Abstract
Cordyceps, a highly valued traditional Chinese medicine, comprising the caterpillar larvae invaded by the parasitic fungus Cordyceps sinensis. Previous studies have demonstrated that Cordyceps exhibits a broad variety of biological and pharmacological effects towards immune, cardiovascular, hepatic, and renal systems. It has been noted in a famous Chinese medical literature Ben-Cao-Gang-Mu-Shi-Yi (Supplements to Compendium of Materia Medica) written by Zhao Xue-Min in 1765 that the growing courses of fruiting body and larvae’s body are influenced by Yin and Yang, respectively. Thus, it is believed that Cordyceps tonifies Yin and Yang only when both the fruiting body and larvae’s body are consumed altogether. Cordyceps is found in Tibet, Qinghai, Si-chuan and Yun-nan provinces of China, where the altitude is between 3500 to 5000 meters. However, relatively little information is available about the biological and pharmacological resemblance between fruiting body and larvae’s body of Cordyceps as well as Cordyceps of different geographical origin. The constituents of Cordyceps are very complex. It is difficult to comprehensively analyze the possible pharmacological functions using traditional experimental techniques. However, the advent of DNA microarray technology allows researchers to monitor the expression levels of thousands of genes simultaneously. Thus, we would like to apply microarray technology to explore whether it is possible to distinguish the differences between aboveground and underground parts of Cordyceps as well as Cordyceps samples of distinct geological origins. In order to assure the authentication of Cordyceps sinensis, DNA sequence analysis of 18S rRNA gene was performed. In addition, HPLC and ICPMS analysis were performed to reveal the chemical fingerprints of various Cordyceps samples. A human acute myelogenous leukemia cell line KG-1 was used as the experimental cell model. Biological experiment and microarray experiment were performed to determine proper treating period as well as Cordyceps extract concentration. Statistics has played an important role on the experimental design and analysis of microarray data. A set of “Cordyceps marker genes” was identified as significantly influenced by Cordyceps extracts based on statistical methods. These preliminary results will be confirmed by Real-Time PCR assay. According to these results, we will be able to further evaluate the functional distinctions between different parts of Cordyceps and Cordyceps of diverse geological origins. Furthermore, possible pharmacological mechanisms underlying the gene expression data could also be examined in the future.