Bombyx mori-Hosted Cordyceps militaris Polysaccharides: Structural Characterization and Antibacterial Activity of Native and Sulfated Derivatives.

Polysaccharides from Bombyx mori-hosted Cordyceps militaris are abundant but exhibit limited bioactivity, necessitating exploration of sulfated derivatives. In this study, crude polysaccharides (Bm-CMP) were extracted and further sulfated to obtain four derivatives (Bm-sCMP-1∼4). Physicochemical and structural analyses indicated that sulfation significantly modified the characteristics of Bm-CMP, notably reducing the molecular weight (Mw) and particle size while enhancing the negative surface charge and altering the monosaccharide profile. All sulfated derivatives exerted enhanced inhibitory effects against Escherichia coli and Bacillus subtilis, which were closely dependent on the degree of substitution (DS), sulfate content, and negative charge density. Notably, Bm-sCMP-2, with a moderate DS, displayed the optimal antibacterial efficacy. Collectively, this work demonstrates that sulfation is a feasible strategy to valorize polysaccharides from B. mori-hosted C. militaris, transforming them into promising candidates for novel antibacterial agents, although their in vivo efficacy and safety require further validation.