fraxin
fraxin , noun
[From Fraxinus.]
(Chemistry) A colorless crystalline substance (C16H18O10) found in the bark of the ash (Fraxinus), and along with esculin in the bark of the horse-chestnut. It is structurally a derivative of a coumarin glucoside. It shows a delicate blue-green fluorescence in alkaline solutions; -- called also paviin and fraxoside. — MI-11