Antifungal activity of a novel chromene dimer

The activity on Aspergillus spp. growth and on ochratoxin A production of two novel chromene dimers (3) was evaluated. The results of the bioassays indicate that the chromene dimer 3a inhibited mycelia growth by approximately 50% (EC(50)) at 140.1 micromol L(-1) for A. niger, 384.2 micromol L(-1) for A. carbonarius, 69.1 micromol L(-1) for A. alliaceus and 559.1 micromol L(-1) for A. ochraceus. When applied at concentrations of 2 mmol L(-1), 3a totally inhibited the growth of all Aspergillus spp. tested. Furthermore, ochratoxin A production by A. alliaceus was reduced by about 94% with a 200 micromol L(-1) solution of this compound. A moderate inhibitory effect was observed for the analogous structure 3b on ochratoxin A production but not in mycelia growth. No inhibition was registered for compounds 2a and 2b, used as synthetic precursors of the dimeric species 3.