Structural characterization and anti-inflammatory effects of an arabinan isolated from Rehmannia glutinosa Libosch.

Considering that natural polysaccharides are potential anti-inflammatory agents, in this study, an arabinan (RGP70-2) was isolated and purified from Rehmannia glutinosa Libosch. (R. glutinosa) and its structure was characterized. RGP70-2 was a homogeneous polysaccharide with a molecular weight of 6.7 kDa, with the main backbone comprising-*5)-alpha-L-Araf-(1-*,-*3)-alpha-L-Araf-(1-*,-*2,3,5)-alpha-L-Araf-(1-*, and-*2,5)-alpha-L-Araf-(1-* linkages and the side chain comprising an alpha-L-Araf-(1-* linkage. In vivo experiments showed that RGP70-2 inhibited ROS production and downregulated the expression of pro-inflammatory cytokines (TNF-alpha, IL-1 beta, and IL-6). In vitro experiments showed that RGP70-2 decreased levels of pro-inflammatory cytokines, inhibited ROS production, and attenuated NF-KB-p65 translocation from the cytoplasm to the nucleus. Our results showed that RGP70-2 may delay inflammation by regulating the ROS-NF-KB pathway. Thus, RGP70-2 has potential appli-cations as an anti-inflammatory agent in the biopharmaceutical industry.