Детоксификација - Улогата на нутритивните печурки

Mycology News, sept 2004

Detoxification - The Role of Mushroom Nutrition

Professor Amin Karmali- Biotechnology Division, Instituto Superior de Engenharia de Lisboa. Rua Conselheiro Emídio Navarro 1900-Lisboa, Portugal (Tel:00-351-21-831-7052; Fax:00-351-21-831-7267 / akarmali@deq.isel.ipl.pt)

A number of pathological damages including carcinogenesis and cellular degeneration related to aging are due to reactive oxygen species (ROS), or superoxide radicals. These reactive oxygen species are produced by sunlight, ultraviolet radiation, chemical reactions, as well as by metabolic processes, and are toxic to living cells since they oxidize and degrade important biological macromolecules such as lipids and proteins.

Health maintenance and the avoidance of chronic degenerative conditions therefore depends to a large extent on the body’s ability to neutralise, in other words detoxify, such ROS.

Central to the body’s battle against ROS are a number of enzyme systems, prominent among which is Superoxide dismutase (SOD), which catalyses the destruction of superoxide radicals and hence protects oxygen–metabolizing cells from the harmful effect of these free radicals. Several research workers have shown that SOD is involved in diseases such as Parkinson´s disease, cancer and anemia.

Another important enzyme system is cytochrome “P-450” which is located in the endoplasmic reticulum and plays an important role in metabolism and detoxification of endogenous substances. In addition, enzyme therapy has been shown to play an important role in several clinical conditions including cancer, malignant lymphomas and cardiovascular disorders.

Mushrooms have been known to possess medicinal properties for thousands of years and higher basidiomycete mushrooms have been used in clinical nutrition for their anti-tumour, immune modulating, cardiovascular and anti-microbial effects. As well as other complex substances of therapeutic interest, such as protein-bound polysacharide complexes (i.e PSK, PSP and Lentinan) and secondary metabolites (i.e terpenes, alkaloids and lactones) we are now finding that mushrooms are rich sources of many enzymes.

Several mushrooms have been shown to contain substances which mimic SOD activity and the “P450” cytochrome enzyme system has also been found in some higher basidiomycete fungi. Other enzymes present in clinically used mushrooms include laccase, glucose oxidase and peroxidase.

It is likely that the potent enzymatic and ROS detoxifying properties of mushrooms are in large part due to the harsh environments colonized by mushroom mycelia with high concentrations of free radicals that the mushrooms have to protect themselves against.

In this connection it is worth noting that these enzymes are found almost exclusively in the mushroom mycelia and hence preparations derived from the fruiting bodies of mushrooms are likely to have far lower levels of enzymatic activity than those derived from mushroom mycelia.

In the present work, we investigated the levels of SOD, cytochrome “P450”, cytochrome “P450” reductase (NADPH dependent) and secondary thrombin inhibiting metabolites in the following mushrooms: Coriolus versicolor, Cordyceps sinensis, Ganoderma lucidium (Reishi) and Grifola frondosa (Maitake).

There are a number of secondary metabolites in mushrooms which play an important role as thrombin inhibitors and since thrombin is an important protease of the coagulation system it is a suitable target for inhibition of blood coagulation, which is desirable in combating many age related conditions.

In order to simulate the human intestinal tract we treated the mushrooms with the following proteolytic enzymes:

1. Pepsin (500IU/g biomass) at pH2 for 30 min. at 37ºC in an incubator with orbital shaking

2. Trypsin (500IU/g biomass) at pH 7.6 for 30 min. at 37ºC in an incubator with orbital shaking.

The data reveal that simulation of the intestinal tract with pepsin and trypsin decreased the enzyme and secondary metabolite levels by 15-20%.

Conclusions: Mushrooms contain several important enzymes involved in detoxification process (i.e cytochrome “P450”) and destruction of superoxide free radicals (i.e SOD activity) as well as secondary metabolites which act as thrombin inhibitors.

Further research is required to study the effect of mushroom nutrition on the levels of some key proteins and enzymes in vivo which are involved in several clinical conditions including cardiovascular diseases, cancer, HIV and neurological disorders.

* Mushroom samples (in tablet form) were composed of the mycelium and primordia of the respective mushrooms and were provided by Mycology Research Laboratories Ltd. www.mycologyresearch.com