Bioactive C-glycosides from bacterial secondary metabolism.

C-Glycosides are commonly regarded as unusual structures, but they are far more prevalent among natural products than is imagined. This review discusses the C-glycosidic compounds produced by various bacteria, particularly the "biosynthetically talented" Streptomyces. The major structure types are presented, along with brief descriptions of the known biological and pharmacological properties of the compounds. Recent work has uncovered the genetic basis for the biosynthesis of several bacterial C-glycosides, and emphasis is placed on those cases where it has been possible to identify (at least provisionally) the C-glycosyltransferase in the pathway. Prospects for biosynthetic engineering, combinatorial biosynthesis, or glycorandomization in C-glycosidic natural products are briefly discussed.