Maria A. Anagnostopoulou

Bio: Maria A. Anagnostopoulou is an academic researcher from Aristotle University of Thessaloniki. The author has contributed to research in topics: Photocatalysis & Materials science. The author has an hindex of 4, co-authored 5 publications receiving 642 citations.

Analysis of antioxidant compounds in sweet orange peel by HPLC-diode array detection-electrospray ionization mass spectrometry.

Abstract: HPLC-diode array detection-electrospray ionization mass spectrometry was used to determine qualitatively and quantitatively the flavonoid content of several fractions and residues of extracts of Greek navel sweet orange peel (Citrus sinensis) from the region of southern Greece (Leonidi-Tripoli). The main groups of flavonoids found according to HPLC retention times, spectral data and literature references were polymethoxylated flavones, C-glycosylated flavones, O-glycosylated flavones, O-glycosylated flavanones, flavonols and phenolic acids and their derivatives. The ethyl acetate fraction which has been shown in previous work to possess the best radical scavenging activity among the others was found to contain C-glycosylated flavones, polymethoxylated flavones, O-glycosylated flavones, O-glycosylated flavanones, two phenolic acid derivatives and two unknown compounds, all in low concentrations. The group of C-glycosylated flavones was reported for the first time in the peel of Navel sweet orange. The C-glycosylated flavones found according to their spectral characteristics and literature were 6-C-beta-glucosyldiosmin, 6,8-di-C-glucopyranosylapigenin, 6,8-di-C-beta-glucosyldiosmin and two unknown. The results suggest that the ethyl acetate fraction of navel Citrus sinensis peel consists of significant antioxidant compounds and can be used as a food additive of natural origin or a pharmaceutical supplement using as a source of peel the byproducts of the orange juice industry.

Monitoring of heavy metal levels in roadside dusts of Thessaloniki, Greece in relation to motor vehicle traffic density and flow.

Abstract: In recent years, the level of heavy metal pollution in urban areas has been of considerable concern. The principal source has been attributed to the motor vehicle and increasing inner city congestion, which has lead to a change and enlargement of transport stop-start zones. These areas of high traffic density are associated with an increased release of heavy metals into the adjacent residential or commercial areas. Seventy-five roadside dust samples were collected throughout the inner city and by-pass motorway areas of Thessaloniki, Northern Greece. Samples were taken from arterial, major and minor roads, as well as the ring road, to compare and contrast the levels of heavy metals, namely Cu, Zn, Cd, Mn and Pb. Flame Atomic Absorption Spectroscopy (FAAS) was developed to quantitatively determine concentrations of both total element and geochemical fractionation, within the two dust particulate fraction sizes 0.05 or 95% confidence limit. Road type was seen to have little affect on cadmium and manganese, though lead, copper and zinc were all found to show higher levels on the inner city routes. This can be related back to the wear-and-tear of vehicle components as a result of the stop-start traffic patterns (brake pads etc). Both Pb and Zn have shown to be in chemical forms that are bio available to ecosystems.

In vitro and in vivo evaluation of the genotoxic and antigenotoxic potential of the major Chios mastic water constituents.

Abstract: Chios mastic products are well-known for their broad applications in food industry, cosmetics, and healthcare since the antiquity. Given our recent finding that Chios mastic water (CMW) exerts antigenotoxic action, in the present study, we evaluated the genotoxic as well as the antigenotoxic potential of the four major compounds of CMW, namely, verbenone, α-terpineol, linalool, and trans-pinocarveol. The cytokinesis block micronucleus (CBMN) assay in cultured human lymphocytes and the Drosophila Somatic Mutation And Recombination Test (SMART), also known as the wing spot test, were employed. None of the four major CMW's constituents or their mixtures showed genotoxic or recombinogenic activity in either of the assays used. Co-treatment of each of the constituents with MMC revealed that all except trans-pinocarveol exerted antigenotoxic potential. Moreover, co-administration of verbenone with linalool or α-terpineol presented statistically significant reduction of MMC-induced mutagenicity. In conclusion, the major CMW constituents were shown to be free of genotoxic effects, while some exerted antigenotoxic activity either alone or in combinations, suggesting synergistic phenomena. Our results provide evidence on the key antigenotoxicity effectors of the plant extract CMW.

