Screening and Identification of Antioxidants from Ophiocordyceps xuefengensis (Ascomycetes) by Using DPPH-HPLC-DAD-Q-TOF-MS/MS

Ophiocordyceps xuefengensis has recently been identified as a sister taxon of O. sinensis and has long been recognized as a folk tonic, food, or invigorant in South China. This study had 3 aims: First, we analyzed the antioxidant activities of 3 kinds of caterpillar fungi; the antioxidative ability of the various caterpillar fungi were in the order of O. xuefengensis > Cordyceps militaris > O. sinensis. Second, we further identified the antioxidant compounds in O. xuefengensis by using various methods: multiwavelength DPPH high-performance liquid chromatography with diode array detection and quadrupole time-of-flight mass spectrometry. In this way, we found and identified 30 compounds that possessed potential antioxidant activity. Among these compounds, 23 compounds were determined to be composed of nucleosides, nucleotides, and amino acids. To our knowledge, several compounds in O. xuefengensis are reported here for the first time. Third, we compared the antioxidant markers in 3 caterpillar fungi. Results showed that the caterpillar fungi share some common antioxidants, while each also had its own characteristic compounds that correspond to its antioxidant capacity. This is to our knowledge the first report of the screening and identification of antioxidants in O. xuefengensis, and these results might provide beneficial contributions to understandings of O. xuefengensis on the basis of its chemical compounds and antioxidant activity.