Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Molecules ; 29(11)2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38893586

RESUMO

Hemerocallis L. possesses abundant germplasm resources and holds significant value in terms of ornamental, edible, and medicinal aspects. However, the quality characteristics vary significantly depending on different varieties. Selection of a high-quality variety with a characteristic aroma can increase the economic value of Hemerocallis flowers. The analytic hierarchy process (AHP) is an effective decision-making method for comparing and evaluating multiple characteristic dimensions. By applying AHP, the aromatic character of 60 varieties of Hemerocallis flowers were analyzed and evaluated in the present study. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) was employed to identify volatile components in Hemerocallis flowers. Thirteen volatile components were found to contribute to the aroma of Hemerocallis flowers, which helps in assessing their potential applications in essential oil, aromatherapy, and medical treatment. These components include 2-phenylethanol, geraniol, linalool, nonanal, decanal, (E)-ß-ocimene, α-farnesene, indole, nerolidol, 3-furanmethanol, 3-carene, benzaldehyde and benzenemethanol. The varieties with better aromatic potential can be selected from a large amount of data using an AHP model. This study provides a comprehensive understanding of the characteristics of the aroma components in Hemerocallis flowers, offers guidance for breeding, and enhances the economic value of Hemerocallis flowers.


Assuntos
Flores , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Microextração em Fase Sólida/métodos , Flores/química , Odorantes/análise , Monoterpenos Acíclicos/química , Monoterpenos Acíclicos/análise , Óleos Voláteis/química , Óleos Voláteis/análise , Sesquiterpenos/análise , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/análise , Álcool Feniletílico/química , Alcenos , Indóis
2.
Food Res Int ; 187: 114330, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38763633

RESUMO

Processing technology plays a crucial role in the formation of tea aroma. The dynamic variations in volatile metabolites across different processing stages of fresh scent green tea (FSGT) were meticulously tracked utilizing advanced analytical techniques such as GC-E-Nose, GC-MS, and GC × GC-TOFMS. A total of 244 volatile metabolites were identified by GC-MS and GC × GC-TOFMS, among which 37 volatile compounds were concurrently detected by both methods. Spreading and fixation stages were deemed as pivotal processes for shaping the volatile profiles in FSGT. Notably, linalool, heptanal, 2-pentylfuran, nonanal, ß-myrcene, hexanal, 2-heptanone, pentanal, 1-octen-3-ol, and 1-octanol were highlighted as primary contributors to the aroma profiles of FSGT by combining odor activity value assessment. Furthermore, lipid degradation and glycoside hydrolysis were the main pathways for aroma formation of FSGT. The results not only elucidate the intricate variations in volatile metabolites but also offer valuable insights into enhancing the processing techniques for improved aroma quality of green tea.


Assuntos
Manipulação de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Odorantes , Chá , Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Odorantes/análise , Chá/química , Manipulação de Alimentos/métodos , Nariz Eletrônico , Aldeídos/análise , Aldeídos/metabolismo , Monoterpenos Acíclicos/metabolismo , Monoterpenos Acíclicos/análise , Camellia sinensis/química , Camellia sinensis/metabolismo , Cetonas/análise , Cetonas/metabolismo , Octanóis
3.
Food Res Int ; 187: 114398, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38763656

RESUMO

Nowadays, it is important to monitor the freshness of meat during storage to protect consumers' health. Volatile organic compounds (VOCs) are responsible for odour and taste of food, and they give an indication about meat quality and freshness. This study had the aim to seek and select potential new markers of meat spoilage through a semi-quantitative analysis in five types of meat (beef, raw and baked ham, pork sausage and chicken) and then to develop a new quantitative analytical method to detect and quantify potential markers on five types of meat simultaneously. Firstly, a new headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was developed to evaluate the volatile profile of five types of meat, preserved at 4 °C for 5 days. Among the 40 compounds identified, 15 were chosen and selected as potential shelf-life markers on the basis of their presence in most of meat samples or/and for their constant increasing/decreasing trend within the sample. Afterwards, a quantitative HS-SPME-GC-MS analytical method was developed to confirm which VOCs can be considered markers of shelf-life for these meat products, stored at 4 °C for 12 days. Some of the compounds analyzed attracted attention as they can be considered markers of shelf-life for at least 4 types of meat: 1-butanol, 3-methylbutanol, 1-hexanol, 2-nonanone, nonanal, 1-octen-3-ol and linalool. In conclusion, in this study a new quantitative HS-SPME-GC-MS analytical method to quantity 15 VOCs in five types of meat was developed and it was demonstrated that some of the compounds quantified can be considered markers of shelf-life for some of the meat products analyzed.


