Antimicrobial activity of aloe vera and its determination

Namen magistrske naloge je bil proučiti antimikrobne lastnosti Aloe barbadensis in Aloe arborescens na rast različnih mikroorganizmov. Izvedli smo študijo antimikrobne učinkovitosti sveže ter liofilizirane A. barbadensis in A. arborescens, etanolnega ekstrakta A. barbadensis in A. arborescens ter antimikrobne učinkovitosti nekaterih komercialnih produktov iz aloje. Antimikrobne lastnosti izbranih vzorcev A. barbadensis in A. arborescens ter njunih komercialnih produktov smo testirali na različnih mikrobnih celicah kot so Escherichia coli, Staphylococcus aureus, Bacillus cereus, Pseudomonas fluorescens, Pseudomonas aeruginosa, Candida albicans ter Aspergillus brasiliensis. Inhibitorno lastnost posameznega vzorca smo kvalitativno določevali z disk difuzijsko metodo na hranilnih agarjih. Kadar je vzorec izkazoval inhibitorne lastnosti, se je pri vzorcu pokazala cona inhibicije oziroma zaviralna cona rasti mikroorganizma. S kvantitativno dilucijsko metodo v bujonu smo želeli ugotoviti stopnjo inhibicije rasti mikroorganizma pri različnih koncentracijah dodanega vzorca ter tako skonstruirati rastno krivuljo mikroorganizma. Ugotovili smo, da aloji zavirata rast vseh testnih mikrobnih celic, razen rasti glive A. brasiliensis. Najboljši zaviralni učinek na rast testnih mikroorganizmov smo zaznali v primeru uporabe 50 % liofiliziranega soka in gela A. barbadensis ter etanolnega ekstrakta A. barbadensis in A. arborescens, najslabše pa je pri večini mikroorganizmov rast zaviral sveži sok aloj. Popolnoma vsi vzorci A. barbadensis in A. arborescens so dobro zavirali rast bakterije P. aeruginosa, saj smo pri vseh vzorcih zaznali visoko stopnjo inhibicije rasti mikroorganizma.The aim of the master thesis was to examine antimicrobial characteristics of Aloe barbadensis and Aloe arborescens on the growth of different microorganisms. We performed a study of antimicrobial effectiveness of fresh and lyophilizated A. barbadensis and A. arborescens, ethanol extract of A. barbadensis and A. arborescens and antimicrobial effectiveness of some commercial products made of aloe. Antimicrobial characteristics of the chosen samples of A. barbadensis and A. arborescens and their commercial products were tested on different microbial cells, such as Escherichia coli, Staphylococcus aureus, Bacillus cereus, Pseudomonas fluorescens, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis. The inhibitory property of an individual sample was qualitatively determined with disk diffusion method on nutritional agars. When the sample displayed inhibitory properties, a zone of inhibition or a breakpoint for growth of microorganism was shown. With a qualitative method of broth microdilution we wanted to determine the level of inhibition of the growth of a microorganism in different concentrations of added sample and so constructed a growth curve of the microorganism. We found out that both aloes slow down the growth of all tested microbial cells, except for the growth of fungus A. brasiliensis. The best inhibitory effect on the growth of the tested microorganisms was detected in the case of use of 50 % lyophilizated juice and gel of A. barbadensis and ethanol extract of A. barbadensis and A. arborescens, while the least well was in majority of microorganisms the growth slowed down by fresh juice of aloes. Absolutely all samples of A. barbadensis and A. arborescens slowed down the growth of bacteria P. aeruginosa well, since in all samples we detected high level of inhibition of the growth of microorganism