At least seven species ( Chrozophora plicata, Jatropha gossypifolia, Ricinus communis, Tragia involucrata, Trewia nudiflora, Acalypha hispida, Synadenium grantii) in the family Euphorbiaceae have shown enzymatic oxidizing activity on salts of 1-methyl-nicotinotrile. 4- and 6-pyridones were shown to be the enzymic products in vitro for both Trewia nudiflora and Ricinus communis.