Ophiobolin A, a sesterterpenoid fungal phytotoxin, displays higher in vitro growth-inhibitory effects in mammalian than in plant cells and displays in vivo antitumor activity

Ophiobolin A, a sesterterpenoid produced by plant pathogenic fungi, was purified from the culture extract of Drechslera gigantea and tested for its growth-inhibitory activity in both plant and mammalian cells. Ophiobolin A induced cell death in Nicotiana tabacum L. cv. Bright Yellow 2 (TBY-2) cells at concentrations ≥10 μM, with the TBY-2 cells showing typical features of apoptosis-like cell death. At a concentration of 5 μM, ophiobolin A did not affect plant cell viability but prevented cell proliferation. When tested on eight cancer cell lines, concentrations