Chemical and biological characterization of pectin-like polysaccharides from the bark of the Malian medicinal tree Cola cordifolia

Abstract

The bark of Cola cordifolia used in Malian traditional medicine contains unusual types of polysaccharides with immunomodulating activities. We report for the first time on the structure of a polymer designated CC1P1 having the repeating structure [2→)[α-D-Gal(1→3)]α-L-Rha(1→4)α-d-GalA(1→] as determined by NMR and GC/MS. α-Linked Gal is unusual in pectins. The Mw of 135 kDa was determined by SEC-MALLS. CC1P2 (1400 kDa), another polymer, having the same backbone, but this was substituted with α-4-OMe-GlcA, α-2-OMe-Gal and α-Gal as terminal units. CC1P1 shows a high complement-fixing activity, IC₅₀ being 2.2 times lower than the positive pectin control PMII (IC₅₀ appr. 71 μg/mL) while IC₅₀ of CC1P2 is 1.8 times lower. The simple structure of CC1P1 did not activate macrophages, while CC1P2 (100 μg/mL) showed the same potency as the positive controls PMII (100 μg/mL) and LPS (500 ng/mL). No cytotoxicity was detected.

Structure–activity relationship of immunomodulating pectins from elderberries

“…However, the molecular weight of the sub-fractions-I from elderberries and elderflowers was lower than the native acidic fractions, but did still exhibit higher complement fixating activity. The same findings have also been reported previously [104,109]. Molecular weight is an important factor, but the bioactivity is truly also dependent on chemical compositions and structural differences.…”

Polysaccharides with immunomodulating activity from roots of Gentiana crassicaulis

“…This may be a strong binding so that the calcium is not removed by anion exchange chromatography (Austarheim et al, 2012b). This may lead to less movement in the molecule and could be the explanation for the low intensity of the signals in the area 170-175 ppm (Fig 4).…”

“…The polysaccharide fractions GCP-I-I and GCP-II-I were characterized by 1D NMR spectroscopy and compared with chemical shift values from literature (Chai & Zhao, 2016;Hromádková, Košt'álová, Vrchotová, & Ebringerová, 2014;Košt'álová, Hromádková, & Ebringerová, 2013;Li, Fan, & Ding, 2011;Zou et al, 2014). Fraction GCP-II-I had somewhat better solubility than fraction GCP-I-I, due to lower Mw (Austarheim, et al, 2012b;Shakhmatov, et al, 2015) and…”

“…Fractions were pooled based on the elution profile, as determined by the phenol-sulfuric acid assay, dialyzed and lyophilized. h at 80°C (Austarheim et al, 2012b;Barsett, Paulsen, & Habte, 1992;Chambers & Clamp, 1971). Mannitol was used as an internal standard.…”

Anti-ulcer polysaccharides from Cola cordifolia bark and leaves

“…Polysaccharides will be present in high amounts in the prepared traditional medicine, as a hot water extract (decoction) is the most common way of preparing C. cordifolia prior to use. Polysaccharides present in the bark have been studied previously by Austarheim et al (2012) and Togola et al (2008). Pectins with unusual structures were isolated and these polysaccharides having immunomodulating properties are believed to be relevant for the possible anti-ulcer activity of the tree.…”