The invention relates to a neuroactive substance which is characterised in that it has formula (O), wherein R1, R2, R3 and R4 are identical or different and are methyl or ethyl radicals. Preferably, the neuroactive substance comprises 6S-acetyl-4R,5R-dimethyl-1R(10S)-epoxy-2R-hy-droxy-7R-acetoxydecahydro naphthalene which can be isolated from Rhytisma fulvum cnidaria. The inventive neuroactive substance can be used as a pharmacological reagent in research work and is also suitable for use in the fields of industry (insecticides) and health.