Structural diversity and biological activities of naturally derived bafilomycins from actinomycetes

Background

Bafilomycins (Baf) are plecomacrolide antibiotics characterized by a 16-membered macrocyclic lactone containing two sets of conjugated dienes linked by a 1,3-dimethyl propan-2-ol (C₃) spacer to an unusually folded tetrahydropyran ring. Bafs are known for their vacuolar H⁺-adenosine triphosphatase (V-ATPase) inhibitory activity with potential therapeutic applications as antivirals (against, e.g., Severe acute respiratory syndrome coronavirus 2, Zika virus, rhinovirus), anti-tumor agents (against, e.g., osteosarcoma, various cancer cell lines), and antiparasitic (against e.g. nematodes) among others.

Main body

Since the discovery of the first Bafs in 1983, numerous Baf derivatives with varying biological activities have been isolated from Actinomycetales organisms, primarily Streptomyces and Kitasatospora. Variations in the Baf structure, particularly in the macrocyclic lactone and tetrahydropyran rings, have led to different Baf derivatives with various levels of biological activities and targets.

Short conclusion

This paper reviews the naturally derived Bafs from actinomycetes from 1983 to 2024, their structural diversity, and their biological activities. It also highlights the reported differences in Baf bioactivities with changes in structure. Furthermore, this paper classified Bafs based on structural variations relative to Baf A1, specifically: (1) substitution and (2) dehydration of residues; (3) addition of cyclic rings; and (4) tetrahydropyran ring opening. This paper hopes to shed light on underexplored Baf derivatives with more diverse and potent bioactivities.

Graphical abstract