Bioactive compounds, antioxidant and antimicrobial activities of leaves extracts as affected by various solvents and extraction methods.

The different species of plant can be found in all over the world, and a wide range of medicinal applications has been mentioned for them. Thus, it can also be valued as a source of natural compounds with antioxidant and antimicrobial activities. In this study, the effect of solvents (water, ethanol, ethanol:water (50:50)) and extraction methods (maceration and ultrasound) on the extraction yields and bioactive properties of extracts were analyzed. The antioxidant capacity of leaves extracts was investigated, and the concentrations of total phenolics, tocopherols, tannins and flavonoids were determined. 1,1-diphenyl 2-picrylhydrazyl free radical (DPPH), β-Carotene bleaching, and oxidative stability index (OSI) were used to determine antioxidant activity. The ability to scavenge radicals was measured in these experiments by the discoloration of the solution. Also, the antimicrobial activity of different extracts against Gram-positive () and Gram-negative bacteria ( and was evaluated by using of microdilution and agar diffusion assays. The results demonstrated that ultrasonic extracts (especially ethanol:water (50:50) solvent) had the higher extraction yield and antioxidant potential than maceration extracts. All extracts were effective against all tested bacteria, and was the most sensitive bacterium with lowest MIC value (12.5 mg/ml) and biggest diameter of growth inhibition zone (13.77 mm). Generally, this leaves extracts can be suggested as an economical source of antioxidant and antimicrobial agents and can be a suitable substitute for artificial and chemical food preservatives.