Serkos A. Haroutounian

Disinfectant test against monoculture and mixed‐culture biofilms composed of technological, spoilage and pathogenic bacteria: bactericidal effect of essential oil and hydrosol of Satureja thymbra and comparison with standard acid–base sanitizers

Aims:  To assess the antimicrobial action of three natural‐derived products (essential oil, decoction and hydrosol of Satureja thymbra) against biofilms, composed of useful, spoilage and pathogenic bacteria (formed as monoculture or/and mixed‐culture), and to compare their efficiency with three standard acid and alkaline chemical disinfectants.

CHEMICAL COMPOSITION AND IN – VITRO ANTIMICROBIAL ACTIVITY OF THE ESSENTIAL OILS OF THREE GREEK ACHILLEA SPECIES

The chemical composition of the essential oils of Achillea holosericea, Achillea taygetea, Achillea fraasii was determined by GC/MS analysis. Among the ninety-five assayed constituents, camphor, borneol and 1,8-cineol were found to be the major components. The in-vitro antimicrobial activity of these essential oils was evaluated against six bacteria indicating that the first is totally inactive, while the other two possess moderate to strong activities mainly against the Gram negative strains. The essential oil of A. fraasii was also active against the tested pathogenic fungi

Resveratrol and related stilbenes: their anti-aging and anti-angiogenic properties.

Dietary stilbenes comprise a class of natural compounds that display significant biological activities of medicinal interest. Among them, their antioxidant, anti-aging and anti-angiogenesic properties are well established and subjects of numerous research endeavors. This mini-review aspires to account and present the literature reports published on research concerning various natural and synthetic stilbenes, such as trans-resveratrol. Special focus was given to most recent research findings, while the mechanisms underlying their anti-aging and anti-angiogenic effects as well as the respective signaling pathways involved were also presented and discussed.

1H NMR-Based Metabonomics for the Classification of Greek Wines According to Variety, Region, and Vintage. Comparison with HPLC Data

A sensitive and simple method was developed for the classification of wines according to variety, geographical origin, and vintage using NMR-based metabonomics. Polyphenol-rich extracts were prepared from 67 varietal wines from the principal wine-producing regions of Greece, using adsorption resin XAD-4. 1D (1)H NMR spectra obtained from the corresponding extracts were segmented, integrated, and normalized, and the data were subjected to principal component analysis. The chemometric classification of wines according to their phenolic profile allows discrimination between wines from different wineries of the same wine-producing zone and between different vintages for wines of the same variety.

Antilisterial activities of polyphenol-rich extracts of grapes and vinification byproducts.

The quantitation of the main polyphenols and the assessment of the total polyphenolic content (TPC) in polyphenol-rich extracts of grape berries and vinification byproducts, obtained from Vitis vinifera cultivars of the Greek islands, are presented. The results indicated that seed extracts contain high concentrations of flavan-3-ols and their derivatives, whereas pomace and stem extracts consist of significant amounts of flavonoids, stilbenes, and phenolic acids. In particular, stemsa scarcely studied class of grape byproductwere also characterized by high trans-resveratrol and epsilon-viniferin content. The evaluation of their in vitro antilisterial activities revealed as most potent the seed and stem extracts of the red variety Mandilaria. Their minimum inhibitory concentrations (MICs) were assessed using a Malthus apparatus by two methods, a plate count technique and an automated technique that combines the conductance measurements with the common dilution method. The results revealed the usefulness of the conductance method as an alternative rapid means for the MIC estimation, whereas the respective values (0.26 and 0.34 for seeds and stems) indicated that both extracts represent an inexpensive source of potent natural antilisterial mixtures, which may be incorporated in food systems to prevent the growth of Listeria monocytogenes .

Novel pyrazole derivatives: Synthesis and evaluation of anti-angiogenic activity

The synthesis of a series of novel trisubstituted pyrazole derivatives and their PIFA-mediated conversion to molecules bearing the fused pyrazolo[4,3-c]quinoline ring system is reported. The anti-angiogenic activity of these compounds was evaluated by using in vitro assays for endothelial cell proliferation and migration, and in the chicken chorioallantoic membrane (CAM) assay. Compounds containing the fused pyrazolo[4,3-c]quinoline motifs emerged as potent anti-angiogenic compounds, which also had the ability to inhibit the growth of human breast (MCF-7) and cervical (Hela) carcinoma cells in vitro.

