Thyme, rosemary, and lavender have long been associated with natural medicine. Today, however, these aromatic plants are increasingly being studied by researchers.
“In an era of ever-increasing microbial resistance to antibiotics, there is a growing emphasis on the need to introduce antimicrobial products into therapy to which microbes have not yet developed resistance,” says Dr Malwina Brożyna from Wroclaw Medical University. For nearly a decade, she has been researching the properties of essential oils and their therapeutic potential.”
As the researcher emphasizes, each oil is a complex set of chemical molecules that act simultaneously and multidirectionally on bacterial cells
“You can think of it as a kind of antimicrobial cocktail – a mixture of natural compounds which, in combination therapy, can not only increase the effectiveness of antibiotics, but also reduce the risk of resistance,” she explains.
Thyme and rosemary under the microscope
In a recent study, a team of scientists examined the effects of thyme and rosemary oils on Staphylococcus aureus. This bacterium is well known to doctors – it is responsible for many skin and wound infections, and some of its strains are highly resistant to treatment.
The experiments were conducted in conditions as close as possible to the actual wound environment. The results surprised the researchers: thyme oil exhibited significantly higher antimicrobial activity in this environment than in a standard laboratory medium, whereas rosemary oil showed the opposite.
“Such differences show how much the conditions in which the research is conducted affect its effectiveness,” explains Dr Brożyna. “If we want essential oils actually to find clinical application, we need to design experiments that reflect what happens in the body, not just in a test tube.”
The differences between the bacterial strains themselves proved to be equally important. Some reacted very strongly, others not at all. This confirms that when analyzing the effectiveness of oils, the intraspecies variability of microorganisms must be taken into account.
Responsible research – the idea of “essential oil stewardship”
The team from Wroclaw points out that fascination with oils must not overshadow the need for a rigorous scientific approach. Hence, the idea of “essential oil stewardship” – a set of rules defining how to test and use oils in a responsible and repeatable manner.
“The idea came about when I noticed that a huge number of non-standardized studies, based on inadequate methods, paradoxically slow down the introduction of oil treatment into clinical practice,” says Dr Brożyna.
As part of an NCN Preludium grant, her team developed detailed methodological guidelines for assessing the antimicrobial activity of oils. The aim is to ensure that every researcher, regardless of their laboratory, can obtain reliable, repeatable results. This is the first step towards creating international research standards and a realistic clinical assessment of the effectiveness of these natural substances.
PUMA – the laboratory of the future
The research is conducted within the PUMA (Platform for Unique Model Applications) platform, headed by Dr Adam Junka. This unit develops biological and bioengineering models that enable the effectiveness of antibiotics, antiseptics, and natural compounds to be tested under conditions similar to those of real infections.
“PUMA is an environment where we combine microbiology, bioengineering, and modern technologies to study biological processes with maximum reliability,” explains Dr Brożyna. There are also plans to implement artificial intelligence-based models to help predict the effectiveness of the substances being tested and optimize the experimental process.
What next?
Although essential oils cannot replace classic pharmacotherapy, they can complement it, especially in the treatment of local infections. However, before they can be used in clinical practice, stable formulations and complete standardization will need to be developed.
The biggest challenge is variability – both chemical, resulting from the origin of the plants, and biological, related to the behavior of bacteria. Therefore, as Dr Brożyna emphasizes, a “responsible, evidence-based approach to nature” is needed.
This material is based on articles:
- Toward essential oil stewardship: strain-resolved evaluation of thyme oil activity against Pseudomonas aeruginosa
Authors: Malwina Brożyna , Zuzanna Stepnicka, Natalia Tyminska, Bartłomiej Dudek, Katarzyna Kapczyńska, Adam Matkowski, Yanfang Sun, Michał Tomczyk, Adam Junka - Establishing essential oil stewardship through the case of rosemary and thyme oils against Staphylococcus aureus
Authors: Malwina Brożyna , Zuzanna Stepnicka, Katarzyna Kapczyńska, Bartłomiej Dudek, Adam Matkowski, Adam Junka
These publications were provided as part of the National Science Centre’s Prelude project No. 2021/41/N/NZ6/03305.