Elena Pini

Carotenoid Plasma Concentration, Immune Profile, and Plumage Ornamentation of Male Barn Swallows (Hirundo rustica)

Carotenoids exert immunomodulating, immunostimulating, and antioxidant actions in mammals and are major determinants of coloration in animals. Honest advertisement models of sexual selection propose that male ornaments, including coloration, are reliable indicators of male quality. Because of their simultaneous effects on male coloration and immunity, carotenoids might mediate the hypothesized relationship between the expression of epigamic coloration and parasitism in vertebrates. We analyzed the relationship between immune profile and concentration of lutein, the most abundant carotenoid in the plasma of male barn swallows (Hirundo rustica). Consistent with our predictions, lutein plasma concentration was negatively correlated with gamma‐globulin plasma levels and concentration of selected leukocyte types in peripheral blood, suggesting that, to exert immune function, carotenoids are taken up from plasma, thus becoming unavailable for epigamic signaling. The coloration of red feathers of the throat of adult males was positively related to plasma concentration of lutein, but not with immunologic variables, consistent with the idea that more brightly colored males do not pay a larger immunological cost for their coloration compared with less brightly colored males. Length of male tail ornaments, which is currently under directional sexual selection, was positively correlated with lutein plasma levels. In species where carotenoids limit immune function, demands for pigments for sexual signaling might compete with those for immunity, thus generating a mechanism that enforces honesty on the signal.

The chemical structure of the pigments in Ara macao plumage.

Parrots (Psittaciformes) harbor unusually bright, non-carotenoid, feather pigments. We successfully extracted and purified a sufficient quantity of pigment from the red plumage of the Scarlet Macaw (Ara macao) for a partial chemical analysis. The extracts were analyzed by HPLC coupled with UV-VIS and mass spectroscopy before and after total hydrogenation. We found at least four pigment components. We propose a linear polyenal structure comparable with the molecules tetradecahexenal, hexadecaheptenal, octadecaoctenal and eicosanonenal.

Carotenoids in bird plumage: the complement of red pigments in the plumage of wild and captive bullfinch (Pyrrhula pyrrhula)

We have studied the carotenoid pigments in the red plumage of male bullfinch (Pyrrhula pyrrhula) immediately following capture and after the completion of the moult in captivity under dietary control. Astaxanthin, adonirubin, and alpha-doradexanthin, as well as papilioeritrinone and canthaxanthin (in lower amounts) are in every case the dominant carotenoids in the plumage pigment of wild individuals. alpha-Doradexanthin is responsible for the reddish-rose colour, which captive individuals adopt after a diet consisting mainly of lutein as disposable carotenoid. The red pigmentation biogenesis of captive bullfinch is compared with those of other red pigmented Carduelinae in which male individuals usually lose the red colour in captivity, namely Carpodacus roseus, Carpodacus rubricilloides, Uragus sibiricus, Carduelis cannabina, Carduelis flammea, Loxia curvirostra and Pinicola enucleator.

Nanosuspension improves tretinoin photostability and delivery to the skin.

The aims of this work were to improve cutaneous targeting and photostability of tretinoin by using nanosuspension formulation. Tretinoin is a drug widely used in the topical treatment of various dermatological diseases. The tretinoin nanosuspension was prepared by precipitation method and then characterized by photo correlation spectroscopy for mean size and size distribution, and by transmission electron microscopy for morphological studies. An oil in water tretinoin nanoemulsion was also prepared and used as a control. Dermal and transdermal delivery of both tretinoin nanosuspension and nanoemulsion were tested in vitro by using Franz diffusion cells and newborn pig skin. Photodegradation studies were carried out by UV irradiation (1h, λ=366 nm) of the tretinoin nanosuspension in comparison with the nanoemulsion and a methanolic solution of the drug. During 8h percutaneous experiments, the nanosuspesion was able to localize the drug into the pig skin with a very low transdermal drug delivery, whereas the nanoemulsion greatly improved drug permeation. UV irradiation of the nanosuspension showed a great improvement of tretinoin stability in comparison with both controls. Overall results show that nanosuspension might be a useful formulation for improving tretinoin dermal delivery and stability.

