High-pressure ultrasonic-assisted extraction of polysaccharides from Hovenia dulcis: Extraction, structure, antioxidant activity and hypoglycemic

In this study, high-pressure ultrasonic-assisted extraction (HUE) technology was used for polysaccharide extraction from Hovenia dulcis (HDPS). A maximal extraction yield (11.81 ± 0.26%) was obtained using the response surface method (RSM) with optimized HUE conditions (Ultrasound power 330 W, 68 °C, and 22 min). Results showed that HDPS mainly contained neutral sugar (47.81 ± 1.56%), uronic acid (12.52 ± 0.15%), and protein (3.64 ± 0.24%), specifically. HDPS was comprised of mannose, rhamnose, galacturonic acid, glucose, galactose and arabinose in a molar ratio of 3.20%, 20.40%, 4.81%, 11.14%, 27.37% and 33.08%, respectively. And with an average molecular weight of 185.22 kDa for its major component (accounting for 90.13% for HDPS). The result obtained from the X-ray diffraction pattern confirmed a semi-crystalline nature of the sample. HUE-HDPS suggested typical shear thinning behavior and non-Newtonian properties. Additionally, HUE-HDPS exhibited better chemical antioxidant activities in DPPH, ABTS, hydroxyl radical scavenging and Fe2+ chelation activity. The in-vitro and in-vivo experiments indicated that HUE-HDPS had obviously hypoglycemic effects. Accordingly, the polysaccharides from Hovenia dulcis might serve as a natural antioxidant and hypoglycemic agent.