Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Aug 26;10(9):1045.
doi: 10.3390/antibiotics10091045.

In Vitro Activity of Propolis on Oral Microorganisms and Biofilms

Alexandra Stähli  1 , Hannah Schröter  1 , Simonetta Bullitta  2 , Francesca Serralutzu  2 , Antonio Dore  3 , Sandor Nietzsche  4 , Egle Milia  5 , Anton Sculean  1 , Sigrun Eick  1
Affiliations

In Vitro Activity of Propolis on Oral Microorganisms and Biofilms

Alexandra Stähli et al. Antibiotics (Basel). .

Abstract

Natural products are being discussed as alternatives to commonly used chemicals in antimicrobial therapy. The study aimed to investigate the antimicrobial activity of propolis against microbial species associated with caries, periodontal disease, and Candida infections. Two commercially available ethanolic extracts of Brazilian and one of European propolis (EEP) were used. The minimal inhibitory concentrations (MIC) of propolis and controls against eight microbial strains were determined. Scanning and transmission electron microscopy (SEM and TEM) images visualized the effect of propolis on microorganisms. Subsequently, the activity on three different multi-species biofilms (both formation and existing biofilms) was assessed. All MIC values of the Brazilian EEPs were low against the tested oral species (≤0.1 mg/mL-3.13 mg/mL propolis (Candida albicans)). The European EEP had slightly higher MICs than the Brazilian EEPs. The SEM and TEM images suggest an interaction of propolis with the microbial cell wall. The European EEP exhibited the strongest effect on retarding biofilm formation, whereas the Brazilian EEPs were highly active against preformed biofilms (100 mg/mL propolis of both EEPs reduced colony forming unit counts always by more than 6 log10). The antimicrobial and anti-biofilm activities point to the potential of propolis as an adjunct in oral health care products.

Keywords: candidiasis; caries; minimal inhibitory concentrations; oral multi-species biofilm; periodontal disease; propolis preparations.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest. The funder had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Figures

Figure 1
Figure 1
Scanning electron microscopy images of Streptococcus mutans (A–C), Porphyromonas gingivalis (D–F), and Candida albicans (G–I) without (A,D,G) and with 5 min exposure to 25 mg/mL propolis of the different ethanolic propolis extracts (European: (B,E,H); green Brazilian: (C,F,I)). Bar (A–I) 1 µm.
Figure 2
Figure 2
Transmission electron microscopy images of Streptococcus mutans (A–C), Porphyromonas gingivalis (D–F), and Candida albicans (G–I) without (A,D,G) and with 5 min exposure to 25 mg/mL propolis of the different ethanolic propolis extracts (European: (B,E,H); Brazilian green: (C,F,I)). Bar (A–I) 500 nm for bacteria, 2 µm for C. albicans; After exposure to propolis there are attachments visible (arrowhead), an enclosing compartment—maybe made of EPS (arrows), and a lot of small (40 nm) vesicles (asterisks).
Figure 3
Figure 3
Activity of the different ethanolic extracts of propolis (European and red and green Brazilian (Braz.)) on colony forming units (cfu; (A,B)), metabolic activity (C,D) and quantity (E,F) in a formed cariogenic biofilm after 4 h (A,C,E) and 24 h (B,D,F). */** p < 0.05/p < 0.01 vs. control 0.9% NaCl.
Figure 4
Figure 4
Activity of the different ethanolic extracts of propolis (European and red and green Brazilian) on colony forming units (cfu) (A), metabolic activity (B), and quantity (C) on a 48 h cariogenic biofilm. */** p < 0.05/p < 0.01 vs. control 0.9% NaCl.
Figure 5
Figure 5
Activity of the different ethanolic extracts of propolis (European and red and green Brazilian (Braz.)) on colony forming unity (cfu) (A,B), metabolic activity (C,D), and quantity (E,F) in a formed periodontal biofilm after 4 h (A,C,E) and 24 h (B,D,F). */** p < 0.05/p < 0.01 vs. control 0.9% NaCl.
Figure 6
Figure 6
Activity of the different ethanolic extracts of propolis (European and red and green Brazilian) on colony forming units (cfu) (A), metabolic activity (B), and quantity (C) on a 5-day-old periodontal biofilm. */** p < 0.05/p < 0.01 vs. control 0.9% NaCl.
Figure 7
Figure 7
Activity of the different ethanolic extracts of propolis (European and red and green Brazilian (Braz.)) on colony forming units (cfu) (A,B), metabolic activity (C,D), and quantity (E,F) in a formed Candida biofilm after 4 h (A,C,E) and 24 h (B,D,F). */** p < 0.05/p < 0.01 vs. control 0.9% NaCl.
Figure 8
Figure 8
Activity of the different ethanolic extracts of propolis (European, Brazilian red, and Brazilian green) on colony forming units (cfu) (A), metabolic activity (B), and quantity (C) on a 5-day old Candida biofilm. */** p < 0.05/p < 0.01 vs. control 0.9% NaCl.
See this image and copyright information in PMC

References

    1. Nyvad B., Crielaard W., Mira A., Takahashi N., Beighton D. Dental caries from a molecular microbiological perspective. Caries Res. 2013;47:89–102. doi: 10.1159/000345367. - DOI - PubMed
    1. Chapple I.L.C., Mealey B.L., Van Dyke T.E., Bartold P.M., Dommisch H., Eickholz P., Geisinger M.L., Genco R.J., Glogauer M., Goldstein M., et al. Periodontal health and gingival diseases and conditions on an intact and a reduced periodontium: Consensus report of workgroup 1 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J. Clin. Periodontol. 2018;45:S68–S77. doi: 10.1111/jcpe.12940. - DOI - PubMed
    1. Papapanou P.N., Sanz M., Buduneli N., Dietrich T., Feres M., Fine D.H., Flemmig T.F., Garcia R., Giannobile W.V., Graziani F., et al. Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J. Clin. Periodontol. 2018;45:S162–S170. doi: 10.1111/jcpe.12946. - DOI - PubMed
    1. Lombardi A., Ouanounou A. Fungal infections in dentistry: Clinical presentations, diagnosis, and treatment alternatives. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. 2020;130:533–546. doi: 10.1016/j.oooo.2020.08.011. - DOI - PubMed
    1. Buonavoglia A., Leone P., Solimando A.G., Fasano R., Malerba E., Prete M., Corrente M., Prati C., Vacca A., Racanelli V. Antibiotics or No Antibiotics, That Is the Question: An Update on Efficient and Effective Use of Antibiotics in Dental Practice. Antibiotics. 2021;10:550. doi: 10.3390/antibiotics10050550. - DOI - PMC - PubMed

LinkOut - more resources