Medical Definition of purpurin
1: an orange or red crystalline compound C14H8O5 obtained from madder root along with alizarin or by oxidation of alizarin and used in dyeing
2also pur·pu·rine \-rən, -ˌrēn\play : any of various colored compounds obtained from chlorophyll or related compounds by the action of cold alcoholic alkali and oxygen
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