Cordyceps has been said to possess multiple biopharmaceutical effects, some of which benefit immune health.
Researchers at Chonbuk National University conducted a study using a preparation of a cordyceps mycelium culture extract, Paceilomyces hepiali, CBG-CS-2, to test the herb's efficacy in enhancing the immune system, as well as its safety in healthy adults.
They recruited 79 healthy male and female adults between the ages of 20 and 75, 39 of whom were assigned to the intervention group and the remaining to the control group.
Over the course of eight weeks, those in the intervention group were each given a total 1.68g of CBG-CS-2 in the form of two capsules a day (one taken after breakfast and the other after dinner), while those in the control group received an equivalent dose of placebo taken at the same frequency.
The researchers collected fasting blood samples from all the subjects, and as a primary outcome, assessed the activities of natural killer (NK) cells and serum levels of monocyte-derived mediators at baseline and after eight weeks.
As a secondary outcome, they measured a range of cytokines that included interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), and five interleukin cytokines (IL-1β, IL-2, IL-4, IL-10, and IL-12).
They also used an electrocardiogram (ECG) and laboratory tests — including those for LDL and HDL cholesterol, fasting blood glucose, haemoglobin, albumin, blood pressure, pulse and total protein — to test the extract's safety parameters in the subjects.
Subsequently, they reported that the intervention group "showed a significant 38.8 ± 17.6% enhancement from the baseline of NK cell cytotoxic activity relative to the placebo group after the administration of the capsules for eight weeks".
This result represented a greater immunomodulatory effect observed in the intervention group when compared to the placebo group.
This was an important observation, as human NK cells have been known to be involved in innate immunity by detecting and killing virus-infected cells, tumour cells, and abnormal cells.
Furthermore, activated NK cells are said to promote the release of cytokines such as IFN-γ and TNF-α, which are vital in supporting immune health.
The researchers wrote that CBG-CS-2's major components, cordyceps polysaccharides and adenosine, had "positively contributed to the immune-regulatory effects" and that "simple and protein-bound polysaccharides separated from cordyceps had excellent immunomodulatory effects".
Polysaccharides had reportedly helped to increase innate immune and cell-mediated immune responses, and inhibited tumour growth by increasing NK cell, IFN-γ and TNF-α activity levels.
They added: "Therefore, we believe that the major components of CBG-CS-2 in this study, cordyceps polysaccharides and adenosine, play an important role in presenting immune reactions as a trigger and induce an immunomodulatory effect by enhancing both the NK cell activity and phagocyte reactions via the activation of macrophages."
Conclusions on cordyceps
The researchers noted that despite the differences in immunomodulatory effects between the intervention and placebo groups, there was no significant difference in terms of the immune index of the Th1 cytokine cluster.
They attributed this to the cytokine index having been measured without any triggering factors, which could have caused specific immune reactions, as well as the blood samples having been taken from healthy participants who had no specific diseases.
In conclusion, they wrote: "The results suggest that the immune system functions well with CBG-CS-2 supplementation, perhaps with less accompanying inflammation. Thus, CBG-CS-2 is safe and effective for enhancing cell-mediated immunity in healthy adults.
"It will be necessary to investigate changes in immune-related cytokines in participants with depressed immune responses and to precisely design a challenge test that can externally stimulate immune depression.
"Furthermore, a long-term study will also be required. It is expected that the continuous dose of CBG-CS-2 obtained from cordyceps increases Th1 immune responses and activates NK cells, which results in immunomodulatory effects by improving cell-mediated immunity."
Source: BMC Complementary and Alternative Medicine
"Immunomodulatory effects of a mycelium extract of Cordyceps (Paecilomyces hepiali; CBG-CS-2): a randomized and double-blind clinical trial"
Authors: Su-Jin Jung, et al.