Total phenolic contents, antioxidant and antibacterial activities of Limoniastrum guyonianum (Plombaginaceae) extracts

This work was carried out to study the antioxidant capacity and antibacterial activity of Limoniastrum guyonianum (Plombaginaceae) extracts, traditionally used in folk medicine in Algeria. The aerial part were submitted to extraction by water and methanol to give methanolic (Met.E) and aqueous (Aq.E) extracts with that yields are 10%and 17,5% respectively. Quantitative analysis of polyphenols and flavonoids content showed that the Met. E had the highest amount (285.37µg EAG/mgE and 44.11µg EQ/mg E, respectively). The antioxidant activity of extracts was evaluated by 2,2’-diphenyl-1-picrylhydrazyl (DPPH) and ABTS free radical-scavenging test. Results showed that the Met. E exhibited the highest antiradical activity against DPPH and ABTS free radical with EC50=0,099 mg/ml, and EC50=0.024mg/ml, respectively. Moreover, the antibacterial activity was determined on the five bacterial strains, using disk diffusion method. The Met. E showed inhibition zone averages only on M. luteus, and S. aureus (12 and 13 mm respectively) and with MIC is 25 μg/ml. Our results showed that the methanolic extract of L. guyonianum reported a considerable antioxidant and antibacterial activities which may be due to their richness on polyphenols and flavonoids.