Sebastiano Sciuto

Amino acids and low-molecular-weight carbohydrates of some marine red algae

Abstract Amino acids and low-MW carbohydrates of 18 red algae have been analyzed. Several non-protein amino acids have been identified, including pyrrolidine-2,5-dicarboxylic acid ( 3 c) and N -methylmethionine sulfoxide ( 5 ), new natural products, and 13 known compounds, citrulline, β-alanine, γ-aminobutyric acid, baikiain ( 1 ), pipecolic acid ( 2 ), domoic acid ( 3 a), kainic acid ( 3 b), azetidine-2-carboxylic acid ( 4 ), methionine sulfoxide taurine, N -methyltaurine, N,N -dimethyltaurine and N,N,N -trimethyltaurine. Sugars present were mainly floridoside, isofloridoside and mannoglyceric acid. Details of the structural elucidation of new compounds are also given.

Antiproliferative Activity of Methylated Analogues of E- and Z-Resveratrol

Abstract The stilbenoids E-resveratrol (E-3,5,4′-trihydroxystilbene, 1), E-3,5,4′-trimethoxystilbene (2), E-3,4,4′-trimethoxystilbene (3) and E-3,4′-dimethoxy-5-hydroxystilbene (4) were converted by photoisomerization to their corresponding Z-isomers 5D8. Compounds 1D8 were subjected to antiproliferative activity bioassays towards a set of four different human cancer cell lines, namely DU-145 (androgen not responsive human prostate tumor), LNCaP (androgen responsive human prostate tumor), M-14 (human melanoma) and KB (human mouth epidermoid carcinoma). The methylated analogues of 1 are more active than the natural lead in the majority of bioassays. The most active compound was Z-3,5,4′-trimethoxystilbene (6), which showed against DU-145 and LNCaP cells GI50 values close to those of the anticancer drug vinorelbine; 6 resulted more active than its E-isomer 2 towards DU-145, LNCaP and especially KB cell lines. A number of methylated Z-isomers displayed a higher activity than their E-isomers, but E-resveratrol (1) was more active than Z-resveratrol (5) towards all the tested cell lines.

A new betaxanthin from Glottiphyllum longum

Abstract The new betaxanthin (II) dopaxanthin was isolated from flowers of Glottiphyllum longum . Its structure was confirmed by chemical synthesis.

Use of fluorescence EEM to monitor the removal of emerging contaminants in full scale wastewater treatment plants

This study investigated the applicability of different techniques for fluorescence excitation/emission matrices data interpretations, including peak-picking method, fluorescence regional integration and PARAFAC modelling, to act as surrogates in predicting emerging trace organic compounds (ETOrCs) removal during conventional wastewater treatments that usually comprise primary and secondary treatments. Results showed that fluorescence indexes developed using alternative methodologies but indicative of a same dissolved organic matter component resulted in similar predictions of the removal of the target compounds. The peak index defined by the excitation/emission wavelength positions (λex/λem) 225/290nm and related to aromatic proteins and tyrosine-like fluorescence was determined to be a particularly suitable surrogate for monitoring ETOrCs that had very high removal rates (average removal >70%) (i.e., triclosan, caffeine and ibuprofen). The peak index defined by λex/λem=245/440nm and the PARAFAC component with wavelength of the maxima λex/λem=245, 350/450, both identified as humic-like fluorescence, were found remarkably well correlated with ETOrCs such as atenolol, naproxen and gemfibrozil that were moderately removed (51-70% average removal). Finally, the PARAFAC component with wavelength of the maxima λex/λem=<240, 315/380 identified as microbial humic-like fluorescence was the only index correlated with the removal of the antibiotic trimethoprim (average removal 68%).

Sterols of some red algae

Abstract The sterol composition of 17 red algae has been determined. Only C-27 sterols have been found in substantial amounts; details of the structural elucidation of liagosterol (cholesta-5,23-diene-3β,25-diol) are given. The possible taxonomic significance of the sterol distribution is briefly discussed.

The extracutaneous pigmentary system: evidence for the melanosynthesis in Amphibia and Reptilia liver

Abstract 1. 1. In vitro incorporations of [ 14 C] l -tyrosine and [ 14 C] l -DOPA into purified melanin, extracted from frog and turtle liver after incubation of surviving tissue and purified melanosomes were measured. 2. 2. The results show an incorporation of labelled precursors in melanin both in incubating tissue slices and incubating isolated melanosomes and that the radioactivity detected in purified melanin was not due to an adsorption or binding phenomenon of labelled tyrosine. 3. 3. We conclude that melanins occurring in the pigment cells of Amphibia and Reptilia liver originate from the melanosynthetic activity of Kupffer cells and that these pigment cells are to be considered as belonging to the extracutaneous pigmentary system.

Light control of amaranthin synthesis in isolated Amaranthus cotyledons

Abstract The effect of light on the amaranthin synthesis stimulated by exogenous precursors has been studied in isolated cotyledons of Amaranthus tricolor and A. caudatus . The results indicate that light acts at the level of the formation of the dihydropyridine moiety of the pigment.

Betanidin glucosylation in opuntia dillenii

Abstract In fruits of Opuntia dillenii 14C-labelled betanidin was incorporated into betanin (5-O-β- d -glucoside of betanidin). This result shows that glucosylation occurs late in the biosynthesis of the pigment and is possibly the last step.

Levels of chlorinated hydrocarbons in marine animals from the central Mediterranean

Abstract Concentrations of chlorinated hydrocarbons (DDT and metabolites, PCBs, aldrin, dieldrin, HCB and BHCs) have been determined in the tissues of five species of marine animals sampled in selected areas of the central Mediterranean.

Biosynthesis of amaranthin in Celosia plumosa

Abstract Seedlings of a yellow betaxanthin-producing variety of Celosia plumosa when fed with appropriate precursors are capable of synthesizing the red-violet pigment normally present in red varieties of the same species, namely amaranthin. Synthesis of amaranthin occurs in seedlings following administration of betanidin and betanin but much greater accumulation was observed after feeding cycloDOPA and its 5- O -β- d -glucoside. Possible pathways in the biosynthesis of amaranthin are discussed.