Antilisterial effect of juniper (Juniperus communis) and its mixed application with winter savory (Satureja montana) in beef protection

Abstract Juniperus communis essential oil and post-distillation waste were tested for their antibacterial potential against common food contaminants. Results of microdilution assay directed further study of Listeria monocytogenes. Checkerboard assay showed synergistic antilisterial effect of both substances with conventional antibiotics. By evaluating of their cytotoxicity on human colon cells, post-distillation waste was denoted as selective against L. monocytogenes, being able to interfere with its in vitro adhesion on colon cells. On the other hand, the food preservative potential of J. communis essential oil was studied and compared with the activity of Satureja montana essential oil. In a microdilution assay, both substances induced antilisterial effect against reference ATCC 19111 strain and three wild isolates. A checkerboard assay showed synergism against isolates. An in vitro time-kill assay was used to confirm the types of interaction, and to estimate curve MIC values. Finally, in situ antilisterial efficacies of the individual essential oils and their mixture on red wine-marinated beef, previously inoculated with ATCC 19111 strain or primoisolate from beef carcass, were determined. All treatments enhanced the antilisterial potential of wine marinade. In conclusion, derivatives of J. communis possess significant antilisterial potential both in in vitro and in situ conditions, so further research is advised.</jats:p

Can yellow gentian (Gentiana lutea) be useful in protection against foodborne mutagens and food contaminants?

Abstract Gentiana lutea is a wellknown and respected medicinal plant that is used in many pharmacopoeias, mainly against different gastrointestinal disorders. The plant is under protection regimes in its natural habitats and for that reason is grown on plantations. In addition, it could be cultivated in vitro. The plants grown on plantation and in in vitro conditions were used to prepare methanolic and 50% ethanolic extracts of root and leaf/shoot, which were tested for antigenotoxic and antibacterial properties, against foodborne mutagens (heterocyclic aromatic amines PhIP and IQ) and food contaminants, respectively. The results obtained pointed out the excellent genoprotective effect (up to 78% inhibition of PhIP/IQ genotoxicity) based mostly on the antioxidative potential. The antibacterial effect was mainly weak; only the extracts of in vitro grown plant induced moderate activity against Listeria monocytogenes and Staphylococcus aureus (MICs ranged 0.15-5 mg/ml). In addition, the extracts’ potential to prevent biofilm formation by L. monocytogenes was very high (up to 90% inhibition). Taken together, the results obtained encourage further research that would be directed to the formulation of potent antigenotoxic and antibiofilm agents based on G. lutea.</jats:p

Potential of Frangula alnus to contribute to food safety: antibiofilm effect against Staphylococcus aureus

Abstract Contamination by numerous food-borne pathogens is a major challenge facing the food industry daily. Even though there are many strategies in the fight against contamination, pathogens able to attach to different surfaces and form biofilms are the biggest concern. Staphylococcus aureus is a common food-borne pathogen capable of forming biofilms on foods and food contact surfaces. The prevalence of multidrug resistant S. aureus is high in raw products, high-protein foods and processed products. Bearing in mind S. aureus resistance to numerous antibacterial agents, the aim of this study was to investigate antibiofilm activity of an ethyl-acetate extract of the medicinal plant, Frangula alnus, against S. aureus ATCC 25923 and S. aureus ATCC 43300. It was demonstrated that extract reduced survival of both tested strains by up to 67%. Furthermore, quantification of biofilm biomass showed that extract possesses the extraordinary ability to inhibit biofilm formation of both tested strains (up to 91%). On the other hand, the effect on preformed biofilm was less pronounced and measured only for S. aureus ATCC 43300, wherein about 28% of preformed biofilm was eradicated. The results obtained in this study encourage further investigation of F. alnus as a novel antibiofilm agent or preservative in the food industry.</jats:p

Antioxidative properties and antigenotoxic potential of Gentiana lutea extracts against the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine, PhIP

Abstract Lipid oxidation that occurs in different types of food can cause alterations in nutritional qualities, flavour, texture and shelf life of foods. Furthermore, high temperature cooking of protein-rich food can lead to formation of heterocyclic aromatic amines capable of compromising the integrity of DNA molecules. To reduce these harmful effects, research has been focused on investigating plants as a source of potential natural food additives and preservatives. Thus, the aim of this study was to estimate antioxidant and antigenotoxic activities of 50% ethanolic-aqueous root and leaf extracts of the medicinal plant, Gentiana lutea. Antioxidative effect was investigated using the DPPH assay, while antigenotoxicity against the mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was determined using Salmonella Typhimurium TA 1535 in the SOS/umuC assay. Leaf extract showed high antioxidative effect with the ability to neutralize up to 87% of free radicals at 400 µg mL-1. Antigenotoxicity testing revealed that both extracts exhibited remarkable genoprotective activity against PhIP-induced DNA damage, with the highest inhibition levels being 70% and 85% for root and leaf extracts, respectively. Results obtained are encouraging and suggest further research of G. lutea extracts as potential food preservatives and additives in improving food quality and human health.</jats:p

Protective effect of Gentiana lutea root and leaf extracts against heterocyclic aromatic amines IQ and PhIP produced in thermally processed meat

Abstract During high-temperature cooking of protein rich foods, especially meat and fish, heterocyclic aromatic amines can be formed. These amines are a class of potent mutagens that can cause alterations in the structure of DNA and chromosomes. In recent decades, research has been focused on investigating plants and their phytochemicals as potential antimutagens. The aim of this study was to examine the anti-genotoxic effect of methanolic root and leaf extracts of Gentiana lutea against the food mutagens 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) produced in thermally processed meat. To determine the protective potential of extracts, the alkaline comet assay was applied. The results obtained indicated strong anti-genotoxic effect of both extracts against the tested mutagens. The highest inhibition of IQ-induced genotoxicity was recorded for leaf extract (72%). Regarding PhiP, root extract achieved inhibition of 80% of DNA damage, so was more successful than leaf extract. The data obtained in this study stimulates further research of G. lutea extracts and its constituents as potential dietary supplements in improving human health.</jats:p