Polysaccharopeptide (PSP) isolated from the edible mushroom Coriolus versicolor was tested for its potential as an anti-human immunodeficiency virus type 1 (HIV-1) compound in a series of in vitro assays. It demonstrated inhibition of the interaction between HIV-1 gp 120 and immobilized CD4 receptor (IC50=150 microgram/ml), potent inhibition of recombinant HIV-1 reverse transcriptase (IC50=6.25 microgram/ml), and inhibited a glycohydrolase enzyme associated with viral glycosylation. These properties, coupled with its high solubility in water, heat-stability and low cytotoxicity, make it a useful compound for further studies on its possible use as an anti-viral agent in vivo.
Currently, extracts of Coriolus versicolor called polysaccharide-K (PSK) and polysaccharopeptide (PSP) are under study as immune stimulants for use alongside chemotherapy in the treatment of cancer. These two related substances, made from slightly different strains of the fungus, are thought to act as “biological response modifiers,” meaning that they affect the body’s response to cancer.
School of Biological Sciences, Kadoorie Biological Sciences Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR.
OBJECTIVES: Lymphocyte homoeostasis is essential in inflammatory and autoimmune diseases. In search of natural fungal metabolites with effects on lymphocyte homoeostasis, we recently reported that polysaccharopeptide (PSP) from Coriolus versicolor exhibited ciclosporin-like activity in controlling aberrant lymphocyte activation. This object of this study was to investigate its effect on lymphocyte homoeostasis. This was done by investigating the mechanistic actions of PSP in relation to ciclosporin by performing cell cycle and cell death analysis of human lymphocytes in vitro.
METHODS: We investigated the effect of PSP in the presence and absence of ciclosporin on cell proliferation, cell cycle, cell death, immunophenotype and cell cycle regulatory proteins in human lymphocytes.
KEY FINDINGS: The data showed that PSP exhibited homoeostatic activity by promoting and inhibiting the proliferation of resting and phytohaemagglutinin (PHA)-stimulated lymphocytes, respectively. PHA-stimulated lymphocytes exhibited G0/G1 cell cycle arrest that was accompanied by a reduction of cyclin E expression with PSP treatment. Both PSP and ciclosporin blocked the reduction of the CD4/CD8 ratio in stimulated lymphocytes. PSP did not induce cell death in human lymphocytes, but the suppression of the Fasreceptor suggested a protective role of PSP against extrinsic cell death signals. These homoeostatic effects were more potent with combined PSP and ciclosporin treatment than with either fungal metabolite alone.
CONCLUSIONS: Collectively, the results reveal certain novel effects of PSP in lymphocyte homoeostasis and suggest potential as a specific immunomodulatory adjuvant for clinical applications in the treatment of autoimmune diseases.
PMID: 20663037 [PubMed – in process]
We found that PSK has an antiviral effect on human immunodeficiency virus (HIV) in vitro. One of the mechanisms of this effect is attributable to the inhibition of binding of HIV with lymphocytes. Here, we found that PSK inhibits reverse transcriptase in a non-competitive way in vitro. Such inhibition may be important in its anti-HIV effect as well as its inhibitory effect on the binding of HIV with lymphocytes.
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What Hartford Hospital in Conneticut has to say about Coriolus Versicolor
“Currently, extracts of Coriolus versicolor called polysaccharide-K (PSK) and polysaccharopeptide (PSP) are under study as immune stimulants for use alongside chemotherapy in the treatment of cancer. These two related substances, made from slightly different strains of the fungus, are thought to act as “biological response modifiers,” meaning that they affect the body’s response to cancer.
According to most but not all reported trials, most of which were performed in Asia, both PSK and PSP can enhance the effects of various forms of standard cancer treatment. For example, in a 28-day double-blind , placebo-controlled study of 34 people with advanced non–small-cell lung cancer, use of Coriolus extracts along with conventional treatment significantly slowed the progression of the disease.
It is thought that Coriolus extracts work by stimulating the body’s own cancer-fighting cells. PSK and PSP may also have cancer-preventive effects.
In addition, very weak evidence hints that extracts of Coriolus versicolor might be helpful for HIV infection.”