By Paul Stamets

A new class of anti-viral drugs has been recently discovered in mushrooms. Dr. Frank Piraino, University of Wisconsin Medical School, has found a new antiviral, RC-183, which shows activity inhibiting in vitro the herpes simplex I and II viruses, as well as varicella zoster virus, influenza A virus, and the respiratory syncytial virus. (Piraino & Brandt, 1999). The mushroom yielding this novel antiviral is Rozites caperata, the Gypsy Mushroom, a mycorrhizal species associated with pines and Douglas firs. A resident of Old Growth Forests of Washington and Oregon, this mushroom has thus far resisted cultivation attempts due to its complex interdependence with the host tree. In a more recent article, Brandt & Piraino (2000) have identified a new class of anti-viral drugs from mushrooms.

Hunting for Rozites caperata in the Old Growth Forests of the Pacific Northwest

Antivirals from other mushrooms have been identified previously: lentinan from Shiitake, Lentinula edodes, (Sarkar et al., 1993); PSP from Turkey Tail, Trametes versicolor, and ganaderiol-F, ganoderic acid-ß, lucidumol from Reishi, Ganoderma lucidum,) A number of unique antivirals from mushrooms have shown efficacy in inhibiting the replication of the human immunodeficiency virus. (Suzuki, 1989; Nanba, 1992; Kim et al., 1994; Collins & Ng, 1997; Ghoneum, 1998; Hattori, 1997). Other antivirals, not yet characterized, but having shown activity from hot water extracts from Chaga , Inonotus obliquus, (Kahlos et al. 1997) and Zhu Ling, Polyporus umbellatus (Yan, 1988).

Rozites caperata, the Gypsy Mushroom

The predominant mushrooms showing promise for their antiviral activities are polypores—the so-called woody conks, thought to be the ancestors of most, if not all, gilled mushrooms. (Interestingly we know of no poisonous polypores whereas there are more than hundred poisonous gilled mushrooms, of which only a few are deadly.) Most all these antivirals are water soluble, relatively heat-stable, and most of the mushrooms mentioned and/or their mycelia can be cultured to commercially significant levels. The causal compounds are present both in the mycelium and in the fruiting bodies. The current literature points to mushrooms, particularly those in the Polyporaceae, as a rich frontier of new medicines. Many of these mushroom species are long-term residents of Old Growth Forests, playing an essential role in nutrient recycling by decomposing aged trees. In a time when new anti-viral medicines are critically needed, mushrooms stand out as an untapped resource and deserve intensive studies.

Supporting Bibliography

Brandt, C.R. & F. Piraino, 2000. "Mushroom Antivirals." Recent Research Developments in Antimicrobial Agents & Chemotherapy 4:11-26.

Collins, R.A., and T.B. Ng, 1997. "Polysaccharopeptide from Coriolus versicolor has potential for use against human immunodeficiency virus type 1 infection." Life Sciences 60(25): PL383-7.

Ghoneum, M., 1998. "Anti-HIV activity in vitro of MGN-3, an activated arabinoxylane from rice bran." Biohechemical and Biophysical Research Communications 243: 25—29.

Hattori, M., 1997. "Inhibitory effects of components from Ganoderma lucidum on the growth of human immunodeficiency virus (HIV) and the Protease Activity" in Proceedings of the 1st International Symposium on Ganoderma lucidum in Japan, Nov. 17-18th, 128-135. Tokyo.

Kahlos, K. et al., 1996. "Preliminary tests of antiviral activity of two Inonotus obliquus strains". Fitopterapia 6 (4) 344-7.

Kim, B.K., H.W. Kim and E.C. Choi, 1994. "Anti-HIV effects of Ganoderma lucidum." In Ganoderma: Systematics, Phytopathology & Pharmacology: Proceedings of Contributed Symposium 59 A, B. 5th International Mycological Congress. Vancouver, Canada.

Nanba, H., 1992. "Immunostimulant activity in-vivo and anti-HIV activity in-vitro of 3 branched ß-1-6 glucans extracted from Maitake mushroom (Grifola frondosa)." Proceedings of the VIII International Conference on AIDS and the III STD World Congress.

Piraino, F. & C.R. Brandt, 1999. "Isolation and partial characterization of an antiviral, RC-183, from the edible mushroom Rozites caperata." Antiviral Research 43:67-68.

Sarkar, S., J. Koga, R.J. Whitley, and S. Chatterjee, 1993. "Antiviral effect of the extract of culture medium of Lentinus edodes mycelia on the replication of herpes simplex virus 1." Antiviral Research. April 20(4): 293-303.

Suzuki, H., A. Okubo, S. Yamazaki, K. Suzuki, H. Mitsuya & S. Toda, 1989. "Inhibition of the infectivity and cytopathic effect of human immunodeficiency virus by water soluble lignin in an extract of the culture medium of Lentinus edodes mycelia (LEM)." Biochemical and Biophysical Research Communications vol. 160, no. 1.

Tochikura, 1987. "A biological response modifier, PSK, inhibits immunodeficiency virus infection in vitro." Biochemical and Biophysical Research Communications. 148: 726-733.

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