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

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.

Antioxidant activity and phytochemical screening of Nepeta nepetella aqueous and methanolic extracts from Algeria.

Plant phenolics constitute one of the major groups of components that act as primary antioxidant free radical terminators. This paper reports the antioxidative activity of methanolic and water extract of Nepeta nepetella. Phytochemical screening of the crude extracts of stems, leaves and flowers revealed the presence of different kind of chemical groups such as flavonoids, tannins, alkaloids, saponins and carbohydrates. The amounts of total phenolics solvent extracts (methanol and water extract) for the three parts of plant were determined spectrometrically. From the analyses, leaves methanolic extract had the highest total phenolic content (58.11± 1.24 mg GAE/g), the highest DPPH scavenging ability with the lowest IC50 value (1.45 ± 0.07 mg/ml), the same tendency was observed with ferric reducing power. Concerning β-carotene bleaching assays results showed that the stems methanolic extract exhibited the highest antioxidant ability with an IC50 higher than standards (0.148 ± 0.003 mg/ml).