In order to obtain fungal isolates, which produce bioactive compounds, random screening was carried out using okara (an insoluble residue of the whole soybean homogenate) as a cultural medium. We observed three kinds of activities against silkworms: insecticidal activity, convulsive activity and paralytic activity. A soil isolate, Penicillium simplicissimum ATCC 90288, produced novel insecticidal indole alkaloids that we designated as okaramines. Okaramines were found to be produced by not only this strain but also other strains belonging to P. simplicissimum. The isolate, Aspergillus aculeatus KF-428 also produced two okaramine congeners: okaramines H and I. These data strongly supported the fact that okaramines are widely produced by fungi. Till now, eighteen okaramine congeners have been isolated; their biogenesis and structure-activity relationships are described in this review. We also describe the results of synthetic studies for the okaramines J and N. The isolate, Penicillium expansum MY-57 produced five insecticidal compounds: the new communesin congeners, communesins D, E, and F, and the known communesins A and B. Convulsive compounds, verruculogen and penitrems, were produced by the isolates P. simplicissimum MF-24 and P. simplicissimum ATCC 90288, respectively, indicating that our convenient bioassay system with silkworms could be used to search for convulsive compounds. Novel convulsive compounds, brasiliamides A, B, C, D, and E, were found in the cultural media of Penicillium brasilianum JV-379. Finally, chance observation led to the isolation of new paralytic compounds, asperparalines A, B, and C, from Aspergillus japonicus ATCC 204480. Asperparalines have unique structures consisting of a bicyclo [2,2,2] diazaoctane core and a spiro-succinimide moiety. © 2005 Elsevier B.V. All rights reserved.