An active heteropolysaccharide from the rinds of Garcinia mangostana Linn.: Structural characterization and immunomodulation activity evaluation.

A previously undescribed polysaccharide, GMP70-1, was isolated from the rinds of Garcinia mangostana Lin. Physicochemical characterization analysis showed that GMP70-1 (absolute molecular weight: 2.01 × 104 g/mol) is a multi-branched acidic heteropolysaccharide with a compact coil chain conformation in sodium chloride solution. The repeated unit of GMP70-1 was mainly composed of (1 → 5)-linked α-L-Araf, (1 → 3, 5)-linked α-L-Araf, (1 → 2, 4)-linked α-L-Rhap, (1 → 4)-linked β-D-Galp, terminating with t-α-L-Araf, t-α-D-GalpA, and t-β-D-Galp. To explore the medicinal potential responsible for the bioactivity of G. mangostana, an immunomodulatory assay was performed. The in vitro cell test showed that GMP70-1 possessed a prominent immunoregulatory activity by enhancing the phagocytic uptake of neutral red and promoting the secretion of nitric oxide (NO), reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β of macrophages. Furthermore, an in vivo zebrafish evaluation revealed that the production of ROS and NO was significantly increased after treated with GMP70-1.