Environmental effect on essential oil composition of Aloysia citriodora from Corrientes (Argentina)

Lemon verbena (Aloysia citriodora Palau) is indigenous to South America and was introduced into Europe. It is cultivated mainly due to the lemon-like aroma emitted from its leaves, which are utilized for the preparation of herbal tea reputed to have antispasmodic, antipyretic, sedative and digestive properties. In this work we introduce the enantiomeric distribution of sabinene and limonene by bidimensional gas chromatography (chiral GC-GC) as a genuine quantitative parameter in order to improve the knowledge so far available on A. citriodora oil. Multivariate analysis afforded information on the similarities and differences of wild and cultivated A. citriodora populations during different seasons in the same environmental conditions. The results indicated that it was possible to discard the environmental and seasonal effect on the chemical composition of A. citriodora for wild and cultivated materials belonging to the same genetic origin.

Environmental Effect on Essential Oil Composition of Aloysia citriodora from Corrientes (Argentina)

Lemon verbena ( Aloysia citriodora Palau) is indigenous to South America and was introduced into Europe. It is cultivated mainly due to the lemon-like aroma emitted from its leaves, which are utilized for the preparation of herbal tea reputed to have antispasmodic, antipyretic, sedative and digestive properties. In this work we introduce the enantiomeric distribution of sabinene and limonene by bidimensional gas chromatography (chiral GC-GC) as a genuine quantitative parameter in order to improve the knowledge so far available on A. citriodora oil. Multivariate analysis afforded information on the similarities and differences of wild and cultivated A. citriodora populations during different seasons in the same environmental conditions. The results indicated that it was possible to discard the environmental and seasonal effect on the chemical composition of A. citriodora for wild and cultivated materials belonging to the same genetic origin.

Neutralizing Effects of Nectandra angustifolia Extracts against Bothrops neuwiedi Snake Venom

Leaves extracts and essential oil of Nectandra angustifolia were explored for the first time for neutralization of Bothrops neuwiedi diporus snake venom. The ethanol extract was the most active and inhibited both venom activities (hemolytic and coagulant), while the oil was only active on the coagulant activity. These observations confirmed that certain medicinal plants from Corrientes and Chaco Provinces possess significant snake venom neutralizing capacity and need further examination for their active constituents. Analysis by GC and GC-MS of the essential oil and the enantiomeric excess found for α-pinene, β-pinene and limonene allowed a better characterization of this species.

Neutralizing effects of Nectandra angustifolia extracts against Bothrops neuwiedi snake venom

Leaves extracts and essential oil of Nectandra angustifolia were explored for the first time for neutralization of Bothrops neuwiedi diporus snake venom. The ethanol extract was the most active and inhibited both venom activities (hemolytic and coagulant), while the oil was only active on the coagulant activity. These observations confirmed that certain medicinal plants from Corrientes and Chaco Provinces possess significant snake venom neutralizing capacity and need further examination for their active constituents. Analysis by GC and GC-MS of the essential oil and the enantiomeric excess found for alpha-pinene, beta-pinene and limonene allowed a better characterization of this species.

Effect of Saccharomyces cerevisiae inoculum size on wine fermentation aroma compounds and its relation with assimilable nitrogen content

Different commercial Saccharomyces cerevisiae strains have been applied at the winemaking level, trying to establish a dominant population of selected strains from the start of fermentation and ensuring the complete consumption of sugars. Although a large population of active yeast cells can be introduced in the inoculated wines, resulting in a complete fermentation, this does not necessarily mean an improvement of the sensory characteristics of the wines. The impact of the size of the inocula in wine quality parameters has been very little studied, and in no case the nutrient balance of the grape must utilized was taken into account. In this work we present results obtained for wine aroma compounds at three inoculum levels (10(4), 10(5) and 10(6)cells/mL), and two different yeast assimilable nitrogen (YAN) in a white grape must, using two S. cerevisiae strains commonly used for winemaking. A significant effect in the final concentrations of higher alcohols, esters, fatty acids, free monoterpenes and lactones was attributed to the size of inoculum in both strains but not in an easily predictable way. However, a consistent increase of desired aroma compounds (esters, lactones and free monoterpenes), and a decrease of less desired compounds for white wine (higher alcohols and medium chain fatty acids), was shown at inoculum sizes of 10(5)cells/mL for both strains in real winemaking conditions. In a discriminant analysis six aroma compounds discriminate the three inoculum sizes for all wine samples: 1,8-terpine, hodiol I (trans-3,7-dimethyl-1,5-octadiene-3,7-diol), isobutyl alcohol, iso C4 acid, ethyl C6 ester and C8 acid.

