Academic literature on the topic 'C13-norisoprenoids'

BACKGROUND: Monoterpenes and C13-norisoprenoids are key terpenoid compounds for wine aroma. The enzyme encoded by VviDXS1 participates in terpenoid biosynthesis in grapevine fruits and gain-of-function mutations in this gene lead to characteristic muscat aroma. OBJECTIVE: To assess for VviDXS1 contribution to aroma variation in Northwestern Iberian wine cultivars, we resequenced this gene in 111 cultivars and compared grape juice terpenic composition in 12 of them. METHODS: VviDXS1 was capture-targeted for resequencing with Illumina paired-end reads, SAMtools was used for variant calling and gene haplotypes were reconstructed with PHASE. Monoterpenes and C13-norisoprenoids were quantified in free and glycosidically-bound forms from grape juice by gas chromatography-mass spectrometry. RESULTS: Terpenic composition discriminated between muscat, terpenic and neutral profiles across cultivars. While the terpenic profile of Loureira and Albariño white cultivars was not associated with muscat-like mutations, Albariño carries a V34L substitution in VviDXS1 that is also present in other aromatic cultivars and was not reported before. Tempranillo and Cabernet Sauvignon red cultivars accumulated higher levels of C13-norisoprenoids, which was not associated with specific variation in VviDXS1. CONCLUSIONS: Apart from the uncharacterized substitution present in Albariño, findings suggest that terpenoid pathway-related genes other than VviDXS1 could contribute to the aromatic attributes of these cultivars.

The fruit of Averrhoa carambola L. (Oxalidaceae), commonly known as star fruit or carambola, is popular in tropical and subtropical regions. Carotenoid-derived components, mainly C13- and C15-norisoprenoids, contribute greatly to the flavor of star fruit. Previously reported norisoprenoids were tentatively identified by GC-MS analysis after enzymatic hydrolysis. To gain accurate information about glycosidically bound flavor precursors in star fruit, a phytochemical study was conducted, which led to the isolation of 16 carotenoid derivatives—One new C13-norisoprenoid glucoside, (5R,6S,7E,9R)-5,6,9-trihydroxy-7-megastigmene 9-O-β-d-glucoside (1); one new C15-norisoprenoid, (6S,7E,10S)-Δ9,15-10-hydroxyabscisic alcohol (11); and 14 known ones, of which 12 were in glucoside form. The structures of the two new compounds were elucidated on the basis of extensive spectroscopic data analysis and chemical reaction. Compound 11 was a rare C15-norisoprenoid with a double bond between C-9 and C-15, and its possible biogenetic pathway was proposed. The known compounds were identified by comparison of their mass and nuclear magnetic resonance (NMR) data with those reported in the literature. The structure identification of one new (1) and seven known (3–7, 9, and 10) C13-norisoprenoid glucosides from the genus Averrhoa for the first time enriches the knowledge of carotenoid-derived flavor precursors in star fruit.

Background: Rootstock is a viticultural practice used to combat the devastating Phylloxera vitifoliae (Fitch). Additionally, it is well-known that wine aroma composition depends mainly on variety, viticulture management and winemaking; therefore, rootstocks can affect to berry quality. This study evaluated the influence of nine rootstocks (110R, SO4, 196-17C, Riparia G, 161-49C, 420A, Gravesac, 3309C and 41B) on volatile composition of Albariño wine in two consecutive vintages. Material and Methods: Volatile compounds belonging to eight groups (alcohols, C6-compounds, ethyl esters+acetates, terpenes + C13-norisoprenoids, volatile phenols, volatile acids, lactones and carbonyl compounds) were determined in Albariño wines by GC–MS, during 2009 and 2010 vintages. Results: Rootstock 110R had a positive influence on Albariño wines, increasing total volatile concentration, due mainly to 2-phenylethanol, decanoic and hexanoic acids, ethyl esters and acetates, and C13-norisoprenoids. However, the higher contribution of volatile fatty acids to Albariño wine was shown when grapevines were grafted onto SO4. Conclusions: This work provides new information about the impact of rootstocks on Albariño wine volatile composition, where 110R had a positive influence on Albariño wines under the edaphoclimatic conditions of Salnés Valley (Galicia, Spain).

