Essential Oils from Hyssopus officinalis and Agastache foeniculum (Pursh) Kuntze as Promising Antimicrobial

The increasing demand for clean-label food products and the limitations of synthetic preservatives have driven interest in natural antimicrobial alternatives such as EOs. Hyssopus officinalis L. and Agastache foeniculum (Pursh) Kuntze, produce essential oils (EOs) with significant biological activities. In the food sector, their EOs can enhance organoleptic properties and exhibit antimicrobial effects. EOs were obtained by hydrodistillation, characterized by GC–MS, and tested against food-related bacterial and fungal strains using a resazurin-based microdilution method. Hyssop EO was characterized by iso-pinocamphone (32.50%) and α-fenchene (25.14%) as major compounds, while anise hyssop EO was dominated by estragole (71.86%) and limonene (20.45%). Hyssop EO showed the highest antibacterial activity against Staphylococcus aureus (MIC 1.81 µL/mL) and Streptococcus pyogenes (MIC 0.095 µL/mL), while anise hyssop EO was most effective against S. pyogenes (MIC 0.56 µL/mL). Hyssop EO demonstrated a stronger antifungal activity against Candida species (MIC: 10.8 µL/mL); meanwhile, anise hyssop EO exhibited a higher antifungal activity against Aspergillus spp. (MIC: 10.8 µL/mL). Overall, hyssop EO demonstrated stronger and more consistent effects against Gram-positive bacteria, while anise hyssop EO exhibited weaker, strain-dependent activity. The results are based on in vitro assays that may differ in real food systems.