PADI55 For example, diphenhydramine (Benadrylâ„¢), targets and inhibits the H1 histamine receptor to relieve symptoms of allergic reactions. Tritoqualine, as well as various catechins, such as epigallocatechin-3-gallate, a major component of green tea, have been shown to target HDC and histamine-producing cells, reducing histamine levels and providing anti-inflammatory, anti-tumoral, and anti-angiogenic effects. In humans, histidine decarboxylase is encoded by the HDC gene. Eukaryotes, as well as gram-negative bacteria share a common HDC, while gram-positive bacteria employ an evolutionarily unrelated pyruvoyl-dependent HDC.|Know your Enemy (Rage against the Machine Song)