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Abstract

Histamine is a bioactive amine that affects a wide range of biological activities in the human body.  In this review, we discuss the active components of spices and herbs that can inhibit histidine decarboxylase (HDC), an enzyme that catalyzes synthesis of histamine.  We screened 21 spices and 122 medicinal plants by carrying out inhibition assays with recombinant human HDC.  Among spices, flavonoid glycosides of allspice, quercetin 3-O-b-D-glucuronide 6"-methyl ester and quercetin 3-O (2-O-galloyl) glucoside, at 1 mM inhibited HDC by 64 and 55%, respectively.  Among medicinal plants, ellagitannins of meadowsweet, rugosin D, rugosin A, rugosin A methyl ester, and tellimagrandin II inhibited HDC significantly with K_i values of approximately 0.35-1 mM.  These results indicate that plant components are promising sources for novel inhibitors of HDC.