# Propolis as Natural Product in the Oral Cavity Bacterial Infections Treatment: A Systematic Review
## 4 Results
### Antibacterial Activity of Propolis in Oral Cavity Bacterial Infections
#### 4.2.1 In Vitro Studies
[PERSON] et al. [62] evaluated the antimicrobial activity of propolisis against _S. salivarius_, _S. sanguinis_, _S. mitis_, _S. mutans_, _S. sobrinus_, and _L. casei_. The authors noticed that propolisis possesses antimicrobial activity against all the strains of bacteria that were investigated. The determination of the MIC results showed that _S. sanguinis_ and _S. mitis_ were more susceptible to the propolisis (Table 3) [62]. [PERSON] et al. [63] investigated the antimicrobial activity of ethanolic extract and fractions of Brazilian green propolis (BGP) collected by bees from _Baccharis dracunculifolia_. The results indicated that _S. mutans_, _S. sobrinus_, _P. gingivalis_, _F. nucleatum_, _F. necrophorum_, and _A. actinomycetemontinans_ were susceptible to BGP (Table 3). Antimicrobial activity was evaluated by MIC, MBC, and the inhibition zone. Inhibition zones were 18.3 \(\pm\) 1.15, 28.6 \(\pm\) 0.57, 14.0 \(\pm\) 0.00, 15.2 \(\pm\) 0.26, 17.3 \(\pm\) 0.57, and 14.6 \(\pm\) 0.57 mm, respectively. None of the assayed fractions (coumaric acid, kaempfer, pinobank-3-acetate, chrysin, galangin, kaempfer, and artepillin C) was found to be more active than the extract. Thus, it can be concluded that the antimicrobial activity results from a synergistic effect of propolisis constituents [63]. The antimicrobial activity of propolisis ethanolic extracts from Iran-Turanian, European-Siberian, Brazil, and Turkey against certain oral pathogens was analyzed by [PERSON] et al. [19]. Nine different strains were analyzed: _P. anaerobins_, _P. micros_, _P. oralis_, _P. melaninogenica_, _P. gingivalis_, _F. nucleatum_, _V. parvula_, _L. acidophilus_, and _A. naslundii_. The propolisis extracts from Rize (17.5% _w/o_), Kazan (9.4% _w/o_), Mugla (13.6% _w/e_), Tahtakopru (5.8% _w/e_), and Brazil (4.6% _w/v_) were analyzed. The Kazan propolisis sample showed significantly lower MIC values in comparison to other samples. The obtained MIC values are shown in Table 3. Moreover, the microorganisms died within 4 h (_P. anaerobins_, _P. micros_, _L. acidophilus_, and _A. naslundii_), 8 h (_P. oralis_, _P. melaninogenica_, and _P. gingivalis_), 12 h (_F. nucleatum_), and 16 h (_V. parula_) of incubation. The researchers did not identify any viable cells (CFU) after the above-listed periods of time [19]. The antimicrobial effect of Cretan propolisis against _S. mutans_ was investigated by [PERSON] et al. [64]. The researchers observed a 20 mm inhibition zone for _S. mutans_ after ethanolic propolisis extract treatment. Moreover, the MIC value was calculated to be 0.17 mg/mL. The observed effect was weaker than in case of sanguinarine used as the control (28 mm inhibition zone, MIC = 0.0015 mg/mL) [64]. [PERSON] et al. [65] determined the optimal concentration of Korean propolisis against _S. mutans_ and _S. sobrinus_ isolated from Koreans. A dry extract of propolisis was obtained and dissolved in ethanol at a concentration of 448 mg/mL. The researchers found out that propolisis at a concentration of 35 mg/mL could be used _in vivo_ to prevent the development of dental caries. The determination of the MIC was used to obtain those results. After 24 h of incubation in appropriate conditions, the researchers adopted the lowest concentration of ethanol propolisis solution which was required to inhibit visible growth as MIC (Table 3) [65]. [PERSON] et al. [66] researched the antimicrobial activity of _M. fasciculata_ geopropolis against oral pathogens, its effects on _S. mutans_ biofilms, and the chemical composition of the extracts. Moreover, the researchers investigated a gel for whose preparation a geopropolis extract was used to evaluate its effectiveness against _S. mutans_ as well as its immuno-toxicological potential. The researchers concluded that geopropolis would exhibit antimicrobial activity against _S. mutans_. The agar diffusion method and the broth dilution technique were employed to assess antimicrobial activities of three hydroalcoholic extracts (HAEs) of geopropolis, and hexane and chloroform fractions of one extract.