In vitro Study of the Antimicrobial Effects of Phenolic Extract of the Salvadora persica (Miswak) on the Growth of Certain Microorganisms Responsible for Oral Infections

Abstract

Background and Objective: Salvadora persica, commonly known as the miswak tree or the toothbrush tree is thought to contain a number of phenolic compounds. The objective of this study is to identify these phenolic compounds and to evaluate their antimicrobial effects on the growth of some germs implicated in certain oral infections. Materials and Methods: Phenolic ethanol extracts were obtained by vacuum evaporation of hydroalcoholic solutions after extraction from varying amounts of crushed root, bark and stem of the test plant. The resulting pure extracts were then diluted with sterile distilled water at different increasing ratio from 0-100%. The phenolic compounds were analyzed by the HPLC method. The antimicrobial effects of these extracts were tested on many reference germs. The antimicrobial activity was tested by monitoring the growth of the germs in specific media while using disk diffusion assays. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) of the plant extracts were determined according to the micro broth dilution technique. Data were statistically analyzed by ANOVA and the Newman-Keuls test. Results: The qualitative analysis revealed that chlorogenic acid, catechin and epicatechin emerged as major phenolic compounds from root and stem of Salvadora persica, while bark extracts were rather rich in caffeine, theobromine and trigonelline. The MIC and MFC of Candida albicans were obtained with 40% phenolic extracts of the stem. The data seems to indicate that stem extracts caused a fungicidal action against Candida albicans. The growth of Streptococcus mutans w a s n o t a f f e c t e d b y t h e d i f f e r e n t s o l u t i o n s o f p h e n o l i c extracts. However, other bacteria belonging to Streptococcus genus such as Streptococcus mitis and Streptococcus faecalis and those belonging to Staphylococcus genus including Staphylococcus aureus and Staphylococcus epidermidis and the Lactobacillus casei were compl etel y i nhi bi ted wi th the extracts prepared at 7. 5 g of vegetal matter. Conclusion: The antimicrobial effects of phenolic extracts of miswak coming out of this study were close to those described in the study by most researchers. These extracts could be used as a medicament to prevent and to cure oral diseases in Algeria.