Structure Studies of the Extracellular Polysaccharide from Trichoderma sp. KK19L1 and Its Antitumor Effect via Cell Cycle Arrest and Apoptosis

An extracellular polysaccharide TP1A was purified from the fermented broth of Trichoderma sp. KK19L1 by combination of Q Sepharose fast flow and Sephacryl S-300 chromatography. TP1A was composed of Man, Gal, and Glc in a molar ratio of about 3.0:5.1:8.1. The molar mass of TP1A was about 40.0 kDa. Methylation and NMR analysis indicated that the probable structure of TP1A was [→4,6)-α-D-Glc p (1→6)-β-D-Gal f (1→6)-β-D-Gal f (1→2,6)-β-D-Gal f (1→2,6)-β-D-Gal f (1→2,6)-β-D-Gal f (1→2,6)-α-D-Man p (1→2,6)-α-D-Man p (1→] with [α-D-Glc p (1→] and [α-D-Man p (1→6)-α-D-Glc p (1→6)-α-D-Glc p (1→] as branches. The antitumor study showed that TP1A was able to inhibit the cell viability of HeLa and MCF-7 cells. TP1A could arrest HeLa cells in G2/M phase and induce HeLa cell apoptosis. These findings suggest that fungal polysaccharides could be a potential source for antitumor agents.