A water-soluble acidic polysaccharide containing 3-O-methyl galactose, named YB-PS4, was isolated from the twigs and leaves of Juniperus tibetica Kom. Its structure was characterized by monosaccharide composition analysis, methylation, and NMR spectroscopy. It was concluded that YB-PS4 had a backbone composed of -> 2,4)-alpha-Rhap-(1 ->, -> 3,5)-alpha-Araf-(1 ->, -> 2,4)-alpha-Galp-(1 -> and -> 4)-alpha-GalpA-(1 ->, with branches of -> 2)-alpha-Rhap-(1 ->, -> 3)-alpha-Araf-(1 -> and -> 2)-3-O-Me-alpha-Galp-(1 ->. The possible repetitive units were speculated and further analyzed by oligosaccharide analysis. YB-PS4 showed inhibitory effects on complement activation through the classical pathway (CH50 = 94.23 8.90 mu g/mL) and alternative pathway (AP(50) = 194.76 +/- 9.20 mu g/mL). Preliminary mechanism study indicated that it interacted with C1q, C2, C3, C4 and C5. These studies pointed a way to understand the active constituents of J. tibetica and provided scientific bases for YB-PS4 as a complement inhibitor. (C) 2019 Elsevier B.V. All rights reserved.
[1]Fudan Univ, Sch Pharm, Inst Integrat Med, Shanghai, Peoples R China
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