Polysaccharides from Basidiocarps of the Polypore Fungus <i>Ganoderma resinaceum</i>: Isolation and Structure
oleh: Roman Bleha, Lucie Třešnáková, Leonid Sushytskyi, Peter Capek, Jana Čopíková, Pavel Klouček, Ivan Jablonský, Andriy Synytsya
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2022-01-01 |
Deskripsi
In this study, we focused on the isolation and structural characterization of polysaccharides from a basidiocarp of polypore fungus <i>Ganoderma resinaceum</i>. Polysaccharide fractions were obtained by successive extractions with cold water at room temperature (20 °C), hot water under reflux (100 °C), and a solution of 1 mol L<sup>−1</sup> sodium hydroxide. The purity of all fractions was controlled mainly by Fourier transform infrared (FTIR) spectroscopy, and their composition and structure were characterized by organic elemental analysis; neutral sugar and methylation analyses by gas chromatography equipped with flame ionization detector (GC/FID) and mass spectrometry detector (GC/MS), respectively; and by correlation nuclear magnetic resonance (NMR) spectroscopy. The aqueous extracts contained two main polysaccharides identified as a branched <i>O</i>-2-<i>β</i>-<span style="font-variant: small-caps;">d</span>-mannosyl-(1→6)-<i>α</i>-<span style="font-variant: small-caps;">d</span>-galactan and a highly branched (1→3)(1→4)(1→6)-<i>β</i>-<span style="font-variant: small-caps;">d</span>-glucan. Mannogalactan predominated in the cold water extract, and <i>β</i>-<span style="font-variant: small-caps;">d</span>-glucan was the main product of the hot water extract. The hot water soluble fraction was further separated by preparative anion exchange chromatography into three sub-fractions; two of them were identified as branched <i>β</i>-<span style="font-variant: small-caps;">d</span>-glucans with a structure similar to the corresponding polysaccharide of the original fraction. The alkaline extract contained a linear (1→3)-<i>α</i>-<span style="font-variant: small-caps;">d</span>-glucan and a weakly branched (1→3)-<i>β</i>-<span style="font-variant: small-caps;">d</span>-glucan having terminal <i>β</i>-<span style="font-variant: small-caps;">d</span>-glucosyl residues attached to <i>O</i>-6 of the backbone. The insoluble part after all extractions was identified as a polysaccharide complex containing chitin and <i>β</i>-<span style="font-variant: small-caps;">d</span>-glucans.