Biological Characterization and Essential Oil Profiles of Eastern European Cultivars of Thymus, Satureja, and Monarda

<i>Thymus</i>, <i>Satureja</i>, and <i>Monarda</i> are three plant genera, belonging to the Lamiaceae family, that are particularly valued for their essential oils (EOs) abundant in phenolic terpenoids. In this study, a botanical characterization of the following eight Eastern European cultivars (some of them newly bred) grown in Ukraine is distinguished: <i>Thymus vulgaris</i> ('Yalos', '101'), <i>Thymus richardii</i> ('Fantasia'), <i>Satureja montana</i> ('Krymsky smaragd', 'Lunata', '4-18'), <i>Monarda fistulosa</i> ('Premiera'), and <i>Monarda</i> × <i>hybrida hort.</i>, which is a <i>Monarda didyma</i> × <i>Monarda fistulosa</i> hybrid ('Tonya'). The EO of those cultivars was obtained and characterized in detail using GC-MS and GC-FID. Additionally, some biological activities of these oils were tested. Antimicrobial activity was verified against <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, and <i>Candida albicans</i> using disk diffusion and microdilution methods. Furthermore, some preliminary tests were performed on the motility of bull sperm using the CASA system. All the <i>Thymus</i> cultivars were very rich in thymol (57.99-67.62%), and all the <i>S. montana</i> cultivars were very abundant in carvacrol (62.22-75.53%). <i>M. fistulosa</i> cv. 'Premiera' contained mainly thymol (49.87%), and <i>M.</i> × <i>hybrida</i> cv. 'Tonya' contained both thymol (46.70%) and carvacrol (10.37%). All the tested EOs, as well as thymol and carvacrol, exhibited strong antibacterial and antifungal action with minimal inhibitory concentrations ranging from <0.25-0.5 mg/mL for <i>Satureja</i>, through <0.25-0.5 mg/mL for <i>Monarda</i>, to 0.5-4 mg/mL for <i>Thymus</i>. The EOs, at a concentration of 0.4 µL/mL, exhibited cytotoxicity towards bull spermatozoa when compared to the control sample.