Résumé
Polysaccharides were extracted from Ononis natrix leaves using various methods, including hot water maceration (HWM), ultrasound-assisted extraction (USE), enzyme-assisted extraction (ENE), combined enzyme-ultrasound (EUS) and combined maceration-ultrasound (MUS) treatment. The extracted crude polysaccharides were characterized in terms of physicochemical, structural, techno-functional features, and biological activities. HWM extraction showed the highest yield (13.7 +/- 0.3%), carbohydrate content (54.1 +/- 1.4%), and uronic acid content (23.7 +/- 0.8%) compared to other methods. The various polysaccharides were characterized using SEM, FT-IR, NMR, and TGA. All polysaccharides obtained using different methods present similar structural characteristics and exhibit outstanding techno-functional properties (solubility, water-holding capacity, and emulsifying properties). The antioxidant and antibacterial activities of polysaccharides were evaluated using DPPH radical-scavenging capacity, ferric reducing activity power (FRAP), iron chelating capacity, total antioxidant activity, and agar diffusion test, respectively. The results indicate that HWM polysaccharides present the best overall biological activities. It is thus concluded that polysaccharides from O. natrix leaves could be a promising natural source as functional foods or potential therapeutic agents.