xanthin
 黃色色素


 Xan·thin n.
 1. same as xanthine.
 2. Chem. A yellow insoluble coloring matter extracted from yellow flowers; specifically, the coloring matter of madder.  [Formerly written also xanthein.]
 3. Chem. One of the gaseous or volatile decomposition products of the xanthates, and probably identical with carbon disulphide.  [Obs.]


 Xan·thine n. Also Xan·thin .  Physiol. Chem. A type of purine obtainable as a white microcrystalline powder, C5H4O2N4, present in muscle tissue, in the liver, spleen, pancreas, and other organs, and also in urine (in small quantities) and some urinary calculi, and in the juices of certain plants; -- so called because it leaves a yellow residue when evaporated to dryness with nitric acid. It is also present in guano.  Xanthine is closely related to uric acid.

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