Comparative screening of dose-dependent and strain-specific antimicrobial efficacy of berberine against a representative library of broad-spectrum antibiotics

Widespread use of antibiotics has resulted in the emergence of antibiotic-resistant bacteria strains, increasing the necessity in research towards the identification of novel antibiotic agents. Berberine, a natural alkaloid that is extracted from the roots and stems of plants in the genus Berberis, has been documented to have medicinal potential since 3000 BC, where it was used as an antibacterial agent in ancient Chinese medicine. Since then, berberine and synthesized analogs have been studied for a wide range of medicinal properties, including antimicrobial activity. Based on berberine’s history, we hypothesize that berberine has broad-spectrum antibacterial properties, along with potency that is comparable to current broad-spectrum antibiotics that are commercially available. Here, we screened berberine against four strains of bacteria and evaluated its antimicrobial activity against five broad-spectrum antibiotics from different classes to better quantify berberine’s antibacterial activity and compare its efficacy as an antibacterial agent to the broad-spectrum antibiotics. Our results indicated that berberine had strain-selective cytotoxic effects and was significantly less potent than most of the broad-spectrum antibiotics. A better understanding of the antimicrobial activity of the berberine may inform the design of future antimicrobial therapies.