Leaf essential oil composition and bioactivity of Psidium guajava from Kathmandu, Nepal

The essential oil from the leaves of Psidium guajava, collected from Kathmandu, Nepal, was obtained by hydrodistillation and analyzed by GC-MS. A total of 53 compounds were identified, accounting for 100% of the oil composition. The major components of the essential oil were (E)-nerolidol (35.6%) and (E)-caryophyllene (15.8%), with lower concentrations of (2Z,6E)-farnesol (6.7%), and ledol (5.5%). A cluster analysis of the major components of P. guajava leaf oils has revealed at least nine chemotypes; the sample from Nepal belongs to the nerolidol/caryophyllene chemotype. P. guajava leaf oil showed notable larvicidal activity against Chaoborus plumicornis, marginal nematicidal (Caenorhabditis elegans) and insecticidal (Drosophila melanogaster) activities, and showed no antimicrobial or cytotoxic activity.