Browsing by Subject "kansanlääkintä"
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(2023)African medicinal plants have been used to treat symptoms of infection successfully for thousands of years. However, no antimicrobial drugs have been developed from these plants. As antibiotic resistance is increasing rapidly, these traditional African herbal medicines can be an important solution in the fight against antibiotic resistance due to their antimicrobial properties. In this research, various extracts o the leaves of Combretum adenogonium (Combretaceae) and the fruits of Piper cubeba (Piperaceae) and Xylopia aethiopica (Annonaceae) were tested for their growth inhibitory effects against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Extracts were made with methanol, water, hexane, and chloroform. In addition, water and ethyl acetate extracts were separated from an 80 % methanol extract using solvent partition. All the studied plants are used for the treatment of infections and wounds in African traditional medicine. Water was used as extraction solvent since it is commonly used in African folk medicine. Both single solvent technique and sequential extraction were used. The antibacterial effects were screened using agar diffusion and microdilution methods. The interaction between an extract and an antibiotic was measured with a checkerboard method. Time-kill experiments were performed using microdilution and plate count methods. In this study, the chloroform extract of C. adenogonium leaves gave the best inhibitory effect of all studied plants against B. cereus (MIC 78.125 µg/ml). In general, B. cereus was the most susceptible of the selected bacteria against extracts and E. coli was the one with most resistance. Time-kill test showed that the antibacterial efficacy was fairly stable throughout the 24-hour period considered with few exceptions. According to checkerboard results, C. adenogonium chloroform extract and tetracycline appeared to inhibit each other's antibacterial activity against B. cereus. However, only one extract was studied in this study, and it is possible that C. adenogonium contains compounds that would have a potentiating effect on antimicrobials. In general, C. adenogonium extracts were effective against B. cereus. The extracts of P. Cubeba were particularly effective against S. aureus. X aethiopica extracts were equally effective for both B. cereus and S. aureus. Methanol extract X. aethiopica is the only extract studied that gave more than 90% inhibition against P. aeruginosa. Therefore, it could be concluded that X. aethiopica has the broadest activity range of the examined plants.
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(2021)Antimicrobial resistance is a growing problem worldwide. It has been shown that more than 70% of the bacteria that cause nosocomial infections are resistant to at least one antibiotic commonly used to treat them. Two concomitant phenomena that aggravate the diarrheal disease situation, especially in developing countries, are general contamination (spread of pathogens due to unclean water, poor sanitation, and malnutrition) and resistant bacterial strains (the adverse consequences of infections increase as infections prolong). According to the WHO, foodborne diseases (FBDs) were estimated to have caused approximately 91 million people to become ill and 137,000 deaths in Africa in 2010. The number is about a third of the deaths caused by FBD worldwide. Diarrhea caused about 70% of the FBD burden. Bacteria that cause food poisoning include Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus and Yersinia enterocolitica, some of which are discussed in more detail in this master’s thesis; antibiotics against which resistance has developed, how bacteria resist antibiotics, and the emergence of resistance in Africa. The antibiotic resistance of bacteria and the mechanisms of resistance against antimicrobial drugs are also discussed shortly. In addition to food poisoning, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus can cause difficult-to-treat infections such as wounds. In addition, this work has first dealt with antimicrobial plant derived compounds in general and their modes of action, and then focused on compounds, fractions and extracts of species of the genera Combretum, Terminalia, Pteleopsis and Anogeissus, as well as their antibacterial effects and uses in traditional medicine. In addition, the antibacterial mechanisms of action of different groups of compounds have been discussed in more detail. This work also deals with the combination studies of some plant extracts, fractions and compounds with antibiotics. Combination studies with antibiotics have generally been studied less than the antibacterial effects alone or the effects of combinations of many plant extracts, as used in African traditional medicine. The experimental part covers, among other things, the preparation and yield determination of crude extracts (water and methanol) as well as the agar diffusion method, the microdilution method, the Time kill tests and the checkerboard method in interaction tests to determine MIC, MBC and FIC values. Due to the Covid 19 pandemic, study results were obtained only by the agar diffusion method against Bacillus cereus. The most antimicrobial extracts were extracts of species of the genus Terminalia.
