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Annalisa Romani

Publications and source records attributed to Annalisa Romani.

13 recordsLinked to original sources
PubMed2007

Hydrolyzable tannins with the hexahydroxydiphenoyl unit and the m-depsidic link: HPLC-DAD-MS identification and model synthesis.

This study was designed to develop efficient analytical tools for the difficult HPLC-DAD-MS identification of hydrolyzable tannins in natural tissue extracts. Throughout the study of the spectroscopic characteristics of properly synthesized stereodefined standards, it was observed that the UV-vis spectra of compounds with the m-depsidic link showed a characteristic shoulder at 300 nm, consistent with the simple glucogalloyl esters, whereas compounds with the hexahydroxydiphenoyl (HHDP) unit gave a diagnostic fragmentation pattern, caused by a spontaneous lactonization in the mass spectrometer. These observations were confirmed by HPLC-DAD-MS analyses of tannic acid and raspberry extracts, which are rich in hydrolyzable tannins with the m-depsidic link and the HHDP unit, respectively.

Chromatography, High Pressure Liquid↗
PubMed2006

Antioxidant effect of two virgin olive oils depends on the concentration and composition of minor polar compounds.

In vitro studies show that some individual minor polar phenolic compounds (MPC) present in virgin olive oil prevent oxidation of human low-density lipoproteins (LDL), but few data are available on the antioxidant effect of whole oil extract. Thus, whole virgin olive extracts were studied to determine whether they maintain the antioxidant activity and whether this last is linked to MPC composition of a single virgin oil. Using HPLC-DAD the MPC content in Taggiasca and Seggianese virgin olive oils was measured. Taggiasca oil was less rich in total MPC (208.5 mg/L) than Seggianese oil (441.9 mg/L). In addition, the major compounds of Taggiasca oil were lignan derivatives, whereas the major compounds in Seggianese oils were secoiridoid derivatives. Moreover, Taggiasca oil was practically free of 5-hydroxytyrosol and 5-hydroxytyrosol derivatives, deacetoxy-oleuropein aglycone and oleuropein aglycone. The antioxidant activity of the oils on human LDL was evaluated by measuring malondialdehyde and conjugate diene generation induced by copper ions. In both tests, the oil extracts dose-dependently reduced malondialdehyde and conjugate diene generation. Moreover, antioxidant potency correlated with total MPC; thus, Seggianese extract was more active. The two oils differed quantitatively and qualitatively, and these differences influenced their biological activities; thus clinical trials focused on studying the effects of olive oils should specify the oils used.

Antioxidants↗
PubMed2006

HPLC-DAD/MS characterization of flavonoids and hydroxycinnamic derivatives in turnip tops (Brassica rapa L. Subsp. sylvestris L.).

Flavonoids and hydroxycinnamic derivatives of turnip tops (Brassica rapa L. subsp. sylvestris L.) were characterized for the first time in four samples from different origins. Turnip tops exhibit a high polyphenols content (ranging from 107 to 191 mg/100 g, fresh weight) and a good antiradical activity, determined with the DPPH* test. After a liquid-liquid extraction and fractionation procedures, most flavonoids (isorhamnetin, kaempferol, and quercetin glycosides) and hydroxycinnamic derivatives were identified by means of HPLC-DAD/MS techniques. Isorhamnetin glycosides were the main flavonoid derivatives, differing from that found in the vegetables belonging to the Brassica oleracea group.

Brassica rapa↗
PubMed2006

Daily consumption of a high-phenol extra-virgin olive oil reduces oxidative DNA damage in postmenopausal women.

