leaf against seven bacteria (Gram-positive and Gram-negative) which are Staphylococcus aureus , Bacillus subtilis, Salmonella typhi, Klebsiella pneumonia, Escherichia coli, Proteus mirabilis and Pseudomonasaeruginosa known to be pathogenic to human causing high mortality among human. This study involves the extraction of essential oils from air- dried leaves of medicinal aromatic plant ( Persea americana & Citrus sinensis ) using soxhlet method with n- hexane as solvent. Antibacterial activity was carried out using agar well diffusion technique. Both plants essential oil shows high antibacterial property. The antibacterial sensitivity test revealed Escherichia coli having the widest zone of inhibition (20.0 mm) with Citrus sinensis essential oil at 100 mg/ml while the least zone of inhibition (5.0 mm) was recorded for Staphylococcus aureus at 12.5 mg/ml with essential oil of Persea americana however, Pseudomonas aeruginosa was found to be resistant to the oil. Phytochemical analysis of the plants shows the presence of active components such as Cardiac glycoside, Steroid, Anthraquinone, Flavonoid, Phenol, Alkaloid and reducing sugars. The presence of these components enhances the effectiveness of plants essential oil in the treatment of various diseases and also helps to act as an antibacterial agent. Persea americana essential oil was further analyzed by gas chromatography–mass spectroscopy (GC/MS), the main constituents were Squalene (45.94%), vitamin E (12.50%), Diisooctyl phthalate (7.45%) and 12-Methyl-E,E-2,13- octadecadien-1-ol (7.20%). These components aid the antibacterial activities of Persea americana essential oil.