Browsing by Subject "bioaktiivisuus"
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(2017)The aim of this thesis was to synthesize abietic acid derivatives, and to determine their antimicrobial activity. The study was performed in two parts. The first part was carried out at VTT (Technical Research Centre of Finland) and the second part at the Faculty of Pharmacy, University of Helsinki, the Division of Pharmaceutical Chemistry and Technology. Abietic acid as well as its isomers and precursors are important antimicrobial substances among plant kingdom. They are produced in big scale by conifers, which extractives of pitch and wood they are. Abietic acid and its many derivatives have shown to have many bioactivities. Emerging antibiotic resistance of bacteria, viral diseases that are spreading and mutating throughout the world and serious diseases caused by protozoa, cause an ever-growing need to develop new active agents against these pathogens. Abietic acid derivatives are worthy candidates for research into new drug substances. At VTT a synthetic route with abietic acid chloride as intermediate was used (synthetic route 1). It did not work well in the synthesis of esters and yields were low. The synthetic route worked fairly well for amide synthesis. The purifications and analysis of the compounds, two esters and one amide of abietic acid, were left partially unfinished, and none of the products of these reactions were tested for bioactivity. At the Division of Pharmaceutical Chemistry and Technology eight derivatives of abietic acid, from abietic acid and four different amino acids, were obtained via synthetic route 2. Some of these were sent to tests for antibacterial activity. Six synthesized compounds were sent to tests for their bioactivity against bacteria. However, the results were not obtained in time for this Master's thesis, and therefore any conclusions of their structure-activity relationships could not be drawn.
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(2023)Diseases caused by foodborne pathogens are a global threat, which is why new bioactive compounds are expected in the food industry. The purpose of this work was to investigate the antimicrobial effects of three different plants, blackcurrant (Ribes nigrum), rhubarb (Rheum spp.), and Scots pine (Pinus sylvestris), against seven pathogenic bacteria. Bioactivity of these plants has been previously shown, but results have varied widely depending for example on the plant part, extraction solvent and pathogen. The plant samples were extracted with 30 % or 80 % ethanol-water solution. There was a total of 12 extracts: rhubarb petiole (dried at 45 °C or lyophilized), rhubarb root (dried at 50 °C), blackcurrant berry (dried at 45 °C or lyophilized) and lyophilized juice of Scots pine needles. Extracts were dissolved in dimethyl sulfoxide and bioactivity screening of the extracts was determined at a concentration of 1,0 mg/ml, after which the active extracts were subjected to minimum inhibitory concentration (MIC) determination (n=2-3) at eight concentrations (0,0625-4,0 mg/ml). Antimicrobial experiments were performed on a 96-well plate following Clinical and Laboratory Standards Institute guidelines. Bioactivity was determined based on absorbance measurements and visual inspection. The extract of rhubarb root showed most potential against tested bacteria. The lowest MIC values (0,25 mg/ml and 0,50 mg/ml) were obtained with rhubarb root extracts (extracted with 80% or 30 % ethanol-water solution) against Staphylococcus aureus and Bacillus cereus and 1,0 mg/ml against Listeria monocytogenes. Based on this study rhubarb root extract could be a potential natural antimicrobial against foodborne pathogens.
Now showing items 1-2 of 2