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A 70% ethanol(aq) extract of the rhizome bark of the invasive alien plant species Japanese knotweed (JKRB) with potent (in the range of vitamin C) and stable antioxidant activity was incorporated in 1% w/v into a chitosan biofoil, which was then characterized on a lab-scale. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay confirmed the antioxidant activity of the JKRB biofoil upon contact with the food simulants A, B, C, and D1 (measured half-maximal inhibitory concentrations—IC50) and supported the Folin–Ciocalteu assay result. The migration of the antioxidant marker, (−)-epicatechin, into all food simulants (A, B, C, D1, D2, and E) was quantified using liquid chromatography hyphenated to mass spectrometry (LC-MS). Calculations showed that 1 cm2 of JKRB biofoil provided antioxidant activity to ~0.5 L of liquid food upon 1 h of contact. The JKRB biofoil demonstrated antimicrobial activity against Gram-positive bacteria. The incorporation of JKRB into the chitosan biofoil resulted in improved tensile strength from 0.75 MPa to 1.81 MPa, while elongation decreased to 28%. JKRB biofoil’s lower moisture content compared to chitosan biofoil was attributed to the formation of hydrogen bonds between chitosan biofoil and JKRB compounds, further confirmed with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The JKRB biofoil completely degraded in compost in 11 days. The future upscaled production of JKRB biofoil from biowastes for active packaging may support the fights against plastic waste, food waste, and the invasiveness of Japanese knotweed, while greatly contributing to the so-called ‘zero-waste’ strategy and the reduction in greenhouse gas emissions.

Ova doktorska disertacija je koncipirana sa ciljem da se ispita fitohemijski sastav i potencijalna biološka aktivnost ekstrakata biljnih vrsta Daphne blagayana L., Daphne cneorum L. i Daphne alpina L. Upotrebom različitih rastvarača izvršena je ekstrakcija grančica i listova. Ispitivanja hemijskog sastava dobijenih ekstrakata obuhvatala su određivanje sadržaja ukupnih fenola, ukupnih flavonoida i HPLC-UV analizu ekstrakata. Ispitivani ekstrakti su pokazali visok sadržaj ukupnih fenola (68,77 ± 0,95 mg EGA/g - 90,26 ± 0,69 mg EGA/g) i flavonoida (24,67 ± 0,35 mg ERU/g - 35,24 ± 0,55 mg ERU/g). HPLC-UV analizom potvrđeno je prisustvo sekundarnih metabolita iz grupa fenola i kumarina: dafnetin, umbeliferon i 4- hidroksibenzoeva kiselina. Ispitivanje bioloških aktivnosti ekstrakata obuhvatalo je određivanje ukupne antioksidativne aktivnosti, određivanje DPPH „skevindžer” aktivnosti, određivanje inhibicije lipidne peroksidacije, Fe2+ helatizaciona aktivnost, određivanje antioksidativne aktivnosti na nivou hidroksil radikala i određivanje antimikrobne aktivnosti (in vitro). Ekstrakti ispoljavaju antioksidativnu aktivnost u svim primenjenim modelima. Takođe, ekstrakti su ispoljili i antimikrobnu aktivnost sa vrednostima minimalnih inhibitornih koncentracija koje su se kretale od 15,62 μg/ml do 125 μg/ml. Na osnovu dobijenih rezultata, može se zaključiti da vrste roda Daphne mogu predstavljati izvor novih, prirodnih, farmakološki aktivnih jedinjenja koja mogu imati potencijalnu primenu u farmaceutskoj, kozmetičkoj i industriji hrane. This doctoral thesis has been conceived with the aim to investigate phytochemical and potential biological activity of extracts obtained from plants species Daphne blagayana L., Daphne cneorum L. и Daphne alpinа L. Using different extraction solvents extracts of twigs and leaves were prepared. The chemical composition of extracts obtained from different parts was analysed. These analyses included the determination of total phenols, total flavonoids and HPLC-UV analysis. All the tested extracts showed the high total phenols (68,77 ± 0,95 mg EGA/g - 90,26 ± 0,69 mg EGA/g) and flavonoids (24,67 ± 0,35 mg ERU/g - 35,24±0,55 mg ERU/g) contents. HPLC-UV analysis was confirmed the presence secondary metabolites which belong to the phenol and coumarin group: daphnetin, umbelliferone and 4-hydroxybenzoic acid. Obtained extracts of tested plants were the subjected of determining the total antioxidant activity, DPPH determination activities, methods of inhibiting lipid peroxidation, the ferrous ion chelating ability, antioxidant activity at the level of hydroxyl radicals, the determination of antimicrobial activity (in vitro). The extracts exhibit antioxidant activity on the basis of all conducted tests. Also, the extracts shows antimicrobials activity with MIC value ranged from 15,62 μg/ml to 125 μg/ml. Based on these results it can be concluded that species from the Daphne genus may represent a source of new, natural, pharmacologically active compounds, which may potentially be used in pharmaceutical, cosmetic and food industry.

