RG-I regions from elderflower pectins substituted on GalA are strong immunomodulators

• Published in: International journal of biological macromolecules 2016-11, Vol.92, p.731-738
• Main Authors: Ho, Giang Thanh Thi, Zou, Yuan-Feng, Wangensteen, Helle, Barsett, Hilde
• Format: Article
• Language: English
• Subjects: Animals; Artemia; Carbohydrate Sequence; Cell Line; Complement Fixation Tests; Complement system; Erythrocytes - cytology; Erythrocytes - drug effects; Flowers - chemistry; Hexuronic Acids - chemistry; Humans; Hydrolysis; Immune Sera - chemistry; Immune Sera - pharmacology; Immunologic Factors - chemistry; Immunologic Factors - isolation & purification; Immunologic Factors - pharmacology; Immunological activity; LPS; Macrophage stimulation; Macrophages - cytology; Macrophages - drug effects; Macrophages - immunology; Mice; Molecular Weight; Nitric Oxide - biosynthesis; Nitric Oxide - immunology; Pectic polysaccharides; Pectins - chemistry; Pectins - isolation & purification; Pectins - pharmacology; Plant Extracts - chemistry; Polygalacturonase - chemistry; Sambucus nigra; Sambucus nigra - chemistry; Sheep
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2016.07.090

Sambuci flos, also known as elderflower, has traditionally been used and is still in use for treatment of various types of illnesses related to the immune system such as cold, flu, fever and inflammation. Pectic polysaccharides from 50% EtOH, 50°C water and 100°C water extracts from elderflowers were treated with endo-α-d-(1–4)-polygalacturonase after previous de-esterification with the intention of isolating hairy regions and relate variation in structure to immunomodulating activity. High molecular weight sub-fractions (25–29kDa) and medium molecular weight sub-fractions (6–17kDa) were isolated after enzymatic treatment in addition to oligogalacturonides. Structural elucidation indicated that RG-I regions with AG-I and AG-II sidechains were the predominant structures in the high molecular weight sub-fractions, and two of three 1,4-linked GalA units in the rhamnogalacturonan backbone were branched in either position 2 or 3. The medium molecular weight sub-fractions had monomers and linkages typical for both RG-I and RG-II. The results showed that the high molecular RG-I containing polymers exhibit the highest dose-dependent complement fixing and macrophage stimulating activities.