vitamin P(redirected from permeability vitamin)
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A substance isolated from citrus rind that was thought to be a vitamin that reduced the permeability of capillaries. It was later determined to be a mixture of flavonoids.
n, pl P vitamins
(Biochemistry) any of a group of water-soluble crystalline substances occurring mainly in citrus fruits, blackcurrants, and rosehips: they regulate the permeability of the blood capillaries. Also called: citrin or bioflavonoid
bi•o•fla•vo•noid(ˌbaɪ oʊˈfleɪ vəˌnɔɪd)
any of a group of water-soluble yellow compounds, present in citrus fruits, rose hips, and other plants, that in mammals maintain the resistance of capillary walls to permeation and change of pressure. Also called vitamin P.