Polysaccharide isolated from Chinese jujube fruit (Zizyphus jujuba cv. Junzao) exerts anti-inflammatory effects through MAPK signaling

A peptic polysaccharide (ZJP) was isolated from Zizyphus jujuba cv. Junzao by hot water extraction and chromatographic purification. Structural characterization showes that ZJP has a weight-average molecular weight of 153.3 kDa and consists of galacturonic acid. The linkage type of ZJP was proven to be 1,4-linked D-GalpA by methylation, NMR and MS analysis. The anti-inflammatory effects of ZJP were tested on RAW264.7 macrophages. ZJP was found to significantly suppress nitric oxide (NO) production and decrease levels of pro-inflammatory cytokines such as COX-2, TNF-α, IFN-γ and IL-17. Molecular profiling showed that ZJP could inhibit phosphorylation of the signaling proteins p-38 and JNK, but not ERK, revealing ZJP exert anti-inflammatory effects through inhibition of NF-κB and p38/JNK MAPK signaling. This study suggests that ZJP can be used to treat inflammatory diseases or as a supplement to health products.