Purification and structural characterization of two polysaccharides with anti-inflammatory activities from Plumbago zeylanica L.

Plumbago zeylanica L., a traditional Chinese medicine, has anti-bacterial and anti-inflammatory effects, and it is critical important to explore the chemical compounds and evaluate their biological actions from the medicinal plant. However, the chemical structure and biological activities of polysaccharides from P. zeylanica. were still poorly understood. In this study, two water-soluble polysaccharides named WPZP-2-1 and WPZP-2-2 were purified from P. zeylanica L. Chemical and spectroscopic tests showed that the main chain of WPZP-2-1 was →4)-α-D-GalpA-(1 → 2)-α-L-Rhap-(1→, and the branch chain was galactose or arabinose. The main chain of WPZP-2-2 was composed of →4)-α-D-GalpA-(1 → 2)-α-L-Rhap-(1→, and the O-2 and O-3 of →4)-α-D-GalpA had a small amount of acetylation. In addition, in vitro test showed that WPZP-2-1 and WPZP-2-2 significantly improved the inflammatory damage of LPS + IFN-γ-induced THP-1 cells via reducing the protein levels of CD14, TLR4 and MyD88, thereby promoting IL-10 expression and inhibiting the mRNA levels of TNF-α and IL-1β. Those findings indicated that WPZP-2-1 and WPZP-2-2 from the plant should be served as the potential anti-inflammatory agents.