Biosynthetic relationships among the secalonic acids. Isolation of emodin, endocrocin and secalonic acids from Pyrenochaeta terrestris and Aspergillus aculeatus.

摘要: Cynodontin, emodin, endocrocin and secalonic acids A, E G have been isolated from five strains of Pyrenochaeta terrestris. Aspergillus aculeatus produces B, D F. No cynodontin was detected. Isolation emodin in small amounts supports previous evidence that it is an intermediate acid biosynthesis. endocrocin, which are co-produced with other organisms, suggests these compounds formed by a common branching pathway. A natural isolate P. terrestris contained variant produced different relative G. From the combinations organisms so far examined concluded precursor tetrahydroxanthone units pairs differing stereo-chemistry only at C-5 or trans-invariant C-6 : C-10a positions. possible biosynthetic pathway discussed.