Researchers have found that substances extracted from marigold flowers create an environment lethal to bacteria. This discovery was made by specialists from Immanuel Kant Baltic Federal University (IKBFU) as part of an international research collaboration. The findings have been presented in the Journal of Luminescence.
Scientists explained that certain biological compounds, specifically flavonoids, present in marigold flowers—common in flower beds and balcony boxes—can enhance the ability of sunlight to activate oxygen molecules. The energy from the sun`s ultraviolet (UV) radiation converts ordinary O₂ gas molecules into a highly reactive form of oxygen, capable of destroying bacteria and inorganic contaminants.
The team from IKBFU, along with colleagues from Kaliningrad State Technical University and Brazilian specialists, observed this sterilizing effect when extracts from marigolds (Tagetes patula) were combined with porphyrin.
“It`s comparable to sunlight powering a small device that then cleans the air or treats tissues. However, here it occurs at the molecular level using natural ingredients,” explained Dmitry Artamonov, Junior Researcher at the IKBFU Center for Fundamental and Applied Photonics and Nanophotonics and one of the study`s authors.
Artamonov added that marigold flowers could potentially be used to develop antibacterial coatings, devices for detecting pollutants in water and air, and in medical applications. The identified effect of light “enhancement” in the complex based on marigold flavonoids and porphyrin shows promise for treating skin infections and superficial tumors without the need for toxic drugs.
“Unlike antibiotics, microorganisms cannot develop resistance to the action of active oxygen. This means readily available, natural marigold components could be the basis for new therapeutic agents against bacterial diseases,” Artamonov further noted.
Currently, 1 mg of marigold flower extract can generate 60–70 percent of the active oxygen produced by commercial synthetic analogs, but with significantly higher biocompatibility. Looking ahead, the researchers plan to develop material prototypes based on these complexes, aiming to improve their stability, controllability, and targeted delivery, particularly for applications like photodynamic therapy in tissues.
Rupert Blackwood 
Clement Ashworth