Cordyceps militaris (Ascomycetes) Intracellular Polysaccharide Nanoemulsion for Improving Antimicrobial Activities

This study aimed to develop a Cordyceps militaris intracellular polysaccharides nanoemulsion (CMIPS-NE) to improve its antimicrobial properties. Based on the results of pseudoternary phase diagram, the formulation of nanoemulsion was optimized as Tween 80-Span 80/anhydrous ethanol/Olive oil/polysaccharide = 40/10/38/12 (w/w/w/w), were used as the surfactant, co-surfactant, oil, and aqueous phase, respectively. Under these conditions, the particle size of water-in-oil CMIPS-NE is 83.61 ± 3.52 nm, with the polydispersity index is 0.252 ± 0.025, the pH is 6.12 ± 0.09, and the viscosity is 168.34 ± 1.95 mPa·s. The prepared CMIPS-NE exhibited excellent stability and a sustained release. Moreover, the antimicrobial activity of C. militaris intracellular polysaccharide was notably improved after nanoemulsification, an effect demonstrated to be driven by the polysaccharide itself and not the nanoemulsion vehicle. The results showed that CMIPS-NE might be valuable and antimicrobial and show potential for application in health and medicine as well as in the food industry.