This present study aims to characterize the essential oil compositions of the aerial parts of M. spicata L. and endemic M. longifolia ssp. cyprica (Heinr. Braun) Harley by using GC-FID and GC/MS analyses simultaneously. In addition, it aims to perform multivariate statistical analysis by comparing with the existing literature, emphasizing the literature published within the last two decades, conducted on both species growing within the Mediterranean Basin. The major essential oil components of M. spicata were determined as carvone (67.8%) and limonene (10.6%), while the major compounds of M. longifolia ssp. cyprica essential oil were pulegone (64.8%) and 1,8-cineole (10.0%). As a result of statistical analysis, three clades were determined for M. spicata: a carvone-rich chemotype, a carvone/trans-carveol chemotype, and a pulegone/menthone chemotype, with the present study result belonging to the carvone-rich chemotype. Carvone was a primary determinant of chemotype, along with menthone, pulegone, and trans-carveol. In M. longifolia, the primary determinants of chemotype were identified as pulegone and menthone, with three chemotype clades being pulegone-rich, combined menthone/pulegone, and combined menthone/pulegone with caryophyllene enrichment. The primary determinants of chemotype were menthone, pulegone, and caryophyllene. The present study result belongs to pulegone-rich chemotype.

The genus Eucalyptus L’Hér., is native to Australia with 61 introduced taxa in Cyprus, including E. torquata Luehm., which has a wide distribution on the island. The aim of this study was to investigate the possible seasonal variations in the chemical composition of the essential oils of juvenile and mature leaves collected from Nicosia, Cyprus, by using multivariate statistical analysis. The leaves of 12 monthly collections were separately hydrodistilled, and GC-FID and GC/MS analyses were conducted. In general, the results revealed 1,8-cineole (mature: 3.6–27.8%; juvenile: 12.7–21.5%) and torquatone (mature: 27.6–48.8%; juvenile: 28.8–41.5%) as major compounds as well as an inverse relation between 1,8-cineole and torquatone content. Other important compounds found were α-pinene, β-eudesmol and α-eudesmol for all samples. The data support the existence of three major clusters, distinguished by the concentration of torquatone and miniatone. Minor compounds were also temporally relevant. The present study is among the first of its kind, analyzing the essential oils for a one-year period in Cyprus as well as conducting statistical analysis on E. torquata to reveal possible temporal variations between heterophyllous leaves, and also performing Hierarchical Cluster Analysis, determining the primary components of variability.