This study evaluated the chemical composition and biological potential of Lepidium sativum and Nigella sativa seeds from Biskra, Algeria, aiming to produce high-quality extracts for medicinal or food applications. Three extraction methods were applied using four solvents: hexane, chloroform, methanol, and water. The aqueous extract of L. sativum obtained by Soxhlet had the highest polyphenol content (252.08 mu g GAE/mg). At the same time, ultrasound-assisted methanol extraction yielded the highest polyphenol content for N. sativa (180.6 mu g GAE/mg). The highest flavonoid content was found in both species' methanolic extracts obtained by ultrasound-assisted extraction. HPLC-DAD analysis of methanolic extracts identified seven phenolic compounds and six flavonoids in L. sativum, while N. sativa contained eleven phenolic acids and five flavonoids. Antioxidant activity, measured by DPPH, ABTS, FRAP, and Phenanthroline assays, demonstrated that aqueous and methanolic extracts had superior radical scavenging and reducing potential. Enzymatic activity assays showed that ultrasound extraction improved alpha-amylase inhibition in L. sativum, particularly with chloroform extracts (IC50: 5.40 mu g/mL). N. sativa seeds demonstrated remarkable inhibitory activity with hexane extracts, achieving IC50 values below 6.26 mu g/mL across all extraction methods.