Cordyceps in Modern Medicine: What the Science Says.

Cordyceps is one of the most intensively researched TCM herbs largely due to its cancer-fighting properties. However, it would be fair to say that its primary use is as an immune boosting agent (Koh, et al., 2002). Although mechanisms of action of Cordyceps in cancer remain to be devised, a progressively increasing body of work suggests that most of the tumor-suppressive effect is achieved through activation of the immune system or by induction of apoptosis (Yu et al. 2004; Jordan, Nowak, Lee 2009) . Well-documented clinical trials, however, are lacking and most studies to date were performed using cancer cell lines or mouse models (Zhou et al., 2009).

Conquering Cancer

Macrophages attack cancer cells.
Source: axisorigin.com

In a recent study, S.E. Park and colleagues (2009) looked at the effect of aqueous Cordyceps extract in immune deficient mice xenografted with human lung cancer cells. Use of nude mice with human cell lines is a common method to measure anti-tumor action of a therapeutic agent (Park et al., 2009). The investigation was based on previous in vitro studies looking at tumor growth inhibition by administration of hot water extract of Cs (Sung et al., 2002; Kim et al., 2001). It was generally found that mice treated with 300 mg of Cordyceps per kilogram body weight per day showed significant reduction in tumor mass and volume. The mice in this experimental group also survived approximately 4-7 days longer, however these results were not statistically significant due to error.

Source: nature.com

The suitability of experimental set up is supported by the fact that there was a significant reduction of tumor volume in the mouse models compared to the control. However, the method is not effective in measuring effects on survival rate, amelioration of symptoms or effectiveness in conjunction with chemotherapy, which would be a requirement for human subjects. Such experiments establish the ground for clinical use of a given drug, but are largely inconclusive as to how the agent will act in a human setting. The experiment does not reflect the etiology nor body chemistry in a human cavity. Despite the drawbacks, the results of this and other numerous in vivo and in vitro studies demonstrate, Cordyceps extract is effective in tumor regression assays when applied to human cancer cells.

Boosting the Immune System

Macrophage attacks a fungal spore.
Source: dv.com

With respect to its immune-boosting action, a study was conducted by Jordan and colleagues (2008), which demonstrated that aqueous C. sinensis extract activated murine macrophages in vitro. Administration of Cs caused macrophages to release cytokines as well as nitric oxide, which are both markers of macrophage activation and are the molecules used to target bacterial infections. The experiment has also shown to significantly decrease the bacterial load in vivo (in murine models) and speed up recovery from a Listeria monocytogenes infection based on a statistical analysis. Resolution of this infection directly depends on the level of activation on macrophages, thus further demonstrating that C. sinensis is capable of enhancing and modulating innate immunity.

Macrophage engulfing Streptococcus
bacteria.
Source: allstarhealth.com

The methods chosen by Jordan allow for logical set up and progression of the experiment, primarily demonstrating that Cs does in fact activate macrophages in a dose-dependent manner. This led to the in vivo experiment, which has shown reduced bacterial load, due to increased macrophage recruitment. Since the experiment was performed in vivo it was not determined exactly whether the reduced bacterial load was due solely to increased number of activated macrophages or whether other immune system cells had a role to play.

Although much remains to be done, the existing body of research points to immense therapeutic benefits of the Cordyceps fungi for both cancer and the immune system (Holliday & Cleaver 2005). With respect to evidence based medicine, its application and effectiveness in humans in conjunction with western medicine practices should be investigated further, yet the 2000-year old history of use should not be overlooked.

Up-regulation of macrophage recruitment by Cordyceps, allows for efficient
attack of cancer cells and pathogens, as well as prevention of metastasis.