Why Scientists Are Eyeing Turmeric and Rhubarb in the Fight Against Superbugs

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According to the World Health Organization, antibiotic resistance has become a global health emergency. The UN health agency has described the phenomenon as a “silent pandemic,” warning that common infections are becoming increasingly difficult — and sometimes impossible — to treat.

In its latest Global Antimicrobial Resistance and Use Surveillance System (GLASS) report, which draws on data from more than 100 countries, the WHO found that roughly one in three infections in Southeast Asia and the Eastern Mediterranean regions were resistant to commonly used antibiotics, as were one in five infections in Africa. “Antimicrobial resistance is outpacing advances in modern medicine, threatening the health of families worldwide,” WHO director-general Tedros Adhanom Ghebreyesus said in a statement accompanying the report.

While most public attention focuses on hospitals and clinical settings, scientists are increasingly concerned about another, less visible front in the fight against antibiotic resistance: wastewater.

In a 2025 laboratory study published in the peer-reviewed journal Frontiers in Microbiology, researchers examined whether naturally occurring plant compounds could help limit the spread of antibiotic-resistant bacteria in public wastewater systems. The focus on wastewater reflects growing concern that sewage can act as a reservoir where bacteria are repeatedly exposed to low levels of antibiotics excreted by people taking the drugs, conditions that can accelerate the development of resistance.

“Without improved treatment, wastewater could serve as a breeding ground for ‘superbugs’ that may enter water resources such as rivers, lakes, and reservoirs, posing potential risks to public health,” Dr. Liyuan “Joanna” Hou, an environmental microbiologist at Utah State University and the study’s senior author, said in a statement.

“Our goal was to isolate and characterize multidrug-resistant bacteria, explore the molecular mechanisms of resistance through whole-genome sequencing, and assess the potential of natural compounds as alternative mitigation strategies,” Hou said, adding that genomic analysis helps researchers understand how resistance traits persist and spread in wastewater environments.

To investigate this risk, Hou and her colleagues collected samples from a wastewater treatment plant in Logan, Utah. In laboratory experiments, they isolated bacteria from the samples and tested their resistance to sulfamethoxazole, a commonly used antibiotic. The team then selected the four most resistant bacterial strains and screened them against 11 plant-derived compounds previously reported to have antimicrobial or anti-biofilm properties.

Two compounds stood out: curcumin, found in turmeric, and emodin, a naturally occurring compound in rhubarb. In lab conditions, both inhibited the growth of certain Gram-positive multidrug-resistant bacteria.

“We selected a panel of compounds primarily derived from plants, such as curcumin from turmeric, quercetin from onions and apples, and emodin from rhubarb,” Hou said. “These compounds were chosen based on their reported antimicrobial or anti-biofilm properties in previous studies and their natural abundance, making them promising candidates for exploring new, environmentally friendly approaches to mitigate resistance.”

However, researchers stress that the findings are early-stage and do not suggest that these compounds are ready for real-world use — nor that they could treat infections in people. The experiments were conducted under controlled laboratory conditions and focused on a single wastewater treatment facility, which may not reflect the complexity of larger or less advanced systems, particularly in regions most affected by antibiotic resistance.

Experts also caution that scaling up such approaches would require extensive testing to determine appropriate concentrations, environmental safety, cost, and compatibility with existing wastewater treatment technologies.

“While natural compounds like curcumin and emodin show promise in inhibiting certain multidrug-resistant bacteria, further research is needed,” Hou said. “Future work should include testing these compounds in complex wastewater matrices, exploring synergistic effects with existing treatment processes, and assessing long-term impacts on microbial communities and resistance dynamics. Additionally, scaling up from laboratory studies to pilot-scale trials will be critical for evaluating feasibility and environmental safety.” 

For now, the research highlights wastewater as an often-overlooked battleground in the fight against antibiotic resistance — and underscores that addressing the crisis will require interventions far beyond the doctor’s office.