Liquid and vapour-phase bioactivity of Hertia maroccana (Batt.) Maire essential oil: an endemic Asteraceae from Morocco

Analysis of essential oil (EO) obtained from H. maroccana revealed that germanicol (17.8 %), β- pinene (14.6 %), α- guaiene (5.83 %), germacrene D (5.55 %), α- pinene (5.3 %) and δ- cadinene (5 %) were found to be the major components of this essential oil. Antimicrobial potential of H. maroccana oil in liquid and vapor phase against different bacterial strains (Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 8739, Salmonella abony NCTC 6017) and fungal strains (Alternaria sp., Pencillium expansum, Rhizopus stolonifer, Fusarium oxysporum f. sp. albedinisand Aspergillus brasiliensis ATCC 16404) was determined by the disc volatilization method and agar dilution method. The EO is considered moderately active against gram-negative strains (E. coli, S. abony), and those of gram-positive (S. aureus, B. subtilis). S. abony was the most sensitive bacteria, providing the lowest growth with an MIC equal to 0.156 mg mL-1. However, the mycelium growth was totally inhibited in the presence of the vapor generated by 0.5 µl mL-1 air for Alternaria sp.