This study was designed to evaluate antimicrobial and antioxidant activities of the mint extracts from Mentha piperita L. and Mentha aquatica L. In vitro antibacterial activity against two foodborne bacteria (Listeria monocytogenes, Staphylococcus aureus) was evaluated by the well diffusion method. The activity was assessed by the diameter of the inhibition zone. Four of the five extracts from Mentha piperita were active against S. aureus, but none of the extracts was active against L. monocytogenes. Extracts obtained from Mentha aquatica showed no activity against both foodborne bacteria. The horseradish peroxidase/guaiacol assay was used to investigate in vitro antioxidant activity of two mint extracts (Mentha piperita and Mentha aquatica). The ascorbic acid was tested as a reference compound with known antioxidant activity to validate our approach. Extracts from Mentha aquatica showed strong antioxidant activity, but on the other hand, extracts from Mentha piperita showed no antioxidant activity. Študija je bila zasnovana z namenom oceniti antimikrobno in antioksidantno delovanje ekstraktov mete iz Mentha piperita L. in Mentha aquatica L. Protimikrobni konzervansi se uporabljajo za preprečevanje ali zaviranje rasti mikroorganizmov, ki lahko predstavljajo tveganje za okužbo živil. Antioksidanti so vse tiste snovi, ki upočasnjujejo ali preprečujejo oksidacijske reakcije. Delujejo torej kot lovilci prostih radikalov, ki prekinejo verižne radikalske reakcije. In vitro antibakterijsko delovanje proti bakterijama Listeria monocytogenes in Staphylococcus aureus, ki se prenašata s hrano, je bilo določeno z difuzijsko metodo v jamicah. Bakteriji Staphylococcus aureus in Listeria monocytogenes sta bili izbrani za antimikrobno delovanje, ker predstavljata pomembna patogena mikroorganizma v hrani. Delovanje je bilo ocenjeno s pomočjo premera inhibicijske cone. Štirje od petih ekstraktov vrste Mentha piperita so delovali proti bakteriji S. aureus, noben od ekstraktov pa ni deloval proti bakteriji L. monocytogenes. Ekstrakti, pridobljeni iz vrste Mentha aquatica niso delovali proti nobeni od omenjenih bakterij, ki se prenašata s hrano. Preizkus s hrenovo peroksidazo/gvajakolom je bil uporabljen za raziskovanje in vitro antioksidantnega delovanja obravnavanih ekstraktov mete (Mentha piperita in Mentha aquatica). Za validacijo našega pristopa smo testirali askorbinsko kislino kot referenčno spojino, ki je znana po svojem antioksidantnem delovanju. Medtem ko so ekstrakti vrste Mentha aquatica pokazali močno antioksidantno delovanje, pri ekstraktih vrste Mentha piperita takšnega delovanja ni bilo moč zaznati.

