Terpenoid composition and antibacterial activity of essential oil obtained from the whole aerial parts of <i>Cyananthus lobatus</i> Wall. ex Benth

<i>Cyananthus lobatus</i> Wall. ex Benth. is a Tibetan medicinal plant, but very little is known about its chemical composition in the literature. The essential oil obtained by steam distillation of whole aerial parts was analysed by GC and GC/MS, leading to identification of a total of 49 constituents, representing 86.8% of the total essential oil composition. The essential oil from the entire aerial parts was dominated by non-terpenic compounds (72.0%) and followed by 3.9% of sesquiterpene hydrocarbons, 3.2% oxygenated sesquiterpenes, 3.1% oxygenated monoterpenes, 2.6% oxygenated diterpene, 1.4% monoterpene hydrocarbons, and 0.6% of diterpene hydrocarbon. The principal constituents identified in the essential oil from the whole aerial parts were nonadecanol (24.3%), massoia lactone (10.2%), hexadecanoic acid (4.4%), nonanal (3.0%), pentacosane (3.0%), and non-3-en-2-one (2.8%). The essential oil exhibited good activity against <i>Staphylococcus aureus</i>, <i>Klebsiella pneumoniae</i>, <i>Escherichia coli</i>, and <i>Bacillus subtilis</i> and an antibacterial effect at 250 µL/mL against <i>Bacillus subtilis</i>.