Arenicolide Family Macrolides Provide a New Therapeutic Lead Combating Multidrug-Resistant Tuberculosis.

Area of Science:

• Natural Product Chemistry
• Microbiology
• Medicinal Chemistry

Background:

• Multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis (Mtb) strains present a critical global health challenge.
• Discovering novel antimicrobial agents is crucial for combating drug-resistant tuberculosis.

Purpose of the Study:

• To identify and characterize new chemical entities with activity against MDR- and XDR-Mtb.
• To elucidate the structure and mechanism of action of promising compounds.

Main Methods:

• Chemical investigation of Micromonospora sp. GR10 led to the isolation of eight new arenicolides and arenicolide A (Ar-A).
• Genomic analysis, quantum mechanics-based computation, chemical derivatizations, and bioinformatic analysis were used to establish absolute stereochemistry.
• In vitro antimicrobial assays, mechanistic studies (ATP depletion, cell wall destabilization), macrophage infection models, and in vivo mouse models were employed.

Main Results:

• Eight new arenicolides (Ar-D-K) and Ar-A were discovered. Their absolute stereochemistry was fully elucidated.
• Ar-A demonstrated potent in vitro antimicrobial activity against MDR- and XDR-Mtb.
• Ar-A induced ATP depletion, destabilized the Mtb cell wall, showed efficacy in macrophages, and exhibited synergistic effects with amikacin in a mouse model.

Conclusions:

• Ar-A is a promising drug lead for treating drug-resistant tuberculosis.
• The findings highlight the potential of natural products from microbial sources for developing new anti-TB therapies.