Acremonium sp. - a leucinostatin A producing endophyte of European yew (Taxus baccata)

Acremonium sp. occurs as an endophyte in European yew (Taxus baccata). It produces a series of peptide antifungal-anticancer agents known as the leucinostatins. Leucinostatin A is especially active against the oomycetous-plant pathogenic fungus-Pythium ultimum with an effective 1 day 50% inhibitory concentration of < 1 mu mol. Leucinostatin A also possesses activity against certain human cancer cell lines, for instance, its IC50 value is 2.3 nM for breast cancer cell line BT-20 contrasted with 640 nM for a normal mammary cell line. Leucinostatin A can be effectively prepared radiolabeled via the administration of [C-14]leucine or [C-14]pyruvate to standing cultures of Acremonium sp. The data point to a biological role of antifungal agents being produced by endophytic fungi as a means to allow for their survival. Also, since antifungal agents such as taxol and leucinostatin A are produced by some endophytic fungi, oomycetes such as P. ultimum may serve as initial screening tools for anticancer agents. (C) 1997 Elsevier Science Ireland Ltd.