Cordyceps (Dong Chong Xia Cao)
Cordyceps (Dong Chong Xia Cao) is unique among the medicinal mushrooms in growing on an insect host rather than a plant host. To date over 700 species of cordyceps (Dong Chong Xia Cao) have been identified worldwide. In most cases they grow parasitically on their insect hosts. However, it appears likely that in some cases a symbiotic relationship exists whereby the insect host derives a selective advantage from the fungal anamorph (the fungus growing in a single cell form), giving them a competitive advantage, especially in marginal environments where energy efficiency is at a premium, such as the high Tibetan plateau above 3,000m where the main species used traditionally, cordyceps (Dong Chong Xia Cao) sinensis, occurs naturally .
Although traditionally harvested cordyceps (Dong Chong Xia Cao) is still available, the vast majority of cordyceps (Dong Chong Xia Cao) on the market today is cultivated on non-insect, grain-based substrates leading to improved quality control and affordability. Despite the commercially cultivated cordyceps (Dong Chong Xia Cao) being grown on a different substrate from the wild collected cordyceps (Dong Chong Xia Cao), HPLC analysis of both shows identical chemical profiles and the two are seen to be interchangeable clinically.
As well as polysaccharides and lipids, cordyceps (Dong Chong Xia Cao) species contain a large number of nucleoside analogues, prominent among which is cordycepin, 3-deoxyadenosine3. This molecule differs from adenosine in the absence of oxygen at the 3 position of its ribose part. Because it is similar to adenosine some enzymes cannot distinguish between the two and so it is able to participate in certain biochemical reactions, including RNA/DNA synthesis where its incorporation leads to the termination of the RNA molecule as there is no oxygen at the 3 position to bond with the next nucleotide4-7.
This ability to interrupt RNA synthesis has led to the use of such nucleoside analogues, termed reverse transcriptase inhibitors, in the treatment of viral infections, including HIV and Hepatitis, as well as cancer, under pharmaceutical names including AZT (Retrovir), Videx and Epivir. In normal healthy cells such reverse transcriptase inhibitors are out competed by the corresponding nucleoside but in rapidly dividing cancer cells and virally infected cells they are able to exert effective inhibition of replication.
Adenosine in the form of adenosine monophosphate and adenosine triphosphate also plays a central role in energy metabolism and cyclic nucleotides including cAMP play an important role in signal transduction and regulating hormone production, activities which correlate well with the observed activity of cordyceps (Dong Chong Xia Cao) in these areas.