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Background/aim: This study was designed to evaluate the effect of antimicrobial photodynamic treatment (APDT) in a biofilm model using combinations of various dyes (rose bengal, riboflavin, and methylene blue) as photosensitizers and light sources (LED and UVA) against staphylococcal and candidal biofilms. Materials and methods: Sterile microtiter plates were used for the development and quantification of the biofilms. APDT was carried out using combinations of the light sources and dyes. The percentage of the growth inhibition was then calculated using a spectrophotometer. The broth media in the wells were aspirated, wells were stained with crystal violet, and optical density values were measured spectrophotometrically. SEM analysis of the impact of APDT on bacterial and fungal biofilms was also performed. Results: The experiments showed that the most efficacious combination was red LED + methylene blue against both staphylococcal and candidal biofilms. A marked inhibition (45.4%) was detected on both C. albicans and C. parapsilosis biofilms. Red LED + methylene blue was also effective on S. aureus and S. epidermidis biofilms. SEM images suggested that the number of adherent cells and biofilm mass were markedly reduced after APDT treatment. Conclusion: Although the results of this study indicated the in vitro efficacy of APDT, it might also be a promising technique for the control of biofilm growth within intravenous catheters. [ABSTRACT FROM AUTHOR]

The antimicrobial activities of chloroform, acetone, ethanol, and water extracts of 25 plants, mostly used as remedies against various diseases in Turkish traditional medicine, were tested against 10 pathogenic bacteria and one fungus (Candida albicans) using the disk diffusion method. Among the tested plant species, Ziziphora clinopodioides Lam (Labiatae), Thymus fallax Fisch et Mey. (Labiatae), and three Hypericum species [H. heterophyllum Vent., H. hyssopifolium Chaix. subsp. elongatum(Ledeb.) Woron var. elongatum, and H. scabrum L.] (Guttiferae) showed antimicrobial activity at a broader spectrum. In particular, chloroform, acetone, and ethanol extracts of Z. clinopodioides inhibited the growth of all microbial species. Minimal inhibition concentration values of Z. clinopodioides extracts were also found to be low. The antioxidant activity of the acetone, ethanol, and water extracts of 20 plants was also evaluated by lipid peroxidation inhibition and DPPH free radical scavenging methods. It was found that water, ethanol, and acetone extracts of Z. clinopodioides, T. fallax, three Hypericum species, Artemisia santonicum L. (Compositae), and Echinophora tenuifolia L. subsp. sibthorpiena (Umbelliferae) have strong antioxidant activities among the tested plant species. In general, there is a correlation between the antioxidant potential and total phenolic contents of the extracts. In light of the current study, it can be concluded that Z. clinopodioides and T. fallax may have potential use in the food industry as antioxidants and antimicrobial herbs, as well as pharmaceutical interest. [ABSTRACT FROM AUTHOR]