Assuntos
Armazenamento de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Produtos da Carne , Microextração em Fase Sólida , Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Produtos da Carne/análise , Animais , Suínos , Odorantes/análise , Bovinos , Aldeídos/análise , Galinhas , Cetonas/análise , Pentanóis/análise , Monoterpenos Acíclicos/análise , Octanóis
4.
J Pharmacol Toxicol Methods ; 127: 107509, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38701958

RESUMO

Myrcene (ß-myrcene), found in essential oils from plant species such as hops and cannabis, has many advantageous properties, but its use is limited due to volatility and low solubility in water. One way to circumvent these limitations is to encapsulate the essential oils in a polymer matrix. However, these hydrophobic molecules are difficult to quantify when dispersed in water. Seeking to study the release of this terpene in drug release tests from polymeric matrices, this work aimed to develop an easy and cheap UV spectrophotometric method for the quantification of ß-myrcene in aqueous medium. To achieves this goal, samples were prepared in 0.05% (w/v) polysorbate 80 solution, with concentrations of ß-myrcene ranging from 0.01% to 0.1% (v/v), and were analyzed at 226 nm. Each sample was analyzed in triplicate and repeated on three different days, to evaluate the repeatability of the results. The results were subjected to Q, F and Student's t-tests. The regression parameters obtained for ß-myrcene were above 0.99 and through statistical analysis, it was possible to confirm the repeatability for the results. The values of the limits of detection and quantification indicated that the method is not affected by intrinsic factors of the equipment. The results of accuracy, robustness and selectivity showed recovery rates within acceptable limits. This demonstrates that the quantification of ß-myrcene in aqueous medium by UV spectrophotometry is feasible.


Assuntos
Quitosana , Espectrofotometria Ultravioleta , Água , Espectrofotometria Ultravioleta/métodos , Água/química , Quitosana/química , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/química , Alcenos/análise , Alcenos/química , Polissorbatos/química , Polissorbatos/análise , Solubilidade , Reprodutibilidade dos Testes , Óleos Voláteis/análise , Óleos Voláteis/química
5.
J AOAC Int ; 107(3): 506-511, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38400759

RESUMO

BACKGROUND: Myrcene and cymene, aromatic monoterpenes found in plants and essential oils, possess distinctive aromatic qualities. However, their volatility and limited solubility pose challenges in precise handling and formulation. Meanwhile, nanoemulsions emerge as promising drug delivery systems, improving the bioavailability and stability of these active ingredients. OBJECTIVE: This article aimed to develop an HPLC method for the quantification of two monoterpenoids, p-cymene and myrcene, in nanoemulsions. METHOD: The method used a Phenomenex® Synergi™ Fusion-RP column (150 mm × 4.6 mm id, 4 µm particle size) on an HPLC system with isocratic elution. The mobile phase was composed of acetonitrile and water (60:40, v/v) and was validated in terms of specificity, linearity, accuracy, precision, robustness, and selectivity. RESULTS: The method provided accurate and precise results with a correlation coefficient of 0.999 and RSD values of less than 2%. The method can be used for quality control of nanoemulsions containing these monoterpenoids and as a reference for future studies on their efficacy and stability. CONCLUSIONS: The study demonstrates the feasibility of using HPLC for the quantification of monoterpenoids in nanoemulsions and its potential as a quality control tool for nanoemulsion-based drug delivery systems. HIGHLIGHTS: The method's accuracy, precision, and reliability, as evidenced by high correlation coefficients and low RSD values, underscore its suitability for ensuring the consistent formulation of these monoterpenoid-containing nanoemulsions, while also serving as a reference point for future research endeavors in this field.


