Giovanna Oriente

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.

Diterpenes based on the dolabellane skeleton from dictyota dichotoma

From a variety of Dictyota dichotoma we have isolated, in addition to previously reported dolabellane (6-8) and perhydroazulene diterpenes (9,10), four new diterpenoids (2-5). Their structure have been elucidated by spectral analysis and chemical degradation. All the new dolabellane derivatives possess antimicrobial activity against gram-positive and gram-negative organisms.

Further perhydroazulene diterpenes from marine organisms

3 novel diterpenes,4–6, having the perhydroazulene skeleton already found in pachydictiol A (1) and dictyol A (2) and B (3), have been isolated from both the digestive gland of Aplysia depilans and algae of the family Dictyotaceae.

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.

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.

A quinone-hydroquinone couple from the Brown alga Cystoseira stricta

Abstract 2′ E ,6′ E )-2-(10′,11′-Dihydroxygeranylgeranyl)-6-methylquinol and 2′ E ,6′ E )-2(10′,11′-dihydroxyeranylgeranyl)-6-methyl-1,4-benzoquinone have been isolated from the brown alga Cystoseira stricta . The structures of the new algal metabolites have been elucidated by spectral analysis and chemical degradation.

Novel acyclic diterpenes from the brown alga Cystoseira crinita

Abstract Three acyclic diterpenes have been isolated from the brown alga Cystoseira crinita and characterized as (2 E ,10 E )-1,6-dihydroxy-7-methylene-13-keto-3,11,15-trimethylhexadeca-2,10,14-triene, (2 E ,5 E ,10 E )-1,7-dihydroxy-13-keto-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetracne and (2 E , 1O E )-1-hydroxy-6,13-diketo-7-methylene-3,11,15-trimethylhexadeca-2,10,14-triene.

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.

Tetraprenyltoluquinol derivatives from the brown alga Cystoseira zosteroides

Abstract From the brown alga Cystoseira zosteroides five new tetraprenyltoluquinols have been isolated and their structures determined by spectral analysis.