Free and glycosidically-bound aromatic characterization of 21 minority red grapevine varieties was carried out, along three consecutive vintages, using solid phase microextraction followed by gas chromatography-mass spectrometry methodology (SPME-GC-MS). The two main study aims were to evaluate the possibility of aromatically differentiated varieties based on their origin and to test the aromatic profile for being used as a chemotaxonomic tool. Based on the results obtained in this research, it would be also interesting to verify in future studies if this varietal diversity could translate into a diversification of quality products in the current globalized wine market. A volatile profile was established grouping aroma compounds into thirteen families: acids, alcohols, esters, C6 compounds, thiols, ketones, aldehydes, phenols, terpenes, C13-norisoprenoids, lactones, polycyclic aromatic hydrocarbons (PAHs), and sesquiterpenes. Significant differences were found among varieties for esters, phenols, terpenes, and total compounds in the free fraction and for alcohols, acids, C6 compounds, C13-norisoprenoids, terpenes, sesquiterpenes, and total compounds in the glycosidically-bound fraction. Subtle differentiation between different groups of varieties with common genetic origin was achieved by free aromatic profile (PCA) component analysis. Nevertheless, more in-depth studies are considered necessary to confirm the usefulness of the aromatic profile as a chemotaxonomic tool.

Doutoramento em Química
Vitis vinifera L., the most widely cultivated fruit crop in the world, was the starting point for the development of this PhD thesis. This subject was exploited following on two actual trends: i) the development of rapid, simple, and high sensitive methodologies with minimal sample handling; and ii) the valuation of natural products as a source of compounds with potential health benefits. The target group of compounds under study were the volatile terpenoids (mono and sesquiterpenoids) and C13 norisoprenoids, since they may present biological impact, either from the sensorial point of view, as regards to the wine aroma, or by the beneficial properties for the human health. Two novel methodologies for quantification of C13 norisoprenoids in wines were developed. The first methodology, a rapid method, was based on the headspace solid-phase microextraction combined with gas chromatography-quadrupole mass spectrometry operating at selected ion monitoring mode (HS-SPME/GC-qMS-SIM), using GC conditions that allowed obtaining a C13 norisoprenoid volatile signature. It does not require any pre-treatment of the sample, and the C13 norisoprenoid composition of the wine was evaluated based on the chromatographic profile and specific m/z fragments, without complete chromatographic separation of its components. The second methodology, used as reference method, was based on the HS-SPME/GC-qMS-SIM, allowing the GC conditions for an adequate chromatographic resolution of wine components. For quantification purposes, external calibration curves were constructed with β-ionone, with regression coefficient (r2) of 0.9968 (RSD 12.51 %) and 0.9940 (RSD of 1.08 %) for the rapid method and for the reference method, respectively. Low detection limits (1.57 and 1.10 μg L-1) were observed. These methodologies were applied to seventeen white and red table wines. Two vitispirane isomers (158-1529 L-1) and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) (6.42-39.45 μg L-1) were quantified. The data obtained for vitispirane isomers and TDN using the two methods were highly correlated (r2 of 0.9756 and 0.9630, respectively). A rapid methodology for the establishment of the varietal volatile profile of Vitis vinifera L. cv. 