Assuntos
Monoterpenos Acíclicos , Alcenos , Cimenos , Emulsões , Monoterpenos , Cromatografia Líquida de Alta Pressão/métodos , Cimenos/química , Cimenos/análise , Emulsões/química , Monoterpenos/análise , Monoterpenos/química , Alcenos/análise , Alcenos/química , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/química
6.
Planta ; 257(4): 79, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36912967

RESUMO

MAIN CONCLUSION: Ambrosia species differ both in their trichome types and in metabolic profiles of leaf volatiles. The current study provides tools for easier taxonomic identification of ragweed species. The genus Ambrosia (Asteraceae) includes some of the most noxious allergenic invasive weeds in the world. Due to high polymorphism in this genus, identification of species is often difficult. This study focuses on microscopic investigation of foliar features and GC-MS identification of the main leaf volatile components of three Ambrosia species currently found in Israel-invasive species Ambrosia confertiflora and A. tenuifolia, and transient A. grayi. A. confertiflora and A. tenuifolia have three trichome types: non-glandular trichomes, capitate glandular trichomes and linear glandular trichomes. Their non-glandular trichomes and capitate trichomes have distinct structures and can serve as taxonomic characters. A. grayi (the least successful invader) has only very dense covering trichomes. All three Ambrosia species have secretory structures in their leaf midrib. A. confertiflora, the most problematic invasive plant in Israel, had a ten times higher volatiles content than the other two species. In A. confertiflora, the most abundant volatiles were chrysanthenone (25.5%), borneol (18%), germacrene D and (E)-caryophyllene (both around 12%). In A. tenuifolia, the most abundant volatiles were ß-myrcene (32.9%), (2E)-hexenal (13%) and 1,8-cineole (11.7%). In A. grayi, the most abundant volatiles were ß-myrcene (17.9%), germacrene D (17.8%) and limonene (14%). The three examined species have distinct trichome types and metabolic profiles. Non-glandular trichomes show structural diversification between species and are a good descriptive character. Considering the anthropocentric significance of this highly problematic genus, the current study provides tools for easier identification of ragweed species.


Assuntos
Ambrosia , Asteraceae , Asteraceae/metabolismo , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/metabolismo , Tricomas/metabolismo , Folhas de Planta/metabolismo
7.
Molecules ; 27(3)2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35164249

RESUMO

Phenolic and non-phenolic chemotypes of Thymus pulegioides L. are common in Europe. Essential oils of these chemotypes, as various compositions of allelochemicals, can have different phytotoxic effects on neighboring plants in natural habitats. The aim of this study was to establish the distribution of carvacrol and geraniol in T. pulegioides, growing wild in Lithuania, and compare phytotoxity of essential oils of carvacrol and geraniol chemotypes on selected plant species. In investigating 131 T. pulegioides habitats, essential oils were isolated by hydrodistillation and analyzed by GC-FID and GC-MS. Phytotoxity of essential oils extracted from carvacrol and geraniol chemotypes transmitted through water and air to selected plants was determined under laboratory conditions. Pharmacologically valuable Hypericum perforatum L. and the important forage grass Phleum pratense L. were respectively selected for experimentation from among 35 medicinal plants and 10 feed Poaceae species, growing in T. pulegioides habitats. Field results showed that carvacrol is common throughout Lithuania's territory, whereas the geraniol is predominantly located under the continental climatic conditions of the eastern region of the country. In the laboratory experiment, it was established that there was stronger inhibition of P. pratense seed germination by the essential oil of the geraniol chemotype than the carvacrol chemotype. None of the H. perforatum seeds germinated after exposure to the essential oil of the geraniol chemotype. In general, this study builds on previous studies by providing further evidence that different T. pulegioides chemotypes have contrasting phytotoxic effects on neighboring plants within their natural habitats.


