Biosynthesis of photodynamically active rubellins and structure elucidation of new anthraquinone derivatives produced by Ramularia collo-cygni

Incorporation of [1-13C]-, [2-13C]-acetate and [U-13C6]-glucose circumstantiate that rubellins were biosynthesised via the polyketide pathway. The figure shows incorporation of [U-13C6]-glucose into rubellin B. Structures of two anthraquinone derivatives were elucidated. Rubellins generate singlet oxygen and oxygen radicals.