The effect of bacterial strain and aging on the secondary volatile metabolites produced during malolactic fermentation of tannat red wine

During malolactic fermentation (MLF), lactic acid bacteria influence aroma and flavor of wines by the production of volatile metabolites and the modification of aroma compounds derived from grapes and yeasts. In an effort to isolate these bacteria properties as advantages for winemaking, this study aimed to assess the relative contribution of two aspects: the effects of lactic acid bacteria activity on the volatiles compounds in Tannat wines and the consequences of aging in bottle on aroma compounds produced during MLF. To our knowledge, this is the first report related to the effect of wine aging in bottle on the aroma chemical compounds produced by MLF. Solid phase extraction complemented with chromatographic techniques was used to study the wine aroma compounds. A sensory evaluation of the wines was also performed through descriptive methods. We demonstrated modifications in the concentration of acetates, ethyl esters, and other secondary metabolites during MLF. Major sensorial differences between wines that had undergone MLF were also noted. In addition, some modifications detected in the composition of Tannat wines as a consequence of the aging in bottle contributed to the change in differences between wines with and without MLF and furthermore between strains. These changes probably influence its fruity character.

Chemical Variability of Essential Oils of Lippia Alba (Miller) N. E. Brown Growing in Costa Rica and Argentina

Lippia alba (Verbenaceae) is a shrub whose essential oil has important biological, pharmacological, and aromatizing properties. The species has a natural range from Central America to Argentina, being cultivated for its commercial value in Brazil, Argentina and Guatemala, and has been introduced into India and Spain. To reach the economic potential of the plant, the present study was aimed at evaluating L. alba for different chemotypes. The composition of the essential oil from two native populations of L. alba, collected from Argentina and two accessions from Costa Rica, were screened by GC and GC-MS. The results obtained led us to adopt the concept of a biodistribution map, as was proposed previously for the species, representing an approach to the natural biological distribution of the species in America based on the chemotypes described and their geographical distribution. Moreover, the biodiversity reported for the species (seven of eight chemotypes described for L. alba are present in Argentina) suggests the southern region of South America as the centre of distribution for L. alba.

Chemical variability of essential oils of Lippia alba (Miller) N. E. Brown growing in Costa Rica and Argentina

Lippia alba (Verbenaceae) is a shrub whose essential oil has important biological, pharmacological, and aromatizing properties. The species has a natural range from Central America to Argentina, being cultivated for its commercial value in Brazil, Argentina and Guatemala, and has been introduced into India and Spain. To reach the economic potential of the plant, the present study was aimed at evaluating L. alba for different chemotypes. The composition of the essential oil from two native populations of L. alba, collected from Argentina and two accessions from Costa Rica, were screened by GC and GC-MS. The results obtained led us to adopt the concept of a biodistribution map, as was proposed previously for the species, representing an approach to the natural biological distribution of the species in America based on the chemotypes described and their geographical distribution. Moreover, the biodiversity reported for the species (seven of eight chemotypes described for L. alba are present in Argentina) suggests the southern region of South America as the centre of distribution for L. alba.

Searching for Natural Bioactive Compounds in Four Baccharis species from Bolivia

The volatile oil composition of four Baccharis species ( Baccharis papilosa, B. polycephala, B. buxifolia, and B. convawyi) growing wild in Bolivia were studied by GC and GC/MS. The antimicrobial activity of the oils was determined by the agar diffusion and bioautography methods. Solvent extracts, polar and non-polar, of the same species were also tested for antimicrobial and antioxidant activities. Extracts from B. polycephala, B. papilosa and B. convawyi presented significant antioxidant activity, determined using the DPPH radical scavenging method, showing EC50 values of 4.74, 7.17 and 7.97 μg/mL, respectively. Screening for antimicrobial activity was conducted using the agar diffusion test. The most active extracts (% inhibition ≥ 50) were further examined by the dilution method. All the plant extracts studied showed higher antimicrobial activity against S. aureus (Gram-positive) than against E. coli and P. fluorescens (Gram-negative).

Terpenoids in Grapes and Wines: Origin and Micrometabolism during the Vinification Process

Terpenoids, which are typical components of the essential oils of flowers and fruits, are also present as free and glycosylated conjugates amongst the secondary metabolites of wine grape varieties of Vitis vinifera. Hence, when these compounds are present in wine, they are considered to originate from the grapes and not from fermentation. However, the biosynthesis of monoterpenes by Saccharomyces cerevisiae in the absence of grape derived precursors was shown recently to be of de novo origin in wine yeast strains. The contribution of yeast and bacterial fermentation metabolites to the aromatic profile of wine is well documented. However, the biotechnological application of this knowledge is still rather limited and often contradictory. Redox conditions, size of inoculums, temperatures of fermentation, osmotic pressure and the medium nutritional content can profoundly affect the profile of yeast and bacterial metabolites produced or their biotransformation capacity in wine. Results obtained in the last decades in relation to microbial micrometabolism of aroma compounds measured with more sophisticated GC-MS methods are discussed in relation to the known terpenoid biosynthetic pathways and wine composition. Further development of metabolic footprinting techniques for the discrimination of wine quality must be one of the main challenges for wine biotechnologists in the near future.

