Effect of Ultrasound-Assisted Extraction on Polyphenol Content and Free Radical Scavenging Activity of Prickly Pear Cactus Leaves (Opuntia littoralis)

Prickly pear cactus leaves have shown potential as a functional food due to their valuable biocompounds, particularly polyphenol bioactive compounds which contain antioxidants that offer significant health benefits. The study examines the effect of varying ultrasound-assisted extraction (UAE) parameters ultrasound power, time, phenolic material size, and solid-to-solvent ratio on the phenolic extraction efficiency of prickly pear cactus leaves. Determination of the polyphenolic content and antioxidant capacity was accomplished through spectrophotometric analysis using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Results indicated that all tested concentrations were effective, with the material size being the most significant factor. Optimal conditions were 0.5 mm material size and a solid-to-solvent ratio of 1:4 w/v, achieved under an ultrasound power of 20 W/g for 10 minutes. Under these conditions, the extract exhibited its highest scavenging ability against DPPH free radicals, reaching 78.8±2.05% and polyphenol ground reached 7.39±0.20 mgGAE/g. Keywords: Opuntia littoralis, antioxidant activity, bioactive phytochemicals, free radical scavenging, ultrasound-assisted extraction