  By studying the literature about Tetracyclines (TCs), it becomes clearly
evident that TCs are very dynamic molecules. In some cases, their
structure-activity-relationship (SAR) are known, especially against bacteria,
while against other targets, they are virtually unknown. In other diverse
yields of research, such as neurology, oncology and virology the utility and
activity of the tetracyclines are being discovered and are also emerging as new
technological fronts. The first aim of this paper is classify the compounds
already used in therapy and prepare the schematic structure in which include
the next generation of TCs. The aim of this work is introduce a new framework
for the classification of old and new TCs, using a medicinal chemistry approach
to the structure of that drugs. A fully documented
Structure-Activity-Relationship (SAR) is presented with the analysis data of
antibacterial and nonantibacterial (antifungal, antiviral and anticancer)
tetracyclines. Lipophilicity of functional groups and conformations
interchangeably are determining rules in biological activities of TCs.
