# 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
The impact of 5% Peruvian propolis ethanolic extract on _S. mutans_ growth was analyzed by [PERSON] et al. [88]. The results indicated that Peruvian propolisils extract possesses better antimicrobial activity than chlorhexidine digluconate. The negative control was 96% ethanol, while the positive control was 0.12% chlorhexidine digluconate. The inhibition growth area after the propolisis treatment was 18.2 \(\pm\) 1.8 and 26.4 \(\pm\) 2.6 mm for summer and autumn samples, respectively. The inhibition area for chlorhexidine was 13.0 mm. The growth of _S. mutans_ was not inhibited by the negative control [88]. The antibacterial activity of Italian propolisis against _S. pyogenes_ was investigated by [PERSON] et al. [89]. The study showed that propolisis is an effective antimicrobial agent. The authors used ethanol extract. The obtained MIC value was 156 \(\upmu\)g/mL and the effect was not influenced by the ethanol (MIC 100-125 \(\upmu\)g/mL) [89]. The antibacterial activity of mouthwash containing 0.8% of Brazilian red propo-lis extract against _S. mutans_, _S. sanguinis_, _S. salivarius_, and _L. casei_ was analyzed by [PERSON] et al. [14]. The study showed that red propoils can be a natural alternative in bacterial infection, since it possesses antibacterial activity against _Streptococcus spp._ and _L. casei_ as well as a similar cytotoxicity and antibofilm effect in comparison to chlorhexidine. The authors analyzed MIC and MBC of 0.05% sodium fluoride (NaF); 0.8% red propolis extract (RPE); 0.8% RPE + 0.05% NaF, and 0.12% chlorhexidine containing mouthwash. The results are shown in Table 3. The analysis of antimicrobial activity showed also that using RPE mouthwash resulted in highly reduced viable microorganisms (7.74 Log\({}_{10}\)CFU/mL) in comparison to RPE+NaF (7.95 Log\({}_{10}\)CFU/mL), chlorhexidine (7.93 Log\({}_{10}\)CFU/mL), and the ordinary mouthwash. The greatest effectiveness in reducing _Streptococcus spp._ was found for chlorhexidine, which did not vary from RPE and RPE+NaF [14]. [PERSON] et al. [90] determined the antimicrobial activity of Iranian propolis against _S. mutans_ and _L. acidophilus_. MIC values are presented in Table 3.0 Moreover, the researchers observed a rise in bacterial levels in water, which suggests that water did not decrease the number of both bacteria. In case of _L. acidophilus_, propolisis most significantly reduced the number of bacteria (from 6.14 to 5.35, 5.68, and 5.97, after 12 hours, 1 week, and 2 weeks, respectively). Listerine and chlorhexidine (0.12%) reduced the number of bacteria, but after 1-week treatment, they reached the baseline level. Regarding _S. mutans_, propolisis most significantly reduced the number of bacteria (from 4.15 to 3.37, 3.81, and 4.05, after 12 hours, 1 week, and 2 weeks, respectively). Listerine and chlorhexidine reduced the number of bacteria, but after 2 weeks of treatment, they reached the baseline level. Thus, propolisis was more efficient than other mouthwashes [90]. [PERSON] et al. [91] analyzed the impact of propolisis extracts from the western region of Cameroon on _Lactobacillus spp._ and _S. mutans_. They proved that an inhibition diameter was greater for the aqueous extract of propolisis than the one for the hydroalcoholic extract. The authors used hydroalcoholic and aqueous extracts of propolisis as well as gentamycin to determine MIC and MBC. Table 3 presents the obtained results. The inhibition diameters of extracts on _S. mutans_ corresponding to MICs were 10, 26, and 8 mm, respectively for aqueous, gentamycin, and hydro alcoholic extract. In case of _Lactobacillus spp._ the inhibition diameters were 11, 29, and 8 mm, respectively, for aqueous, gentamycin, and hydroalcoholic extract. The authors suggest that the difference between the aqueous and hydro alcoholic extract may be caused by the fact that the chemical components may vary, and resin-like substance may be present.