Structure-activity relationship of Aminoglycosides

sar of aminoglycosides

Aminoglycosides antibiotics have two distinct structural characteristics. They are the amino sugar part and the hexose ring in the center, which can be 2-deoxystreptamine or streptidine.

  • In this antibiotic contains two or more amino sugars joined in glycoside linkage and a centrally located substituted 1,3-diaminocyclo hexane (aminocyclitol) loop.
  • Except for streptomycin, where the ring is streptidine, all aminoglycosides have a 2-deoxy streptamine ring. Two amino sugars are bound to strepidine in streptomycine.
  • Two amino sugars are bound to 2-deoxy strepamine in the kanamycin and gentamycin families.
Neomycin sulfate aminoglycosides
neomycin sulfate aminoglycosides
  • Amino sugars are bound to 2-deoxy streptamine in the neomycin family.
amino sugar portion aminoglycosides
amino sugar portion
  • The C-6 and C-2 positions are targeted by bacterial inactivating enzymes, and the substitution of a methyl group at C-6 increases enzyme resistance.
  • The activity is unaffected by cleavage of the 3-hydroxyl, 4-hydroxyl, or both groups.
Aminocyclitol ring
Aminocyclitol ring-Centrally placed hexose ring
  • While acylation (for example, amikacin) and ethylation (for example, 1-N-ethylsisomycin) do not increase activity, they do help to maintain antibacterial potency.
  • Substitution on position 2 (2-hydroxylation) and substitution on position 5 (5-deoxygenation) increase bacterial inactivating enzyme system inhibition. (Derivatives of sisomicin)
sisomicin sulfate aminoglycosides
sisomicin sulfate

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