Monoamine oxidase inhibitors isolated from fermented broths

Cultured broths were screened by measuring the inhibition of monoamine oxidase. Using serotonin as the substrate, two active agents were isolated from Actinomycetes and shown to be pimprinine and trans-cinnamic acid amide, and a compound isolated from a mushroom was identified to be harman. Using benzylamine as the substrate, an inhibitor was isolated from a Streptomyces and shown to be phenethylamine.