Extra-virgin olive oils (EVOO), high in phenolic compounds with antioxidant properties, could be partly responsible for the lower mortality and incidence of cancer and CVD in the Mediterranean region. The present study aims to measure oxidative DNA damage in healthy human subjects consuming olive oils with different concentrations of natural phenols. A randomised cross-over trial of high-phenol EVOO (high-EVOO; 592 mg total phenols/kg) v. low-phenol EVOO (low-EVOO; 147 mg/kg) was conducted in ten postmenopausal women in Florence. Subjects were asked to substitute all types of fat and oils habitually consumed with the study oil (50 g/d) for 8 weeks in each period. Oxidative DNA damage was measured by the comet assay in peripheral blood lymphocytes, collected at each visit during the study period. Urine samples over 24 h were collected to measure the excretion of the olive oil phenols. The average of the four measurements of oxidative DNA damage during treatment with high-EVOO was 30 % lower than the average during the low-EVOO treatment (P=0.02). Urinary excretion of hydroxytyrosol and its metabolite homovanillyl alcohol were significantly increased in subjects consuming high-EVOO. Despite the small sample size, the present study showed a reduction of DNA damage by consumption of an EVOO rich in phenols, particularly hydroxytyrosol.

Aged↗
PubMed2005

Solid olive residues: insight into their phenolic composition.

Solid olive residues (SOR) are byproducts of the olive-milling process, but they have an increasing importance in the pharmaceutical industry due to their rich content of biophenols. Such compounds are studied widely for their antioxidant and antimicrobial activities, but there is a lack of information about their quantitative recovery. This research highlighted the key role played both by the selection of the cultivar and by the degree of olive fruit ripening on the phenolic content on the SOR. The extraction methods were selected to reach the best quantitative results mainly using a safe food solvent. In light of the results the Soxhlet extraction with ethanol could be proposed as preferential for a higher recovery of verbascoside and its analogues.

Chromatography, High Pressure Liquid↗
PubMed2005

Rapid tests to assess the antioxidant activity of Phaseolus vulgaris L. dry beans.

The antiradical activity of dry beans was evaluated in order to assess the validity of this test and to correlate the results with those achieved with the Folin-Ciocalteu method and with a rapid spectrophotometric method for the analysis of total flavonoids. Four landraces (12 samples) of common beans (Phaseolus vulgaris L.), collected in two regions of Italy (Tuscany and Basilicata) in three different years, were analyzed. The EC50 values ranged from 39 to 2810 mg sample/mg 1,1-diphenyl-2-picrylhydrazil radical. The phenolic content of each sample was expressed as gallic acid equivalents; it changed from 1.17 to 4.40 mg/g. The flavonoid content, expressed as mg of (+)-catechin per g of dry seeds, ranged from 0.24 to 1.43 mg/g. The qualiquantitative composition of polyphenols has been also elucidated by means of high-performance liquid chromatography (HPLC)-diode array detection and HPLC/MS. These investigations showed that rapid tests can contribute to assessing the quality of functional food.

Antioxidants↗
PubMed2005

Nondestructive evaluation of anthocyanins in olive (Olea europaea) fruits by in situ chlorophyll fluorescence spectroscopy.

Anthocyanins (Anths) in olive (Olea europaea L.) fruits at different degrees of pigmentation were assessed nondestructively by measuring chlorophyll fluorescence (ChlF). The method is based on the comparison of the ChlF excitation spectra from olives with different pigmentation from green to green-red, reddish-purple, and purple. The logarithm of the ratio between the fluorescence excitation spectra (logFER) from two different colored zones gave the difference in the absorption spectrum between them. The absorbance spectrum derived from the logFER between a red olive and the same olive devoid of the skin showed the typical Anth green band (at 550 nm). It matched that recorded by microspectrophotometry on a single pulp cell and the in vitro absorbance spectrum of the olive skin extract. As expected, the in vivo Anths absorption maximum increased in intensity going from less to more mature olives and was higher in the sun-exposed olive side with respect to the sun-shaded side. Absolute quantitative nondestructive determination of Anths for each olive sample was obtained by the logFER calculated for two excitation wavelengths, 550 and 625 nm, of ChlF at 740 nm. Going from green to purple skin colors, the Log[ChlF(625)/ChlF(550)] was fairly well-correlated to the extract Anths concentration. Finally, the relationship between the Anths and the other main phenolics present in the olives analyzed by high-performance liquid chromatography was evaluated. The main result was a net increase of verbascoside with increasing Anths content. On the basis of our results, the development of a new rapid and noninvasive method for the monitoring of olive development and ripening can be envisaged.

