Mariola Kozłowska

Fatty acids and sterols composition, and antioxidant activity of oils extracted from plant seeds.

This study determined and compared the contents of bioactive components in plant seed oils extracted with n-hexane (Soxhlet method) and chloroform/methanol (Folch method) from coriander, caraway, anise, nutmeg and white mustard seeds. Oleic acid dominated among unsaturated fatty acids in nutmeg and anise seed oils while petroselinic acid was present in coriander and caraway oils. Concerning sterols, β-sitosterol was the main component in seed oils extracted with both methods. The content of total phenolics in nutmeg, white mustard and coriander seed oils extracted with chloroform/methanol was higher than in their counterparts prepared with n-hexane. The seed oil samples extracted according to the Folch method exhibited a higher ability to scavenge DPPH radicals compared to the oil samples prepared with the Soxhlet method. DPPH values of the methanolic extracts derived from oils produced with the Folch method were also higher than in the oils extracted with n-hexane.

New opportunities of the application of natural herb and spice extracts in plant oils: application of electron paramagnetic resonance in examining the oxidative stability.

The aim of this study was to establish the applicability of natural water-ethanol extracts of herbs and spices in increasing the oxidative stability of plant oils and in the production of novel food. Different concentrations (0, 100, 300, 500, and 700 ppm) of spice extracts and butylated hydroxyanisole (BHA) (100 ppm) were added to the studied oils. The antioxidant activity of spice extracts was determined with electron paramagnetic resonance (EPR) spectroscopy using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. The study showed that the extracts significantly increased the oxidative stability of the examined oils when compared to one of the strongest synthetic antioxidants--BHA. The applied simple production technology and addition of herb and spice extracts to plant oils enabled enhancement of their oxidative stability. The extracts are an alternative to the oils aromatized with an addition of fresh herbs, spices, and vegetables because it did not generate additional flavors thus enabling the maintenance of the characteristic ones. Moreover, it will increase the intake of natural substances in human diet, which are known to possess anticarcinogenic properties.

Anti-Pentatrichomonas hominis activity of newly synthesized benzimidazole derivatives — in vitro studies

Pentatrichomonas hominis, a parasitic protozoan often detected in human diarrheic stools, is the cause of severe morbidity in newborns and children, particularly in tropical zones. The flagellate is resistant to many disinfectants and anti-protozoan drugs. Therefore in this study we have synthesized three novel 4,5,6,7-tetrabromobenzimidazole (TBBI) derivatives carrying a polyfluoroalkyl substituent in position 2 of the benzimidazole scaffold, namely 2-trifluoromethyl-TBBI (CF3-TBBI), 2-nonafluorobutyl-TBBI (C4F9-TBBI), and 2-nonadecafluorononyl-TBBI (C9F19-TBBI), that next we tested for their in vitro activity against P. hominis.Widely applied anti-protozoal drug, metronidazole as a reference was used. All the investigated agents were added to 24 h P. hominis cultures; each of them was administered at three different concentrations. Number of the moving trichomonads was determined and compared with the control cultures. Different anti-trichomonal activity occurred depending on a kind of compound and its concentration. C4F9-TBBI was the most effective TBBI derivative tested: the agent, at the highest concentration 24.2 μg/ml, after 72 h reduced the number of viable trichomonads to 44.3%; C9F19-TBBI, at the concentration 24 μg/ml reduced the number of the flagellates to 58.5%. Paradoxically, metronidazole after the same time given at the highest concentration increased trophozoite counts by 464.6% in comparison with the control cultures (100%).

Antioxidant properties and effect on lactic acid bacterial growth of spice extracts

The total phenolic content (TPC) and antioxidant capacity as determined by 2,2-diphenyl-1-picrylhydrazyl, 2,2ʹ-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid and ferric reducing antioxidant power assays of spice extracts such as rosemary, lemon balm, hyssop, nettle and cumin seeds were investigated. The effect of spice extracts on the growth of selected lactic acid bacteria (LAB) was also analysed. Lemon balm extract exhibited the highest TPC and antioxidant capacity while the nettle and cumin seeds extracts were characterized by the lowest values. Spice extracts had no impact on the growth of the most tested LAB except for rosemary extract, which showed an inhibitory effect towards all strains of Lactobacillus acidophilus and L. delbrueckii. These results suggest that spice extracts may be considered as additives in dairy and meat products in which LAB are present.

