Researchers at the University of Kent, working with University College London, report that madecassic acid—a compound derived from the medicinal herb Centella asiatica and widely used in skincare—can inhibit the growth of antibiotic-resistant E. coli by targeting a bacterial respiratory system not found in humans or other animals.
Scientists at the University of Kent, in collaboration with University College London (UCL), have reported antibacterial activity for madecassic acid, a plant-derived compound commonly found in skincare products.
In work described by the University of Kent and published in RSC Medicinal Chemistry, the team combined computer-based screening with laboratory experiments and found that madecassic acid can inhibit the growth of antibiotic-resistant Escherichia coli in lab tests.
According to the researchers, the compound acts by binding to the cytochrome bd complex (also described as cytochrome bd oxidases), a bacterial respiratory system that helps microbes survive during infection. The study notes that these enzymes are found in prokaryotes and not in humans or other animals, making them a potential target for antimicrobial development.
The team reported that the compound’s structure could be chemically modified. They extracted madecassic acid from a Centella asiatica plant sample sourced in Vietnam and produced three modified derivatives. The University of Kent summary says each derivative blocked the cytochrome bd complex and halted bacterial growth, and that one derivative killed E. coli at higher concentrations.
Lead author Dr. Mark Shepherd, a Reader in Microbial Biochemistry at the University of Kent, said the work highlights how modern techniques can clarify how plant-derived compounds function: “Plants have been a source of natural medicines for millennia, and now contemporary research approaches can reveal the mechanisms of action. This is an exciting time, and we hope to further our understanding of natural antimicrobials from plants, nature's great chemical factories.”
The findings arrive as global health researchers continue to warn about the growing burden of antimicrobial resistance. A major modelling analysis has estimated that, under a reference scenario, bacterial antimicrobial resistance could be directly responsible for about 39 million deaths worldwide between 2025 and 2050.
Beyond potential medical applications, the University of Kent summary also suggests the research may help scientists better understand how madecassic acid could affect the skin microbiome when used in skincare. The researchers said they plan additional work to refine the compounds and further evaluate their potential as starting points for drug development.