Cordyceps is a parasitic fungus and has in the past been shown to have a number of pharmacological properties; however, it has never before been investigated for its ability to protect against DNA damage following UV radiation, explained the scientists based at the Hong Kong Polytechnic University.
According to the team, the polysaccharides in the fungus may offer photoprotection and help lower the risk of basal cell carcinoma.
UVB radiation can interact with the DNA of skin cells altering its structure. The most common UVB-induced mutations are the cyclobutane photoproducts dimers (CPDs), according to the researchers, which can result in the substitution of a cytosine base for a thymine base.
According to the researchers, one of the most common types of skin cancer (basal cell carcinoma) is caused by this kind of mutation in the p53 gene.
Therefore, the team investigated the potential of Cordyceps extracts to reduce the number of CPDs in the DNA of human fibroblast cells.
Two different extracts were tested: one rich in water-soluble, low molecular weight components and one insoluble in water with mainly high molecular weight components.
Relative decrease in CPDs
According to the study, compared to irradiated cells with no Cordyceps treatment, those pre-incubated for 24 hours with the water soluble extract showed a relative decrease of 27 percent in CPDs. With the insoluble extract the relative decrease in CPDs after 24 hours was slightly more at 34 percent.
Although the team has said the extracts have ‘significant DNA protective effects’, it said the results are preliminary and further research is needed.
For example, the researchers said the mechanism of action is not clear. The Cordyceps extracts did not absorb UV light directly, so are not acting as a barrier against UV light unlike the more traditional UV filters on the market.
In addition, cells were broken down immediately after irradiation leaving no time for the extracts to have helped promote DNA repair.
Furthermore, although the researchers suggest the polysaccharides are the key to the action, they said further work was needed to identify the bioactive compounds.
Source: British Journal of Dermatology
DOI: 10.1111/j.1365-2133.2010.10201.x
Photoprotective potential of Cordyceps polysaccharides against ultraviolet B radiation-induced DNA damage to human skin cells
W.C.Wong, J.Y. Wu, I.F.F. Benzie