XANTHIN

noun a yellow insoluble coloring matter extracted from yellow flowers; specifically, the coloring matter of madder.

2. xanthin ·noun one of the gaseous or volatile decomposition products of the xanthates, and probably identical with carbon disulphide.

3. xanthin ·noun a crystalline nitrogenous body closely related to both uric acid and hypoxanthin, present in muscle tissue, and occasionally found in the urine and in some urinary calculi. it is also present in guano. so called from the yellow color of certain of its salts (nitrates).

4. xanthin ·add. ·- a white microcrystalline nitrogenous compound, 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. xanthine is closely related to uric acid.