The following study was conducted to investigate the efficacy of several leaf and berry extracts against a range of food-borne pathogens and food spoilage bacteria. The methanol, ethanol, and ethyl acetate extracts of Myrtus communis leaves and berries were examined for in vitro antibacterial activity. The methanolic leaf extract of M. communis, which was seen to have antibacterial activity against Listeria monocytogenes CECT 4032 and Pseudomonas aeruginosa IH, was further investigated to determine the effect of the extract on viable counts of bacteria using the bacterial cell-death time. Most of the extracts showed relatively high antibacterial activity against most of the tested microorganisms. None of the extracts was active against Escherichia coli K12. The results obtained confirm the antibacterial potential of the extracts of M. communis.

The total phenolic content and antioxidant activity of methanolic, ethanolic and aqueous extracts of myrtle (Myrtus communis) leaves and berries were measured to find new potential sources of natural antioxidants. Total phenolic content was assessed by the Folin-Ciocalteau assay, while the antioxidant activity was evaluated by three methods: diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, the reducing antioxidant power assay and β-carotene linoleic acid assay. The total phenol content of myrtle extracts ranged between 9.0 and 35.6 mg GAE per g extract. For each solvent, leaf extracts contained significantly higher amount of total phenolic compounds than berry extracts. All of the extracts presented antioxidant capacity assessed by the three methods, but at different levels depending on the concentration, the extraction solvent and the part of the plant used. Generally, leaf extracts showed higher antioxidant activities than berry extracts, while the overall antioxidant strength was in the order methanol > water > ethanol in leaf extracts and methanol > ethanol >water in berry extracts. The phenolic content exhibited a positive correlation with the antioxidant activity: DPPH assay showed the highest correlation (r = 0.949), followed by the reducing power assay (r = 0.914) and the lowest for the β-carotene linoleic acid assay (r = 0.722).

The essential oil of Origanum elongatum is known by numerous biological activities, which are linked to its chemical composition. The aim of this study was to evaluate the effect of hydro-distillation time on the chemical composition and the antibacterial activity of the essential oil extracted from the aerial parts of O. elongatum growing in the north of Morocco. The essential oil fractions were captured at nine regular time intervals after the beginning of hydro-distillation process. Maximum essential oil yield was achieved at a hydro-distillation time of 140 min. The dissolved volatile fraction was extracted from the hydrosol at the end of hydro-distillation process. The chemical composition was determined by GC-FID and GC/MS. The chemical profile of the essential oil showed the predominance of oxygenated compounds (65.14 %) followed by hydrocarbon compounds (28.02 %). Thymol accounted for 63.44 % of the total EO. Dissolved volatile fraction was dominated by oxygenated monoterpenes with 91.93 % of thymol. The results revealed that hydro- distillation time produces oil fractions with specific chemical profiles. The antibacterial activity was tested against four bacterial strains. The results showed that essential oil fractions captured from 80 to 160 min had greater antibacterial activity than fractions recovered at the beginning of the distillation and the whole oil. The inhibitory zones diameters were linearly correlated with the increase of thymol concentration in each fraction up to 160 min (r-Pearson ranges between 0.95 and 0.97 with p < 0.0001). The strongest activity was observed with essential oil fractions from 141 to160 min of hydro-distillation time with MIC values ranged from 0.0312 to 0.125 % (v/v) and MBC from 0.0312 to 0.25 % (v/v). These data may help to reduce the cost and the time of essential oil extraction and to select the oil fraction with desirable composition for it use in pharmaceutical, cosmetic or food industries.