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.

Antimicrobial effects of three essential oils on multidrug resistant bacteria responsible for urinary infections.

Urinary tract infections (UTIs) are ones of the most common nosocomial infections worldwide. Lesions which are mainly caused by microorganisms that inhabiting in hospitals, known and characterized by their both resistance against antibiotics and high ability of biofilms formation. In this study, we have evaluated the effect of three essential oils, which are Cinnamomum cassia, Coriandrum sativum and Ziziphora hispanica, against bacterial species most responsible for UTIs. A total of 18 bacterial strains were tested, which varies between reference strains and clinical multidrug resistant. Cassia oil was the most antimicrobial active against all strains, with interesting MICs values which doesn’t exceed 5 mg/ml. The finding of this study indicate that essential oil appears as an excellent solution for treatment of nosocomial UTIs, especially against failure problems seen in care services, which are over common in the last years.

Evaluation of antimicrobial activity of solvent extracts from different parts of Daucus crinitus Desf.

The objective of this work was to examine the phytochemicals present in different aqueous and organic extracts from different organs of Daucus crinitus Desf. and to evaluate their antimicrobial activity. Phytochemical screening was done to characterize the secondary metabolites in various solvent extracts, and antimicrobial activity was evaluated by agar disk diffusion and broth microdilution to determine inhibition zone diameters and MICs. A remarkable antimicrobial effect was observed in organic extracts of stems and seeds (MIC = 0.31-0.83 mg/ml on S. aureus, B. cereus, and C. albicans) containing many phytochemical families such as coumarins, flavonoids, reducing sugars, steroids, tannins, and terpenes. Daucus crinitus may be a good source of bioactive molecules endowed with antimicrobial activity.