Determination of volatile phenols in red wines by dispersive liquid–liquid microextraction and gas chromatography–mass spectrometry detection

A new method was developed for analysing 4-ethylguaiacol and 4-ethylphenol in the aroma of red wines using dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry detection (GC-MS). Parameters such as extraction solvent, sample volume and disperser solvent were studied and optimised to obtain the best extraction results with the minimum interference from other substances, thus giving clean chromatograms. The response linearity was studied in the usual concentration ranges of analytes in wines (50-1500 microg/L). Repeatability and reproducibility of this method were lower than 5% for both volatile phenols. Limits of detection and limits of quantification were also determined, and the values found were 28 and 95 microg/L for 4-ethylguaiacol and 44 and 147 microg/L for 4-ethylphenol, respectively. This new method has been used for the determination of the volatile phenols concentration in different samples of Tannat wine affected by Brettanomyces contamination.

Aging effect on the pigment composition and color of Vitis vinifera L. Cv. Tannat wines. Contribution of the main pigment families to wine color

Red wines made from Vitis vinifera L. cv. Tannat grapes are known to possess high contents of tannins and intense color, features that are responsible for the originality of these wines. This work aimed to study the evolution of the pigment composition and CIELAB color parameters as Tannat wines become older, as well as to establish the contribution to wine color of the main pigment families. Tannat wines produced in Uruguay from grapes of the same vineyard in six consecutive vintages (1998-2003) and Tannat grapes of the 2003 harvest were analyzed by means of HPLC-DAD-MS and UV-vis spectrometric techniques. The correlations between the different pigment families and the CIELAB parameters revealed the importance of the variations of the percentage, found in anthocyanins and flavanol-anthocyanin acetaldehyde-mediated condensation products (decrease) and pyranoanthocyanins and direct condensation products (increase), in the modification of the color from purple-red hues to more orange-red ones. The color suffered qualitative rather than quantitative changes, that is, the hue (h*ab) increased, whereas the chroma (C*ab) and lightness (L) did not show a defined trend with time.

De novo synthesis of monoterpenes by Saccharomyces cerevisiae wine yeasts

This paper reports the production of monoterpenes, which elicit a floral aroma in wine, by strains of the yeast Saccharomyces cerevisiae. Terpenes, which are typical components of the essential oils of flowers and fruits, are also present as free and glycosylated conjugates amongst the secondary metabolites of certain wine grape varieties of Vitis vinifera. Hence, when these compounds are present in wine they are considered to originate from grape and not fermentation. However, the biosynthesis of monoterpenes by S. cerevisiae in the absence of grape derived precursors is shown here to be of de novo origin in wine yeast strains. Higher concentration of assimilable nitrogen increased accumulation of linalool and citronellol. Microaerobic compared with anaerobic conditions favored terpene accumulation in the ferment. The amount of linalool produced by some strains of S. cerevisiae could be of sensory importance in wine production. These unexpected results are discussed in relation to the known sterol biosynthetic pathway and to an alternative pathway for terpene biosynthesis not previously described in yeast.

Terpene compounds as possible precursors of 1,8-cineole in red grapes and wines

While the contribution of 1,8-cineole to the aroma of wine has been reported, it is a matter of controversy that the vineyards producing such wines are surrounded by Eucalyptus trees, which may contribute their essence to the grapes. However, experimental information presented in this paper suggests that 1,8-cineole can be produced by chemical transformation of limonene and alpha-terpineol, and this process may be responsible for the occurrence of Eucalyptus-like aroma in Tannat wines from vines not grown in the vicinity of Eucalyptus trees. A mechanism for the chemical transformation of these aroma compounds is proposed.

Application of multidimensional gas chromatography to the enantioselective characterisation of the essential oil of Eupatorium buniifolium Hooker et Arnott

The qualitative and quantitative composition of the essential oil from aerial parts of Eupatorium buniifolium Hooker et Arnott (Asteraceae) has been investigated for the first time. The essential oils were obtained by steam distillation of leaves and analysed by GC-MS; 44 components were identified. Monoterpene and sesquiterpene hydrocarbons, especially alpha-pinene (14.7%), beta-elemene (12.2%), germacrene D (11.5%), trans-beta-guaiene (6.5%) and (E)-caryophyllene (4.3%), were the major constituents found in the oils. The characterisation of E. buniifolium by enantioselective GC was performed by evaluation of the enantiomeric ratios of alpha-pinene, sabinene, beta-pinene, limonene, terpinen-4-ol and germacrene D.

