Structural correlates of antifungal and cytotoxic activity of brefeldin A: the importance of a rigid planar lactone ring.

Molecular modelling of brefeldin A and its derivatives shows that the presence of a rigid and planar lactone ring conformation is necessary for cytotoxic and anti-fungal activity. Cytotoxic compounds had lactone ring torsion angles of -28.77 +/- 6.13 degrees, while non-cytotoxic compounds had torsion angles of -88.25 +/- 14.6 degrees.