Juniperus phoenicea (Family: Cupressaceae) is an evergreen tree widely distributed in North Africa including Algeria. The aim of this investigation was to analyse the antimicrobial potential of essential oils from J. phoenicea on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Streptococcus sp, Bacillus sp and Candida albicans using wells and discs diffusion methods. Broth dilution method was utilized to study the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). The results showed a variable degree of antimicrobial activity. The diameters of inhibition zones for all test organisms were in the ranges of 7-21 mm, while MIC was from 62.5 to >500µl/ml and MBC from 250 to >500µl/ml. The highest antimicrobial activities were observed against Gram positive bacteria followed by Gram negative ones then Candida albicans. The findings provide the evidence that J. phoenicea as a good medicinal plant for further investigations.

No abstract

The objectives of this study were to optimize the conditions for cell growth and exopolysaccharides (EPS) production by using pure and mixed microbial cultures of Streptococcus thermophilus and Lactobacillus bulgaricus, and to evaluate the antioxidant and antibacterial activities of EPS in vitro. The mixed cultures of two strains showed a higher cell growth whereas the higher EPS production was detected in pure culture with S. thermophilus. The optimal medium were determined as follows (g/l): sucrose 50, yeast extract 10, KH2PO4 3 , MgSO4.7H2O 0.05 and pH initial 6.5 at 30°C. Under the optimized conditions, the values of dry cell weight (DCW) and EPS were 5.2± 0.8 g/l and 56.8 ± 0.62 mg/ml, respectively.  The EPS demonstrated a positive antioxidant potential on DDPH radical scavenging. The agar diffusion assay showed that purified EPS exhibited antibacterial activities against tested pathogens such as Escherichia coli ATCC 250922 and Staphyloccocus aureus ATCC 250923 at (62-1000) μg/mL. In conclusion, EPS have an antioxidant activity and could have applications in the food industry.

The purpose of this research was to evaluate the in vitro antibacterial activity of the essential oils from the resin of Pistacia lentiscus against Staphylococcus aureus (Gram–positive bacteria) and Escherichia coli (Gram–negative bacteria). The agar disc diffusion method was used for microbial growth inhibition at various dilutions of the oils. Results showed that the tested essential oils possess antibacterial activity against S. aureus but inactive on E. coli. These results may have significant implications for the future development of resin oils of P. lentiscus as an antimicrobial agent for the treatment of the infections caused by S. aureus.