Assuntos
Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/toxicidade , Cimenos/análise , Cimenos/toxicidade , Ecossistema , Óleos Voláteis/química , Plantas/efeitos dos fármacos , Germinação/efeitos dos fármacos , Lituânia
8.
Molecules ; 26(23)2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34885940

RESUMO

Peperomia Ruiz and Pav, the second largest genus of the Piperaceae, has over the years shown potential biological activities. In this sense, the present work aimed to carry out a seasonal and circadian study on the chemical composition of Peperomia circinata essential oils and aromas, as well as to evaluate the preliminary toxicity in Artemia salina Leach and carry out an in silico study on the interaction mechanism. The chemical composition was characterized by gas chromatography (GC/MS and GC-FID). In the seasonal study the essential oil yields had a variation of 1.2-7.9%, and in the circadian study the variation was 1.5-5.6%. The major compounds in the seasonal study were ß-phellandrene and elemicin, in the circadian they were ß-phellandrene and myrcene, and the aroma was characterized by the presence of ß-phellandrene. The multivariate analysis showed that the period and time of collection influenced the essential oil and aroma chemical composition. The highest toxicity value was observed for the essential oil obtained from the dry material, collected in July with a value of 14.45 ± 0.25 µg·mL-1, the in silico study showed that the major compounds may be related to potential biological activity demonstrated by the present study.


Assuntos
Artemia/efeitos dos fármacos , Óleos Voláteis/análise , Óleos Voláteis/toxicidade , Peperomia/química , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/toxicidade , Alcenos/análise , Alcenos/toxicidade , Animais , Monoterpenos Cicloexânicos/análise , Monoterpenos Cicloexânicos/toxicidade , Pirogalol/análogos & derivados , Pirogalol/análise , Pirogalol/toxicidade , Estações do Ano
9.
Molecules ; 26(18)2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34577081

RESUMO

The quality control of essential oils (EO) principally aims at revealing the presence of adulterations and at quantifying compounds that are limited by law by evaluating EO chemical compositions, usually in terms of the normalised relative abundance of selected markers, for comparison to reference values reported in pharmacopoeias and/or international norms. Common adulterations of EO consist of the addition of cheaper EO or synthetic materials. This adulteration can be detected by calculating the percent normalised areas of selected markers or the enantiomeric composition of chiral components. The dilution of the EO with vegetable oils is another type of adulteration. This adulteration is quite devious, as it modifies neither the qualitative composition of the resulting EO nor the marker's normalised percentage abundance, which is no longer diagnostic, and an absolute quantitative analysis is required. This study aims at verifying the application of the two above approaches (i.e., normalised relative abundance and absolute quantitation) to detect EO adulterations, with examples involving selected commercial EO (lavender, bergamot and tea tree) adulterated with synthetic components, EO of different origin and lower economical values and heavy vegetable oils. The results show that absolute quantitation is necessary to highlight adulteration with heavy vegetable oils, providing that a reference quantitative profile is available.


Assuntos
Citrus/química , Lavandula/química , Melaleuca/química , Óleos Voláteis/química , Controle de Qualidade , Monoterpenos Acíclicos/análise , Contaminação de Medicamentos , Cromatografia Gasosa-Espectrometria de Massas , Isomerismo , Monoterpenos/análise , Óleos Voláteis/análise , Óleos de Plantas/análise , Óleos de Plantas/química , Padrões de Referência , Óleo de Melaleuca/análise , Óleo de Melaleuca/química
10.
Artigo em Inglês | MEDLINE | ID: mdl-34224966

