Antibacterial activity of red alga extract Actinotrichia fragilis collected from Bushehr province coast against cariogenic pathogens

Antibacterial activity of red alga extract Actinotrichia fragilis collected from Bushehr province coast against cariogenic pathogens
marzieh taherzadeh,^1,* somayeh heidari,² zahra shahrsabzi,³ yasmina alizadeh,⁴
1. The Persian Gulf Marine Biotechnology Research Center, Bushehr University Of Medical Sciences, Bushehr, Iran
2. The Persian Gulf Marine Biotechnology Research Center, Bushehr University Of Medical Sciences, Bushehr, Iran
3. Bushehr University Of Medical Sciences, Bushehr, Iran
4. Bushehr University Of Medical Sciences, Bushehr, Iran
Introduction: The aim of this study was to evaluate the antibacterial effect of extract of red alga, Actinotrichia fragilis collected from Persian Gulf coast in Bushehr city against cariogenic pathogens.
Methods: Antibacterial effect of aqueous, methanolic and ethyl acetate extracts of Actinotrichia fragilis, collected from Bushehr coast, were tested on three strains of gram positive bacteria: »Streptococcous mutans«, »Streptococcous sanguis« and »Streptococcous salivarius«. Ampicillin and cholorhexidine gluconate % 0/2 were used as controls. After a pre-test investigation, the antibacterial effects were evaluated by well diffusion method and serial dilutions to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Data were analyzed with analysis of variance, post hoc and independent t test.
Results: The results showed that in well diffusion test, inhibition zone of all extracts were widely less than ampicillin and cholorhexidine’s zone of inhibition. Minimum inhibitory concentration and minimum bactericidal concentration of extracts revealed that aqueous extract had no bacteriostatic effect at any examined concentration (p> 0/5), but had the highest bactericidal effect on Streptococcous sanguis and Streptococcous salivarius at concentration of 0/4 gr/ml. Methanolic extract showed the highest bacteriocidal and bacteriostatic effect on Streptococcous salivarius at concentration of 0/2 gr/ml. Ethyl acetate extract revealed inhibitory effect only at concentration of 0/1 gr/ml on Streptococcous sanguis, but the highest bactericidal effect at concentration of 0/00019 gr/ml on Streptococcous salivarius.
Conclusion: Streptococcous mutans has found to have less sensitivity to all extracts of Actinotrichia fragilis compared to Streptococcous sanguis and Streptococcous salivarius. Ethyl acetate extract reveals more bacteriocidal effect than Ampicillin, and Streptococcous salivarius is the most sensitive one to this effect while methanolic extract shows significant bacteriostatic effect on all three bacteria which is equal to ampicillin and more than cholorhexidine at tested concentrations.
Keywords: Antibacterials , Red algae, Actinotrichia fragilis, S. mutans , S. sanguis, S. salivarius, MIC, MBC