Reattività di legami C-H in 2,2'-bipiridine promossa da metalli del gruppo del platino

2,2’-bipyridines constitute an old and widely studied class of ligands whose most common bonding mode is as N,N neutral chelating donors. In contrast, the so called "rollover cyclometallation" is a rare and particular behaviour which entails a C(3)-H bond activation. This reaction proceeds, in the case of platinum(II), with a variety of 6-substituted 2,2’-bipyridines. We report here that under strictly controlled conditions and starting from [Pt(DMSO)2(Me)2] the reaction occurs also with the unsubstituted 2,2’-bipyridine to give both mono- and dinuclear rollover complexes. The study was articulated as follows: 1) Synthesis of mononuclear "rollover" species [Pt(X)(N’,C(3))(L’)]. (X= Me, Cl; L’ = neutral ligand). 2) Activation of a second C-H bond: synthesis of homo- and hetero-dinuclear species, symmetric and not-symmetric. 3) Synthesis of unusual mono- and polinuclear hydrides: [Pt(H)(N’,C(3))(L’)] and [Pt(H)(N’,C(3))]n. 4) Protonation with acids to yield cationic species containing a zwitterionic bipy ligand. In addition, some results obtained in the course of the main study induced us to follow additional points: a) Sinthesis of hydrido complexes of platinum(II) with tridentate nitrogen ligands [Pt(H)(N,N,C)] (N,N,CH = 6-substituted 2,2’-bipy). b) Insertion of CO into the Pd-C(3) bond of a palladium "rollover" derivative to give derivatives of nicotinic acid. c) Study of the organometallic behaviour of 6,6’-diphenyl-2,2’-bipyridine. d) Synthesis of platinum(II) cyclometalated NHC carbene complexes

seasonal variation of essential oil in rosmarinus officinalis leaves in sardinia

Rosmarinus officinalis L. is an aromatic plant belonging to the Lamiaceae family widely distributed in the Mediterranean area. The interest on this species is related to the multiple uses of the plant as a food ingredient, in the pharmaceutical and cosmetic industries. The chemical composition of essential oil (EO) from 5 accessions of R. officinalis L., collected monthly through a full year in Sardinia, has been studied by gas chromatography (GC) and GC-mass spectrometry technique. The EO ranged from 0.29% to 0.89%. The qualitative determinations revealed the presence of 27 compounds belonging to 6 chemical groups (hydrocarbon monoterpene, alcohols, aldehydes, ketones, esters, hydrocarbon sesquiterpene). Overall the GC-flame ionization detector analysis showed the presence of 7 major compounds: α-pinene (26%-28%), camphene (5%-8%), 1,8-cineole (15%-25%), borneol (5%-11%), camphor (3%-12%), verbenone (6%-15%), and bornyl acetate (4%-7%). Chromatographic data were also subjected to a chemometric approach that evidenced discrimination of the samples according to the site of collection

Bentonite as a refining agent in waste cooking oils recycling: flash point, density and color evaluation

Clarification of waste recycled cooking oil (WCO) is very important in order to refine the intermediate regenerated base resulting from the previous steps. Bentonite has been historically employed as a filling material for oil refining filters due to its easy availability and its cheap price. In the present communication our early results from the filtration of degummed WCO through a pad of bentonite are presented. In particular, the variation of density, flash point and color have been monitored prior and after the filtration process and compared with samples of non-filtered WCO. An early classification of the bentonite employed has been conducted on the basis of FT-IR and XRD measurements

Geographical variation of the chemical composition in essential oils extracted from Sardinian Salvia verbenaca

: Salvia verbenaca is a perennial herbaceous plant well appreciated as medicinal herb which can be found in Mediterranean area, Europe, Africa and Asia. In this study, S. verbenaca flowers and leaves were collected in six different geographical areas of Sardinia (Italy). Information about the variation of the chemical composition of plants grown in different locations were obtained from gas chromatography analysis of the extracted essential oils. Gas chromatography analysis detected 33 compounds, which have been grouped in oxygenated monoterpenes, monoterpene hydrocarbons, sesquiterpenes and other compounds. The chemical composition of each group resulted significantly affected by sampling site in terms of geography and altitude. Concerning the geographical distribution of the detected chemicals, sesquiterpenes were found in considerable amount in three localities, monoterpenes hydrocarbons in two and other compounds were predominant only in one site. Regarding the altitude level, monoterpenes, sesquiterpenes and other compounds were predominant, respectively, at medium and medium-high altitude

