ABSTRACT
Microbial metabolites and their derivatives hold an important position in the development of medicinal drugs. Research on fungal metabolites as medicinal candidates was initiated when Fleming discovered penicillin in the culture of a filamentous fungus identified as Penicillium notatum. This was followed by Brotz who discovered cephalosporin in the culture of another filamentous fungus, Cephalosporium acremonium (now renamed Acremonium chrysogenum). Nowadays, about 30 penicillin derivatives and 49 cephalosporin derivatives are used in clinics in Japan. Although fungal metabolites had been the major target for screening of antimicrobial agents, they were overtaken by metabolites of actinomycetes after Waksman discovered streptomycin in 1945. This might be partly due to the fact that fungi frequently produce mycotoxins with potent cytotoxicity to humans and animals, such as aflatoxins from Aspergillus flavus, known to induce chronic hepatotoxicity ultimately leading to a malignant tumor.
