, and Essential Oils and Hydrolates: Evaluation of Liquid and Vapor Phase Chemical Composition and Biological Activities.

, and essential oils (EOs) and hydrolates (HYs) were investigated to define their chemical compositions and biological properties. Gas-chromatography/Mass-spectrometry (GC/MS) and Headspace-GC/MS (HS-GC/MS) techniques were used to characterize the liquid and vapor phase chemical composition of EOs and HYs. 1,8-Cineole (42.2%, 33.5%) and α-pinene (16.7%, 39.0%) were the main compounds of EO; 1,8-cineole (30.3%, 48.4%) and camphor (17.1%, 8.7%) were for EO; linalyl acetate (62.6%, 30.1%) and linalool (11.1%, 28.9%) were for EO for the liquid and vapor phase, respectively. Chemical profile of HYs was characterized by 1,8-cineole (65.1%, 61.4%) as a main constituent of and HYs, while linalool (89.5%) was the main constituent of HY. The antioxidant activity of EOs and HYs was carried out by DPPH and ABTS assays and antimicrobial properties were also investigated by microdilution and the disc diffusion method for liquid and vapor phase against five different bacterial strains such as ATCC 25922, ATCC 13525 and DSM 102855 among Gram-negative and ATCC 10876 and DSM 16420 among Gram-positive. and EOs demonstrated considerable antibacterial activity, while EO proved to be less effective. Agar diffusion method and vapor phase test showed the EOs activity with the biggest halo inhibition diameters against and . A remarkably high antioxidant activity was determined for showing low EC values and also for good EO results were obtained in both of the used assays. EC values were slightly higher to which corresponds to a lower antioxidant activity. Concerning the HYs, the EC values for , and were remarkably high corresponding to an extremely low antioxidant activity, as also obtained by expressing the values in Trolox equivalent antioxidant capacity (TEAC).