Preparation and in vitro Immunoreactivity of <i>Rosa rugosa</i> Polysaccharide Liposomes

Abstract

Background: Rosa rugosa polysaccharides (RRP), a principal active component derived from R. rugosa Thunb., exert immunomodulatory effects. However, their therapeutic application is limited by rapid metabolism, short duration of action, and low bioavailability. Objectives: To optimize the preparation process of Rosa rugosa polysaccharide liposomes (RRPL) and evaluate their immune cell activation in vitro. Methods: The RRPL were prepared using the reverse-phase evaporation method, with encapsulation efficiency (EE) as the primary evaluation criterion. An orthogonal test was employed to optimize the preparation parameters. Various characteristics of RRPL were assessed, including morphology, particle size, Polydispersity Index (PDI), zeta potential, cumulative release rate in vitro, and stability. The immunological effects of RRPL were evaluated through cellular assays involving mouse spleen lymphocytes, peritoneal macrophages, and bone marrow-derived dendritic cells (BMDCs). Results: The RRPL demonstrated an EE of approximately 81.96%, an average drug loading (DL) capacity of 13.86%, a particle size of 124.00 nm, a PDI of 0.23, and a zeta potential of -12.97 mV. The formulated RRPL exhibited high EE and DL capacity, alongside favorable slow-release properties and stability. These enhancements led to improved drug bioavailability and prolonged duration of action. Furthermore, RRPL significantly promoted the proliferation of spleen lymphocytes; enhanced the phagocytic activity of peritoneal macrophages; increased the secretion of interleukin (IL)-6, IL-1β, and interferon (IFN)-γ; activated immature BMDCs; and induced the maturation of BMDCs, resulting in increased production of IL-12p70 and tumor necrosis factor (TNF)-α. Conclusions: This study successfully developed RRPL that markedly enhance immune cell activation compared with RRP. These findings provide a theoretical foundation for further exploration and development of these liposomal formulations.