ABSTRACT
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Macrocyclic antibiotics represent a class of antibiotics used in therapy against infections caused by gram-positive and gram-negative bacteria and having ring structures with at least 10 members. Despite their common features, macrocyclic antibiotics differ in several of their physicochemical properties and in biological activity. There are hundreds of natural and semisynthetic macrocyclic antibiotics, which comprise a large variety of structural types, including polyene-polyols, ansa compounds
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(e.g., aliphatic-bridged aromatic ring systems), glycopeptides, peptides, and peptideheterocycle conjugates. In general, these compounds have molecular masses ranging between 600 and 2200 and a variety of functional groups. There are acidic, basic, and neutral types. Some macrocyclic antibiotics absorb quite weakly in the ultraviolet (UV) and visible spectrum while others possess large conjugated groups and absorb intensely [1-3].
