Jul 20, 2019   2:03 p.m. Iľja
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Ing. Alžbeta Medveďová, PhD.
Identification number: 19372
University e-mail: alzbeta.medvedova [at] stuba.sk
 
Odborná asistentka CSc.,PhD. - Department of Nutrition and Food Quality Assessment (IFSN FCFT)

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Basic information

Basic information about a final thesis

Type of thesis: Diploma thesis
Thesis title:Evaluation of inhibitory potential of selected synthetic and natural resources
Written by (author): Ing. Lucia Michalová
Department: Department of Nutrition and Food Quality Assessment (IFSN FCFT)
Thesis supervisor: Ing. Alžbeta Medveďová, PhD.
Opponent:Ing. Petra Vanková, PhD.
Final thesis progress:Final thesis was successfully defended.


Additional information

Additional information about the final thesis follows. Click on the language link to display the information in the desired language.

Language of final thesis:Slovak

Slovak        English

Title of the thesis:Evaluation of inhibitory potential of selected synthetic and natural resources
Summary:The aim of this study was to analyse the antimicrobial activity of synthetic and natural resources against undesirable microorganisms in cosmetic and food sector. Synthetic substances used for this work were alkyl-L-rhamnosides, xylosides and lyxozides of which individual as well as complementary inhibitory activity against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Salmonella Typhimurium, Escherichia coli, Candida albicans and Aspergillus niger was observed. Based on these results, it can be concluded that glycosides inhibited microbial growth only by complementary effect. During 25 hours of incubation, tested microbial cultures reached a density level from 107 to 108 CFU/ml. The glycosides were tested in economically acceptable concentrations ranged from 1 to 10 %, but the concentration dependence of inhibitory effect was not observed. In addition, also inhibitory potential of two types of garlic homogenates was described on microorganisms mentioned above and 3 types of lactic acid bacteria. Results of experiments showed that the presence of 1.5 % garlic homogenate in a medium reduced the initial number of microorganisms to a lower degree than in the presence of 3 % homogenate of garlic. However, after 9 hours tested microorganisms were able to reach the exponential phase of growth and multiplied to undesirable concentrations. Absolute antifungal activity against filamentous fungus A. niger was confirmed by 8 used ramnosides. Inspite of all positives, the probiotic bacteria were inhibited to undesirable level of about 102 to103 CFU/ml. The monitoring of the cytotoxic activity of garlic homogenates showed that the viability of human malignant melanoma and mouse leukemia cells decreased below 40 % within 72 hours in presence of whichever garlic homogenate in concentration from 0.625 to 6.25 %. Moreover, home-grown garlic inhibited almost 90 % of melanoma cells. The addition of 0.25 % or 12.5 % garlic homogenates did not induced sufficient cytotoxic activity on the analysed cell lines. Based on the obtained results with respect to the simultaneous inhibition of undesirable microorganisms, lactic acid bacteria and cell lines the inhibitory potential of garlic was confirmed. For optimal results, it is advisable to use 1.5 % garlic homogenate at intervals of 9 hours with simultaneous supplementation of probiotic cultures.
Key words:alkyl-L-ramnosides, garlic, growth dynamics, inhibitory activity

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