Evaluation of oxidative stability of vegetable oils enriched with herb extracts by EPR spectroscopy

Vegetable oils are important constituents of a healthy diet. Still, unsaturated fatty acids present in vegetable oils are susceptible to oxidation, which leads to undesirable changes in sensory, chemical and nutritional properties of oils. To prevent this problem, antioxidants are applied with herbs and spices being one of the most important sources of natural antioxidants. Electron paramagnetic resonance spectroscopy (EPR) can be used to detect free radicals, which are the short-lived intermediates of lipid oxidation, and to monitor changes in oxidation susceptibility. In this study, the ESR spin trapping technique was used as a potential method for the evaluation of the resistance to free radical formation in rapeseed and sunflower oils enriched with herb extracts. The antioxidant effect of herb extracts on vegetable oils was also investigated by measuring their ability to scavenge DPPH free radical using EPR spectroscopy. The herb extracts generally improved the radical scavenging properties of sunflower and rapeseed oils but their influence on the onset of rapid lipid oxidation as measured by spin-trapping EPR depended on the type of oil and on the extract concentration.

Effect of Oils Extracted from Plant Seeds on the Growth and Lipolytic Activity of Yarrowia lipolytica Yeast

This study was aimed at evaluating the capability of Yarrowia lipolytica W29 for the synthesis of lipolytic enzymes in a medium containing plant oils from non-conventional sources with some components displaying bioactivity. Oils from almond, hazelnut, and coriander seeds were obtained by using n-hexane (Soxhlet method) and a chloroform/methanol mixture of solvents (Folch method), and their effect on the growth and lipolytic activity of Y. lipolytica was compared. A comparison of these two extraction methods showed that the extraction with n-hexane was less effective regarding the oil extraction yields than the extraction conducted according to Folch’s procedure. The lipolytic activity of the studied yeast was higher in the culture media containing oils extracted with the Soxhlet method than the Folch method but it was lower compared to olive oil medium. Among all oils tested, almond oil extracted with n-hexane was the best inducer of extracellular lipases synthesized by Y. lipolytica. Its lipolytic activity achieved the maximum value of 2.33 U/mL after 48 h of culture. After 24 h of culture, it was close to the value obtained for the medium containing olive oil. Almond oil was a source of oleic and linoleic acids, which may determine differences in the lipolytic activity. The linoleic acid content in almond oil was higher than that found in other oils. When n-hexane was used for extraction, the resultant oils were characterized by lower contents of polyphenols and poorer antioxidative activity.

Oxidative stability of the lipid fraction in cookies – the EPR study

Abstract Cookies are a group of convenient food products that are popular among consumers. They may contain high amounts of fats, which can be prone to oxidation. To retard the oxidative deterioration, synthetic and natural antioxidants may be added. Herb and spice extracts can be sources of natural biologically active substances with antioxidant activity. In this work, electron paramagnetic resonance spectroscopy was used to monitor the lipid oxidation in cookies with rosemary and thyme extracts subjected to the storage in elevated temperature. It was shown that thyme extract can be used as a natural antioxidant source for the preparation of bakery products, while the rosemary extract should be used with care in fat-rich products exposed to high temperatures.

Characterization of the essential oil from cone-berries of Juniperus communis L. (Cupressaceae)

Summary Juniperus communis L. (Cupressaceae) is a plant widely cultivated in the Northern hemisphere. Juniper berries, the fruit of Juniperus communis L. are a highly valued, essential oil-rich plant material used traditionally in folk medicine as antiseptic, diuretic, antirheumatic, anti-inflammatory, antibacterial and antifungicidal agent. This paper reviews information on extraction methods of the essential oil from the juniper berries, its chemical composition and antimicrobial as well as antioxidant properties.