The biological activity of polyphenol substances contained in food supplements prepared from Vitis vinifera can affect the microorganisms present in the digestive tract in terms of their representation and activity of the individual species. This study deals with resveratrol and two polyphenol-rich extracts (extract from V. vinifera canes and the commercial product Regrapex-R-forte) and their effect on selected gut microbiota (Bifidobacterium animalis subsp. lactis Bb-12, Lactobacillus acidophilus LA-5, Lactobacillus casei Lafti L-26, Citrobacter freundii DBM 3127, Escherichia coli DBM 3125). The effect of the studied agents on planktonic and biofilm growth of the microorganisms was determined as minimum inhibitory concentration (MIC80) and minimum biofilm inhibitory concentration (MBIC80), respectively. The extracts induced metabolic activity as well as total biofilm biomass production in probiotic strain L. acidophilus LA-5 while successfully inhibiting the growth of opportunistic pathogenic microorganisms C. freundii DBM 3127 and E. coli DBM 3125.

Nutritional value and disease-preventive effects of cabbage are well-known. Levels of the antioxidant compounds ascorbic acid (AA) and glucosinolates (GSL) in new Czech cabbage cultivars were determined in the context of different production systems. The contents of AA and GSLs in cabbage biomass were determined by HPLC. Individual GSLs were identified according to their exact masses with sinigrin used as the external standard. Artificial infection with A. brassicicola generally raised the AA levels. The major GSLs (≥10 mg kg−1) were glucobrassicin, sinigrin, and glucoiberin. Indole and aliphatic GSLs were present, but no aromatic ones were detected. Ecological growth conditions and the artificial fungal infection increased the total content of GSLs and, also, of the methoxylated indole GSLs. Sulforaphane, iberin, indole-3-carbinol, and ascorbigen resulting from the hydrolysis of GSLs were found in both cultivars. The amounts and profiles of GSLs present in the two Czech cultivars demonstrated their good nutritional value. The decomposition products sulforaphane, iberin, indole-3-carbinol, and ascorbigen detected improve its health-promoting qualities and represent a suitable component of the human diet.

This paper describes a single-laboratory validation of a liquid chromatography–diode array detection (LC–DAD) method for quantification of 12 major cannabinoids in Cannabis dried plant materials, concentrates, and oils. The method met Standard Method Performance Requirements for quantitative analysis of cannabinoids in Cannabis concentrates and Cannabis dried plant materials. The LOQs were in the range 0.003–0.10% (w/w), depending on the analyte and matrix. Spike recoveries were between 96.7 and 101.3% with relative SDs (RSDs) ≤2.3%. Precision expressed as repeatability and intermediate precision was within 0.3–4.8 and 1.1–5.1%, respectively. The chromatographic separation conditions used in this versatile method are compatible with both DAD–UV and MS detection. During method validation, high-resolution quadrupole time-of-flight MS was employed as a secondary detector (connected in series to the LC–DAD instrument) to provide high confidence identification of target analytes and as a tool for monitoring other cannabinoids for which reference standards were not available. The obtained results demonstrate applicability of the method to quantitative analysis of important cannabinoids in dried plants, concentrates, and oils. Limited data were generated for a food matrix (Cannabis-containing cookies) using this method with LC coupled to a compact single quadrupole mass spectrometer.

This paper describes a single-laboratory validation of a liquid chromatography–diode array detection (LC–DAD) method for quantification of 12 major cannabinoids in Cannabis dried plant materials, concentrates, and oils. The method met Standard Method Performance Requirements for quantitative analysis of cannabinoids in Cannabis concentrates and Cannabis dried plant materials. The LOQs were in the range 0.003–0.10% (w/w), depending on the analyte and matrix. Spike recoveries were between 96.7 and 101.3% with relative SDs (RSDs) ≤2.3%. Precision expressed as repeatability and intermediate precision was within 0.3–4.8 and 1.1–5.1%, respectively. The chromatographic separation conditions used in this versatile method are compatible with both DAD–UV and MS detection. During method validation, high-resolution quadrupole time-of-flight MS was employed as a secondary detector (connected in series to the LC–DAD instrument) to provide high confidence identification of target analytes and as a tool for monitoring other cannabinoids for which reference standards were not available. The obtained results demonstrate applicability of the method to quantitative analysis of important cannabinoids in dried plants, concentrates, and oils. Limited data were generated for a food matrix (Cannabis-containing cookies) using this method with LC coupled to a compact single quadrupole mass spectrometer.

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 (MBEC) 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 (MBEC = 700 mg/L), which is routinely used in clinical practice.