What is a yellow crystalline dyestuff, regarded as a glucoside, extracted from a species (Rhamnus Frangula) of the buckthorn; -- called also rhamnoxanthin called?

frangulin — A yellow crystalline dyestuff, regarded as a glucoside, extracted from a species (Rhamnus Frangula) of the buckthorn; -- called also rhamnoxanthin. (Webster's 1913.)

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