Abstract
The study aims to elucidate the physicochemical properties and immunomodulatory activity of two polysaccharides (ACP t0 and ACP t2) from Abrus cantoniensis. Results revealed that ACP t0 with a molecular weight of 26.0 kDa, was mainly composed of glucose (83.1%) and galactose (6.1%), and that ACP t2 with a molecular weight of 145.6/8.9 kDa, consisted of galactose (25.6%), galacturonic acid (22.2%), arabinos (16.6%) and galactose (11.0%) respectively. AFM and Congo red experiments suggested that ACP t0 and ACP t2 might be spherical particles with triple-helix conformation in aqueous solution. ACP t0 and ACP t2 exhibited immunomodulatory activity by promoting the proliferation, augmenting pinocytic and phagocytic capacities, releasing immunoactive molecules such as ROS, NO, iNOS, TNF-α, IL-6 and IL-1β, upregulation of the mRNA levels of corresponding cytokines in macrophages. Moreover, ACP t0 and ACP t2 were recognized by toll-like receptor 4 (TLR4) and exerted immunomodulatory effects via activating Myeloid differentiation factor 88 (MyD88), mitogen-activated protein kinases (MAPKs) and serine/threonine kinase (Akt) signaling pathways in macrophages. Notably, ACP t2 had higher immunomodulatory activity than ACP t0. Based on the present findings, ACP t0 and ACP t2 could be explored as an active component of immunomodulators in the food and pharmaceutical fields.