Due to climate change and the consequent rise in grape pH, there is often the necessity of acidifying musts or wines during winemaking. In this study, the effect of early (on musts, during fermentation) and late (on wines, after the end of the fermentation) acidification was evaluated. The experimental design consisted of the preparation of seven wines from the same batch of grapes fermented in a first tank at the original pH of 3.2 and two other tanks in which the pH was adjusted to 3.5 (3.5W) and 3.9 (3.9W). On the third day of fermentation, and one week after the end of the fermentation–maceration process, aliquots of both 3.5W and 3.9W were treated to lower pH to thus obtain four more wines. After one year of aging, wines treated so as to reach a 3.2 pH significantly differed from the control wine in terms of contents of acetaldehyde, tannins reactive towards proteins and polymeric pigments. Differences were more conspicuous when acidification was carried out after the end of the fermentation–maceration process. Data highlight that the timing of acidification has a significant effect on polymerization reactions typically occurring during wine aging.
Abstract Butanolic extracts of the Mediterranean sponge Aplysina (= Verongia ) cavernicola have given, by reverse‐phase HPLC, the antibacterial quinols (±)‐3‐bromoverongiaquinol (= (±)‐3‐bromo‐1‐hydroxy‐4‐oxo‐2,5‐cyclohexadine‐1‐acetamide; 1d) and (±)‐3‐bromo‐5‐chloroverongiaquinol (= (±)‐3‐bromo‐5‐chloro‐1‐hydroxy‐4‐oxo‐2,5‐cyclohexadine‐1‐acetamide; 1c ) besides the products of their formal cyclization 5‐chlorohexadiene‐1‐acetamide; 1c ) besides the products of their formal cyclization 5‐chlorocavernicolin (= 5‐cloro‐3,3a,7,7aβ‐tetrahydro‐3aβ‐hydroxy‐2,6(1 H )‐indoledione; 6) , the C(7)‐epimerizing 7β‐bromo‐5‐chlorocavernicolin (=7 β‐bromo‐5‐chloro‐3,3a,7,7aβ‐tetrahydro‐3aβ‐hydroxy‐2,6( 1H )‐indoledione; 4a and 7α‐bromo‐5‐chlorocavernicolin (4b) , and the C(7)‐epimerizing 5‐bromo‐7β‐chlorocavernicolin ( = 5‐bromo‐7β‐chloro‐3,3a,7,7aβ‐tetrahydro‐3aβ‐hydroxy‐2,6(1H)‐indoledione; 5a) and 5‐bromo‐7α‐chlorocavernicolin (5b) . The latter four were isolated as mixtures of C(7)‐epimerizing monoacetates 4a′/4b′ and 5a′/5b′. Both 1 and 1c proved to be racemic from NMR examination of their esterification products with (–)‐methyl‐oxyacetic acid, whilst 6 had a ca . 6% enantiomeric purity as shown by a 1 H‐NMR study of its monoacetate 6′ in the presence of a chiral shift reagent. These chiroptical data of the first chiral quinols from the Verongida and of 6 suggest phenol oxidative routes from tyrosine precursors for their formation. In view of their bioactivities, 1d and 1c have been synthesized from ( p ‐hydroxyphenyl)acetic acid byt phenol oxidative routes.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydroxyicosatetraenoic, Hydroxyicosapentaenoic, Hydroxydocosapentaenoic, and Hydroxydocosahexaenoic Acids from the Sponge Echinochalina mollis of the Coral SeaAntonio Guerriero, Michele D'Ambrosio, Francesco Pietra, Olivier Ribes, and Daniel DuhetCite this: J. Nat. Prod. 1990, 53, 1, 57–61Publication Date (Print):January 1, 1990Publication History Published online1 July 2004Published inissue 1 January 1990https://pubs.acs.org/doi/10.1021/np50067a006https://doi.org/10.1021/np50067a006research-articleACS PublicationsRequest reuse permissionsArticle