Stevia rebaudianaBertoni (Stevia), is a plant species in the genus Stevia. This study aimed to explore the main active constituents of dried Stevia leaves. Besides, the antimicrobial and cytotoxic properties of 6 Stevia extracts (aqueous, methanol, ethanol, acetone, chloroform, and petroleum ether) were assessed. Stevia leaves were dried by solar energy then the proximal chemical analysis and the total antioxidant capacitywere conducted. The antimicrobial effects of the 6 different solvent extracts of Stevia leaves were assessed against 7 different pathogens using agar well diffusionmethod. Furthermore, the cytotoxic effect of the 6 Stevia extracts was assessed against human breast carcinoma cell line MCF7. Stevia leaves have good nutritional value as well as have a good amount of total antioxidant capacity, total phenols and total flavonoids (20.788mg AAE/g, 29.5 mg GAE/g and 7.105 mg QE/g, respectively). All Stevia extracts decreased the growth of MCF7 cells. The IC50 of acetone, chloroform, water, ethanol, petroleum ether, and methanol were 150, 100, 374, 180, 79, and 228 µg/ml, respectively. The petroleum ether Stevia leaves extract exerted the most potent cytotoxic activity against MCF7. The aqueous extract of Stevia leaves was the most effective against Bacillus cereus, Salmonella typhi, Pseudomonasaeruginosa, Listeria monocytogenes, Escherichiacoli, and Bacillus cereus. The methanolic extract was the most effective extract against Staphylococcus aurous andAspergillusflavus. In conclusion, Stevia leaves contain considerable amounts of several macro and micronutrients. The aqueous extract of Stevia leaves has a significant potential antimicrobial action. Besides, the petroleum ether extract of Stevia leaves was the most potent cytotoxic extract against MCF7 cancer cells.
