Biosynthetic studies on chlorinated anthraquinones in the lichen Nephroma laevigatum

摘要: Abstract Eight anthraquinones were produced by the lichen Nephroma laevigatum Ach. during laboratory incubation. They characterized 1H NMR, 13C NMR and mass spectrometry as emodin, 7-chloromodin, 7-chloro-1-O-methylemodin, 7-chloro-1-O-methyl-ω-hydroxyemodin, 5-chloroemodin, 5-chloro-1-O-methylemodin, 5-chloro-1-O-methyl-ω-hydoxyemodin 5-chloro-ω-hydroxyemodin. The 5-chloroemodins are new substances, although 5-chloro-1-O-methylemodin was isolated previously from a fungus. Radiolabelled 7-chloroemodin derivatives obtained upon incubation of with Na [2-14C]acetate, demonstrating utilization acetate in their formation. 7-Chloro-1-O-methylemodin, enriched 13C, following [1-13C]acetate. Analysis its spectrum showed that biosynthesized through polyketide pathway. Efficient incorporation label Na36Cl into 7-chloro-1-O-methylemodin is capable chlorinating preformed anthraquinones.