Adsorption of Methyl Orange on a Novel Palygorskite/UiO-66 Nanocomposite

Abstract: Herein, a novel composite material containing UiO-66 and palygorskite (Pal) clay mineral was prepared using a facile one-pot synthesis process. The material was studied using a variety of techniques and applied as did not affect the structure of the metal-organic framework (MOF) part, but induced a small increase in specific surface area. The developed Pal/UiO-66 composite presented excellent adsorption efficiency against MO removal, as evidenced by detailed kinetic and isotherm experiments. An impressive maximum adsorption capacity at equilibrium was evidenced; 340 mg g−1 at pH = 5 and T = 25 °C. This corresponds to a 34.5 % increase compared with pure UiO-66, considering only the MOF content. Furthermore, the Pal/UiO-66 composite was proven stable and highly recyclable, losing less than 9% of the removal capacity after five consecutive cycles. The study highlights the synergistic effect of the coupling of MOF structures with low-cost and abundant clay minerals for the development of advanced absorbents.

Flavonoid composition of Citrus juices.

Abstract: In the early nineties the presence of flavonoids in Citrus juices began to attract the attention of a number of researchers, as a result of their biological and physiological importance. This short review will explore two different aspects. The first part will focus on analytical techniques for the characterization of juices from different Citrus fruits regarding their flavonoid content (even if present in only trace amounts), concentrating on the most widely used methods (LC-MS and LC-MS-MS). The second part analyzes data reported in the literature regarding the composition of Citrus juices. The main components that have been detected so far are flavanone-O-glycosides and flavone-O- or -C-glycosides. The presence of such derivatives in various hand-squeezed and industrial juices is discussed, with special emphasis on their correlation to different species.

Antioxidant activity, phenol and flavonoid contents of 13 citrus species peels and tissues.

Abstract: Methanolic extracts of 13 commercially available citrus spp., peels and tissues growing in Iran were investigated for their antioxidant activity by DPPH method. IC50 for antioxidant activity ranged from 0.6-3.8 mg ml(-1). Total phenolic content of the citrus spp. samples (based on folin Ciocalteu method) varied from 66.5 to 396.8 mg gallic acid equivalent/g of extract and flavonoids content (based on colorimetric AlCl3 method) varied from 0.3 to 31.1 mg quercetin equivalent/g of extract. There were no correlation between the total phenolic and/or flavonoids contents and antioxidant activity in tissues and/or peels.

Upgrading of grape skins: Significance of plant cell-wall structural components and extraction techniques for phenol release

Abstract: In grape skins, phenols may be classified as (1) cell-wall phenols, which are bound to polysaccharides by hydrophobic interactions and hydrogen bonds, and (2) non-cell-wall phenols, encompassing phenols confined in the vacuoles of plant cells and phenols associated with the cell nucleus. The phenolic composition of wines determines the colour quality, the sensory, and the potential health promoting properties of wines, and the extraction of phenols from the grapes into the must and wine is to a large extent governed by how the phenols are bound and entangled in the grape skins. Degradation of cell-wall polysaccharides is a fundamental step to improve the release of phenols from grape skin whether this is in winemaking or in upgrading of wine pomace. Cellulases, hemicellulases, pectinases, and other enzymes able to catalyze the hydrolysis of bonds in plant cell-wall polysaccharides can be employed to decompose the cell-wall structure. In addition, novel extraction principles and optimization of extraction conditions such as temperature, solvent-to-solid ratio, use of supercritical fluids and new extraction cell designs have shown promise for optimizing the release of phenols from grape skins for valorization of wine pomace. An in-depth knowledge of how phenols are bound in grape skins will allow us to employ the most suitable techniques to release phenols in order to optimize the phenol-related properties of wine and maximize the phenol recovery from grape byproducts.