Kinotannic acid is the chief constituent of the kino gum, of which it contains 70 to 80 per cent. Kino also contains kino red, a phlobaphene produced from kinotannic acid by oxidation. It is closely related to the tannin from catechu; its non-glucosidal nature was established by Bergholz.
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Kinotannic acid Wikipedia(Text) CC BY-SA