Teresa Papalia

Artificial light-harvesting antenna systems grafted on a carbohydrate platform

An enantiopure α-D-glucopyranoside derivative has been used as a platform to prepare artificial antenna systems based on bodipy subunits. Efficient and ultrafast energy transfer (in the fs and ps time regimes) takes place in the multibodipy systems.

Synthesis and biological evaluation of a new class of glycoconjugated disulfides that exhibit potential anticancer properties.

A synthetic strategy, based on the in situ generation of sulfenic acids and their thermolysis in the presence of thiols, was developed for obtaining a collection of polyvalent disulfides in which a benzene scaffold accommodates two or three flexible arms connecting saccharide moieties. Targeting carbohydrate metabolism or carbohydrate-binding proteins may constitute important approaches in the discovery process of new therapeutic anticancer agents. Therefore, a preliminary screening to ascertain the cytostatic/cytotoxic potential of this new class of enantiopure glycoconjugated disulfides has been conducted. Among them, products with two disulfide arms, harbouring galactose rings, induced high levels of apoptosis on U937 histiocytic lymphoma cells, but lower levels of cell death on peripheral blood mononuclear cells from healthy donors. Further experiments indicated that apoptosis induced by these glycoconjugated bis(disulfides) in U937 cells corresponds to the Bcl-2-sensitive, intrinsic form of apoptotic cell death. The bioinvestigation was extended to a panel of human cancer cell lines with different levels of malignancy and resistance to chemotherapeutic agents. Compounds under study proved to induce detectable levels of cell death towards all the tested cancer cell lines.

Antioxidant Properties and Flavonoid Profile in Leaves of Calabrian Lavandula multifida L., an Autochthon Plant of Mediterranean Southern regions

Lavandula multifida is a rare short‐lived plant characteristic of Mediterranean basin able to survive in hot and arid climatic conditions on poorly evolved limestone soils. In this work, we characterize the enzymatic antioxidant system and phenolic composition, as well as the antioxidant properties of L. multifida fresh leaves. Enzymatic patterns show high level of peroxidases, ascorbate peroxidase, and dehydroascorbate reductase activities, when compared with L. angustifolia. The same trend is evident in total carotenoids, ascorbic acid, and reduced glutathione, and in the total antioxidant capacity assay. Moreover, RP‐DAD‐HPLC analyses of EtOH extract, obtained from fresh leaves, reveal main components, carvacrol, vitexin, and 7‐ or 8‐glucoside derivatives of hypolaetin, scutellarein, luteolin, isoscutellarein, apigenin, and chrysoeriol. The analysis of this autochthon plant depicted a series of strategies adopted by L. multifida to survive in its stressful natural habitat and richness in health‐promoting compounds that can be a resource for the preservation of this variety in dangerous of extinction.

Oligo(phenylene ethynylene) glucosides: modulation of cellular uptake capacity preserving light ON.

A new family of oligo(phenylene ethynylene) (OPE) glucosides has been prepared and characterized. Our results demonstrate that fine-tuning of their photophysical properties can be obtained by acting on the electronics of the core and molecular skeleton. Modulation of the hydrophobic chain length and substituents on the central moieties influences the bioaffinity too. In particular, introducing a NMe2 group on the aromatic central core affords a highly efficient biocompatible fluorescent probe that can be taken up in cytoplasmic vesicles of HEp-2 cells (cells from epidermoid carcinoma larynx tissue). The photophysical behavior, high quantum yield, and stability open the way to the use of the OPE family as stains for cellular imaging analysis by fluorescence microscopy.

Anaerobic co-digestion of recalcitrant agricultural wastes: Characterizing of biochemical parameters of digestate and its impacts on soil ecosystem

Anaerobic digestion (AD) of organic wastes is a promising alternative to landfilling for reducing Greenhouse Gas Emission (GHG) and it is encouraged by current regulation in Europe. Biogas-AD produced, represents a useful source of green energy, while its by-product (digestate) is a waste, that needs to be safely disposal. The sustainability of anaerobic digestion plants partly depends on the management of their digestion residues. This study has been focused on the environmental and economic benefits of co-digest recalcitrant agricultural wastes such olive wastes and citrus pulp, in combination with livestock wastes, straw and cheese whey for biogas production. The aim of this work was to investigate the effects of two different bioenergy by-products on soil carbon stock, enzymes involved in nutrient cycling and microbial content. The two digestates were obtained from two plants differently fed: the first plant (Uliva) was powered with 60% of recalcitrant agricultural wastes, and 40% of livestock manure milk serum and maize silage. The second one (Fattoria) was fed with 40% of recalcitrant agricultural wastes and 60% of livestock manure, milk serum and maize silage. Each digestate, separated in liquid and solid fractions, was added to the soil at different concentrations. Our results evidenced that mixing and type of input feedstock affected the composition of digestates. Three months after treatments, our results showed that changes in soil chemical and biochemical characteristics depended on the source of digestate, the type of fraction and the concentration used. The mainly affected soil parameters were: Soil Organic Matter (SOM), Microbial Biomass Carbon (MBC), Fluorescein Diacetate Hydrolysis (FDA), Water Soluble Phenol (WSP) and Catalase (CAT) that can be used to assess the digestate agronomical feasibility. These results show that the agronomic quality of a digestate is strictly dependent on percentage and type of feedstocks that will be used to power the digester.

