Onitin is a natural product, that can be isolated from Onychium siliculosum. Onitin is also a non-competitive antagonist of histamine. Onitin shows activity in blocking the peristaltic reflex of the guinea-pig ileum, in inhibition of the responses of guinea-pig ileum to histamine and of inhibition of the responses of guinea-pig tracheal muscle to histamine[1].
[1] Wu T S, et al. Flavanone and other constituents from Onychium siliculosum. Phytochemistry, 1981, 20(3):527–529.
