Structural, rheological and antioxidant properties of pectins from Equisetum arvense L. and Equisetum sylvaticum L

• Published in: Carbohydrate polymers 2019-04, Vol.209, p.239-249
• Main Authors: Patova, O.A., Smirnov, V.V., Golovchenko, V.V., Vityazev, F.V., Shashkov, A.S., Popov, S.V.
• Format: Article
• Language: English
• Subjects: Characterization; Horsetails; NMR; Pectin; Radical scavenging activity; Textural property
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2018.12.098

[Display omitted] •Pectins from E. sylvaticum and E. arvense have similar structure.•Horsetail pectins mainly composite of HG regions with minor low branched RG regions.•Horsetail pectins are partially acetylated in low methyl-esterified HG regions.•Pectin EA forms stronger ionotropic gel than pectin ES.•Anti-DPPH activity of pectin EA is higher than pectin ES. The pectins were isolated from sterile stems of E. arvense (EA, yield 5.9%) and E. sylvaticum (ES, yield 4.8%) (Equisetaceae) using ammonium oxalate extraction after preliminary treatment with dilute HCl (рH 4.0). The pectins possessed high molecular weight (Mw, 340–360 kDa), high GalA content (ca. 85%), low degrees of methyl-esterification (14–16%) and acetylation (3–8%). NMR analysis indicated extensive regions of partially methyl-etherified and 3-O-acetylated HG and minor regions of low branched RG in the fragment isolated after hydrolysis of pectin EA by pectinase. Pectin EA produced a higher viscosity solution, formed a stronger and more rigid ionotropic hydrogel than pectin ES. The pectins scavenged DPPH and hydroxyl radicals, but not the superoxide radical and hydrogen peroxide. Phenolic compounds (0.11 and 0.23%) associated with polysaccharide moieties were apparently responsible for the differences in the anti-DPPH scavenging activity of pectins EA and ES (63 and 49%). The findings suggested that pectin from E. arvense should be more perspective than pectin from E. sylvaticum on their use as components of wound healing remedies.