RESUMO

In this work, a novel strategy was developed for separation and enrichment of sibiskoside by dummy molecular imprinting technology and magnetic separation technology. The structural analogue geniposide was selected as the dummy template, using 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, and acetonitrile as the porogen. The molecularly imprinted layer was formed on the surface of the magnetic carrier to prepare dummy template molecularly imprinted polymers (DMIPs) with a core-shell structure. The DMIPs were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Vibration sample magnetometer (VSM). The results of adsorption kinetics experiments and isothermal adsorption experiments showed that DMIPs can reach adsorption equilibrium in a short period of time and the maximum adsorption capacity can reach 14.67 mg/g. The imprinting factor was 2.08. Compared with the andrographolide, polydatin, arbutin, caffeic acid, neohesperidin dihydrochalcone and quercetin, DMIPs have good adsorption capacity for the sibiskoside. And the reusability was better. After the adsorption of DMIPs, the purity of sibiskoside in the crude extracts from Sibiraea angustata increased to 78%. It provided a basis for the further development and utilization of Sibiraea angustata as well as the separation and enrichment of monoterpenes.


Assuntos
Monoterpenos Acíclicos , Glicosídeos , Nanopartículas de Magnetita/química , Polímeros Molecularmente Impressos/química , Rosaceae/química , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/química , Monoterpenos Acíclicos/isolamento & purificação , Adsorção , Cromatografia Líquida de Alta Pressão , Glicosídeos/análise , Glicosídeos/química , Glicosídeos/isolamento & purificação , Extratos Vegetais/química
11.
Food Chem ; 360: 130033, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34023716

RESUMO

Some black teas demand high market prices. Black tea samples (306) collected from 10 geographic origins, including China (Guxi, Likou, Jinzipai, Guichi, Dongzhi, Changning, Wuyishan, Shaowu), India (Darjeeling), and Sri Lanka (Kandy), were analyzed using headspace volatilization followed by GC/MS (HS-GC/MS). Forty-eight volatile compounds were identified. The aroma compounds were mainly identified as alcohols, aldehydes, ketones, and esters. Analysis of either full-spectrum data or 22 tea compounds shared among the samples with k-Nearest Neighbor (k-NN) and Random Forest (RF) models discriminated all origins at 100% using KNN and 95% with RF using either data set. The discrimination rates using 2 key aroma compounds (linalool and geraniol) by k-NN were 100% for nine origins, with the rate for Guxi area at 89%, because 3 samples were classified to Jinzipai. The findings support the use of HS-GC/MS combined with chemometrics as a tool to identify the origin of black tea.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Filogeografia , Chá/química , Monoterpenos Acíclicos/análise , Aldeídos/análise , China , Ésteres/análise , Índia , Odorantes/análise , Microextração em Fase Sólida , Sri Lanka , Compostos Orgânicos Voláteis/análise , Volatilização
12.
Molecules ; 26(8)2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33923848

RESUMO

Lippia alba (Mill.) N. E. Br. (Verbenaceae) is an aromatic shrub whose essential oils have stood out as a promising source for application in several industrial fields. In this study, the essential oils chemical characterization of eight new L. alba genotypes was performed. The selected materials were collected from the Active Germplasm Bank of the Agronomic Institute and the essential oils were extracted by hydrodistillation. Flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) was employed for chemical characterization and evaluation of possible co-eluted compounds. In addition, the chemical analyses were submitted to multivariate statistical analyses. From this investigation, 73 metabolites were identified in the essential oils of the genotypes, from which α-pinene, ß-myrcene, 1,8-cineole, linalool, neral, geranial, and caryophyllene oxide were the most abundant compounds among the accessions. This is the first report disclosing α-pinene in higher amounts in L. alba (19.69%). In addition, sabinene, trans-verbenol, myrtenol, (E)-caryophyllene, α-guaiene, germacrene D, and α-bulnesene were also found in relevant quantities in some of the genotypes, and myrtenal and myrtenol could be well separated through the second dimension. Such results contributed to the understanding of the chemical composition of those new genotypes, being important to drive a future industrial applicability and studies in genetic breeding.


