Chemical and Antibacterial Polymorphism ofJuniperus oxycedrusssp.oxycedrusandJuniperus oxycedrusssp.macrocarpa(Cupressaceae) Leaf Essential Oils from Tunisia
Essential oils fromJuniperus oxycedrusL. have been used since antiquity for fragrance, flavoring, medicinal, antimicrobial, insecticidal, and cosmetic purposes. Several works studied the chemical composition of the essential oils ofJuniperus oxycedrusleaves. The aim of this study is to investigate the chemotaxonomic relationships and antibacterial activity of two Tunisian subspecies:Juniperus oxycedrusssp.oxycedrus(L. K.) Deb. andJuniperus oxycedrusssp.macrocarpa(S. & m.) Ball. In addition, and for the first time, we reported the antibacterial activities of TunisianJ. oxycedrusssp.macrocarpaandJ. oxycedrusssp.oxycedrusagainst four bacteria. Essential oils obtained by hydrodistillation were analysed by GC and GC/MS. Fifty-five constituents were identified. Thirty four major compounds were retained for the study of the chemical variability, andα-pinene, sylvestrene,p-cymene, and 13-epi-manoyl oxide were the main ones. The chemical principal components analysis (PCA) identified three chemotypes. The study of the antibacterial activity showed thatEscherichia coliwas found to be extremely resistant (zone diameter 0 mm) to all the oils tested, whileStaphylococcus aureuswas the most sensitive strain (zone diameter 13.5 mm and MIC ranged from 600 to 650 μg/mL).