Clove oil offers promise as antimicrobial alternative that could target healthcare-associated infections in low-income countries
A research study presented at MLS Future Forum has revealed that clove essential oil could offer potential as a sustainable alternative to conventional antimicrobials.
Yesmin Ali Begum, a BSc (Hons) Applied Biomedical Science student at Aston University, UK, won a poster prize for her study which investigated the antimicrobial properties of two essential oils that are known as traditional remedies - clove oil and turpentine oil.
While clove oil showed antibacterial and antifungal effects, the turpentine oil demonstrated little antimicrobial activity.
“The research revealed that clove essential oil exhibits a potent, concentration-dependent inhibitory and bactericidal/fungicidal effect against two key healthcare-associated infection (HCAI) pathogens, Staphylococcus aureus and Candida albicans, with minimum inhibitory concentrations (MICs) of 3.125% and 1.56% (v/v) respectively,” Yesmin said.
“Importantly, these effects were achieved at lower concentrations than previously reported in the literature, and through dual mechanisms: disruption of microbial membrane integrity and induction of oxidative stress. Turpentine oil, by contrast, demonstrated negligible antimicrobial activity.
“These findings offer novel insight into the therapeutic potential of plant-derived compounds and contribute valuable evidence toward the development of low-cost, accessible treatments in the global fight against antimicrobial resistance (AMR), especially in resource-limited settings.”
Yesmin’s work is aimed at addressing the escalating global health crisis of antimicrobial resistance (AMR), which is primarily driven by the overuse and misuse of antibiotics, coupled with the limited development of new antimicrobial agents. She said her research is dedicated to low-income countries like Bangladesh, where she has seen first-hand the devastating effects of limited access to healthcare.
“Healthcare-associated infections (HCAIs) are a major contributor to this crisis. They affect between 3.5% and 12% of patients in high-income countries, with prevalence rates rising as high as 40% in intensive care units,” Yesmin said.
“These infections are particularly difficult to manage in low- and middle-income settings, where access to effective antimicrobial treatments is often limited and the burden of drug-resistant pathogens like Staphylococcus aureus and Candida albicans is disproportionately high.
“In response, this study aimed to evaluate whether clove and turpentine essential oils, plant-derived substances with traditional medicinal use, could offer sustainable, low-cost alternatives to conventional antimicrobials.
“Specifically, the research investigated the antimicrobial potency of these oils, their potential to disrupt microbial membranes, and their ability to induce oxidative stress in pathogens. The goal was to determine whether they could serve as viable candidates for further development in the global effort to tackle drug-resistant HCAI pathogens.”
Yesmin carried out a series of experiments to assess the antimicrobial activity of the oils. These included growth inhibition assays as well as mechanistic studies, such as membrane depolarisation, outer membrane permeabilisation, and reactive oxygen species (ROS) detection assays, to examine how the oils disrupted microbial cell membranes and whether they induced oxidative stress, potentially leading to cell death. She also compared the efficacy of each oil individually and in combination to assess any synergistic effects.
The findings revealed that clove essential oil exhibited significant antimicrobial activity. It effectively inhibited microbial growth, compromised cell membrane integrity, and induced oxidative stress, all of which contributed to microbial cell death.
In contrast, turpentine oil showed minimal efficacy, requiring much higher concentrations to produce any noticeable effect. These results suggest that clove oil holds promise as a natural, accessible alternative to antibiotics, particularly in resource-limited settings where access to modern treatments may be restricted.
“One of the most surprising findings in this study was the stark contrast in performance between the two essential oils, despite both being traditionally used for their medicinal properties,” Yesmin said.
“Clove essential oil (CEO) demonstrated strong and consistent antimicrobial activity - it not only inhibited the growth of Staphylococcus aureus and Candida albicans at relatively low concentrations (MICs of 3.125% and 1.56% v/v respectively), but also disrupted microbial membranes and triggered oxidative stress, leading to cell death.
“In contrast, turpentine essential oil (TEO) showed almost no significant antimicrobial activity unless used at full, undiluted strength (100% v/v). This was surprising given that TEO contains α- and β-pinene, compounds previously reported to have antimicrobial effects.
“However, the results of this study suggest that either the concentration of these active components in the oil used was too low, or that the whole oil formulation lacked the necessary potency or stability to exert a strong biological effect. Additionally, turpentine failed to show a clear dose-response relationship and produced inconsistent results in membrane disruption and ROS assays, suggesting weak or non-specific interactions with microbial cells.
“Another unexpected outcome was that combining CEO and TEO did not enhance their effectiveness. The interaction was classified as "indifferent" based on FICI values, meaning the combination offered no additional antimicrobial benefit.
“This suggests that TEO may not only lack synergistic potential, but could also dilute or interfere with the action of more potent agents like CEO. These findings underscore the importance of evidence-based evaluation of natural products, historical use or shared chemical components do not always translate into predictable or effective antimicrobial activity.”
The results suggest that clove essential oil could offer a practical and affordable alternative to conventional antibiotics, especially in the fight against HCAIs and AMR. The strong antimicrobial activity of clove oil, particularly its ability to kill harmful microbes by disrupting their membranes and generating oxidative stress, means it could be developed into a natural, plant-based treatment option, Yesmin said.
“In real-world terms, this is especially important for low- and middle-income countries, where access to expensive or advanced antibiotics is often limited. A low-cost, sustainable antimicrobial like clove oil could help reduce the burden of resistant infections in hospitals and healthcare settings, ultimately saving lives and reducing the strain on healthcare systems,” she said.
“More broadly, the research highlights the importance of exploring traditional remedies through modern science. As the world faces a growing crisis of drug-resistant infections, identifying effective natural alternatives is a critical step in ensuring we have more tools available to protect public health, particularly for vulnerable populations who may not have other treatment options.”