Macrolike

Macrolike is an adjective used in chemistry and pharmacology to describe substances that resemble macrolides in structure or function. It is not a formal taxonomic term, but a descriptive label applied to compounds that share key features of macrolide antibiotics or macrocyclic lactones more broadly.

In structural terms, macrolides are defined by a large macrocyclic lactone ring, typically containing 12 to 16 atoms, often with various sugar moieties attached. Macrolike compounds are those that have a similar macrocyclic lactone core and related substituents, even if they are not classified as strict macrolides. This similarity can be relevant for how the molecule interacts with biological targets.

Functionally, some macrolike substances may inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit, as macrolides do, although potency, spectrum, and resistance profiles can vary. The term is often used for semi-synthetic derivatives or related natural products that retain the macrocyclic scaffold and a macrolide-like mechanism of action.

Examples and related groups include classic macrolides such as erythromycin, clarithromycin, and azithromycin. Ketolides, such as telithromycin, are described as macrolide-like because they are structurally related and designed to address resistance. Fidaxomicin is another macrocyclic antibiotic with a distinct mechanism and is sometimes discussed in a macrolide-adjacent context due to its macrocycle, though it is not a macrolide.

Usage notes: because macrolike describes resemblance rather than a formal subclass, its use varies across literature. It is most common in pharmacology and medicinal chemistry to signal similarity to macrolides while avoiding strict classification.