ABSTRACT Background: Natural products remain crucial as a foundation for drug discovery. Lactuca serriola (L), a member of the family Astereceae, is one of such plants used in traditional medicine. Objective: The present research aims to evaluate the biological activity of L. virosa leaf extract as antioxidant and antibacterial agent, Methods: Different concentrations of ethanol (Solvent A (100%), Solvent B (75%), Solvent C (50%), and Solvent D (25%)) and distilled water (Solvent E) were used for extraction of Lactuca serriola (L.) leaf parts by maceration method. Extracts at concentrations of 100, 75, 50, and 25 mg/ml were prepared for each solvent to detect antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus using agar well diffusion method. The antioxidant activity was assessed using the DPPH assay. Results: Solvent A achieved the highest antioxidant activity, while Solvent D recorded the lowest effect. All concentrations of extracts inhibited bacterial growth, and the inhibition effect increased with increasing extract concentration. The highest inhibition zone against S. aureus was recorded at Solvent D with 100 mg/ml (Mean ± SD = 26.00±2.65 mm), while the highest inhibition zone against P. aeruginosa was recorded at Solvent I with 100 mg/ml (Mean ± SD = 26.00±2.65 mm). Conclusion: the possibility of using ethanolic extracts as antibacterial and antioxidant agent
AL-Saeedi et al. (Sun,) studied this question.