Purification, characterization, antioxidant, and antitumor activity of polysaccharides isolated from silkworm cordyceps

Two new water‐soluble polysaccharide fractions (SCP II‐1 and SCP II‐2) were obtained from silkworm cordycepsusing DEAE Sepharose FF and Superose 6 columns chromatography. The characterization of their basic structure was studied by high performance liquid chromatography, high performance ion chromatography, infrared spectroscopy and atomic force microscope (AFM). The results showed that the molecular weight of SCP II‐1 and SCP II‐2 were 35.2 kDa and 23.4 kDa, and they were mainly composed of ribose, mannose, glucose, and galactose in molar ratio of 1.0:27.38:8.52:17.99 and 1.0:21.21:1.95:14.28, respectively. The AFM topography confirmed the highly branched chain conformation of SCP II‐1, while SCP II‐2 had more polymerized chain morphology. These two fractions possessed excellent antioxidant and antitumor activities, especially SCP II‐1 showed better inhibition than SCP II‐2. Those data suggested that purified polysaccharides from silkworm cordyceps have potential application in functional food and pharmaceutical industry. Practical applications Silkworm cordyceps is cultivated on the 5th instar larvae inoculated with Cordyceps sp. and the functions of cordyceps have been reported recently. The separation and purification of silkworm cordyceps polysaccharide is helpful to better exert important biological functions. The study on the structure‐function relations of polysaccharides will be useful to the application of polysaccharides in functional food and pharmaceutical industry. The activity of fungal polysaccharides is related to the specific structural characteristics. Most of the literature have reported the optimization of the extraction process and the study of the pharmacological activity of the polysaccharide from C. militaris. Thus, the present research is mainly focused on the silkworm cordyceps polysaccharide to reveal its structure‐function relations.