Phytochemical screening and antibacterial activity of rosmarinus officinalis l. against Escherichia coli. local isolates

Abstract

Rosmarinus officinalis is a medicinal plant which belongs to family Lamiaceae. It is an evergreen bush. It was analyzed for its phytochemical constitution and antibacterial activity. For this purpose flowers, leaves and stem of aqueous and methanolic extracts were used. The tests of phytochemical screening showed that flavonoids, terpenoids, reducing sugar and saponins were present in different concentrations, while tannin was absent in all parts of plant. The antibacterial activity was determined against E. coli with different concentrations (i-e 0.5gm, 1gm and 1.5gm) kept for 24 hours and 48 hours duration. The results showed that the highest mean inhibition zone was observed in the methanolic extracts of leaves 1.5gm kept for 48 hours (28.6 ± 4.261mm).In the stem the methanolic extracts showed the highest inhibition zone with the concentration of 1.5gm (13.4 ± 1.624mm) kept for 24 hours. In the flower the highest inhibition zone in methanolic extracts was observed in 1gm (25.4 ± 2.416mm) kept for 48 hours. In the aqueous extracts the highest inhibition zone values were (17.6 ± 4.029mm, 15.8 ± 2.993mm, 14.4 ± 2.33mm) for stem, flower and leaves respectively.