indirubin

noun

in·di·ru·bin | \ ˌin-də-ˈrü-bən, ˈin-də-ˌ

Medical Definition of indirubin

: a dark red crystalline pigment C₁₆H₁₀N₂O₂ isomeric with indigo (sense 1b) found in natural indigo and sometimes in urine