Microbial glucosidation of 1,2,4-trihydroxy-9,10-anthraquinone (purpurin).

Streptomyces aureofaciens glucosidizes 1,2,4-trihydroxy-9,10-anthraquinone (purpurin) added to the cultivation medium to yield the corresponding 2-beta-D-glucoside. The identity of the glucoside was demonstrated by comparing its physico-chemical properties with data of an authentic sample prepared synthetically. A further chemical glucosidation of the acetylated 2-beta-D-glucoside gives rise to 2-(hepta-O-acetyl-beta-gentiobiosyl)-4-(tetra-O-acetyl-beta-D-gluc opyranosyl) purpurin. All the derivatives are immunoactive.