A Study About The Anti-bacteria Effect Of Orange Peel Extracts On Main Oral Pathogenic Microorganisms

Purpose:Dental caries is a multifactorial, chronic infectious disease, which mainly caused by dental plaque. The cariogenic bacteria such as Streptococcus mutans can metabolize carbohydrates whose products can lead to demineralization. Dental plaque, a complex and dynamic microbial ecosystem, plays a vital role on the formation of caries and periodontal disease. Strategies to control and prevent dental caries are mostly based on antiplaque or antimicrobial agents. Considering the bacteria resistance, more and better strategies for the prevention of caries and periodontal disease are needed.In this study, we investigate the anti-bacteria effects of orange peel extracts (OPE) by the main pathogenic microorganisms found in mouth, such as Streptococcus mutans, Staphylococcus aureus, Staphylococcus albus,Candida albican and herpes simples virus-1. Moreover, we observed the anti-adhesive effect of Streptococcus mutans and an unidentified bacterium on the smooth glass. Another purpose of my study is to analyze the cell-toxicity of the OPE, which can prove that the application of OPE is a new, natural and safety bacteriostatic agent on the prevention and control of oral diseases.Methods:1. Dilute the OPE in different proportion, add it in the bacterio-culture medium, and culture at 37℃for 24 hours. Then measure the diameter of bacteriostasis ring and analyze its inhibition effect on the growth of Streptococcus mutans, Staphylococcus aureus, Staphylococcus albus and Candida albican.2. Make use of colony forming unit (CFU) to examine the inhibition effect of adhesiveness of Streptococcus mutans to the smooth glass rod in OPE with different concentration.3. Use scanning electron microscope (SEM) to observe the effect of the OPE on the adhesiveness of Streptococcus mutans and an unidentified bacterium.4. Examine the toxicity of the OPE to human 293 cells.5. Adopt MTT method to examine the effect of the OPE on herpes simples virus-typel (HSV-!).Results:1. The orange peel extracts (OPE) diluted by 1600 times can inhibit growth of Streptococcus mutans; diluted by 6400 times,it can inhibit growth of Staphylococcus aureus; diluted by 12800 times, it can inhibit growth of Staphylococcus albus; diluted by 800 times,it can inhibit growth of Candida albican. The inhibition effect is related to the different concentration of the OPE.2. After diluted by 25600 times the OPE still can inhibit adhesion of Streptococcus mutans. Under the scanning electron microscope, the different adhesive forms of inhibition effect of adhesive attraction of Streptococcus mutans can be obsereved. This result shows that the OPE can inhibit the adhesive ability of Streptococcus mutans and an unidentified bacterium to smooth glass. The inhibition effects are related to the concentration of the OPE.3. OPE has shown a very low toxicity to human 293 cells.4. The OPE can inhibit the pathogenicity of herpes simples virus-type1.Conclusion:Orange peel extracts have anti-bacterial effect on main oralpathogenic microorganisms and they can inhibit the adhesion of Streptococcus and an unidentified bacterium to smooth glass. Besides, the OPE have the anti-virus effect on herpes simples virus-type 1. The original fluid has shown a very low toxicity to human 293 cells.The application of OPE is a new, natural and safety bacteriostatic agent on the prevention and control of oral diseases.