Evaluation of Chemical Composition and Anti‐Staphylococcal Activity of Essential Oils from Leaves of Two Indigenous Plant Species Litsea leytensis and Piper philippinum from Leyte, Philippines

Indigenous plants from Southeast Asia, specifically those from the Philippines, remain underex-plored in terms of their essential oils (EOs) potential. The chemical composition of hydrodistilled leaf EOs from two indigenous EOs-bearing species, namely Litsea leytensis (Lauraceae) and Piper philippinum (Piperaceae), was described, using dual-column/dual-detector GC-MS analysis. When analysed using two columns differing in their polarity (HP-5MS/DB-WAX), L. leytensis EO had high amounts of caryophyllene oxide (15.70/16.76%) as the primary component, followed by β-caryophyllene (11.04/11.12%) and α-copaene (8.85/8.87%). Ishwarane (26.98/24.9%), nerolidol (10.14/10.42%) and 3-ishwarone (6.84/2.46%) were the most abundant constituents of P. philippinum EO. Additionally, the in vitro growth-inhibitory activity of the EOs in the liquid and vapor phases against Staphylococcus aureus was evaluated using the broth microdilution volatilization assay; however, both EOs had no anti-staphylococcal effect. This is the first study evaluating antibacterial activity and chemical composition of EOs from L. leytensis and P. philippinum. However, the iden-tification of potentially bioactive compounds in both EOs suggests further investigation of these species.