Etude de l’activité antioxydante et le pouvoir antibiofilm des extraits de plante Artemisia herba alba et Thymus capitatus

Abstract

Natural plant extract it contain a variety of phenolic compounds which are assigned various biological activities. For this we have established an experimental study to determine the antioxidant activity, the antibacterial effect and the antibiofilm potentiel of crude extracts obtained from two plants that have high pharmaceutical value, are the Thymus capitatus (L.) and Artemisia herba alba (Asso). The total content of phenolic compounds was determined using the Folin-Ciocalteu, it is (161,64mg / ml) and (131,48mg / ml) in the extracts of Artemisia herba alba and Thymus capitatus, respectively. Flavonoids have been measured using the method of aluminum chloride (AlCl3), their content is (16,83mg / ml) and (14.96 mg / ml) in the extracts of Artemisia alba herba and Thymus capitatus, respectively. The methanolic extract of Artemisia herba alba shows a higher content of polyphenols and flavonoids with respect to the methanol extract of Thymus capitatus. The antioxidant capacity was evaluated by using technique of free radical (DPPH) and the reduction of iron (FRAP). For the first test the IC50 values was estimated (2,35mg / ml) and (13,62mg / ml) for the extract of Artemisia herba alba and Thymus capitatus, respectively. The extract of Artemisia herba alba exhibited good antioxidant activity with a high percentage of free radical scavenging compared to T. capitatus extract. For the second test Artemisia herba alba extract (1.131 ± 0.001) represented the highest activity in comparison with the extract of T. capitatus (0.721 ± 0.001). Evaluation of the antimicrobial activity of the methanolic extracts by the well diffusion method in a solid medium, showed that the two extracts have antibacterial power over all tested strains of Staphylococcus aureus and Bacillus cereus. The preventive effect of plant extracts and enzymes against growth and biofilm formation showed that both extracts Artemisia herba alba and Thymus capitatus have a greater effect on the inhibition of biofilm formed by the strains studied than both enzymes proteinase K and trypsin.