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(2019)Kasvavan antibioottiresistenssin vuoksi terveydenhuollossa tarvitaan uusia antibiootteja ja antibioottien apuaineita. Tästä syystä tässä työssä tutkittiin Combretaceae- ja Annonaceae-heimoihin kuuluvien tansanialaisten lääkekasvien antibakteerisia vaikutuksia. Kansanlääketieteessä näitä kasveja on perinteisesti käytetty mm. bakteerien aiheuttamien sairauksien ja oireiden hoitoon, mikä antaa viitteitä siitä, että ne sisältävät antibakteerisia yhdisteitä. Tutkimuksen tarkoituksena oli pyrkiä löytämään raakauutteita ja neste-nesteuutolla saatuja fraktioita, joilla on mahdollisimman hyvät estovaikutukset bakteerien kasvuun. Lisäksi oli tarkoitus selvittää Annonaceae-heimon lajien sisältämiä yhdisteitä, mikä voi osaltaan auttaa löytämään uusia antibiootteja. Antibakteerisia tutkimuksia tehtiin Combretaceae- ja Annonaceae-heimoihin kuuluvien Combretum-, Terminalia-, Friesodielsia- ja Hexalobus-sukujen lajien uutteille ja fraktioille käyttäen agardiffuusio- ja mikrodiluutiomenetelmiä. Yhteensä 45 eri uutteen ja fraktion estovaikutuksia tutkittiin ruokamyrkytyksiä aiheuttavien Bacillus cereus - ja Salmonella enterica -bakteerien kasvuun. Lisäksi tutkittiin Annonaceae-heimoon kuuluvien Friesodielsia obovata - ja Hexalobus monopetalus -lajien uutteiden ja fraktioiden sisältämiä yhdisteitä käyttäen HPLC-DAD - ja UHPLC/Q-TOF-MS -menetelmiä. Tutkimustulosten perusteella useilla Combretaceae- ja Annonaceae -heimoihin kuuluvilla lajeilla on antibakteerisia vaikutuksia grampositiivista B. cereus -bakteeria vastaan, mutta ei niinkään gramnegatiivista S. enterica -bakteeria vastaan. Aiemmissakin tutkimuksissa on usein, ei kuitenkaan aina, saatu parempia estovaikutuksia grampositiivisten kuin gramnegatiivisten bakteerien kasvuun. Tässä tutkimuksessa parhaimmat tulokset (MIC = 156 µg/ml) saatiin mikrodiluutiomenetelmällä B. cereus -bakteerin kasvun estoon Combretum fragrans -lajin lehtien kuumalla Soxhlet-metanoliuutteella ja Friesodielsia obovata -lajin lehtien metanoliuutteen veteen liukenemattomalla fraktiolla. Tarvitaan kuitenkin vielä paljon lisätutkimuksia, varsinkin H. monopetalus - ja F. obovata -lajien kohdalla, jotta voidaan selvittää, voidaanko tutkituista kasviuutteista ja niiden fraktioista eristää mahdollisia uusia antibiootteja tai antibioottien apuaineita ihmisten ja eläinten infektioiden lääkintään. Annonaceae-heimon lajeista löydettiin samantapaisia yhdisteitä kuin on löydetty aiemmissa tutkimuksissa, mutta 6,8-dimetyyli-monohydroksi-pinosembriiniä karakterisoitiin ensimmäistä kertaa F. obovata -lajista. F. obovata -lajin lehdistä tunnistettiin ensimmäistä kertaa (-)-krotepoksidi ja krotepoksidin johdannaisia. Lisäksi H. monopetalus -lajin juuresta karakterisoitiin ensimmäistä kertaa 3-(2',3'-dihydroksi-3'-metyylibutyyli)-5-(3''-metyylikrotonyyli)indolia, 3-(1,3-dihydroksi-3-metyylibut-2-yyli)-6-(2-hydroksi-3-metyyli-3-butenyyli)indolia sekä heksalobiini C:tä ja D:tä.
Now showing items 1-3 of 3