These shoyuflavones
are specific to fermented soy sauce, because they have not
been found in soybeans or any other soy products. Therefore,
it was estimated that shoyuflavones are produced during
fermentation. These shoyuflavones showed inhibitory
activities against histidine decarboxylase (HDC), resulting
in the production of histamine from L-histidine (44). Histamine
is a representative mediator of inflammation, allergy,
gastric acid secretion, and neurotransmission. In the studies