Actinomycetes polyene macrolides

Most polyene macrolides show antifungal activity, and they are produced by actinomycetes. Polyene macrolides are precisely described in Chapters 9 and 12 of the first edition of this book [1]. Though a few octaene macrolides have been reported, their structures have not been elucidated. 

Actinomycetes are the largest source of natural macrolides. They produce more than three hundred 16-membered macrolides (including spiroacetals) and nearly one hundred 14-membered macrolides (Table III). They also produce various sizes of macrolides up to a 60-membered ring, including polyene macrolides, macrodiolides, macrotetrolides, and immunosuppressive macrolide lactams. Compounds already described in the first edition of this book [1] are mentioned here briefly. 

Bacteria other than actinomycetes also produce macrolides. About 100 macrolides have been produced by myxobacteria, and about 40 by other bacteria (Tables IV and V). Myxobacteria produce macrolides with up to 42-membered rings including polyene macrolides, macrodiolides, macrolide lactams, and oxazole-containing macrolides. The other bacteria produce macrolides with up to 26-membered rings including polyene macrolides, macrodiolides, and macrotriolides. 

In 1950, Hazen and Brown published a report [1] on a new antifungal substance called nystatin produced by Streptomyces noursei, representing the first example of a polyene macrolide. Thereafter a great number of natural substances with a similar structure [2-5] were discovered, mostly produced by soil Actinomycetes belonging to the genus Streptomyces [5]. The primary interest in these anti-... 

Many of the naturally occurring secondary metabolites from bacteria and plants are glycosylated, mostly by 6-deoxyhexoses derived from dTDP-glucose (deoxythymidine 5 -diphospho glucose). 6-Deoxyhexose derivatives are present in a variety of antibiotics from actinomycetes, including macrolides, polyenes, and aminoglycosides, among others. 

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