Degradation of polysaccharides from Lycium barbarum L. leaves improves bioaccessibility and gastrointestinal transport of endogenous minerals.

Acidic heteropolysaccharide (LP) from Lycium barbarum L. leaves has compact globular structure which wrapped abundant endogenous minerals inside by ionic interactions with uronic acid. This study investigated the efficacy of chemical degradation of LP on the bioaccessibility and transport of endogenous minerals in simulated gastrointestinal fluids. Results showed that the degradation using vitamin C and hydrogen peroxide mildly decreased LP molecular weight from 162.0 kDa to 94.3 kDa, and the structure of degraded LP (LPD) was converted to loose coil. After the simulated intestinal digestion, the accessibility of Ca, Fe, Zn, and Mg in LPD increased by119%, 52%, 103% and 112.5% compared with the intact LP, respectively, and in particular, the uptake rate increased by 15.8%, 8.1%, 23.4% and 21.6% for Ca, Fe, Zn, and Mg, respectively. These results demonstrated that the chemical degradation is a helpful strategy to improve the uptake of endogenous minerals wrapped in polysaccharide.

Degradation enhances the anticoagulant and antiplatelet activities of polysaccharides from Lycium barbarum L. leaves.

In the current study, a carboxyl-rich polysaccharide purified from Lycium barbarum L. leaves (hereafter, LP) and its degradation with ascorbic acid and hydrogen peroxide were characterized. Degradation decreased the molecular weight of LP from 4.63 × 104 to 3.45 × 104 Da, and increased its zeta potential from -8.01 to -5.35 mV. In vitro experiments showed that degradation significantly increased the anticoagulant activity and, in particular, antiplatelet activity of LP (p < 0.05). The polysaccharide with the highest degree of degradation had higher inhibitory activity than aspirin against arachidonic acid- and thrombin-induced platelet aggregation at 0.5 g/mL. A reduction in uronic acids between LP and its degradation products significantly decreased their antiplatelet activity (p < 0.05). Further analysis confirmed that polysaccharides changed from a compact spherical structure to a random coil in aqueous solution following degradation, which facilitated the interaction of polysaccharides and platelets.