Abstract
Histamine, known as bioactive amine, is synthesized through histidine decarboxylase (HDC). HDC is the sole enzyme that catalyzes histamine production in the human body and thus HDC inhibitor is expected to control histamine-mediating biological activity by controlling histamine production. In the present study, active compound that inhibits HDC activity was sought from strawberry cultivar 'Tokun' that was the most effective cultivar among 11 different cultivar of strawberries. From active fraction of ethyl acetate soluble part, tiliroside, a flavonoid glucoside, was isolated as an HDC inhibitor with IC50 = 40.3 μM. Casuarictin, an ellagitannin, was detected from some active fractions and showed potent inhibition with IC50 = 3.3 μM. Judging from potency of inhibition and content of 'Tokun' extract, casuarictin rather than tiliroside contributed to HDC inhibition of 'Tokun' extract more effectively. Tiliroside, on the other hand, was thought to be a possible marker to predict effective strawberry cultivar for HDC inhibition.
