A simple and rapid bioassay was developed to search for novel insect neuroactive substances.This method was based on the electrophysiological response of the metathoracic legnerve of Periplaneta americana.Using this assay,41 methanol extracts of Kenyan plant and 15 methanol extracts of Indonesia plants were tested to show various activities.Several compounds were isolated from these methanol extracts with the guidance of the activity increasing spontaneous-impulse frequencies.