Comparative characterization of diamine oxidase (DAO) activity from plant, animal and microbial matrices

Abstract

Histamine intolerance is associated with impaired histamine metabolism caused by a deficiency of the enzyme diamine oxidase (DAO). A recommended strategy to alleviate symptoms is a low-histamine diet supplemented with exogenous DAO. Recent studies suggest plant-based DAO from legume sprouts could be a viable active ingredient for supplements. This study aimed to assess the impact of germination parameters (time-temperature binomial and salinity stress) on the histamine-degrading enzymatic activity of four species of edible Leguminosae sprouts and its stability during different storage conditions. The time-temperature binomial was found to strongly influence sprout DAO activity. Chickpea sprouts exhibited the highest activity at 14°C on day 8 of germination, whereas lentil, soybean, and green pea sprouts showed peak activity at 30°C between days 4 and 5. On the other hand, salinity stress did not enhance DAO activity and reduced the germination rate by 20-30% compared to the control. Freezing was the only storage condition that preserved the DAO activity of the active ingredient intact for at least 12 months.