A member of the class of 2,5-diketopiperazines obtained by cyclodimerisation of N(5)-acetyl-N(5)-hydroxy-L-ornithine. ChEBI: Rhodotorulic acid is a member of the class of 2,5-diketopiperazines obtained by cyclodimerisation of N(5)-acetyl-N(5)-hydroxy-L-ornithine. It has a role as a siderophore and a fungal metabolite. It is a member of 2,5-diketopiperazines, a hydroxamic acid and a L-ornithine derivative.