Structure-activity relationship of captopril derivatives as New Delhi metallo beta-lactamase 1 inhibitors

New Delhi Metallo beta-lactamase-1 (NDM-1) is a zinc-dependent enzyme that confers resistance to several antibiotics; therefore, there is an urgent requirement for effective inhibitors. Captopril has been exploited as a scaffold in the design of NDM-1 inhibitors; however, a comparative evaluation of these derivatives from structure activity relationship perspective has not been conducted. This review aimed to evaluate captopril-derived NDM-1 inhibitors and to identify possible structure-activity relationships that govern their NDM-1 inhibitory action.

The literature was searched in a structured manner using scholarly databases to locate original studies that reported captopril derivatives and evaluated them in vitro against NDM-1 with the explicit reporting of the inhibitory concentration values (IC₅₀). Eligible studies were filtered using predefined criteria and analysed using a qualitative approach, because heterogeneity in assay conditions and experimental methods prevented a direct quantitative comparison across studies.

The activity of captopril derivatives depends on the free thiol group (masking it reduces activity), with stereochemistry governing optimal binding orientation within the NDM-1 active site, hydrophobic substitutions enhance activity only within steric limits, and the carboxylate motif serves as a secondary anchoring feature.

Captopril emerges as a promising scaffold for NDM-1 inhibitors and reveals significant structural features associated with NDM-1 inhibitors. Despite limited in vivo data and heterogeneity in assay conditions, the findings provide a rational framework for optimizing captopril-inspired NDM-1 inhibitors.