Antioxidant and Cytotoxic Effects of Ophiocordyceps sinensis and Identification of Bioactive Proteins Using Shotgun Proteomic Analysis

Abstract

Research background. Ophiocordyceps sinensis, a highly valued medicinal fungus is close to extinction due to overexploitation. Successful cultivation of O. sinensis fruiting body (OCS02®) shows the cultivar consists promising nutritional value and numerous bioactive compounds. Antioxidant and antiproliferative properties and biologically active proteins of the OCS02® are investigated for possible development into nutraceuticals.\nExperimental approach. The chemical compositions of the OCS02® cold water extract was determined, and the antioxidant activities were examined using ferric reducing, DPPH\uf09f and O2\uf09f- scavenging assays. MTT cytotoxic assay was performed to assess the antiproliferative activity of the extract. Bioactive proteins in the active fraction of the extract were identified using liquid chromatography (LC) and tandem-mass spectrometry (MS/MS). \nResults and conclusions. The OCS02® extract exhibited strong O2\uf09f- scavenger ((18.40±1.12) mol TE/g extract) and potent cytotoxicity towards A549 cells (IC50=(58.17±6.79) µg/mL). High molecular mass polysaccharides, proteins and protein-polysaccharide complexes could have contributed to the antioxidant and cytotoxic selectivity of the OCS02®. LC-MS/MS analysis identified several potential cytotoxic proteases and an oxalate decarboxylase oxdC protein which may exhibit protection effects on kidneys. \nNovelty and scientific contributions. The findings reported the promising superoxide anion radical scavenging capacity, cytotoxic effect and presence of bio-pharmaceutical active proteins in of OCS02® extract, thus demonstrates the potential of OCS02® to be developed into functional food.