Anthocyanins↗
PubMed2004

Germplasm characterization of Zolfino landraces (Phaseolus vulgaris L.) by flavonoid content.

The flavonoid composition of three phenotypes of "Zolfino" landraces, a typical bean grown in Tuscany, has been elucidated by means of HPLC-DAD and HPLC-MS analysis. Flavonols, isoflavones, and anthocyanins have been separated and determined in the different samples chosen on the basis of their seed coat color. A flavonol that has not been previously found in Phaseolus vulgaris L. seeds has been characterized. The quantitative data show the presence of flavonols (ranging from 709 to 118 mg/kg of fresh weight), isoflavones (ranging from 14 to 2 mg/kg of fresh weight), and anthocyanins, in black beans only. These results show that this genotype could be very interesting from a nutritional point of view.

Chromatography, High Pressure Liquid↗
PubMed2004

Evaluation of antioxidant effect of different extracts of Myrtus communis L.

Oxidative stress is involved in the pathogenesis of numerous diseases. Nevertheless, no optimal natural antioxidant has been found for therapeutics, therefore polyphenol antioxidants have been looked for in myrtle leaves, a plant that in folk medicine has been used as anti-inflammatory drug. Antioxidant-rich fractions were prepared from myrtle (Myrtus communis L.) leaves liquid-liquid extraction (LLE) with different solvents. All myrtle extracts were very rich in polyphenols. In particular, hydroalcoholic extracts contain galloyl-glucosides, ellagitannins, galloyl-quinic acids and flavonol glycosides; ethylacetate extract and aqueous residues after LLE are enriched in flavonol glycosides and hydrolysable tannins (galloyl-glucosides, ellagitannins, galloyl-quinic acids), respectively. Qualitative and quantitative analysis for the single unidentified compound was also performed. Human LDL exposed to copper ions was used to evaluate the antioxidant activity of the myrtle extracts. Addition of these extracts did not affect the basal oxidation of LDL but dose-dependently decreased the oxidation induced by copper ions. Moreover, the myrtle extracts reduce the formation of conjugated dienes. The antioxidant effect of three myrtle extracts decreased in the following order: hydroalcoholic extracts, ethylacetate and aqueous residues after LLE. The extracts had the following IC50: 0.36, 2.27 and 2.88 microM, when the sum of total phenolic compounds was considered after the correction of molecular weight based on pure compounds. Statistical analysis showed a significant difference among hydroalcoholic extracts vs. the ethylacetate and aqueous residues after LLE. These results suggest that the myrtle extracts have a potent antioxidant activity mainly due to the presence of galloyl derivatives.

Acetates↗
PubMed2003

Polyphenolic content in different plant parts of soy cultivars grown under natural conditions.

Roots, cotyledons, leaves, stems, pods, and seeds of three soy cultivars were analyzed for their content of isoflavones, flavonols, coumarins, and phenolic acid derivatives with three samplings during a three-month period. The extracts were analyzed by HPLC/DAD and HPLC/MS, allowing us to confirm the presence of daidzein and genistein derivatives as the major isoflavones and to characterize coumarins, most flavonols and phenolic acid derivatives. Seeds exhibited the highest content of isoflavones: 12.61 g/kg of dry weight (DW) in cv. Emiliana; 8.97 g/kg of DW in cv. Elvir; 4.49 g/kg of DW in cv. Kure, and roots are the only part with coumarins, ranging from 4.08 g/kg of DW (cv. Emiliana) to 1.29 g/kg of DW (cv. Elvir) for the longest sampling period. Leaves, pods, and stems have flavonols, and in particular leaves showed: 7.28 g/kg of DW in cv. Emiliana; 6.57 g/kg of DW in cv. Elvir; 7.08 g/kg of DW in cv. Kure. The high content of isoflavones found in the seeds could be ascribed to the natural conditions under which the soy plants were grown.

