Vitis vinifera canes are waste material of grapevine pruning and thus represent cheap source of high-value polyphenols. In view of the fact that resistance of many pathogenic microorganisms to antibiotics is a growing problem, the antimicrobial activity of plant polyphenols is studied as one of the possible approaches. We have investigated the total phenolic content, composition, antioxidant activity, and antifungal activity against Candida biofilm of an extract from winter canes and a commercially available extract from blue grapes. Light microscopy and confocal microscopy imaging as well as crystal violet staining were used to quantify and visualize the biofilm. We found a decrease in cell adhesion to the surface depending on the concentration of resveratrol in the cane extract. The biofilm formation was observed as metabolic activity of Candida albicans, Candida parapsilosis and Candida krusei biofilm cells and the minimum biofilm inhibitory concentrations were determined. The highest inhibition of metabolic activity was observed in Candida albicans biofilm after treatment with the cane extract (30 mg/L) and blue grape extract (50 mg/L). The composition of cane extract was analyzed and found to be comparatively different from blue grape extract. In addition, the content of total phenolic groups in cane extract was three-times higher (12.75 gGA/L). The results showed that cane extract was more effective in preventing biofilm formation than blue grape extract and winter canes have proven to be a potential source of polyphenols for antimicrobial and antibiofilm treatment.

• Keywords
• antioxidant activity, prevention of biofilm formation, resveratrol, waste product utilization,
• Publication type
• Journal Article MeSH

Microorganisms that cause chronic infections exist predominantly as surface-attached stable communities known as biofilms. Microbial cells in biofilms are highly resistant to conventional antibiotics and other forms of antimicrobial treatment; therefore, modern medicine tries to develop new drugs that exhibit anti-biofilm activity. We investigated the influence of a plant polyphenolic compound resveratrol (representative of the stilbene family) on the opportunistic pathogen Trichosporon cutaneum. Besides the influence on the planktonic cells of T. cutaneum, the ability to inhibit biofilm formation and to eradicate mature biofilm was studied. We have tested resveratrol as pure compound, as well as resveratrol in complex plant extract-the commercially available dietary supplement Regrapex-R-forte, which contains the extract of Vitis vinifera grape and extract of Polygonum cuspidatum root. Regrapex-R-forte is rich in stilbenes and other biologically active substances. Light microscopy imaging, confocal microscopy, and crystal violet staining were used to quantify and visualize the biofilm. The metabolic activity of biofilm-forming cells was studied by the tetrazolium salt assay. Amphotericin B had higher activity against planktonic cells; however, resveratrol and Regrapex-R-forte showed anti-biofilm effects, both in inhibition of biofilm formation and in the eradication of mature biofilm. The minimum biofilm eradicating concentration (MBEC80) for Regrapex-R-forte was found to be 2222 mg/L (in which resveratrol concentration is 200 mg/L). These methods demonstrated that Regrapex-R-forte can be employed as an anti-biofilm agent, as it has similar effect as amphotericin B (MBEC80 = 700 mg/L), which is routinely used in clinical practice.

• Keywords
• Anti-biofilm activity, Plant extract, Stilbene, Trichosporon,
• MeSH
• Amphotericin B pharmacology   MeSH
• Antifungal Agents pharmacology   MeSH
• Biofilms drug effects   growth & development   MeSH
• Microbial Sensitivity Tests MeSH
• Resveratrol pharmacology   MeSH
• Fallopia japonica chemistry   MeSH
• Plant Extracts pharmacology   MeSH
• Trichosporon drug effects   growth & development   metabolism   MeSH
• Vitis chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amphotericin B MeSH
• Antifungal Agents MeSH
• Resveratrol MeSH
• Plant Extracts MeSH

Microbial adhesion to surfaces and the subsequent biofilm formation may result in contamination in food industry and in healthcare-associated infections and may significantly affect postoperative care. Some plants produce substances with antioxidant and antimicrobial properties that are able to inhibit the growth of food-borne pathogens. The aim of our study was to evaluate antimicrobial and anti-biofilm effect of baicalein, resveratrol, and pterostilbene on Candida albicans, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. We determined the minimum inhibitory concentrations (MIC), the minimum adhesion inhibitory concentration (MAIC), and the minimum biofilm eradication concentration (MBEC) by crystal violet and XTT determination. Resveratrol and pterostilbene have been shown to inhibit the formation of biofilms as well as to disrupt preformed biofilms. Our results suggest that resveratrol and pterostilbene appear potentially very useful to control and inhibit biofilm contaminations by Candida albicans, Staphylococcus epidermidis, and Escherichia coli in the food industry.

• Keywords
• Adhesion, Baicalein, Biofilm, Eradication, Pterostilbene, Resveratrol,
• MeSH
• Anti-Infective Agents pharmacology   MeSH
• Biofilms drug effects   growth & development   MeSH
• Candida albicans drug effects   growth & development   MeSH
• Escherichia coli drug effects   growth & development   MeSH
• Flavanones pharmacology   MeSH
• Microbial Sensitivity Tests MeSH
• Pseudomonas aeruginosa drug effects   growth & development   MeSH
• Resveratrol MeSH
• Plant Extracts chemistry   pharmacology   MeSH
• Staphylococcus epidermidis drug effects   growth & development   MeSH
• Stilbenes pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Infective Agents MeSH
• baicalein MeSH Browser
• Flavanones MeSH
• pterostilbene MeSH Browser
• Resveratrol MeSH
• Plant Extracts MeSH
• Stilbenes MeSH

The biofilms of filamentous-forming fungi are a novel and still insufficiently understood research topic. We have studied Aspergillus fumigatus, an ubiquitous opportunistic pathogenic fungus, as a representative model for a study of biofilm formation by filamentous fungi and for assessing the potential anti-biofilm activity of natural substances. The activity of antibiotic amphotericin B and selected natural substances: baicalein, chitosan and rhamnolipid was studied. The minimum suspension inhibitory concentrations (MIC) were determined and the biofilm susceptibility was investigated by determining the metabolic activity of sessile cells (XTT assay) and total biofilm biomass (crystal violet staining). Significant time-dependent differences in substances' anti-biofilm activity were observed. Images of A. fumigatus biofilm were obtained by Cellavista automatic light microscope and spinning disc confocal microscopy. Baicalein and rhamnolipid were not found as suitable substances for inhibition of the A. fumigatus biofilm formation, as neither of the substances inhibited the sessile cells metabolic activity or the total biofilm biomass even at tenfold MIC after 48 h. In contrast, chitosan at 10 × MIC (25 µg mL-1), suppressed the biofilm metabolic activity by 90 % and the total biofilm biomass by 80 % even after 72 h of cultivation. Amphotericin B inhibited only 14 % of total biofilm biomass (crystal violet staining) and 35 % of metabolic activity (XTT assay) of adherent cells under the same conditions. Our results therefore suggest chitosan as potential alternative for treating A. fumigatus biofilm-associated infections.

• Keywords
• Amphotericin B, Aspergillus fumigatus, Biofilm, Chitosan, Rhamnolipid,
• MeSH
• Amphotericin B pharmacology   MeSH
• Antifungal Agents pharmacology   MeSH
• Aspergillus fumigatus drug effects   physiology   MeSH
• Biofilms drug effects   MeSH
• Chitosan pharmacology   MeSH
• Flavanones pharmacology   MeSH
• Glycolipids pharmacology   MeSH
• Microbial Sensitivity Tests MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amphotericin B MeSH
• Antifungal Agents MeSH
• baicalein MeSH Browser
• Chitosan MeSH
• Flavanones MeSH
• Glycolipids MeSH
• rhamnolipid MeSH Browser