Optimization of In Vitro Culture Conditions for Production of Cordyceps bassiana Spores (Ascomycetes) and the Effect of Spore Extracts on the Health of Caenorhabditis elegans

Cordyceps bassiana, an entomogenous fungus, has been used as a dietary therapeutic in traditional Chinese medicine for several millennia. However, naturally occurring C. bassiana is notably scarce in the field, especially at the spore stage. To date, there are few comprehensive studies on the biological characteristics and pharmacological attributes of C. bassiana spores. In this study, an isolate of C. bassiana (Bs1112) was identified as the teleomorph of Beauveria bassiana using morphology and rDNA internal transcribed spacer sequences. In vitro solid substrate fermentation parameters were evaluated; a rice substrate with 0.01% K+ achieved the maximum spore yield. High-performance liquid chromatography analysis of the bioactive components of C. bassiana spore powder (BC-CBSP), which was extracted using alcohol, showed that concentrations of adenosine were higher than concentrations of inosine, uridine, and cordycepin. The pharmacological impact of BC-CBSP was elucidated in a live animal model, Caenorhabditis elegans, at a range of concentrations from 0.145 to 14.5 mg/mL. The reproductive rate, frequency of head swinging and body bending (indicative of C. elegans locomotion), and lifespan of C. elegans were determined and compared with untreated populations. At the lowest concentration of BC-CBSP, reproduction was slowed but the number of eggs was not reduced. However, at both of the higher concentrations (1.45 and 14.5 mg/mL), BC-CBSP reduced the total number of eggs produced during the 8-day observation period. Furthermore, 0.145 mg/mL of BC-CBSP significantly increased the frequency of head swinging/body bending and the lifespan of C. elegans. This is the first report on the pharmacological effects of C. bassiana spores. Results suggest that low concentrations of BC-CBSP have no negative effects on the reproduction rate of C. elegans but could enhance nervous system activity and extend their lifespan.