Structural characterization and antifungal properties of sequentially extracted polysaccharides from Algerian Opuntia...

Opuntia ficus-indica L., a xerophytic cactus native to arid regions, is an understudied source of structurally varied polysaccharides with potential for bioactivity. Four different types of substances were separated in this study, which is the first time this method has been used for Algerian varieties: cellulose (19.1%), pectins (7.20%), hemicelluloses (2.57%), and water-soluble mucilage (8.84% of dry mass). Pectins rich in homogalacturonans (33.5% galacturonic acid) and rhamnogalacturonans (30% rhamnose) were identified by monosaccharide profiling, along with hemicelluloses that were dominated by xylose (55.9%). FTIR spectroscopy validated structural signatures, such as β-glycosidic linkages (890 cm ⁻ ¹) and carboxylate groups (1750 cm ⁻ ¹) in pectins. Penicillium sp. was shown to be dose-dependently inhibited by antifungal assays, with a 75% growth reduction at 100 mg/mL pectin concentration (*p* < 0.05 vs control). The structure of polysaccharides, especially the amount of carboxylate, is correlated with the observed bioactivity. Based on their biocompatibility and regional adaptability, these results establish Algerian O.ficus-indica polysaccharides as viable options for pharmaceutical and food preservation applications.