'Fernão-Pires' (FP) white wines by headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (HS-SPME/GCxGC-TOFMS) was developed. Monovarietal wines from different harvests, Appellations, and producers were analysed. The study was focused on the volatiles that seem to be significant to the varietal character, such as mono and sesquiterpenic compounds, and C13 norisoprenoids. Two-dimensional chromatographic spaces containing the varietal compounds using the m/z fragments 93, 121, 161, 175 and 204 were established as follows: 1tR = 255-575 s, 2tR = 0,424-1,840 s, for monoterpenoids, 1tR = 555-685 s, 2tR = 0,528-0,856 s, for C13 norisoprenoids, and 1tR = 695-950 s, 2tR = 0,520-0,960 s, for sesquiterpenic compounds. For the three chemical groups under study, from a total of 170 compounds, 45 were determined in all wines, allowing defining the "varietal volatile profile" of FP wine. Among these compounds, 15 were detected for the first time in FP wines. This study proposes a HS-SPME/GCxGC-TOFMS based methodology combined with classification-reference sample to be used for rapid assessment of varietal volatile profile of wines. This approach is very useful to eliminate the majority of the non-terpenic and non-C13 norisoprenic compounds, allowing the definition of a two-dimensional chromatographic space containing these compounds, simplifying the data compared to the original data, and reducing the time of analysis. The presence of sesquiterpenic compounds in Vitis vinifera L. related products, to which are assigned several biological properties, prompted us to investigate the antioxidant, antiproliferative and hepatoprotective activities of some sesquiterpenic compounds. Firstly, the antiradical capacity of trans,trans-farnesol, cis-nerolidol, α-humulene and guaiazulene was evaluated using chemical (DPPH• and hydroxyl radicals) and biological (Caco-2 cells) models. Guaiazulene (IC50= 0.73 mM) was the sesquiterpene with higher scavenger capacity against DPPH•, while trans,trans-farnesol (IC50= 1.81 mM) and cis-nerolidol (IC50= 1.48 mM) were more active towards hydroxyl radicals. All compounds, with the exception of α-humulene, at non-cytotoxic levels (≤ 1 mM), were able to protect Caco-2 cells from oxidative stress induced by tert-butyl hydroperoxide. The activity of the compounds under study was also evaluated as antiproliferative agents. Guaiazulene and cis-nerolidol were able to more effectively arrest the cell cycle in the S-phase than trans,trans-farnesol and α-humulene, being the last almost inactive. The relative hepatoprotection effect of fifteen sesquiterpenic compounds, presenting different chemical structures and commonly found in plants and plant-derived foods and beverages, was assessed. Endogenous lipid peroxidation and induced lipid peroxidation with tert-butyl hydroperoxide were evaluated in liver homogenates from Wistar rats. With the exception of α-humulene, all the sesquiterpenic compounds under study (1 mM) were effective in reducing the malonaldehyde levels in both endogenous and induced lipid peroxidation up to 35% and 70%, respectively. The developed 3D-QSAR models, relating the hepatoprotection activity with molecular properties, showed good fit (R2LOO > 0.819) with good prediction power (Q2 > 0.950 and SDEP < 2%) for both models. A network of effects associated with structural and chemical features of sesquiterpenic compounds such as shape, branching, symmetry, and presence of electronegative fragments, can modulate the hepatoprotective activity observed for these compounds. In conclusion, this study allowed the development of rapid and in-depth methods for the assessment of varietal volatile compounds that might have a positive impact on sensorial and health attributes related to Vitis vinifera L. These approaches can be extended to the analysis of other related food matrices, including grapes and musts, among others. In addition, the results of in vitro assays open a perspective for the promising use of the sesquiterpenic compounds, with similar chemical structures such as those studied in the present work, as antioxidants, hepatoprotective and antiproliferative agents, which meets the current challenges related to diseases of modern civilization.
