Two indole-alkaloid isoprenoids were isolated from extracts of Penicillium crustosum Thom grown on rice. Their structures were elucidated on the basis of various NMR experiments and by comparison to the structurally related penitrems. The two compounds, designated thomitrem A and thomitrem E, contain a 18(19)-double bond and lack the characteristic penitrem 17(18)-ether linkage. (C) 2002 Elsevier Science Ltd. All rights reserved.