Assuntos
Lippia/química , Óleos Voláteis/análise , Monoterpenos Acíclicos/análise , Monoterpenos Bicíclicos/análise , Monoterpenos Bicíclicos/química , Cromatografia Gasosa-Espectrometria de Massas , Genótipo , Óleos de Plantas , Terpenos/análise
13.
J Environ Sci Health B ; 56(4): 387-395, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33645426

RESUMO

The purpose of this study was to determine the chemical profile of Litsea cubeba essential oil, carry out an in vitro evaluation of its antioxidant potential and its cytotoxicity, as well as its antifungal and antimicotoxigenic activities against Fusarium verticillioides. Most of the compounds observed in the EO were neral (32.75%) and geranial (37.67%). The radical scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid was 104.4 and 56.4 mmol Trolox mg-1, respectively, indicating good antioxidant activity. The EO studied by us revealed cytotoxic effect against HT-29 and HeLa cancer cells. The Minimum Inhibitory and Minimum Fungicidal Concentrations against F. verticillioides were both 125 µg mL-1. Morphological investigation, performed by fluorescence microscopy and scanning electron microscopy, showed that hyphae and microconidia structures underwent changes after treatment with the EO. Analyses performed with the EO strongly reduced the mycelial development of F. verticillioides and the synthesis of fumonisins B1 and B2 in dose-dependence effect compared (P < 0.01) with the fungal control (105 conidia mL-1) and positive control (fludioxonil + metalaxyl-M). Thus, the results obtained in vitro suggest that L. cubeba EO has excellent antioxidant, fungicidal, and antimycotoxigenic effects.


Assuntos
Antifúngicos/farmacologia , Antioxidantes/farmacologia , Fusarium/efeitos dos fármacos , Litsea/química , Óleos Voláteis/farmacologia , Monoterpenos Acíclicos/análise , Antifúngicos/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/química , Relação Dose-Resposta a Droga , Fumonisinas/metabolismo , Fusarium/metabolismo , Células HT29 , Células HeLa , Humanos , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Óleos Voláteis/administração & dosagem , Óleos Voláteis/química
14.
J Chem Ecol ; 47(3): 294-302, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33523390

RESUMO

Adoxophyes honmai, a serious pest of tea plants, prefers to lay eggs on mature tea leaves rather than young leaves. Here, we examined a hypothesis that Ascogaster reticulata, an egg-larval parasitoid of A. honmai, increases the likelihood of encountering host egg masses by searching mature tea leaves when host-derived cues are not available. In a dual-choice bioassay using a four-arm olfactometer, A. reticulata preferred odor from intact, mature leaves versus young leaves. Based on volatile analysis with gas chromatography-mass spectrometry (GC-MS), we identified 5 and 10 compounds from mature and young leaf volatiles, respectively. The 5 components in the extract from intact mature leaves included (Z)-3-hexenyl acetate, (E)-ß-ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and methyl salicylate. When each individual compound, or quaternary and quintenary blends of them, ratios of which were adjusted to match those of mature leaf volatiles, were provided, parasitoids preferred the full mixture and the quaternary blend devoid of DMNT to the solvent control. Methyl salicylate, one of the components of preferred blends, was not detected among young leaf volatiles. We concluded that the volatile composition of tea leaves changes, depending on their maturity, and that this composition affects foraging behavior of the parasitoid, which is closely related to the host herbivore's oviposition preference.


Assuntos
Camellia sinensis/química , Himenópteros/parasitologia , Odorantes/análise , Folhas de Planta/química , Compostos Orgânicos Voláteis/análise , Acetatos/análise , Acetatos/metabolismo , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/metabolismo , Alcenos/análise , Alcenos/metabolismo , Animais , Camellia sinensis/metabolismo , Ecossistema , Cromatografia Gasosa-Espectrometria de Massas , Larva/parasitologia , Mariposas/parasitologia , Folhas de Planta/metabolismo , Salicilatos/análise , Salicilatos/metabolismo , Terpenos/análise , Terpenos/metabolismo
15.
Food Chem ; 338: 128003, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32932083