Pesticides residues in milks and feedstuff of farm animals drawn from Greece

The objective of this study was to investigate if milk from dairy sheep and goats, fed mainly with supplementary feed during the winter months, was contaminated with pesticides residues. Tauwo hundred milk samples from sheep and goats were collected from 10 farms of each animals. The sheep and goats farms were selected from those which represent common conventional production and feeding systems in Greece. Milk and feed samples (alfalfa hay, wheat straw, shrubs, pasture and concentrates) were taken from each farm to analyze for pesticides residues. The results showed that the summation operatorendosulfan was the main pesticide residue which was detected in all the concentrates samples at a mean concentration of 5.36 mgkg(-1), which is much higher from the maximum residue level (MRL). In addition, the summation operatorendosulfan was also detected in all the alfalfa hay samples but at a mean concentration of 0.10 mgkg(-1) which is lower than the MRL. The mean concentrations of endosulfan alpha and beta were 2.82 and 2.39 mgkg(-1) in the concentrates samples and 0.08 and 0.02 mgkg(-1) respectively in alfalfa hay samples. In the wheat straw, shrubs and pasture samples no pesticides residues were detected. No pesticide residues were also detected in milk samples of sheep and goats. Thus, this milk from the farms sampled presents no human health risks as far as the contaminants analyzed concerned.

Microbiological spoilage and investigation of volatile profile during storage of sea bream fillets under various conditions.

Volatile organic compound (VOC) profile was determined during storage of sea bream (Sparus aurata) fillets under air and Modified Atmosphere Packaging (MAP - CO2/O2/N2: 60/10/30) at 0, 5 and 15°C. Microbiological, TVB-N (Total Volatile Base Nitrogen) and sensory changes were also monitored. Shelf-life of sea bream fillets stored under air was 14, 5 and 2days (d) at 0, 5 and 15°C respectively, while under MAP was 18, 8, and 2d at 0, 5 and 15°C respectively. At the end of shelf life, the total microbial population ranged from 7.5 to 8.5logcfu/g. Pseudomonas spp. were among the dominant spoilage microorganisms in all cases, however growth of Brochothrix thermosphacta and Lactic Acid Bacteria (LAB) were favoured under MAP compared to air. TVB-N production was favoured at higher temperatures and under air compared to lower temperatures and MAP. TVB-N increased substantially from the middle of storage and its value never reached concentrations higher than 30-35mgN/100g, which is the legislation limit, making it a poor chemical spoilage index (CSI). A lot of alcohols, aldehydes, ketones and ethyl esters that were detected in the present study have been reported as bacterial metabolites, others as products of chemical oxidation while others as aroma constituents. VOCs such as 3-methylbutanal, acetic acid, ethanol, ethyl esters of isovaleric and 2-methylbutyric acids, 1-penten-3-ol, 1-octen-3-ol and cis-4-heptenal appeared from the early or middle stages and increased until the end of storage. From those only 3-methylbutanal, acetic acid, ethanol and the ethyl esters have been reported as microbial origin, making them potential CSI candidates of sea bream fillets.

Pomegranate juice consumption increases GSH levels and reduces lipid and protein oxidation in human blood.

The aim of the present study was the assessment of the antioxidant effects of pomegranate juice (PJ) consumption in humans. Thus, 14 healthy volunteers consumed PJ daily for a period of 15days and the changes of oxidative stress markers in their blood were assessed at four different time points, immediately before the experiment (T1), after 15days of juice administration (T2), one (T3) and three weeks (T4) after the interruption of PJ administration. The markers studied were total antioxidant capacity (TAC), levels of malondialdehyde (MDA), and protein carbonyls (CARB) measured in plasma, as well as reduced glutathione (GSH), and catalase activity (CAT) measured in erythrocytes. The MDA was reduced by 24.4% at T3 and CARB were reduced by 19.6% and 17.7% at T2 and T3, respectively, supporting the evidence that PJ consumption enhances the antioxidant status in humans by decreasing lipid peroxidation and protein oxidation. Moreover, GSH levels were significantly increased (22.6%) at T2, indicating that PJ consumption improves the antioxidant mechanisms in erythrocytes by increasing GSH levels. Finally, it was shown that even a week after stopping PJ consumption some of its beneficial effects on antioxidant status still remained in the organism.

Synthesis and biological studies of steroidal cis-platinum(II) complexes

Abstract Several new steroidal cis -platinum(II) complexes ( 4a, 4b, 4c and 4d ) were synthesized by treatment of K 2 PtCl 4 with appropriately substituted steroids. The receptor binding affinities ( RBA ) of the prepared complexes, which may be indicative of their selectivity, were evaluated along with the antitumor testing of one of these steroidal cis -platinum(II) complexes. The latter was found to possess activity comparable to cisplatin, with respect to both activity and therapeutic index.