O ponto de partida para o desenvolvimento da presente tese de doutoramento foi a Vitis vinifera L., que é o fruto mais cultivado a nível mundial. Este tema foi explorado tendo em consideração duas tendências atuais: i) o desenvolvimento de métodos rápidos, simples e com elevada sensibilidade, minimizando a manipulação da amostra e ii) a valorização de produtos naturais como fonte de compostos com potencial efeito benéfico para a saúde. Os compostos voláteis varietais, nomeadamente os mono e sesquiterpenóides e os norisoprenóides em C13, representam as famílias-alvo em estudo, uma vez que estes apresentam propriedades biológicas interessantes do ponto de vista sensorial, podendo contribuir para o aroma do vinho, e com potenciais benefícios para a saúde humana. Foram desenvolvidas duas novas metodologias para quantificação de compostos norisoprenóides em C13 em vinhos. A primeira metodologia, denominada de método rápido, baseou-se na combinação da microextracção em fase sólida em modo espaço de cabeça com cromatografia em fase gasosa-quadrupolo espectrometria de massa, em modo de monitorização de ião selecionado (HS-SPME/GC-qMS-SIM), utilizando condições cromatográficas que permitiram a obtenção do perfil volátil em norisoprenóides em C13.Este método não requer nenhum pré-tratamento da amostra e a composição do vinho em norisoprenóides em C13 é avaliada com base no perfil cromatográfico e fragmentos m/z específicos, sem a completa separação cromatográfica dos compostos. A segunda metodologia, usada como método de referência, foi muito similar à anterior. Neste caso, foram definidas as condições cromatográficas adequadas para que ocorresse separação dos vários componentes voláteis do vinho. Foram preparadas curvas de calibração externas usando a β-ionona como padrão, tendo-se obtido coeficientes de regressão (r2) de 0,9968 (RSD 12,51 %) e 0,9940 (RSD 1,08 %) para o método rápido e método de referência, respetivamente, com baixos limites de deteção (1,57e 1,10 μg L-1, respetivamente). Foram analisados 17 vinhos brancos e tintos, nos quais os isómeros do vitispirano e o TDN (1,1,6-trimetil-1,2-dihidronaftaleno) apresentaram concentrações entre 158 e1529 μg L-1 e entre 6,42 e 39,45 μg L-1, respetivamente. Os dados obtidos pelos dois métodos desenvolvidos para as concentrações dos isómeros do vitispirano e do TDN estão altamente correlacionados (r2 de 0,9756 e 0,9630, respetivamente). O perfil volátil varietal dos vinhos brancos da casta Portuguesa Vitis vinifera L. cv. Fernão-Pires (FP) foi estabelecido por um método rápido baseado na HS-SPME seguida de cromatografia em fase gasosa abrangente bidimensional (HS-SPME/GCxGC-TOFMS). Foram analisados vinhos monovarietais de diferentes colheitas, Regiões Demarcadas e produtores. O estudo focou-se em compostos voláteis que podem contribuir para o caráter varietal dos vinhos, nomeadamente os compostos mono e sesquiterpenóides e norisoprenóides em C13. Foram estabelecidos espaços cromatográficos bidimensionais específicos para as 3 famílias químicas em estudo, utilizando os fragmentos m/z 93, 121, 161, 175 e 204: para os monoterpenóides (1tR = 255-575 s, 2tR = 0,424-1,840 s), para os norisoprenóides em C13 (1tR = 555-685 s, 2tR = 0,528-0,856 s) e para os sesquiterpenóides (1tR = 695-950 s, 2tR = 0,520-0,960 s). Através da aplicação desta metodologia foram identificados um total de 170 compostos varietais em vinhos FP. Quarenta e cinco dos 170 compostos identificados são comuns a todos os vinhos da casta FP, permitindo assim estabelecer o perfil varietal para a casta. Destes, 15 compostos foram descritos pela primeira vez para esta casta. A combinação da metodologia de