Propolis has been used for a long time in popular medicine and gained the attention of the scientific community after proving the various benefits it offers to health, including antioxidant, anti-inflammatory, antimicrobial, immunomodulatory and antitumor actions. The composition of the substance varies depending on its origin, geographic location and species of bee that produces it. Among the various types found in Brazil, a team formed by researchers from the Universidade Estadual Paulista (Unesp) and the University of Southern Denmark (Denmark) chose green propolis manufactured by the bee species Apis mellifera to examine.
Results of cell studies, disclosed in the magazine Life indicate a potential effect against tumor cells to be explored.
This variety of propolis has as its main compound a phenolic acid called Artepillin C, which is derived from the plant Baccharis dracunculifolia, popularly called wild rosemary and known for its antitumor action. “Previous research had already revealed that Artepillin C is capable of altering models of biological membranes, thin films that surround living cells, especially when we vary the pH of the environment in which they are inserted”, he explains. Wallance Moreira Pazin assistant professor at the Department of Physics and Meteorology at the Faculty of Sciences at Unesp, Bauru campus, who participated in the project.
These discoveries motivated scientists to study the biochemical principles of tumor cells when compared to healthy cells in contact with the active substance. To do this, they used fibroblasts, cells involved in the healing and maintenance of connective tissue, and glioblastoma cells, a type of very aggressive malignant brain tumor, to represent healthy and diseased cells, respectively. A variation in the pH of the culture medium was also carried out to assess whether a more acidic microenvironment would lead to different effects of Artepillin C. “This is relevant because tumor tissues convert glucose into lactic acid, which makes the extracellular microenvironment more acidic”, says Pazin.
Next, the effect of propolis on cell membranes was meticulously analyzed using optical microscopy techniques, verifying the integrity, fluidity and morphological changes of these structures. It was clear that Artepillin C was able to interact especially with diseased cells, altering their fluidity and reorganization potential and triggering autophagy, a process that causes the degradation of cell components.
According to Pazin, this study supported by FAPESP (projects 16/09633-4, 17/23426-4, 18/22214-6 It is 20/12129-1) contributes to the understanding of the substance’s mechanisms of action and provides insights for future investigations into innovative therapies in the context of cancer.
“However, even though there is high efficiency in biological activities demonstrated in assays in vitro through the use of this molecule, we highlight that certain particularities of the compound make its oral or topical administration difficult in vivo such as low absorption efficiency and bioavailability”, says Pazin.
“In this context, to advance the use of Artepillin C in antitumor therapy, strategies capable of enhancing its therapeutic action are necessary, for example, through the use of nanocarriers that enable the controlled release of the compound.”
The article pH-Dependence Cytotoxicity Evaluation of Artepillin C against Tumor Cells can be read at: www.mdpi.com/2075-1729/13/11/2186.
Thais Szegö | FAPESP Agency
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