Food industries and consumers are concerned about the negative effect of synthetic preservation and there is growing interest in applying natural alternatives additives for their antioxidant and antimicrobial activities. Therefore the objective of the present work was to evaluatetotal polyphenol, antioxidant activity and antibacterial activity of Moringa (M. oleifera), Olive (Olea europaea), Rosemary (R. officinalis) and Oregano (O. vulgar) dried leaves powders and their extracts. The results revealed that the extracted yield of plant leaves was ranged from 19.82% for rosemary to 30.27% for moringa. The result showed that plant leaves extracts have higher phenolic content than plant leaves powder Whereas, total polyphenols content were ranged from 26.41 to 50.13  mg GAE/g extract for oregano and olive, respectively while it was 9.19  and 17.22 mg GAE/g powder for rosemary and olive, respectively. DPPH radical scavenging activity are ranged in ascending order from 18.45 to 31.81 µmol troloxE/g  of leaves powder for rosemary and moringa, respectively while from 61.80 to 90.20 µmol troloxE/g of leaves extract for oregano and moringa, respectively. The antibacterial activity against chosen bacterial strains are increased in the following order moringa < olive < rosemary < oregano in the plant powders and its extracts. The diameter of inhibition zone is varies between 4.33 mm for moringa powder to 8.00 mm for oregano powder in case of gram-negative bacteria (Escherichia coli) and from 20.66 mm for moringa extract to 29.33 mm for oregano extract in case of gram-positive bacteria (Staphylococcus aureus). The results of present work indicated that plant leaves extracts are very effective as antioxidant and antibacterial than plant leaves powders. Also results indicated that there were significant differences between different plant leaves.