Etude d’activité anti-oxydante et activité antibactérienne d’une plante médicinale de la région d’Ain Témouchent

Abstract

This work aims to study the antimicrobial and antioxidant activity of the essential oil of a medicinal and aromatic plant: the bay laurel (Laurus nobilis). The essential oil was extracted by hydrodistillation. The antioxidant activity of the studied oil using the DPPH method showed a very promising antioxidant effect. This is a value very close to the IC50 of ascorbic acid (vitamin C), while the antioxidant power is stronger than that of BHT. The FRAP test results for bay leaf oil confirmed and agreed with the DPPH test results, revealing that Laurus nobilis oil has a very high reducing capacity, far superior to BHT and very close to ascorbic acid, confirming its status as a first-class antioxidant oil. The antimicrobial activity was studied against five strains: three Gram-negative bacterial strains (Escherichia coli, Citrobacter freundii, and Klebsiella pneumoniae), two Gram-positive bacterial strains (Enterococcus faecalis and Bacillus cereus), and one fungal strain (Candida albicans). With the exception of the bacterium Klebsiella pneumoniae, the essential oil of L. nobilis showed excellent inhibitory activity against all other tested strains, with efficacy ranging from moderately sensitive to extremely sensitive. It should also be noted that this oil proved particularly active against Gram-negative bacteria, especially Escherichia coli, more so than against Gram-positive bacteria and yeasts. These results highlight the great potential of essential oils as natural alternatives to conventional antimicrobial agents; however, further research is needed to understand the mechanisms of action and explore the potential therapeutic applications of essential oils.