Views258Altmetric-Citations12LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Abstract The green seaweed Caulerpa taxifolia (V AHL ) C. A GARDH (Caulerpales), which, after its recent accidental introduction, is growing in the region of Cap Martin much more vigorously than in the tropics, is shown to contain the known sesquiterpenic toxins caulerpenyne ( 1 ) – in larger amounts than in tropical Caulerpales – and oxytoxin 1 ( 2 ). Novel, potentially toxic products isolated in small amounts from this seaweed include the sesquiterpenes taxifolial A ( = (5 E )‐6,10‐dimethyl‐2‐[( E )2‐oxoethylidene]undeca‐5,9‐dien‐7‐ yne‐1,3‐diyl diacetate; 3 ), taxifolial B (= (1 E ,6 E ,10 E )‐3‐[( Z )‐acetoxymethylidene]‐7, 11‐dimethyl‐12‐oxododeca‐1,6,10‐trien‐8‐yne‐1,4‐diyl diacetate; 4 ), 10,11‐epoxycaulerpenyne ( = (1 E ,6 E )‐3‐[( Z )‐acetoxymethylidene]‐10,11‐epoxy‐7, 11‐dimethyldodeca‐1,6‐dien‐8‐yne‐1,4‐diyl diacetate; 1:1 diastereoisomer mixture; 5 ), and taxifolial C ( = (2 Z ,6 E )‐3‐formyl‐7,11‐dimethyldodeca‐2,6,10‐trien‐8‐yne‐1,1, 4‐triyl triacetate; 6 ), besides, as the first example of a monoterpene from the Caulerpales, taxifolial D ( = (2 Z )‐3,7‐dimethylocta‐2, 6‐dien‐4‐ynal; 7 ).
Caulerpa taxifolia (Vahl) C. Agardh (Ulvophyceae, Caulerpales) is an algae of tropical origin that was accidentally introduced into the Mediterranean in 1984. Caulerpenyne (Cau) is the major metabolite present in Caulerpa taxifolia. This metabolite has previously been shown to be cytotoxic against cell lines in culture as in KB cells and fibroblasts from hamsters. Cau along with 6 other drugs representative of the major classes of anticancer products was tested against 8 cancer cell lines of human origin. Cau demonstrated growth-inhibitory effects in all cases with some variability between cell lines; this inter-cell variability was, however, less marked than that observed with the anticancer drug tested. Cells of colorectal cancer origin were the most sensitive to the presence of Cau with IC50 values of 6.1 and 7.7 microM. Increasing the duration of contact between Cau and the cells from 75 min to 29.5 hr did not improve the cytotoxic efficacy of this compound. When Cau was pre-incubated in the culture medium for from 7 to 83 min before being exposed to CAL 27 cells (head and neck cancer origin), there was a constant loss of cytostatic action of Cau as a function of Cau pre-incubation time. As the bovine serum albumin concentration increased in the culture medium, the concentration-response curves showed a constant shift towards the right, indicating a loss of cytostatic activity of Cau. In the presence of Cau, cells in culture clearly exhibited an early and marked shift into S phase followed by a blockade into the premitotic G2 M phase. Possible targets for CAU remain to be identified. Cau needs to be tested on tumor bearing animals to confirm this promising antiproliferative activity.
Abstract Funicolides A–C ( 1–3 ), D ( 5 ), and E ( 7 ) and 7‐epifunicolide A ( 4 ), new 5,8(17)‐diunsaturated briarane diterpenes, as well as the known analogue brianthein W ( 6 ), were isolated from the pennatulacean coral Funiculina quadrangularis (P ALLAS , 1766) collected in the Tuscan archipelago. Easy degradation under oxidative and/or basic conditions served to assign the ester groups at C(2) or C(14), while revealing bis‐allylic reactivity at C(7) with formation of 16‐nortaxane derivatives.
