Growth, essential oil characterization, and antimicrobial activity of three wild biotypes of oregano under cultivation condition in Southern Italy

The biotypes showed differences in both height and width of vegetation and this influenced the PAR absorbance and the biomass production. Oil amount was found to be influenced by the stage of plant growth and reached the maximum value at full bloom. The values were higher for oregano from “Sicignano” that belongs to O. vulgare ssp. virens in respect to the biotypes “Acerno” and “Ricigliano” (O. vulgare ssp. viridulum) despite the oregano from “Ricigliano” having presented some intermediate characteristics. Oils obtained by hydrodistillation were studied by GC and GC-MS and showed differences in the chemical composition. Carvacrol and its derivatives were the major constituents of the oils from “Sicignano” while the oil from “Ricigliano” was characterized by high amount of thymol. The oil from “Acerno” showed the lowest content of phenols. The antibacterial activity was mainly linked to phenolic constituents as carvacrol which was present in high concentrations in the oils from “Sicignano”. For this reason this biotype could be used as preservatives and for pharmaceutical uses.