Profiling of the Bioactive Compounds in Flowers, Leaves and Roots of Vinca sardoa

Vinca sardoa (Stern) Pignatti (Apocynaceae) is largely distributed in Sardinia where it is considered a typical endemism. Since the plant is used in traditional folk medicine, the aim of the present work was to identify and quantify the polyphenolic metabolites, due to the well-known importance of polyphenolic compounds, as well as to evaluate antioxidant activity in different parts of the plant. The compounds were identified and determined in the methanol extracts of leaves, flowers, and roots by developing different LC-MS/MS methods. The obtained data show that leaves possess the highest amount of polyphenols, in particular quinic acid (3401 mg/100 g), chlorogenic acid (1082 mg/100 g), caffeoylquinic acid isomer 1 (190 mg/100 g), and robinin (633 mg/100 g). Likewise, antioxidant tests showed that leaves possess the main radical scavenging activities in both ABTS (49.19 ± 3.41 μg/mL, 30.88 ± 3.04 μg/mL at time zero and after 50 min, respectively) and DPPH assays (223.97 ± 30.81 μg/mL, 109.52 ± 12.89 μg/mL at time zero and after 30 min, respectively). Taking into account that leaves differed most from flowers and roots in the content of caffeoylquinic acid and chlorogenic acid, of which antioxidant properties are widely recognized, it is reasonable to assume that these two compounds are involved in the differences described. The relationship between the high polyphenolic content and interesting antioxidant activities, justifies its use in ethnobotany and may be suggest a use of this specie, after removal of the alkaloid fraction, in the pharmaceutical, phytotherapy, and cosmetic industries

Identifying a Role of Red and White Wine Extracts in Counteracting Skin Aging: Effects of Antioxidants on Fibroblast Behavior

Dermal fibroblasts are the main actor in many proteins' secretion, including collagen, preserving skin function. Free radicals are involved in skin aging and damages involving different cellular components. The imbalance between reactive oxygen species (ROS) amount and natural antioxidant enzymes negatively affects skin homeostasis. Natural compounds have recently emerged as a potential anti-aging tool in tissue regeneration. In the present paper we evaluated the antioxidant activity of white and red wines, considering their probable use, as raw materials, for the formulation of cosmetic products with anti-aging properties. We studied a method that would allow the removal of the alcoholic fraction of wines and determined their composition by LC-MS analysis. We then tested the possible cytotoxic effects of red and white wines on fibroblasts by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay, and their antioxidant activity by the catalase activity test in stressing conditions. Finally, we evaluated their anti-aging potential through the beta-galactosidase colorimetric assay. Our results showed that wine extracts exhibit a remarkable antioxidant and anti-aging activity, especially on cells exposed to a marked stressful event. These properties could suggest their possible application as cosmetical products for skin regeneration

Propionibacteria as promising tools for the production of pro-bioactive scotta: a proof-of-concept study

Dairy propionibacteria are Gram positive Actinomycetota, routinely utilized as starters in Swiss type cheese making and highly appreciated for their probiotic properties and health promoting effects. In this work, within the frame of a circular economy approach, 47 Propionibacterium and Acidipropionibacterium spp. were isolated from goat cheese and milk, and ewe rumen liquor, and characterized in view of their possible utilization for the production of novel pro-bioactive food and feed on scotta, a lactose rich substrate and one of the main by-products of the dairy industry. The evaluation of the Minimum Inhibitory Concentration (MIC) of 13 among the most common antibiotics in clinical practice revealed a general susceptibility to ampicillin, gentamycin, streptomycin, vancomycin, chloramphenicol, and clindamycin while confirming a lower susceptibility to aminoglycosides and ciprofloxacin. Twenty-five isolates, that proved capable of lactose utilization as the sole carbon source, were then characterized for functional and biotechnological properties. Four of them, ascribed to Propionibacterium freudenreichii species, and harboring resistance to bile salts (growth at 0.7–1.56 mM of unconjugated bile salts), acid stress (>80% survival after 1 h at pH 2), osmostress (growth at up to 6.5% NaCl) and lyophilization (survival rate > 80%), were selected and inoculated in scotta. On this substrate the four isolates reached cell densities ranging from 8.11 ± 0.14 to 9.45 ± 0.06 Log CFU mL−1 and proved capable of producing different vitamin B9 vitamers after 72 h incubation at 30°C. In addition, the semi-quantitative analysis following the metabolomics profiling revealed a total production of cobalamin derivatives (vitamin B12) in the range 0.49–1.31 mg L−1, thus suggesting a full activity of the corresponding biosynthetic pathways, likely involving a complex interplay between folate cycle and methylation cycle required in vitamin B12 biosynthesis. These isolates appear interesting candidates for further ad-hoc investigation regarding the production of pro-bioactive scotta

