New lapatin analogues from a fungicolous isolate of Aspergillus sp

As part of our continuing search for new bioactive fungal natural products, analysis of an ethyl acetate extract from cultures of a fungicolous fungal isolate obtained in Hawaii (Aspergillus sp.; MYC-2075) was undertaken. This extract was selected for investigation because it showed significant activity in dietary assays against fall armyworm. Chemical studies of this extract yielded two new lapatin analogues and several known compounds, including sterigmatocystin and aurantiamine. Lapatins are members of the quinazoline class of fungal metabolites. Other members of this group, such as spiroquinazoline, alantrypinone, and serantrypinone, are known to display various kinds of effects, including activity as substance P and GABA receptor antagonists. The two new metabolites were identified as lapatin analogues on the basis of similarities between their NMR and HRESIMS data and those reported for lapatins A and B. The structures of these compounds were assigned through the use of 2D NMR techniques.