Browsing by Subject "MIC"
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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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(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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(2013)The lower respiratory infection tuberculosis (TB) has been the leading cause of death for centuries causing millions of deaths worldwide. The development of antibiotic therapy has reduced the morbidity and mortality during the 20th century, at least in the developed countries. However, tuberculosis is still the world's second leading cause of death from infectious diseases. Although TB can be treated and even cured with drug therapy, the treatment is extremely long and requires 6-9 months constant drug therapy. This prolonged treatment causes poor patient compliance, which is usually the reason for the selection of drug resistant and often multidrug (MDR-TB) or even extensively drug-resistant (XDR-TB) TB bacteria. Limitations of available therapies and the emergence of drug-resistant strains have intensified the search for new drugs from natural sources. Marine micro- and macro-organisms have proven to be an excellent source of structurally unique biologically active natural products. EU FP7 -funded MAREX project, launched in 2010, aims at identifying new biologically active compounds from marine sources. This Master's thesis was carried out as a part of the MAREX project. The aim of this study was to optimize and validate a reproducible method to determine antimicrobial activity of natural products against Mycobacterium smegmatis, which is a widely used non-pathogenic surrogate model for TB. In the present study, spectrophotometric microplate assay was optimized and validated using existing antibacterial agents ciprofloxacin and rifampicin as reference compounds. The assay was performed on 96-well plate by using two detection techniques, absorbance measurement and a colorimetric indicator, for the antibacterial MIC end-point determination. The results obtained by the described methods were compared with each other in order to achieve the most optimal assay conditions. The quality control parameters S/B, S/N and Z' factor were used in order to determine the optimal experimental conditions for the assay. Obtaining reliable results with the turbidimetric method required incubation for two days in the case of ciprofloxacin, and for five days with rifampicin. Colorimetric measurement led to similar results as the turbidimetric measurement for both of the reference compounds. The method was further used for the screening of a group of marine extracts. None of the 21 samples tested showed significant activity against M. smegmatis.
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(2021)Perinteisesti desentralisoituun institutionaaliseen välimiesmenettelyyn perustunut ulkomaisten sijoittajien ja sijoitusten isäntävaltioiden välisten riitojen riidanratkaisujärjestelmä (”ISDS-järjestelmä”) on ollut voimakkaan kritiikin kohteena etenkin 2000-luvulla. Tämän kritiikin puitteissa ISDS-järjestelmän legitimiteetti on kyseenalaistettu varsin kokonaisvaltaisesti. Yhtäältä kyse on institutionaalisesta ja menettelyllisestä ongelmasta, joka on seurausta ISDS-menettelyiden kehyksenä käytettyjen institutionaalisten välimiesmenettelyiden perustavanlaatuisesta yhteensopimattomuudesta voimakkaan julkisen intressin kohteina olevien investointiriitojen ratkaisukeinona. Toisaalta ongelma kytkeytyy välimieslainkäytön kohteena olevien riitojen sisällölliseen puoleen investointisuojasopimusten muodostaessa epämääräisen, tulkinnalle avoimen aineellisoikeudellisen pohjan, jonka puitteissa ISDS-menettelyitä hoitavien välitystuomioistuinten lainkäytön on katsottu haittaavan valtioiden demokraattista prosessia ja itsesääntelyoikeutta perusteettomilla ISDS-järjestelmän puitteissa esitettävillä korvausvaateilla. Investointituomioistuinjärjestelmällä (investment court system) tarkoitetaan EU:n unionin yhteisen kauppapolitiikan alla Kanadan, Vietnamin, Singaporen ja Meksikon kanssa neuvottelemien uuden sukupolven kahdenvälisten kauppa- ja investointisuojasopimuskokonaisuuksien sisältämää uudenlaista ISDS-mekanismia. ICS-reformissa on kyse ennen kaikkea institutionaalisesta ja menettelyllisestä uudistuksesta, jonka tarkoituksena on parantaa niitä perinteisen ISDS-menettelyn alueita, jotka voimakkaimmin vaikuttivat ISDS-järjestelmän legitimiteettiongelmiin. ICS-reformin yhteydessä sopimuskumppanit ovat lisäksi tarkentaneet investointisuojan aineellista puolta, jossa pääpainona on ollut isäntävaltioiden itsesääntelyoikeuden nimenomainen turvaaminen. Tarkastelen ICS:n ohella lyhyesti myös YK:n UNCITRALin työryhmä III:ssa työn alla olevaa monenvälistä investointituomioistuinta (multilateral investment court). MIC-hankkeen pyrkimyksenä on luoda täysin uusi monenvälinen investointiriitojen ratkaisujärjestelmä. Pyrkimys kytkeytyy vaikuttavuudeltaan vahvasti ICS-reformiin sen jakaessa samoja sisällöllisiä tavoitteita ja toisaalta ICS-mekanismin sisältäessä suoran liitäntämekanismin mahdolliseen MIC-mallin mukaiseen tuomioistuinjärjestelmään. Tässä tutkielmassa tavoitteenani on mainitun ICS-reformin systematisoinnin ja vertailun kautta antaa mahdollisimman kokonaisvaltainen kuva uudistuksen sisällöstä. Pohjustan tätä tutkielman lainopillista ja vertailevaa puolta tarkastelemalla aluksi sekä ISDS-järjestelmän rakennetta että sen suhdetta EU-oikeuteen. Näin lainopillinen analyysi saa sellaisen kontekstin, jossa uudistuksen merkittävyys on paremmin hahmotettavissa. Tätä vasten tutkielman varsinaisena tutkimuskysymyksenä on selvittää se, miten ICS-reformi sen nykyisellään julkaistussa muodossa vastaa edellä viitattuun ISDS-järjestelmän kritiikkiin sekä niihin yleisen tason tavoitteisiin, joihin ICS-reformilla alkujaan esitettiin puututtavan. Tältä osin tarkastelu osoittaa, että ICS-reformin insitutionaalinen ja menettelyllinen osuus vastaavat suoraan esitetyn kritiikin ytimeen tuomalla välimieslainkäyttöön kansallisen oikeudenkäyntimenettelyn piirteitä. Institutionaalisesti ICS:n sisäisten mekanismien kautta määräytyvät ICS:n tuomioistuinten tuomarit oletusarvoisesti helpottavat vanhan järjestelmän puitteissa esitettyjä väitteitä ISDS-järjestelmässä vaikuttavien välimiesten vastuullisuuden ja riippumattomuuden puutteista. Menettelyllisellä puolella etenkin UNCITRALin avoimuussääntöjen täysimääräinen implementointi osaksi ICS-mekanismia sekä täysin uutena elementtinä erillisen muutoksenhakutuomioistuimen sisällyttäminen ICS-mekanismiin parantavat menettelyn legitiimiyttä etenkin avoimuuden, vastuullisuuden ja johdonmukaisuuden osalta. Toisaalta uudistuksen kipukohtana vaikuttaisi olevan pyrkimys välimieslainkäytön ja perinteisen oikeudenkäyntimenettelyn parhaiden puolien yhdistämisestä aiheutuviin yhteensopivuusongelmiin, jotka korostuvat etenkin ICS-mekanismiin sisällytetyissä kytkennöissä institutionaalisiin välimiesmenettelysääntöihin. Tässä etenkin ICSID-yleissopimuksen ja sen välimiesmenettelysääntöjen sisältö törmää ICS-mekanismin välimieslainkäyttöön tuomiin modifikaatioihin.
Now showing items 1-4 of 4