Pharmazeutische Anwendungen
Around 100 polyene antibiotics have been described, but few
have been developed for clinical use. They are large amphipathic
molecules: closed macrolide rings with a variable number
of hydroxyl groups along the hydrophilic side, and along
the hydrophobic side a variable number of conjugated double
bonds to which they owe the name ‘polyene’; e.g. tetraene
(four double bonds), heptaene (seven double bonds). They
bind to sterols in the membranes of susceptible fungal cells
, causing impairment of membrane function and cell
death. Polyenes can also damage fungal cells through a cascade
of oxidative reactions linked to lipoperoxidation of the
cell membrane. Non-selective binding of polyenes to cholesterol
in mammalian cell membranes may account for some of
the toxic side effects.
The most important member of the group is amphotericin
B, a heptaene that is administered parenterally for the treatment
of systemic fungal infections.
