Evaluation of the Essential Oil Composition of Five Thymus Species Native to Greece

The genus Thymus encompasses a wide array of taxa, many of which remain underexplored in terms of their phytochemical profile. In this study, we investigated the phytochemical composition of volatile compounds of five Thymus species native to Greece using gas chromatography combined with mass spectrometry. Two samples of T. parnassicus collected from Mts Parnitha and Parnassos were studied. The predominant compounds in the Parnitha sample were alpha-cadinol (13.53%), E-caryophyllene (11.83%) and selin-11-en-4 alpha-ol (7.29%). The sample from Mt. Parnassos exhibited a high concentration of E-caryophyllene (35.20%) followed by beta-bisabolene (10.41%). Additionally, two species, namely T. leucotrichus subsp. leucotrichus and T. atticus, were collected on Mt. Chelmos (Peloponnese). The essential oil of T. leucotrichus was rich in elemol (35.56%), alpha-eudesmol (11.15%) and beta-eudesmol (6.11%). Thymus atticus exhibited a high concentration in linalool (63.04%) and p-cymene (25.63%). In addition, two samples of T. holosericeus collected from Kefalonia Iota sland were both rich in geraniol (89.9% and 87.7%, respectively). We also examined the volatile profile of T. laconicus, a local endemic species of SE Peloponnese (Lakonia area), which remains unexplored. Carvacrol (32.7%) and p-cymene (29.7%) were identified as the dominant compounds. Our study contributes valuable insights into the chemical profile of Thymus spp. and sheds further light on the well-known chemical polymorphism within this genus.