Two heteropolysaccharides from Isaria cicadae Miquel differ in composition and potentially immunomodulatory activity

Two novel heteropolysaccharides (JCH-1 and JCH-2) with molecular weights of 30.9 and 555.3 kDa were first extracted, isolated and purified from Isaria cicadae Miquel (I. Miquel). Monosaccharide analysis showed that JCH-1 and JCH-2 were composed of mannose, glucose and galactose with different monosaccharide ratio. In addition, JCH-1 had higher contents of sulfated and uronic acid compared to JCH-2. Based on MTT assay, JCH-1 and JCH-2 could markedly promote the proliferation of RAW264.7 cells and exhibit no cytotoxicity at a specific concentration range. The immunomodulatory assay exhibited that JCH-1 and JCH-2 could significantly enhance the viability of macrophage cells, and promote the release of NO, IL-6 and TNF-α. Furthermore, the immunomodulatory activity of JCH-1 was significantly better than that of JCH-2. These results proposed that I. Miquel had two polysaccharide fractions with different composition and JCH-1 is better to be developed as a functional food with the better immunomodulator activity.