Plant Histaminase as Bioactive Agent to Lower the Histamine Level: A Mini-Review

Abstract

Histamine is a biogenic amine originating endogenously or exogenously from Histidine by enzymatic decarboxylation. Endogenous histamine is mostly generated by basophils and mast cells that, when activated, will release histamine that is involved in various regulatory processes but also will induce multiple allergic effects (hypotension, tachycardia, vascular risks) including anaphylactic shock and possible death. For some histamine related symptoms (itching, asthma, hyperacidity), there are antihistaminic drugs (e.g. Desloratadine-Aerius ® , Loratadine-Claritin ® , Ranitidine-Zantac ®) whereas for anaphylaxis, epinephrine (EpiPen ®) is required. Exogenous histamine, frequently associated to fermented food and beverages, some fruits, fish, may induce a food histaminosis and trigger pseudo-allergic phenomena for which there is no current treatment available. Histamine may also exert some pro-inflammatory effects, particularly damaging for subjects with Inflammatory Bowel Diseases (IBD) as Crohn's Disease (CD) and Ulcerative Colitis (UC), mostly treated with anti-inflammatory drugs. Histamine deleterious effects and those produced as side-effects of antihistaminic drugs (allergic phenomena) or of anti-inflammatory drugs are inconvenient (nausea, diarheea, dizziness). For this reason, novel enzymatic strategies with Diamine Oxidase (DAO, histaminase) to decrease the histamine levels in allergic reactions to food and in ulcerative colitis were recently proposed. This may alleviate the symptoms associated with IBD and food allergens. The therapeutic concept is that histaminase will decrease the level of histamine in the intestine by oxidation, involving the dissolved oxygen. Since the by-product of the DAO reaction is hydrogen peroxide (H 2 O 2), a pro-oxidant agent generating undesirable oxidative damaging effects, a combination of catalase and vegetal histaminase in tablet formulations for oral administration was proposed. Catalase will decompose H 2 O 2 generating in situ more oxygen, promoting thus the decomposition of histamine under histaminase action. Thus, the dual enzymatic histaminase + catalase tablets, could contribute to a healthier intestinal mucosa.This DAO approach seems a non-toxic way to improve the treatment IBD and related inflammatory pathologies.