Answer: rutin

AnswerCrossword Clue
RUTINA bioflavonoid
rutinbright yellow or greenish-yellow substance, C27H30O16, obtained chiefly from buckwheat, and used in the treatment of capillary fragility
rutina yellow crystalline flavonol glycoside C27H30O16 that occurs in various plants (as buckwheat and tobacco) and is used in medicine chiefly for strengthening capillary walls