The pharmacological properties of Ophiocordyceps xuefengensis revealed by transcriptome analysis

Ethnopharmacological relevance The Yao ethnic group in Xuefeng Mountains area have used Xuefeng cordyceps, the caterpillar–fungus complex of Ophiocordyceps xuefengensis, for treating a variety of diseases for long. Just like some other cordyceps, O. xuefengensis, which is identified as the sister taxon of O. sinensis in 2013, also seems to have broad pharmacological properties, not only enhancing human immunity, anti–bacteria, anti–virus, but also anti–tumor. However, investigation of the medicinal fugal species O. xuefengensis can be found only in few literature records since its pharmacological and therapeutic use is mainly in traditional Yao communities by local healers. Aim of the study The aim of this study is to collect samples of Xuefeng cordyceps and isolate the strain of O. xuefengensis, to determine bioactive components and evaluate the anti-tumor activity, to obtain the gene expression profile of O. xuefengensis and reveal its pharmacological properties by de novo transcriptome analysis. Accordingly, we attempt to provide information and give a comprehensive understanding of this mysterious medicinal fugal species from traditional Yao communities of China. Material and methods Bioactive components were determined with HPLC–DAD–Q–TOF–MS technology; in vitro anti–tumor activity against 6 cell lines was evaluated using standard MTT assay; transcriptome analysis was done by de novo sequencing; unique genes were functionally profiled basing on Gene Ontology Database and the targeted genes were examined by blast. Results Trace cordycepin, an anti–tumor agent, was detected in O. xuefengensis water extract. To some extent, the raw water extract of O. xuefengensis showed in vitro anti–tumor activity, against A549, HepG2, MCF–7, PC–3 and Raji cell lines. A total of 94,858 transcripts and 49,001 unique genes were obtained, amongst, 43.4% unique genes were matched with those of O. sinensis. Not all supposed genes related to cordycepin biosynthetic pathways were found by transcriptome analysis. Conclusion According to the gene expression profile, O. xuefengensis is very close to medicinal fungus O. sinensis. Raw water extract of O. xuefengensis, to a certain degree, could inhibit the growth of tumor cells, indicating that this fungus could be a new resource for the exploration of anti–tumor drug.