Caractérisation partielle des polysaccharides hydrosolubles extraits des fruits de Ziziphus lotus: composition biochimique et Activité antioxydante

Abstract

Water-soluble polysaccharides extracted from the fruits of Ziziphus lotus (Rhamnaceae), a spontaneous medicinal plant, are attracting increasing interest due to their potential biological activities. This study aims to extract, characterize, and evaluate the antioxidant activity of water-soluble polysaccharides obtained from the fruits of Ziziphus lotus collected in the Ghardaïa region. The extraction was carried out by hot maceration, yielding a mass recovery of 6.40%. Biochemical characterization of the water-soluble polysaccharide extract from Ziziphus lotus fruits (PSZL) was performed using colorimetric methods. Total sugars were quantified using the method of Dubois et al. (1956), protein content was determined using Bradford's method (1976), and total polyphenols were quantified using the Folin-Ciocalteu method. The analyses revealed contents of 73.18 ± 0.034% total sugars, 31 ± 0.05% neutral sugars, 4 ± 0.11% proteins, and 1.5 ± 0.007% polyphenols. Monosaccharide composition analysis by thin-layer chromatography (TLC) identified the presence of arabinose, fructose, galactose, glucose, mannose, ribose, xylose, as well as galacturonic acid (Gal.A) and glucuronic acid (Glc.A). Antioxidant activity, assessed through DPPH• radical scavenging assay, showed a notable effect with an IC₅₀ value of 79.51 ± 0.45 µg/mL, indicating significant free radical neutralization potential.