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

Many indigenous plants of the Philippines, including essential oil-bearing species, remain phytochemically and pharmacologically unexplored. In this study, the chemical composition of leaf essential oils (EOs) hydrodistilled from <i>Litsea leytensis</i> (Lauraceae) and <i>Piper philippinum</i> (Piperaceae) was determined using dual-column (HP-5MS/DB-WAX)/dual-detector gas chromatography and mass spectrometry analysis. Caryophyllene oxide (15.751/16.018%) was identified as the main compound in <i>L. leytensis</i> EO, followed by β-caryophyllene (11.130/11.430%) and α-copaene (9.039/9.221%). Ishwarane (25.937/25.280%), nerolidol (9.372/10.519%) and 3-ishwarone (6.916/2.588%) were the most abundant constituents of <i>P. philippinum</i> EO. Additionally, the in vitro growth-inhibitory activity of the EOs in the liquid and vapour phases against <i>Staphylococcus aureus</i> was evaluated using the broth microdilution volatilisation assay. Although the results showed no anti-staphylococcal effect, the presence of various bioactive compounds in both EOs suggests their potential future use in industrial applications.