Soil fungi are known to produce and secrete antibiotics with a strong antimicrobial effect towards eukaryotic organisms. In many occasions, these compounds belong to peptides that are products of non-ribosomal biosynthesis and are called peptaibols. Many peptaibols are cytotoxic and some of them suppress tumor cell lines much better than normal cells by inducing calcium-mediated apoptosis. The main antimicrobial lipoaminopeptaibol—emericellipsin A—isolated from the fungus Emericellopsis alkalina strain VKPM F-1428, which demonstrates promising antifungal activity against different fungal taxons,has been found to exhibit selective cytotoxic activity against HepG2 and Hela cell lines (EC50 2.8 and 0.5 μM, respectively) in MTT assays in vitro. This result corresponds to the standard antitumor antibiotic doxorubicin, which has an EC50 value of 440 nM. In a fibroblast toxicity test, emericellipsin A exhibited less cytotoxic activity than doxorubicin (EC50 14 and 0.34 μM, respectively). Therefore, it is less toxic to normal cells than doxirubicin (~40 times), but it yields a more potent cytotoxic effect on tumor cell lines. That is why emericellipsin A can be considered for future more detailed investigations to be an effective antitumor substance.
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