Medicinal Value of the Caterpillar Fungi Species of the Genus Cordyceps (Fr.) Link (Ascomycetes). A Review

This review looks in depth at the history and medicinal value of the Cordyceps species, especially C. sinensis. The C. sinensis medicinal species, with a long history of use, has only been found growing from the head of one type of subterranean caterpillar, at high altitudes, in the Qinghai-Tibetan plateau. Because of this highly specific growth environment and restricted geographical distribution, C. sinensis has a long reputation of being the single-most expensive raw material used in Oriental Medicine. Due to environmental and ecological factors, the annual harvest has been steadily declining, while at the same time the worldwide demand has been increasing. This situation has driven Cordyceps spp. prices into an ever-increasing spiral over the last few years, driving research to determine ways of cultivating it to make it a more affordable material for commercial trade. Part of the goal of this research has been to understand the complex biological niche such an organism fills. This is a mushroom that is only found in cohabitation with the larvae of an insect, and it is this unique growth parameter that has made it challenging to produce Cordyceps spp. in artificial cultivation. Further complicating this cultivation issue is the rarefied atmosphere, mineral-rich soil, and low temperature in which Cordyceps naturally grows, resulting in a unique profile of secondary metabolites possessing interesting biological potential for medical exploitation, but which are not readily reproduced in normal laboratory cultivation. In this article, we attempt to unravel many of the mysteries of Cordyceps spp., detailing the history, medicinal uses, chemical composition, and cultivation of Cordyceps spp., with special attention to C. sinensis, the world's most costly medicinal mushroom.