A pilot study of the effect of (E, E)-2, 4-undecadienal on the offensive odour of trimethylamine

Abstract

Introduction: Trimethylaminuria is a malodour syndrome caused by a functional defect of flavin-containing monoxygenase 3 (FMO3), resulting in accumulation of trimethylamine in body secretions. Recently, (E, E)-2, 4-undecadienal has been shown to deodorize the offensive odour of cooked porcine intestines (chitlins). We tested the deodorizing effect of commercially available (E, E)-2, 4-undecadienal on the odour of trimethylamine (TMA) in solution. Study Participants: Eleven volunteers among staff of the Children’s Hospital at Westmead, Sydney, Australia. Methods: This was a study in three stages. In the first stage,12 volunteers sniffed and graded a commercially available trimethylamine at variable concentrations (12.5–10,000 μmol/L). Those who could smell trimethylamine scored the odour of mixtures of (E, E)-2, 4-undecadienal and trimethylamine. Finally, the odour of trimethylamine was graded with increasing concentrations of (E, E)-2, 4-undecadienal (0.1–100 ppm). Results: All except one could detect the characteristic trimethylamine odour at varying concentrations (12.5–10,000 μmol/L) and reported the odour as offensive and fish like. There was a dose response effect of the ability of (E, E)-2, 4-undecadienal to deodorize the odour of trimethylamine. (E, E)-2, 4-undecadienal at 10 ppm appeared to deodorize the odour of trimethylamine at 1,000 μmol/L without making the former’s odour obvious. Conclusions: We have demonstrated that (E, E)-2, 4-undecadienal has a deodorizing effect on the offensive odour of trimethylamine in solution. The mechanism of action for this effect and potential for treatment of affected individuals needs further research.