Structural characterization of blackberry wine polysaccharides and immunomodulatory effects on LPS-activated RAW 264.7 macrophages

Three polysaccharide fractions were isolated from blackberry wine. The crude extract BWPs was obtained with ethanol precipitation and freeze-thawing process, it was then submitted to Fehling treatment, giving soluble BWPFs and insoluble BWPFp fractions. These fractions were characterized by Gas Chromatography-Mass Spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR). Major polysaccharides were identified for each fraction: mannan, type II arabinogalactan and type I rhamnogalacturonan for BWPs, a mannan formed by a major chain of alpha-Manp(1 -> 6)-linked units, O-2 substituted with alpha-D-Manp(1 -> 2)-linked side chains for BWPFp and a AG II formed by a major chain of ss-D-Galp(1 -> 3)-linked, substituted at O-6 by side chains of the ss-D-Galp (1. 6)-linked, which then are substituted at O-3 by non-reducing units of alpha-L-Araf and a RG I, formed by [-> 4)-alpha- D-GalpA-(1 -> 2)-alpha-L-Rhap-(1 -> ](n) for BWPFs. Anti-inflammatory effects of polysaccharide fractions were evaluated in RAW 264.7 cells. Fractions markedly reduced nitric oxide (NO) and pro-inflammatory cytokine production (TNF-alpha and IL-1 beta) in LPS-treated cells.