Ultrasound and enzyme extraction of Pleioblastus amarus shoot polysaccharide: A comparative study on chemical characterization, antioxidant, and anti-aging activities.

Pleioblastus amarus shoot is a critical dietary staple for the giant panda and a traditional medicinal resource for preventing senility, with polysaccharides being one of its primary active ingredients. In this study, we extracted polysaccharides using five distinct extraction techniques, including hot water (HWA-BSP), ultrasound (UA-BSP), enzyme (EA-BSP), and two sequential combinations of ultrasound-enzyme (UEA-BSP) and enzyme-ultrasound (EUA-BSP), and systematically investigated the effects of different extraction method on yield, structural characteristics, and biological activities of the five polysaccharides. The extraction method with superior anti-oxidant ability was identified and its anti-aging efficacy was subsequently evaluated through in vivo experiments. Our results demonstrated that while all five polysaccharides shared similar monosaccharide compositions and triple-helical structures, the UEA-BSP method achieved the highest yield (4.73%) and the lowest molecular weight. It also showed the greatest scavenging abilities of DPPH, ABTS, and hydroxyl radical, and superior protection effect on IPEC-J2 cells against H2O2-induced oxidative injury. Therefore, UEA-BSP was selected to confirm its anti-aging ability in D-galactose induced aging mice. UEA-BSP restored: 1) cognitive function (Morris water maze), 2) hippocampal morphology (H&E staining), and 3) antioxidant enzyme activities (CAT, SOD, GSH-Px) along with MDA level, confirming its potent anti-aging bioactivity. Overall, this study demonstrates that sequential ultrasound-enzyme extraction significantly enhances polysaccharide yield and antioxidant activity, providing valuable insights and a foundational data reference for further investigations into the anti-aging potential of P. amarus polysaccharides in functional food and nutritional applications.