Chemical compositions and antimicrobial activities of three lemon odor essential oils of Cupressus macrocarpa, Cymbopogon citratus. and Citrus limon

ABSTRACT Infectious diseases caused by bacteria, fungi and viruses are globally of major concern. Plant essential oils produced by various differentiated structures possess varied properties as significant antiseptic, antibacterial, antifungal, antiviral, antioxidant, anti-parasitic and insecticidal activities. The essential oil of three lemon odor plants; Cupressus macrocarpa, Cymbopogon citratus and Citrus limon were isolated and evaluated for their antimicrobial activities. The analysis of essential oil components of C. macrocarpa by GC-MS revealed D-limonene (38.00%) as the major component followed by citral (9.72%), carveol (6.86%) and citronellal (5.35%). Analyses of the essential oil of C. citratus resulted in the identification of pseudolimonene (19.2%) as the most abundant component followed by D-limonene (12.34%), Ɣ-terpinene (10.89%), citronellol (9.58%), sabinene hydrate (9.24%), (+)-2-bornanone (8.29%) and α-terpinolene (5.53%). Also, GC-MS detected neral dimethyl acetal (41.56%) was the main component of C. limon EO with carveol (12.39%) and citral (11.21%). A study of the antimicrobial activity of the three essential oils against E. coli, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus. and Candida albicans has been evaluated and revealed that C. citratus EO had antibacterial activity against gram-positive organisms and C. limon EO exhibited the strongest antifungal activity against Candida albicans.