Quinocycline A, also known as PA-371-A''1, is a quinocycline-class natural product derived from Streptomyces species, characterized by a tetracyclic core with a unique quinoline moiety. It exhibits potent antibacterial activity, particularly against Gram-positive bacteria, including Staphylococcus aureus and drug-resistant strains such as MRSA. Structurally, it combines features of both tetracyclines and quinolines, contributing to its mechanism of action, which is believed to involve inhibition of bacterial protein synthesis. Quinocycline A is of interest in antibiotic discovery for its novel scaffold and promising bioactivity, offering a potential lead compound for addressing antibiotic resistance.