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Antimicrobial activity of selected natural extracts
Šandová, Lucie ; Veselá, Mária (referee) ; Zemanová, Jana (advisor)
The aim of the bachelor thesis was to determine antimicrobial activity of selected natural extracts, specifically three model extracts made from purple coneflower (Echinacea purpurea) and four commercial extracts – true lavender (Lavandula angustifolia), lemon balm (Melissa oficinalis), echinacea herbal drops (Echinacea purpurea) and echinacea extract (Echinacea purpurea) with ginger, against selected microorganisms. Theoretical part is focused on description of bioactive substances that are found in plants. It also describes extraction methods used for obtaining extracts from plant materials, methods for determining antimicrobial activity and then the use of natural extracts in food and cosmetic industry. In experimental part, antimicrobial effect of the extracts was tested against gram-negative bacteria Escherichia coli, gram-positive bacteria Bacillus cereus and yeast Candida glabrata. For determination of the antimicrobial activity, two methods (hole method and disc diffusion method) were used and compared. The highest antimicrobial activity against selected microorganisms was showed by commercial extract of lemon balm, which contains lot of geraniol and citroneloll. Significant antimicrobial activity had also been shown by commercial extract of true lavender. On the contrary, extracts from Echinacea had not shown any antimicrobial activity against selected microorganisms.
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Encapsulation of plant extracts containing phenolic compounds into nanoparticles and nanofibers
Petrželková, Markéta ; Bokrová, Jitka (referee) ; Skoumalová, Petra (advisor)
The presented bachelor thesis was focused on the encapsulation of extracts containing phenolic substances in order to apply these materials in cosmetics. At work were prepared aqueous, ethanol and lipid extracts of coffee and cocoa. All extracts were characterized on the content of all polyphenols and flavonoids. Their antioxidant aktivity and SPF were also determined. Then the selected extracts were encapsulated into liposomes and polyhydroxybutyrate nanofibres. The basic characteristics of the prepared liposomes were also observed and also their SPF and antioxidant aktivity were monitored. The highest antioxidant aktivity and SPF had liposome particles containing ethanol cocoa extracts. The liposome particles were applied to cosmetic emulsion. These creams evince high antioxidant acitivity and stability determined by analytical centrifugation. Also the prepared nanofibres had high antioxidant aktivity and confirmed the gradual release of the active substances. In conclusion the test cytotoxicity on human keratinocytes confirmed the safety of prepared nanomaterials using the MTT test, which are therefore suitable for cosmetic applications.
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Antimicrobial activity of selected natural extracts
Šandová, Lucie ; Veselá, Mária (referee) ; Zemanová, Jana (advisor)
The aim of the bachelor thesis was to determine antimicrobial activity of selected natural extracts, specifically three model extracts made from purple coneflower (Echinacea purpurea) and four commercial extracts – true lavender (Lavandula angustifolia), lemon balm (Melissa oficinalis), echinacea herbal drops (Echinacea purpurea) and echinacea extract (Echinacea purpurea) with ginger, against selected microorganisms. Theoretical part is focused on description of bioactive substances that are found in plants. It also describes extraction methods used for obtaining extracts from plant materials, methods for determining antimicrobial activity and then the use of natural extracts in food and cosmetic industry. In experimental part, antimicrobial effect of the extracts was tested against gram-negative bacteria Escherichia coli, gram-positive bacteria Bacillus cereus and yeast Candida glabrata. For determination of the antimicrobial activity, two methods (hole method and disc diffusion method) were used and compared. The highest antimicrobial activity against selected microorganisms was showed by commercial extract of lemon balm, which contains lot of geraniol and citroneloll. Significant antimicrobial activity had also been shown by commercial extract of true lavender. On the contrary, extracts from Echinacea had not shown any antimicrobial activity against selected microorganisms.
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Encapsulation of plant extracts containing phenolic compounds into nanoparticles and nanofibers
Petrželková, Markéta ; Bokrová, Jitka (referee) ; Skoumalová, Petra (advisor)
The presented bachelor thesis was focused on the encapsulation of extracts containing phenolic substances in order to apply these materials in cosmetics. At work were prepared aqueous, ethanol and lipid extracts of coffee and cocoa. All extracts were characterized on the content of all polyphenols and flavonoids. Their antioxidant aktivity and SPF were also determined. Then the selected extracts were encapsulated into liposomes and polyhydroxybutyrate nanofibres. The basic characteristics of the prepared liposomes were also observed and also their SPF and antioxidant aktivity were monitored. The highest antioxidant aktivity and SPF had liposome particles containing ethanol cocoa extracts. The liposome particles were applied to cosmetic emulsion. These creams evince high antioxidant acitivity and stability determined by analytical centrifugation. Also the prepared nanofibres had high antioxidant aktivity and confirmed the gradual release of the active substances. In conclusion the test cytotoxicity on human keratinocytes confirmed the safety of prepared nanomaterials using the MTT test, which are therefore suitable for cosmetic applications.
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