Genetic and metabolite diversity of Sardinian populations of <i>Helichrysum italicum</i>

Background: Helichrysum italicum (Asteraceae) is a small shrub endemic to the Mediterranean Basin, growing in fragmented and diverse habitats. The species has attracted attention due to its secondary metabolite content, but little effort has as yet been dedicated to assessing the genetic and metabolite diversity present in these populations. Here, we describe the diversity of 50 H. italicum populations collected from a range of habitats in Sardinia. Methods: H. italicum plants were AFLP fingerprinted and the composition of their leaf essential oil characterized by GC-MS. The relationships between the genetic structure of the populations, soil, habitat and climatic variables and the essential oil chemotypes present were evaluated using Bayesian clustering, contingency analyses and AMOVA. Key results: The Sardinian germplasm could be partitioned into two AFLP-based clades. Populations collected from the southwestern region constituted a homogeneous group which remained virtually intact even at high levels of K. The second, much larger clade was more diverse. A positive correlation between genetic diversity and elevation suggested the action of natural purifying selection. Four main classes of compounds were identified among the essential oils, namely monoterpenes, oxygenated monoterpenes, sesquiterpenes and oxygenated sesquiterpenes. Oxygenated monoterpene levels were significantly correlated with the AFLP-based clade structure, suggesting a correspondence between gene pool and chemical diversity. Conclusions: The results suggest an association between chemotype, genetic diversity and collection location which is relevant for the planning of future collections aimed at identifying valuable sources of essential oil.</br

Complessi ciclometallati di Pt(II) e Pd(II) con la 6,6'- PH₂-2,2'-bipiridina

Proseguendo il nostro interesse sulla reattività di 2,2’-bipiridine con ioni di metalli nobili abbiamo sintetizzato e studiato la reattività di nuovi derivati di platino e palladio con la 6,6’-difenil-2,2’- bipiridina, anche per confrontarne le proprietà con quelle degli analoghi derivati della 6- fenil-2,2’-bipiridina, oggetto di notevole interesse per le proprietà in campo biomedico, fotochimico e fotofisico

Antiproliferative and proapoptotic effects of Inula viscosa extract on Burkitt lymphoma cell line.

Burkitt lymphoma is a very aggressive B-cell non-Hodgkin lymphoma. Although remarkable progress has been made in the therapeutic scenario for patients with Burkitt lymphoma, search and development of new effective anticancer agents to improve patient outcome and minimize toxicity has become an urgent issue. In this study, the antitumoral activity of Inula viscosa, a traditional herb obtained from plants collected on the Asinara Island, Italy, was evaluated in order to explore potential antineoplastic effects of its metabolites on Burkitt lymphoma. Raji human cell line was treated with increasing Inula viscosa extract concentration for cytotoxicity screening and subsequent establishment of cell cycle arrest and apoptosis. Moreover, gene expression profiles were performed to identify molecular mechanisms involved in the anticancer activities of this medical plant. The Inula viscosa extract exhibited powerful antiproliferative and cytotoxic activities on Raji cell line, showing a dose- and time-dependent decrease in cell viability, obtained by cell cycle arrest in the G2/M phase and an increase in cell apoptosis. The treatment with Inula viscosa caused downregulation of genes involved in cell cycle and proliferation (c-MYC, CCND1) and inhibition of cell apoptosis (BCL2, BCL2L1, BCL11A). The Inula viscosa extract causes strong anticancer effects on Burkitt lymphoma cell line. The molecular mechanisms underlying such antineoplastic activity are based on targeting and downregulation of genes involved in cell cycle and apoptosis. Our data suggest that Inula viscosa natural metabolites should be further exploited as potential antineoplastic agents against Burkitt lymphoma