Antimicrobial activity and chemical composition of essential oil and hydrosol extract of Nepeta nepetella subsp. amethystina (Poir.) Briq. from Algeria.

ABSTRACT

The essential oil and hydrosol extract of Nepeta nepetella subsp. amethystina, obtained by hydrodistillation and analysed by GC, GC–MS, 1H and 13C NMR, were evaluated for their antimicrobial activity using disks diffusion method and MICs against thirteen pathogenic microorganisms. The chemical analysis of essential oil and hydrosol extract allowed the identification of 34 and 12 constituents representing 96.77% and 80.07% of total oil and hydrosol extract, respectively. The two isomers 4a,7,7a-nepetalactone and 4a, 7, 7a-nepetalactone were found to be the major components in N. amethystina essential oil and hydrosol extract, , 7-nepetalactone and 4a,7a,7respectively. The two isomers 4a -nepetalactone were found to be the major components in N.7a amethystina essential oil and hydrosol extract. Candida albicans strains were the most sensitive microorganisms towards N. amethystina essential oil and hydrosol extract, which have the largest inhibition zones (˃30mm) and the lower MICs values (<1.25%). The anti-mold activity, carried out by the diffusion method, showed that N. amethystina essential oil has a very interesting activity against Aspergillus flavus and Cladosporium herbarium.