Extraction of Sanguisorba officinalis L. polysaccharide by ultrasound-assisted extraction: structural characterization, antioxidant, hemostatic and immunological activity.

Sanguisorba officinalis L. (S. officinalis) has been widely distributed in various regions of China and holds significant potential for various applications. However, limited studies have focused on S. officinalis polysaccharides (SOPs) and their biological activities. Utilizing response surface methodology (RSM), the process of ultrasonic-assisted extraction of SOPs was optimized. The optimal conditions were 270.2 W, 42.4 mL/g, and 47.7 min. Through separation and purification, a neutral polysaccharide named SOUP-1 was obtained. SOUP-1 (17.1 kDa) mainly includes glucose and a few galactose, mannose, and arabinose. The main chain of SOUP-1 is primarily → 4)-α-D-Glcp-(1 → 4,6)-α-D-Glcp-(1 → substituted at C6 with branch chain → 6)-α-D-Glcp-(1 → . Furthermore, SOUP-1 showed antioxidant activity, including scavenging activities of hydroxyl radicals and DPPH. It also enhances macrophage phagocytic activity and modulates the expression of inflammatory cytokines such as TNF-α and IL-6. Additionally, this study first discovered the hemostatic activity of SOUP-1. This study provides theoretical support for the potential applications and further research of SOPs. It provides a basis for the development of SOPs as novel natural-source immunomodulators in the food and pharmaceutical industries.