Composition and seasonal variation of the essential oils from two mandarin cultivars of southern Brazil

Cold-pressing and hydrodistilled peel oils of two Brazilian mandarin cultivars, commonly called Cai and Montenegrina (Citrus deliciosa Tenore), were obtained from fruits collected on mandarin trees submitted to the same pedoclimatic and cultural conditions. Their chemical composition and seasonal variation of the main volatile constituents were investigated by capillary GC and GC-MS, and the results were submitted to statistical analysis. To better characterize the oils, the enantiomeric distribution ratio of seven components (alpha-pinene, sabinene, beta-pinene, limonene, linalool, terpinen-4-ol, and alpha-terpineol) was determined by multidimensional gas chromatography (MDGC). The similarities found between both C. deliciosa cultivars are strong evidence for the hypothesis that Montenegrina originated from Cai as previously reported from agronomic studies.

Aroma composition of Vitis vinifera Cv. tannat: the typical red wine from Uruguay

The free volatiles, as well as those released from the glycosidically bound forms by enzyme hydrolysis, have been analyzed to chracterize young Tannat wines from two successive vintages. The Tannat wine showed some aroma profile peculiarities detected in the free forms but, above all, in the bound fraction for the level and profile of the norisoprenoidic fraction. Among the free volatile compunds, a rather low content of C(6) alcohols with a prevalence of cis-3-hexen-1-ol on the trans form and sometimes a remarkable level of trans-2-hexen-1-ol seem to be typical for the variety. C(13)-norisoprenoidic and monoterpenic volatiles made up approximately 42% of the total level of the volatiles observed in the glycosidase enzyme-released fraction. The other volatiles were C(6) alcohols (6%) and benzenoid compounds (51%). The dominating monoterpene alcohols were the cis and trans isomers of 3,7-dimethyl-1,6-octadiene-3,8-diol (8-hydroxylinalool). The C(13)-norisoprenoid pattern was composed by 3-hydroxy-beta-damascone, 3-oxo-alpha-ionol, vomifoliol, 4-oxo-beta-ionol, 3-oxo-7,8-dihydro-alpha-ionol, 4-oxo-7,8-dihydro-beta-ionol, grasshopper ketone, and 7,8-dihydrovomifoliol.

Effect of beta-glycosidase activity of Oenococcus oeni on the glycosylated flavor precursors of Tannat wine during malolactic fermentation

Under traditional wine-making conditions, this work examines the beta-glycosidic activity of Oenococcus oeni on glycosylated aroma compounds of Tannat wines during malolactic fermentation (MLF) by comparing the changes on selected aglycones liberated. MLF diminished the content of all the glycosylated compounds. The level of the free aroma components was slightly modified by the action of the malolactic fermentation so that the cleavage of the glycosidic linkage by the beta-glycosidic activity of O. oeni did not appear to increase significatively the aglycone contents. The consequences of further chemical rearrangements of the algycones under wine conditions were explored using synthesized glycoconjugates on synthetic medium. Bacteria could also be responsible for the cleavage of aroma glycosylated compounds, being the aglycone adsorbed on polysaccharides or peptidoglycans and was released into the external medium. This hypothesis was studied through the evaluation of a stable arrangement of aroma compounds with polysaccharides produced by lactic acid bacteria. A possible retaining of free-made aroma compounds into the whole cells of O. oeni was also investigated through cell culture analysis. Through the results obtained, we assume stable linkage of aroma compounds with bacterial polysaccharides.

Uruguayan essential oil. 12. Composition of Nova and Satsuma mandarin oils

The composition of the laboratory-prepared essential oils from Uruguayan Nova and Satsuma mandarins has been studied. The volatile fraction was analyzed by HRGC and HRGC/MS (quadrupole); 79 and 73 components were identified in Nova and Satsuma mandarin oils, respectively. The linear retention indices were calculated for almost all identified components on two different stationary phases. The enantiomeric distribution of beta-pinene, sabinene, limonene, linalool, and alpha-terpineol was studied by multidimensional gaschromatography (MDGC). Polymethoxylated flavones, present in the nonvolatile residue, were analyzed by normal-phase HPLC.

Achyrocline satureioides essential oils from southern Brazil and Uruguay

The essential oils of the aerial parts of Achyrocline satureioides (D.C.) Lam., a regional medicinal plant, from different collection locations in the South of Brazil and Uruguay were examined by GC and GC-MS. Monoterpene and sesquiterpene hydrocarbons were the main fractions of both the oils from Brazil and Uruguay. The oxygenated monoterpenes and sequiterpenes were at much lower percentage in both samples. The Uruguayan samples have 1,8-cineole which is not present in the Brazilian samples and has not been reported in other samples from Brazil. The results indicated a high biodiversity of the native populations of A. satureioides.