A Bodipy as a luminescent probe for detection of the G protein estrogen receptor (GPER)

We report the rational design, based on docking simulations, and synthesis of the first fluorescent and selective probe of GPER for bioimaging purposes and functional dissecting studies. It has been conceived as a Bodipy derivative and obtained by accessible and direct synthesis. Its optical properties have been measured in different solvents, showing insensitivity to their polarity. Its binding to GPER was achieved by competition assays with [3H]E2 and [5,6-3H] nicotinic acid in ER-negative and GPER-positive SkBr3 breast cancer cells. SkBr3 cells, transfected with a GPER expression vector containing a FLAG tag, were used to confirm that the fluorophore binds to GPER in a specific manner.

Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives

Summary A new class of molecules with a triptycene rigid core surrounded by six monosaccharide residues was synthesized. Hexakis(bromomethyl) substituted triptycene was converted into a six-armed triptycene azide (2,3,6,7,14,15-hexakis(azidomethyl)-9,10-dihydro-9,10-[1’,2’]benzenoanthracene). The key step of the synthesis was the cycloaddition of the azide to 2-propyn-1-yl β-D-gluco- or galactopyranosides. All products were isolated in good yields and were fully characterized.

Sulfenic acid – derived glycoconjugated disulfides and sulfoxides: a biological evaluation on human red blood cells

This article examines the effects of some glycoconjugated disulfides and sulfoxides on red blood cells (RBCs). Compounds under study show sugar units connected directly or through a benzene platform, and have been obtained following synthetic pathways based on the sulfenic acid chemistry. In order to evaluate the relationship between the structural features of the thioglycoconjugates under investigation and their potential biological activity, we were interested in assessing both the cytotoxicity and hemolytic activity produced on human RBCs by overnight exposition to the thioglycoconjugates. The absence of both cytotoxic effect and hemolysis produced by the tested compounds on erythrocytes supports the rational design of hemocompatible molecules for biomedical applications. GRAPHICAL ABSTRACT

Assessment of Antioxidant and Cytoprotective Potential of Jatropha (Jatropha curcas) Grown in Southern Italy

Jatropha (Jatropha curcas L.) is a plant native of Central and South America, but widely distributed in the wild or semi-cultivated areas in Africa, India, and South East Asia. Although studies are available in literature on the polyphenolic content and bioactivity of Jatropha curcas L., no information is currently available on plants grown in pedoclimatic and soil conditions different from the autochthon regions. The aim of the present work was to characterize the antioxidant system developed by the plant under a new growing condition and to evaluate the polyphenol amount in a methanolic extract of leaves. Along with these analyses we have also tested the antioxidant and cytoprotective activities on lymphocytes. RP-HPLC-DAD analysis of flavonoids revealed a chromatographic profile dominated by the presence of flavone C-glucosydes. Vitexin is the most abundant identified compound followed by vicenin-2, stellarin-2, rhoifolin, and traces of isovitexin and isorhoifolin. Methanolic extract had high scavenging activity in all antioxidant assays tested and cytoprotective activity on lymphocytes exposed to tertz-buthylhydroperoxide. The results highlighted a well-defined mechanism of adaptation of the plant and a significant content of secondary metabolites with antioxidant properties, which are of interest for their potential uses, especially as a rich source of biologically active products.

Pyrimidine-derived disulfides as potential antimicrobial agents: synthesis and evaluation in vitro

Antibiotic resistance is a worldwide problem. The synthesis and evaluation of new antimicrobial compounds, without cytotoxicity against human cells, are highly desired. In this paper, the preparation of a class of pyrimidine-derived disulfides is described. Sulfenic acids were generated from suitable precursors and used as reactive intermediates that condensed with the thiol function of thiocytosine. An introductory study on the antimicrobial activity of this disulfide family is reported. Three family components, that revealed no cytotoxicity against human erythrocytes, exhibited inhibitory activity against Gram-positive Staphylococcus aureus. GRAPHICAL ABSTRACT