The examinations covered numerous clinical and referent strain of both bacteria, as well as viruses and fungi. The paper presents only one part of the examinations in which referent strains of E. coli NTCC 8116, Proteus mirabilis ATCC 19086, Staphylococcus aureus ATCC 511, Salmonella Choleraeuis ATCC 10653, Enterococcus faecalis ATCC 6055 and Bacillus cereus ATCC 11778 were used. The effect of Peral-S in concentrations of 0.25%, 0.5% and 1% on the listed strain of bacteria was examined using the suspension method at exposition times of 5, 10, 15 and 20 minutes. Examinations were also performed of the antiviral effects of Peral-S in concentrations of 0.1% to 1% and at exposure times from 30 seconds to 5 minutes on the viruses Aujeszky 257/II, P13, Newcastle virus, Coxackie B6 , Herpes simplex type I. The efficacy of the antiviral effects of Peral-S was checked on tissue cultures MDBK, AUBEK and HEP-2 using the floating technique method. Examinations also covered the fungicidal effect of Peral-S in concentrations of from 0.1% to 1%, and of 3%, 4%, and 5% at exposure times of 5, 15 and 60 minutes and cultures aged 1 to 14 days. The investigations covered fungi from the following genera: Penicillium spp., Aspergillus spp. and Mucor spp. Peral-S showed a bactericidal effect on all the examined bacteria strains, in all the applied concentrations and at all exposure times. Peral-S in a concentration of 0.1% and at an exposure time of 30 seconds had a vurcidal effect on all examined viruses. How-ever, there was no fungicidal effect of Peral-S in concentrations of 0.1% to 1% at all expo-sure times on fungi cultures aged from one to 14 days. The preparation did exhibit a fungicidal effect in a concentration of 3% in all examined fungi cultures after 60 minutes of expo-sure, while it exhibited a fungicidal effect in a concentration of 4% after 5 minutes of expo-sure on all examined fungi cultures, regardless of their age. U ispitivanjima su korišćeni mnogobrojni klinički i referentni sojevi kako bakterija, tako i virusa i gljivica. U ovom radu prikazan je samo jedan deo ispitivanja u kome su korišćeni referentni sojevi E. coli NTCC 8116, Proteus mirabilis ATCC 19086, Staphylococcus aureus ATCC 511, Salmonella Choleraesuis ATCC 10653, Enterococcus faecalis ATCC 6055 i Bacillus cereus ATCC 11778. Delovanje na navedene sojeve bakterija Perala-S u koncentracijama od 0,25%, 0,5% i 1% ispitano je primenom suspenzione metode pri vremenu ekspozicije od 5, 10, 15 i 20 minuta. Takođe, obavljena su ispitivanja antivirusnog delovanja Perala-S u koncentracijama od 0,1% do 1% i u vremenima ekspozicije od 30 sekundi do 5 minuta na viruse: Aujeszky 257/II, PI3, Newcastle virus, Coxackie B6, Herpes simplex tip I. Efikasnost antivirusnog delovanja Perala-S proveravana je na kulturama tkiva MDBK, AU-BEK i HEP-2 metodom "ploveće" tehnike. Ispitano je i fungicidno delovanje Perala-S u koncentracijama od 0,1% do 1% kao i 3%, 4% i 5%u vremenima ekspozicije od 5, 15 i 60 minuta i starosti kultura od jednog do četrnaestog dana. Ispitivanjima su obuhvaćene plesni iz rodova: Penicillium spp, Aspergillus spp. i Mucor spp. Peral-S je ispoljio baktericidno delovanje na svim ispitivanim sojevima bakterija, u svim primenjenim koncentracijama i u svim vremenima ekspozicije. Peral-S u koncentraciji od 0,1% i u vremenu ekspozicije od 30 sekundi delovao je virucidno na sve ispitivane viruse. Međutim, Peral-S u koncentracijama od 0,1% do 1% u svim vremenima ekspozicije na kulturama plesni koje su bile stare od jednog do četrnaest dana, nije ispoljio fungicidno delovanje. Fungicidno delovanje preparat je ispoljio u koncentraciji od 3 posto na svim ispitivanim kulturama plesni nakon 60 minuta ekspozicije, dok je u koncentraciji od 4 posto ispoljio fungicidni efekat nakon 5 minuta ekspozicije na svim ispitivanim kulturama plesni, bez obzira na njihovu starost.

Ispitana je antimikrobna aktivnost ekstrakta sjemenki grejpa i to komercijalnog preparata Citroept i vlastitog pripravka. Dokazana je antimikrobna aktivnost oba pripravka na gram-pozitivne bakterije. Djelotvornost vlastitog pripravka potvrđena je i nalazom aktivnih komponenti narginina i hesperidina.