These shoyuflavones
were shown to have inhibitory activities against histidine decarboxylase, which produces histamine,
a mediator of inflammation, allergy and gastric acid secretion. Soy sauce also exhibits antiplatelet
activity. β-Carbolines were isolated from soy sauce as the active compounds. Soybeans
and wheat, which are the main raw materials of soy sauce, are allergenic foods. However, recent
studies by enzyme-linked immunosorbent assay showed the absence of soybean and wheat allergens
in soy sauce