[2] Purpurin and alizarin were isolated from the root by Pierre Robiquet and Colin, two French chemists, in 1826.

[5] Unlike alizarin, purpurin is dissolved by boiling in a solution of aluminium sulfate, from which it can be precipitated by acid.

[7] Purpurin is a fast dye for cotton printing and forms complexes with various metal ions.

[2] A study published in Nature journal Scientific Reports suggests that the purpurin could replace cobalt in lithium-ion batteries.

Extracting purpurin from farmed madder is a simple task; alternately, the chemical could be synthesized in a lab.