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Structural characterization and immunomodulatory activity of novel polysaccharides from Citrus aurantium Linn. variant amara Engl

Shen, Chun-Yan, Jiang, Jian-Guo, Li, Ming-Qiang, Zheng, Chao-Yang, Zhu, Wei
Journal of functional foods 2017 v.35 pp. 352-362
Citrus aurantium, arabinose, galactose, gene expression, glucose, immunomodulators, inducible nitric oxide synthase, interleukin-1beta, interleukin-6, mannose, messenger RNA, mitogen-activated protein kinase, molecular weight, polysaccharides, transcription factor NF-kappa B, tumor necrosis factor-alpha
Two polysaccharides CAVAP-I and CAVAP-II from Citrus aurantium L. var. amara Engl showed significant structural differences. Average molecular weights of CAVAP-I and CAVAP-II were 10.5kDa and 4.5kDa. Triple-helix conformation existed in CAVAP-II rather than CAVAP-I. Arabinose, mannose, glucose and galactose formed main components of CAVAP-I and CAVAP-II at different ratios. (1→3,6)-β-d-Gal and (1→5)-α-l-Ara composed the backbone of CAVAP-I and CAVAP-II. CAVAP-II displayed greater immune enhancement potential than CAVAP-I. CAVAP-II significantly promoted interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production, and inducible nitric oxide synthase, IL-6, TNF-α and interleukin-1 beta mRNA expression by activating phosphorylated extracellular signal-regulated kinase, c-Jun N-terminal kinase, P38 and P65. These results indicated that structures were closely related to immunomodulatory activity of polysaccharides. CAVAP-II showed the greatest immunostimulation potential followed by CAVAP-I and CAVAPs by activating mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways.