Hot-water extracts from the inner bark of Norway spruce with immunomodulating activities

Myriam Le Normand, Hugo Mélida, Bjarne Holmbom, Terje E. Michaelsen, Marit Inngjerdingen, Vincent Bulone, Berit Smestad Paulsen, Monica Ek

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48 Citations (Scopus)


The inner bark of Norway spruce (Picea abies) was sequentially extracted with hot water at 100 C, 140 C and 160 C. The hot-water extracts (IB 100 C, IB 140 C and IB 160 C) contained pectic polysaccharides and showed immunostimulating activities. Structural analyses of their carbohydrate content, including glycosidic linkage analyses, revealed the presence of pectins with a large rhamnogalacturonan RG-I domain ramified with highly-branched arabinans. IB 100 C also contained a large amount of terminal glucosyl residues, indicating the presence of highly substituted polymers. IB 160 C was mainly composed of starch. The hot-water extracts were tested for two biological activities, namely complement fixation and macrophage stimulation. IB 100 C exhibited the highest complement fixation activity, with a 1.7-times higher ICH50 than the control pectin, while IB 140 C and IB 160 C gave similar ICH50 values as the control. Macrophages were stimulated by IB 100 C and IB 140 C in a dose-dependent manner, but not by IB 160 C. IB 100 C presented the highest activity toward macrophages, comparable to the control pectin.

Original languageEnglish
Pages (from-to)699-704
Number of pages6
JournalCarbohydrate Polymers
Publication statusPublished - 30 Jan 2014
Externally publishedYes


  • Bark
  • Biorefinery
  • Compositional analysis
  • Immunomodulating activities
  • Pectins


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