HS-SPME/GCxGC-TOFMS com o processamento de dados por utilização de uma amostra de classificação-referência permitiu a identificação rápida do perfil varietal de vinhos. Esta abordagem foi muito útil para eliminar a maioria dos compostos não-terpénicos e não norisoprenóides em C13 uma vez que: 1) permite definir um espaço cromatográfico bidimensional que contém estes compostos; 2) simplifica a complexidade e o número de dados obtidos comparativamente com os dados originais; e 3) reduz o tempo de análise. A presença de compostos sesquiterpénicos em produtos de Vitis vinifera L., aos quais são atribuídos vários efeitos benéficos para a saúde foi um fator motivador para o estudo de vários efeitos biológicos associados a estes compostos, nomeadamente das atividades antioxidante, antiproliferativa e hepatoprotetora. Inicialmente, foi avaliada a capacidade antioxidante do trans,trans-farnesol, cis-nerolidol, α-humuleno e o guaiazuleno usando modelos químicos (DPPH•, radical hidroxilo) e biológicos (células do tipo Caco-2). A avaliação da atividade anti-radicalar mostrou que o guaiazuleno inibe eficientemente o DPPH• (IC50 0,73), enquanto o trans,trans-farnesol (IC50= 1,81 mM) e o cis-nerolidol (IC50=1,48 mM) foram mais ativos em relação ao radical hidroxilo. A avaliação da atividade antioxidante em condições não citotóxicas (≤ 1 mM) revelou que todos os compostos, com exceção do α-humulene, foram capazes de proteger as células do tipo Caco-2 contra o stresse oxidativo induzido pelo hidroperóxido de tert-butilo. Os compostos foram também avaliados quanto à sua ação antiproliferativa. O guaiazuleno e o cis-nerolidol foram capazes de interromper o ciclo celular na fase da síntese do ADN mais efetivamente que o trans,trans-farnesol e o a-humuleno, sendo o último praticamente inativo. Foi ainda avaliada a capacidade hepatoprotetora relativa de 15 compostos sesquiterpenénicos com estruturas químicas diversas e comuns em plantas, alimentos e bebidas derivadas de plantas. A peroxidação lipídica endógena e a peroxidação lipídica induzida pelo hidroperóxido de tert-butilo foram avaliadas em homogeneizado de fígado de rato. Todos os compostos em estudo (1 mM), com exceção do a-humuleno, foram eficientes na redução dos níveis de malonaldeido na peroxidação lipídica endógena (35%) e na peroxidação induzida (70%). Foram desenvolvidos modelos 3D-QSAR, que relacionam a actividade hepatoprotetora com descritores moleculares, os quais apresentaram valores de calibração de R2LOO > 0,81) e poder de previsão de Q2LOO >0,97 e SDEP < 2%. Verifica-se que há uma rede de efeitos associados com caraterísticas estruturais e químicas dos compostos, tais como a configuração da molécula, maior ou menor grau de ramificação, simetria e a presença de fragmentos eletronegativos, que podem modular a atividade hepatoprotetora observada para estes compostos. Em conclusão, este estudo permitiu o desenvolvimento de métodos rápidos e que também fornecem informação detalhada sobre os compostos voláteis varietais, com potencial impacto positivo nas caraterísticas sensoriais e benéficas para a saúde relacionadas com a Vitis vinifera L. A aplicação deste tipo de metodologia pode ser alargada a outro tipo de matrizes, tais como uvas, mostos e muitos outros tipos de matrizes vegetais. Além disso, é ainda de realçar que os resultados bastante promissores dos ensaios in vitro abrem novas perspetivas ao uso dos compostos sesquiterpénicos, com estruturas químicas similares aos estudados no âmbito deste trabalho, como agentes antioxidantes, hepatoprotetores e antiproliferativos, o que está em linha com os desafios atuais relacionados com as doenças civilizacionais atuais.

