Evaluation of essential oil and hydrolate from a new hyssop variety (Hyssopus officinalis L.)

The main objective of this study was to evaluate the quality of essential oil (EO) and hydrolate (HY) obtained from a new Romanian variety of hyssop (Hyssopus officinalis L., Lamiaceae family), namely ‘Cătălin’. The chemical composition and the concentration of the compounds was established by gas chromatography coupled to mass spectrometry (GC/MS). The main constituents identified in hyssop EO and HY were cis-pinocamphone (34.63% and 67.00%), trans-pinocamphone (11.72% and 14.58%), thujenol (1.39% and 6.05%). The evaluation of the antioxidant capacity was performed by three methods (DPPH, ABTS and FRAP), EO proving a higher oxidizing activity compared to HY one. The antimicrobial activity of the essential oil was evaluated in vitro, in order to detect its ability to inhibit G- phytopathogenic bacteria (Pseudomonas syringae) and plant pathogenic fungi (Fusarium oxysporum). Eugenol, linalool and estragole standards were used as reference volatile compounds. Regarding Pseudomonas syringae (LMG5090) bacterium, assays showed that hyssop oil does not inhibit its growth. Estragole and eugenol showed pronounced antibacterial activity in all tested concentrations, both in the first 24 hours of incubation and after 3 days. Linalool instead has bacteriostatic activity only at high concentrations (50% and 100%), an inhibitory activity that is maintained only in the first 24 hours of incubation. The results obtained against Fusarium oxysporum reveal that the EO tested has no fungicidal activity but only fungistatic, and it is able to delay mycelial growth and the degree of inhibition depending on the concentration used.