Isoquinoline alkaloids, a class of naturally occurring compounds found in various plants (e.g., Berberis species), have attracted scientific interest for their antimicrobial properties. Among the most studied is berberine, which has demonstrated significant antibacterial activity in vitro against a range of pathogens, including Staphylococcus aureus, Escherichia coli, and other clinically relevant bacteria. The mechanisms behind this activity include inhibition of bacterial DNA synthesis, interference with cell wall formation, and disruption of membrane function.

Several laboratory and animal studies have supported the potential of isoquinoline alkaloids as alternatives or adjuncts to conventional antibiotics, particularly in the context of rising antibiotic resistance. Some studies suggest synergistic effects when used in combination with standard antibiotics, possibly enhancing their efficacy or reducing required doses. However, robust clinical trials in humans are limited. The available human data mainly focus on berberine and suggest possible benefits in gastrointestinal infections, but these studies are generally small and of variable quality.

While traditional medicine systems have used plants containing isoquinoline alkaloids for infections, the modern rationale for their use as antibiotic alternatives is primarily based on laboratory and preclinical research. Thus, the use of isoquinoline alkaloids as antibiotic alternatives is supported by a moderate level of scientific evidence but lacks large-scale clinical validation.