Biological Activity Test of the Alcoholic Extract of the Leaves of Catharanthus Roseus (L.) G.Don Treated With Sodium Chloride, Nitrogen, and Selenium in Inhibiting the Growth of Gram-Positive and Gram-Negative Bacteria

Aims: this study aimed to determine the biological activity test of the alcoholic extract of the leaves of catharanthus roseus. materials & methods: catharanthus roseus was used in the implementation of the experiment and it included three factors: the first factor is watering the plants with three concentrations of sodium chloride salt (0, 50, and 100mmol) of sodium chloride, the second factor is three concentrations of nitrogen (urea) (0, 100 and 200mg.l-1) and the third factor three concentrations of selenium (na2seo4; 0,25 and 50mg.l-1), then tested the biological activity of plant leaf extracts from all treatments against gram-positive staphylococcus aureus and gram-negative escherichia coli bacteria through measure the diameters of the areas of inhibition of bacterial growth. findings: the results of the laboratory experiment showed that the extract of the leaves of triple combination plants (100mmol nacl+200mg.l-1 n+50mg.l-1 se) achieved the largest inhibition area for the growth of e. coli reaching 27.50mm compared to the control, which is 4.20mm, and plant leaf extract in the combination (100mmol nacl+100mg.l-1 n+50mg.l-1 se) recorded the largest inhibition area in s. aureus reached 50.27mm compared to the control which recorded 9.10mm. conclusion: the plant leaf extract had an important role in inhibiting the growth of the bacteria studied, and the highest inhibition was observed in the interaction between the three factors salt, nitrogen, and selenium.