Chromatography, High Pressure Liquid↗
PubMed2003

Antioxidant activity of galloyl quinic derivatives isolated from P. lentiscus leaves.

The antioxidant properties of galloyl quinic derivatives isolated from Pistacia lentiscus L. leaves have been investigated by means of Electron Paramagnetic Resonance spectroscopy (EPR) and UV-Vis spectrophotometry. Antioxidant properties have been also estimated using the biologically relevant LDL test. The scavenger activities of gallic acid, 5-O-galloyl, 3,5-O-digalloyl, 3,4,5-O-trigalloyl quinic acid derivatives, have been estimated against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide (O2) radical, and hydroxyl (OH) radical. On the whole, the scavenger activity raised as the number of galloyl groups on the quinic acid skeleton increased. The half-inhibition concentrations (IC50) of di- and tri-galloyl derivatives did not exceed 30 microM for all the tested free radicals. All the tested metabolites strongly reduced the oxidation of low-density lipoproteins (LDL), following a trend similar to that observed for the scavenger ability against OH radical.

Antioxidants↗
PubMed2002

Flavonoid distribution in tissues of Phillyrea latifolia L. leaves as estimated by microspectrofluorometry and multispectral fluorescence microimaging.

A new method for detecting the tissue-specific distribution of flavonoids has been developed by coupling microspectrofluorometry and multispectral fluorescence microimaging techniques. Fluorescence responses of cross sections taken from 1 year old Phillyrea latifolia leaves exposed to full (sun leaves) or 15% (shade leaves) solar radiation in a coastal area of Southern Tuscany were analyzed. Fluorescence spectra of different tissue layers, each normalized at its fluorescence maximum, that were stained or not stained with Naturstoff reagent A (in ethanol), under excitation with UV light (lambdaexc = 365 nm) or blue light (lambdaexc = 436 nm) were recorded. The shape of the fluorescence spectra of tissue layers from shade and sun leaves differed only under UV excitation. The fluorescence of stained cross sections from sun and shade leaves as well as from different layers of sun leaves received a markedly different contribution from the blue (470 nm) and the yellow-red (580 nm) wavebands. Such changes in tissue fluorescence signatures were related to light-induced changes of extractable caffeic acid derivatives and flavonoid glycosides, namely quercetin 3-O-rutinoside and luteolin 7-O-glucoside. Wall-bound phenolics, i.e. hydroxycinnamic acids (p-coumaric, ferulic and caffeic acid) and flavonoids (apigenin and luteolin derivatives), did not substantially differ between sun and shade leaves. A Gaussian deconvolution analysis of fluorescence spectra was subsequently performed to estimate the contribution of flavonoids (emitting at 600 nm, F600 [red fluorescence contribution = signal integrated over a Gaussian band centered at about 600 nm]) relative to the tissue fluorescence (Ftot [total fluorescence = signal integrated over the whole fluorescence spectrum]). The F600/ Ftot ratios sharply differed between analogous tissues of sun and shade leaves, as well as among tissue layers within each leaf type. A highly resolved picture of the tissue flavonoid distribution was finally provided through a fluorescence microimaging technique by acquiring fluorescence images at the blue (fluorescence at about 470 nm [F470]) and yellow-red (fluorescence at about 580 nm [F580]) wavelengths and correcting the F580 image for the contribution of nonflavonoids to the fluorescence at 580 nm. Monochrome images were elaborated by adequate computing functions to visualize the exclusive accumulation of flavonoids in different layers of P. latifolia leaves. Our data show that in shade leaves flavonoids almost exclusively occurred in the adaxial epidermal layer. In sun leaves flavonoids largely accumulated in the adaxial epidermal and subepidermal cells and followed a steep gradient passing from the adaxial epidermis to the inner spongy layers. Flavonoids also largely occurred in the abaxial epidermal cells and constituted the exclusive class of phenylpropanoids synthesized by the cells of glandular trichomes. The proposed method also allowed for the discrimination of the relative abundance of hydroxycinnamic derivatives and flavonoids in different layers of the P. latifolia leaves.

Flavonoids↗