Structure characterization and antitumor activity of the extracellular polysaccharide from the marine fungus Hansfordia sinuosae

A neutral water soluble polysaccharide (HPA) was isolated from the marine fungus Hansfordia sinuosae. Monosaccharide composition analysis indicated that HPA was mainly composed of mannose with minor amounts of galactose and glucose. The molecular weight of HPA was approximately 22.5 kDa as analyzed by HPGPC. Structure analysis of HPA with methylation and 1D, 2D NMR indicated that HPA was composed of [α-d-Manp(1→], [→2)-α-d-Manp(1→], [→3)-α-d-Manp(1→] and [→2,6)-α-d-Manp(1→] with [α-d-Manp(1→] linked to C-6 position of [→2,6)-α-d-Manp(1→]. The antitumor effect of HPA was evaluated in vitro. HPA showed remarkable inhibitory effect on human cervical carcinoma HeLa cells and human breast carcinoma MCF-7 cells. When cells were incubated with HPA at 400 μg/mL for 48 h, the inhibition rate on HeLa and MCF-7 cells was 79.5% and 73.8%, respectively. Furthermore, for HeLa cells, HPA could increase intracellular ROS levels, induce cells apoptosis, decrease mitochondrial membrane potential, and elevate the expression of caspase-3. The results suggested that HPA could be explored as a potential antitumor agent.