Actinomycin Derivatives: Structural Diversification and Biological Activities

Actinomycins constitute a class of bioactive compounds known for their potent cytotoxic properties. Among them, actinomycin D, isolated in the 1940s from Streptomyces antibioticus , is the most extensively studied derivative. Structurally, actinomycins are characterized by a planar phenoxazinone chromophore flanked by two cyclic pentapeptides. They exert their biological effects primarily through DNA intercalation and transcription inhibition. Despite its remarkable bioactivity, the clinical application of actinomycin D is limited by significant adverse effects, including hepatotoxicity and restricted selectivity. These limitations underscore the need for structurally optimized analogs with improved therapeutic profiles and reduced toxicity. Over the decades, natural product discovery, precursor‐directed biosynthesis, and synthetic modification have yielded more than 70 structurally distinct derivatives, incorporating variations in both the peptide rings and the chromophore core. These structural modifications have resulted in diverse antibacterial, antiviral, and cytotoxic activities. Thus, this review critically examines the historical development, chemical diversity, and in vitro and preclinical bioactivity of actinomycin derivatives, highlighting key structural modifications over time and discussing their implications for future drug development.