6-Polyaminosteroid Squalamine Analogues Display Antibacterial Activity against Resistant Pathogens.

Area of Science:

• Medicinal Chemistry
• Antimicrobial Drug Discovery
• Organic Synthesis

Background:

• Antibiotic resistance is a growing global health threat, necessitating novel therapeutic agents.
• Squalamine and its analogues are marine-derived compounds with known antimicrobial activities.
• Existing treatments face challenges from resistant bacterial strains like vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus.

Purpose of the Study:

• To synthesize novel 6-polyaminosteroid analogues of squalamine.
• To evaluate the in vitro antimicrobial efficacy of these analogues against a panel of resistant Gram-positive and Gram-negative bacteria.
• To explore the potential of these compounds as standalone treatments or as adjuvants to existing antibiotics.

Main Methods:

• Synthesis of a series of 6-polyaminosteroid analogues.
• In vitro antimicrobial susceptibility testing using minimum inhibitory concentration (MIC) assays.
• Evaluation of synergistic effects with vancomycin and oxacillin.

Main Results:

• Compounds 4k and 4n demonstrated potent activity against Gram-positive bacteria (MICs 4–16 µg/mL) and showed additive/synergistic effects with vancomycin/oxacillin.
• Derivative 4f, containing a spermine moiety, was most active against resistant Gram-negative bacteria (MIC 16 µg/mL).
• The synthesized analogues exhibited moderate to good yields.

Conclusions:

• 6-polyaminosteroid analogues of squalamine are promising candidates for treating Gram-positive bacterial infections.
• These compounds can serve as potent adjuvants to overcome Gram-negative bacterial resistance.
• Further investigation into these analogues could lead to new strategies against multidrug-resistant pathogens.