Maltodextrin fast dissolving films for quercetin nanocrystal delivery. A feasibility study

The objective of this study was to evaluate the feasibility to prepare fast dissolving films as quercetin nanocrystal delivery systems, using maltodextrins as film forming material and glycerin as plasticizer, with the goal of enhancing quercetin oral bioavailability. Quercetin nanosuspensions were prepared using a high-pressure homogenizer, and then directly used to prepare the films by a casting method. Spectroscopic and calorimetric analysis evidenced that reduction of quercetin size at nanoscale and incorporation in maltodextrin films do not affect the solid state of the active ingredient. The loading of quercetin nanocrystals into the film determined a slight variation of film elasticity and ductility. Indeed, the elastic modulus of the loaded films resulted about a half of the placebo ones, while the elongation at break increased four folds. Free and film loaded quercetin nanocrystals showed a comparable dissolution rate, much higher than that of bulk quercetin.

Formulation strategy and evaluation of nanocrystal piroxicam orally disintegrating tablets manufacturing by freeze-drying.

Piroxicam (PRX) is a non-steroidal anti-inflammatory drug characterized by a poor water solubility and consequently by a low oral bioavailability. In this work, different nanocrystal orally disintegrating tablets (ODT) were prepared to enhance piroxicam dissolution rate and saturation solubility. PRX nanocrystals were prepared by means of high pressure homogenization technique using poloxamer 188 as stabilizer. Three different ODTs were prepared with the same nanosuspension using different excipients in order to study their effect on the PRX dissolution properties. PRX nanocrystal size and zeta potential were determined by photon correlation spectroscopy. Additional characterization of PRX nanocrystal ODT was carried out by infrared spectroscopy, X-ray powder diffractometry, differential scanning calorimetry. Dissolution study was performed in distilled water (pH 5.5) and compared with PRX coarse suspension ODT, PRX/poloxamer 188 physical mixture, bulk PRX samples and a PRX commercial ODT. All PRX nanocrystal ODT formulations showed a higher drug dissolution rate than coarse PRX ODT. PRX nanocrystal ODT prepared using gelatin or croscarmellose as excipient showed a higher PRX dissolution rate compared with the commercial formulation and ODT prepared using xanthan gum. Overall results confirmed that improved PRX dissolution rate is due to the increased surface-to-volume ratio due to the nanosized drug particle but also revealed the important role of different excipients used.

Carotenoids in bird plumage: the complement of yellow and red pigments in true woodpeckers (Picinae)

Woodpeckers typically have colorful, multipatterned plumages. To understand the biochemical basis of the species-specificity of coloration in woodpecker, the complement of carotenoids in the red and yellow feathers of 13 species of true woodpeckers (Picinae) was determined. The pigments were extracted under mild conditions. The extracts were analyzed by HPLC coupled with mass and UV-vis spectroscopy. The 4-oxo-carotenoids (particularly astaxanthin and α-doradexanthin) were responsible for the red colors in these species. Picofulvins were the dominant carotenoids in the yellow feathers of some species. Unmodified lutein, zeaxanthin and β-cryptoxanthin were responsible for the yellow and green colors in other species. Tentative molecular structures for the three main picofulvins are proposed based on the results of spectroscopy (UV-vis, MS) and chemical tests.

[4+2] and [2+2] cycloaddition reactions of 1-(4-methylphenyl) and 1-benzyl-1,3-diaza-1,3-butadienes with ketenes

Abstract [4+2] and [2+2] cycloaddition reactions of 1-(4-methylphenyl) and 1-benzyl-1,3-diaza-1,3-butadienes with monophenyl, diphenyl, monochloro and ethoxycarbonylketenes are described. The mechanism of these reactions is also discussed.

Isothiazoles. Part 12: Isothiazolylphosphonates, a new class of isothiazole dioxides

Abstract We describe a mild and efficient method to prepare 3-amino-4,5-dihydro-5-isothiazolylphosphonates from 3-amino-5-unsubstituted isothiazole dioxides. Starting from 3-amino-5-bromo-isothiazole dioxides either 3-amino-5-isothiazolylphosphonates or 5-diethoxyphosphoryl-4,5-dihydro-4-isothiazolylphosphonates were prepared. Isothiazolylphosphonates represent a new class of isothiazole dioxides. Some preliminary investigations on the reactivity with 1,3-dipoles were reported.

Base promoted reactions of 4-pentynones

Different substituted furans are syntetised by cyclization of 4-pentynones using potassium tert-butoxide in DMF. A different reaction pattern is observed when the same compounds were treated with sodium methoxide in MeOH. A new approach to 2-propargyl-carbonyl compounds is also proposed.