L’arôme fruité des vins rouges est décrit par une large gamme de descripteurs, allant des fruits frais aux fruits mûrs et confiturés, en passant par les fruits confits jusqu'aux notes de pruneaux. La qualité fruitée d’un vin rouge est décrite par des notes de fruits rouges et noirs frais et confiturés. Bien que de nombreux attributs sensoriels soient mentionnés dans la littérature, les connaissances concernant l'arôme fruité qualitatif des vins rouges par rapport à leur composition chimique nécessitent encore d'être approfondies. Cependant, au moins une composante de cette expression fruitée est le reflet d’interactions perceptives impliquant en majorité des esters, mais également d’autres familles de molécules aromatiques. Au cours de ces dernières années, des changements dans l’expression fruitée des vins rouges de Bordeaux, caractérisés par l’apparition des notes de fruits cuits et secs, ont été rapportés et corrélés au changement climatique. Ainsi, les techniciens du secteur vitivinicole et les scientifiques, soulignent la nécessité de prendre des précautions pour préserver l’arôme fruité frais des vins rouges de Bordeaux. Pour cela, une des stratégies d’adaptation consiste à introduire dans le vignoble bordelais des cépages tardifs sélectionnés pour leur cycle végétatif potentiellement adapté aux futures conditions climatiques. Cette thèse propose une meilleure compréhension de l’arôme fruité des vins rouges issus de cépages de Bordeaux, mais également de cépages cultivés autour du bassin méditerranéen, zone simulant les futures conditions climatiques de Bordeaux. Grâce à des approches sensorielles, il a été montré que des vins rouges de Bordeaux présentaient des similitudes avec des vins rouges issus de cépages implantés dans le pourtour méditerranéen au niveau de leur caractère fruité. Une caractérisation approfondie de la contribution des composés volatils d’intérêt dans la perception des notes fruitées a été réalisée. Des interactions perceptives entre des composés de la famille des monoterpènes et des C13-norisoprénoïdes en mélange avec des esters, ont révélé l’importance de ces composés dans la perception des notes fruitées. Enfin, l’addition de ces composés volatils dans un vin rouge montre une diminution des notes de fruits cuits et une augmentation des notes de fruits noirs frais. Ces travaux de recherche ouvrent de nouvelles perspectives en œnologie telles que la maîtrise des teneurs de ces composés d’intérêt par diverses pratiques, mais également la potentielle introduction des « nouveaux » cépages dans l’assemblage des vins de Bordeaux
The fruity aroma of red wines is described by a wide range of descriptors, ranging from fresh fruits to ripe and jammy fruits, to candied fruits and prunes notes. The fruity quality of a red wine is characterized by notes of fresh and jammy red- and black-berry fruits. Although many sensory attributes are mentioned in the literature, knowledge regarding the qualitative fruity aroma of red wines in relation to their chemical composition still requires further investigation. However, at least one component of this fruity expression reflects perceptual interactions primarily involving esters, as well as other families of aromatic molecules. In recent years, changes in the fruity expression of Bordeaux red wines, characterized by the emergence of notes of cooked and dried fruits, have been reported and correlated with climate change. Thus, technicians in the wine industry and scientists emphasize the need to take precautions to preserve the fresh fruity aroma of Bordeaux red wines. One adaptation strategy involves introducing late-ripening grape varieties selected for their potentially suitable vegetative cycle under future climatic conditions into Bordeaux vineyard. This thesis proposes a better understanding of the fruity aroma of red wines derived from Bordeaux grape varieties, as well as those cultivated around the Mediterranean basin, simulating the future climatic conditions in Bordeaux. Through sensory approaches, it has been demonstrated that Bordeaux red wines exhibit similarities with red wines derived from grape varieties grown around the Mediterranean in terms of their fruity character. A detailed characterization of the contribution of volatile compounds of interest in the perception of fruity notes has been conducted. Perceptual interactions between compounds from the monoterpene and C13 norisoprenoid families, mixed with esters, have revealed the importance of these compounds in the perception of fruity notes. Finally, the addition of these volatile compounds to a red wine shows a decrease in cooked fruit notes and an increase in fresh black-berry fruits notes. This research opens up new perspectives in oenology, such as controlling the levels of these compounds of interest through various practices, as well as the potential introduction of "new" grape varieties into Bordeaux wine blends