Mizoribine ( INN, trade name Bredinin) is an

immunosuppressive drug Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified into ...

. The compound was first observed in Tokyo,

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, in 1971. First isolated from the fungus ''

Penicillium brefeldianum ''Penicillium brefeldianum'' is an anamorph fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These org ...

''. Mizoribine (MZB) is an imidazole nucleoside that has been used in renal transplantation, and in steroid-resistant nephrotic syndrome, IgA nephropathy, lupus, as well as for adults with rheumatoid arthritis, lupus nephritis and other rheumatic diseases. MZB exerts its activity through selective inhibition of inosine monophosphate synthetase and guanosine monophosphate synthetase, resulting in the complete inhibition of guanine nucleotide synthesis without incorporation into nucleotides. It arrests DNA synthesis in the S phase of cellular division. Thus, MZB has less toxicity than azathioprine, another immunosuppressant used for some of the same diseases.

References

Immunosuppressants {{antineoplastic-drug-stub Mizoribine (MZB) is an imidazole nucleoside that has been used in renal transplantation, and in steroid-resistant nephrotic syndrome, IgA nephropathy, lupus, as well as for adults with rheumatoid arthritis, lupus nephritis and other rheumatic diseases. MZB exerts its activity through selective inhibition of inosine monophosphate synthetase and guanosine monophosphate synthetase, resulting in the complete inhibition of guanine nucleotide synthesis without incorporation into nucleotides. It arrests DNA synthesis in the S phase of cellular division. Thus, MZB has less toxicity than azathioprine, another immunosuppressant used for some of the same diseases.