Composition of the Leaf Essential Oil of Phoebe formosana from Taiwan and its in vitro Cytotoxic, Antibacterial, and Antifungal Activities

The essential oil from the leaves of Phoebe formosana from Taiwan was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Seventy-one compounds were identified, representing 100% of the oil. The main components identified were a-humulene (16.8%), τ-cadinol (8.9%), α-pinene (8.4%), α-cadinol (8.1%), β-caryophyllene (8.0%), β-phellandrene (6.0%), and β-eudesmol (5.8%). The oil exhibited cytotoxic activity against human lung, liver and oral cancer cells. The active compounds were β-caryophyllene, α-humulene, τ-cadinol, β-eudesmol, and α-cadinol. The antibacterial activity of the oil was tested by the disc diffusion and micro-broth dilution methods against eight bacterial species. The oil exhibited moderate growth suppression against Gram-positive bacteria with inhibition zones of 28 to 36 mm, and MIC values of 250 to 375 μg/mL. The active antibacterial compounds were determined to be τ-cadinol, β-eudesmol, and α-cadinol. The leaf oil displayed excellent antifungal activity with the active compounds determined as α-cadinol, β-eudesmol, τ-cadinol, α-humulene, and β-caryophyllene.