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Browsing by Subject "abietic acid"

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  • Tuhkalainen, Juho (2012)
    Natural products have been used as medicines for thousands of years. Of the drugs on the market today a significant proportion are natural products or natural product derivatives. Natural products can be enhanced by the means of chemical modification. Modification of a natural product may result in lesser toxicity, greater efficacy or better chemical stability. Different ways to modify a natural product are represented in the literature review using approved drugs as examples. Biological screening is an important part of a modern drug discovery process. Libraries containing synthetic molecules or natural products can be screened. The literature review discusses different types of natural product libraries and how they differ from synthetic libraries. Natural product libraries are smaller and more laborious to screen compared with synthetic libraries. Natural product libraries contain more hits in proportion of total compounds because natural products have activity in biological systems more often than synthetic molecules. A remarkable part of antibiotics and anti-cancer agents are derived from nature. A need for especially new antibiotics will be notable in the future due to resistant microbial strains and the need can be met with natural product research. The object of the experimental part was to evaluate the bioactivity of eleven synthetic abietic acid derivatives. Antimicrobial activity of the compounds was determined againts six human pathogens which were S.aureus, E.coli, P.aeruginosa, E. aerogenes, E. faecalis and Candida albicans. Cytotoxicity testing on the compounds was performed using mammalian cell lines CaCo-2 and Huh-7. Compounds were tested for albumin binding using bovine serum albumin. The effect of bovine serum albumin on the antimicrobial effect of compounds was studied. Spectrophotometric studies on compound-albumin complexes were carried out using fluorescence and UV absorbance measurement techniques. A primary antimicrobial screening was performed with all the compounds. Minimum inhibitory concentration (MIC) values were determined for compounds that showed antimicrobial activity in the primary screening. Cytotoxicity testing was carried out with all the compounds. Albumin binding was studied only on compounds that showed activity in the antimicrobial screening. Some of the compounds were noticed to have antimicrobial activity against the studied gram-positive bacteria and yeast Candida albicans. Antimicrobially active compounds were noticed to bind to albumin and have cytotoxic effects.
  • Hassan, Ghada (2016)
    The aim of this study was to synthesize antimicrobial and anti-biofilm agents using abietic (AA) and dehydroabietic acids (DHAA). Bacterial biofilms are formed when bacteria cells cluster together within a self-produced extracellular matrix. This lifestyle makes bacteria highly resilient to different environmental stresses and conventional antibiotics when compared to single-cell bacteria. Currently, there are no approved anti-biofilm agents as drugs and only a few number of compounds can selectively target biofilms and eradicate them at low concentrations. Potent drugs targeting them are needed. AA and DHAA are abietane-type diterpenoids found in the resin of conifer trees. Antibacterial effects of resin acids have been widely studied, specifically against methicillin-resistant Staphylococcus aureus strain (MRSA). Through the combination of DHAA with different amino acids, Manner et al. (2015) discovered a new class of hybrid compounds that target both planktonic and biofilm bacteria in Staphylococcus aureus. The study group also discovered two of the most potent abietane-type anti-biofilm agents reported so far in literature. This thesis followed the work of the research group by designing and synthesizing additional AA and DHAA derivatives to target bacterial biofilms. Rings A, B and C of the diterpenoid core were modified and 24 derivatives were successfully synthesized. Amino acids were attached to the compounds either before or after ring modification. Standard structural elucidation techniques were used to confirm the structure of the synthesized compounds.