The stability and absorption of naturally occurring cAMP by its weak interactions with jujube polysaccharides were greatly improved

Cyclic adenosine monophosphate (cAMP) has received considerable attention because it naturally occurs in jujube fruit and possesses many activities such as antitumor activity. However, its poor membrane permeability limits its applications in food industry. In this study, we found that polysaccharides likewise derived from jujube (ZJP) are able to increase the membrane permeability of cAMP for the first time. To elucidate the mechanism, the interactions of cAMP and ZJP were determined by spectroscopic, thermodynamic and molecular docking methods. Results showed that acidic polysaccharide (ZJPA) owned a stronger affinity to cAMP as compared to neutral polysaccharide (ZJPN). Consequently, the binding of ZJPA to cAMP existed a better synergistic antioxidant capacity and also protected ZJPA against pH-induced degradation. More importantly, the formed ZJPA-cAMP complexes exhibited much better bio-accessibility than unbound cAMP as was approved by Caco-2 cell absorption experiment. These new findings are beneficial for designing polysaccharide-based nanocarriers for cAMP.