Comparative study on composition and antimicrobial activity of Juniperus wallichiana essential oils against clinical isolates

The purpose of the study was to examine the variation in the essential oils composition of Juniperus wallichiana collected from four different locations of North-Western Himalaya of Uttarakhand (India) as well as antimicrobial activity against six clinical isolate microbial strains. The essential oils were obtained through hydro-distillation of the needles using Clevenger type apparatus and then analyzed by GC and GC-MS in order to determine quantitative variation in the oils composition. In addition, the oils were assessed for their antimicrobial activity against six microorganisms, namely Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus fumigatus using broth dilution method. Among the 41 identified compounds in all the locations, the major components were monoterpenoids which made up 76.9–88.7% of the oil with sabinene (22.6–51.0%), terpinen-4-ol (7.3–14.0%), α-pinene (6.2–12.7%) and limonene (1.6–12.5%) as the most abundant constituents. The quality of all the essential oils from various locations was almost similar, although some quantitative variations were observed. The oil of J. wallichiana from Gomukh region strongly inhibited all the microorganisms, except P. aeruginosa, whereas, the other three oil samples were found less effective.