Two structurally distinct polysaccharides from Cistanche deserticola Ma: Isolation, purification, characterization, and functional activities

As a valuable traditional Chinese herb with both edible and medicinal properties, Cistanche deserticola has been used in China for millennia. Two water-soluble homogeneous polysaccharides, CDPs-A2 (8.119 kDa) and CDPs-C1 (117.263 kDa), were isolated from C. deserticola and systematically characterized for their physicochemical properties, structural characteristics, and bioactivities to evaluate potential applications. Structural characterization revealed that CDPs-A2 is a glucan with a 1,4-linked α- D -Glc backbone and mild 1,6-linked α- D -Glc branching. In contrast, CDPs-C1 was identified as an acidic polysaccharide mainly composed of Ara (62.58 %), Gal (14.25 %), Rha (13.05 %), GalA (5.89 %), GlcA (3.19 %), Glc (0.71 %), and Man (0.34 %), featuring a backbone of 3,5-Ara f , 5-Ara f , t-Ara f , 2,4-Rha p , and 4-GalA p residues. Functional evaluation demonstrated that CDPs-A2 exhibited superior antioxidant activities, α-glucosidase and cyclooxygenase-2 inhibition activities than CDPs-C1. At a concentration of 4 mg/mL, CDPs-A2 showed significantly higher radical scavenging activity (83.5 % DPPH, 64.5 % ABTS) than CDPs-C1 (47.51 %, 44.87 %). The IC 50 values of Vc were 5.587 μg/mL and 2.576 μg/mL, respectively. CDPs-A2 showed lower IC 50 values than CDPs-C1 against both α-glucosidase (5.24 vs 14.3 mg/mL) and cyclooxygenase-2 (1.87 vs 9.98 mg/mL), though higher than reference drugs acarbose (0.103 μg/mL) and celecoxib (9.249 ng/mL). The enhanced activity may be related to lower Mw and higher Glc content. This work provides the first systematic comparison of both structural characteristics and multiple bioactivities of C. deserticola polysaccharides. These efforts will not only facilitate the clinical application of C. deserticola polysaccharides but also serve as a valuable reference for their industrial development and in-depth exploration of health benefits. • Two polysaccharides (CDPs-A2 and CDPs-C1) were purified from Cistanche deserticola . • CDPs-A2 was a 1,4-linked α-glucan with mild branching composed of 1,6-linked α- D -Glc. • CDPs-C1 was mainly composed of Ara (62.58 %), Gal (14.25 %), Rha (13.05 %), GalA (5.89 %), and GlcA (3.19 %). • CDPs-A2 and CDPs-C1 were demonstrated to exhibited potential antioxidant activity. • CDPs-A2 and CDPs-C1 exhibited potential inhibition of α-glucosidase and cyclooxygenase-2 in vitro .