SCP-1

In this study, a highly branched glucomannan (SCP-1) from Schizophyllum commune fruiting body with good solubility was isolated, and its structural characteristics and antitumor properties were analyzed. The monosaccharides of SCP-1 were fucose, glucosamine hydrochloride, galactose, glucose and mannose with a relative molar ratio of 14:6:210:593:177, and the molecular weight (Mw) of SCP-1 was 15.1 kDa. SCP-1 showed a rough and dense surface, and it was aggregated to particles in distilled water, though it might have triple-helix conformation. The main backbone chain of SCP-1 was →[3)-β-D-Glcp-(1]₃→3)-β-D-Glcp-(1→2)-α-D-Manp-(1→2)-α-D-Manp-(1→3)-α-D-Glcp-(1→ and three sides chains including α-D-Glcp-(1→[6)-β-D-Glcp-(1]₂→, α-D-Glcp-(1→3)-α-D-Manp-(1→ and α-D-Glcp-(1→[6)-α-D-Galp-(1]₃→ were linked with 1,6-glycosidic bond, which was significantly different with the schizophyllan isolated from the mycelia of S. commune. SCP-1 could significantly inhibit the growth of A549 cells, the inhibition rate reached 41.62 % and the percentage of cells in S phase increased from 27.17 % to 56.40 % (400 μg/mL, 48 h). Moreover, SCP-1 could induce cell apoptosis and the total apoptosis rate reached 28.13 %. SCP-1 exerted apoptosis inducing effect probably by reducing the expression ratio of Bcl-2/Bax and the p-PI3K, p-Akt and p-mTOR expression level. The results showed that SCP-1 might have the potential to act as an antitumor agent for lung cancer therapy.

A novel galacturonoglucan, named SCP-1, is isolated and purified from Schisandra chinensis fruits. The structure of SCP-1 is systematically investigated by a combination of monosaccharide compositions, absolute M_w, methylation analysis, partial acid hydrolysis, isoamylase degradations, and nuclear magnetic resonance spectroscopy. The structure of SCP-1 is theoretically described as follows: (i) Glc and GalA in a molar ratio of 17:3; (ii) → 4)-α-Glcp-(1→, →4,6)-α-Glcp-(1→, →3,4,6)-α-Glcp-(1→, α-Glcp-(1→, →4)-α-GalAp-6-OMe-(1→, α-GalAp-6-OMe-(1→, β-Glcp-(1→, →6-)-β-Glcp-(1 → and →3,4)-β-Glcp-(1 → in a molar ratio of 48:5:3:3:10:5:12:5:9; (iii) a repeating unit of →4)-α-Glcp-(1 → as a backbone with branched points at C-3 and C-6, substituted by different types of acidic and neutral side chains to form multiple branches; and (iv) a rigid rod configuration deduced from α value of 1.26 in Mark-Houwink equation ([η] = kM^α). Anti-tumor assay investigated the effects of SCP-1 on human HepG2 cancer cell lines in vitro. This is for the first time to report a galacturonoglucan in S. chinensis fruits.