RESUMO

UV-C treatment is a commonly known technique to inactivate microorganisms. The objective of this work was to investigate the impact of UV-C treatment of grape must on the sensory characteristics of the resulting wine and on the profile of volatile compounds of grape must and wine. Different UV-C doses were applied to Riesling must and compared with thermal pasteurization. The sensory off-flavor "ATA" and a content of 0.5 µg/L 2-aminoacetophenone were determined in the grape must and in the resulting wine after UV-C treatment with a high dose of 21 kJ/L. Sensory off-flavors did neither occur after thermal pasteurization nor after UV-C treatment with a dose of 2 kJ/L, which is sufficient for the inactivation of microorganisms. Minor changes in the volatiles' profiles of grape must and wine, involving e.g. terpenes and C13-norisoprenoids, occurred in musts treated with thermal pasteurization as well as with a UV-C dose of 2 kJ/L.


Assuntos
Pasteurização , Vitis , Compostos Orgânicos Voláteis/análise , Vinho , Acetofenonas/análise , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Norisoprenoides/análise , Odorantes/análise , Microextração em Fase Sólida/métodos , Paladar , Terpenos/análise , Raios Ultravioleta , Compostos Orgânicos Voláteis/química , Vinho/análise
16.
Nat Prod Res ; 35(2): 342-345, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31140321

RESUMO

In this study, the essential oil composition of Rydingia michauxii was evaluated during the dormant, vegetative and flowering stages. The major chemical constituents of R. michauxii at the dormant stage were eugenol (36.81%), eugenol acetate (21.02%), and carvacrol (9.35%). While the main chemical constituents for the vegetative stage were carvacrol (16.08%), eugenol (13.23%), cumin aldehyde (9.63%), and linalool (8.28%). In addition, carvacrol (14.20%), eugenol (8.98%), δ-cadinene (8.90%), caryophyllene oxide (8.43%) and n-hexadecanoic acid (7.07%) were the major volatile components during the flowering stage. Variation in chemical compositions of R. michauxii during the various developmental stages might be affected by environmental and climatic factors.


Assuntos
Lamiaceae/química , Lamiaceae/crescimento & desenvolvimento , Óleos Voláteis/química , Monoterpenos Acíclicos/análise , Cimenos/análise , Cromatografia Gasosa-Espectrometria de Massas , Óleos Voláteis/análise , Sesquiterpenos Policíclicos/análise
17.
Nat Prod Res ; 35(1): 162-166, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31165644

RESUMO

Glycyrrhiza echinata L. is a perennial plant of considerable commercial importance in medicine, pharmaceuticals, cosmetics, and tobacco industries and the production of food additives as flavoring and sweetening agent. This study, variation on composition and yield of essential oil from the underground parts of five accessions of G. echinata growing wild in northern Iran was investigated. Results showed high variability for the main constituents of essential oil among accessions of G. echinata. The presence of α-pinene and myrcene in two accessions suggests that these volatiles could serve as chemotaxonomic markers and also might be considered as potentially relevant for taste. The presence of ß-caryophyllene and α- caryophyllene in three accessions could be strong potential for being used in medical applications (anticancer and analgesic properties). Generally, the essential oils from G. echinata and other species could be very competitive targets for phytochemical and food studies.


Assuntos
Glycyrrhiza/química , Óleos Voláteis/química , Óleos de Plantas/química , Monoterpenos Acíclicos/análise , Alcenos/análise , Monoterpenos Bicíclicos/análise , Irã (Geográfico) , Sesquiterpenos Monocíclicos/análise , Monoterpenos/análise , Óleos Voláteis/análise , Sesquiterpenos Policíclicos/análise , Sesquiterpenos/análise
18.
J Sci Food Agric ; 101(8): 3280-3289, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33222189

RESUMO

BACKGROUND: The Citrus reticulata 'Chachi' pericarp (CRCP) is one cultivar of Citri Reticulatae Pericarpium (Chenpi), which is widely applied in medicine and food. To determine the potential value of CRCP harvested at different stages and subjected to different drying processes, the dynamic changes in the bioactive components were profiled and evaluated in this study. RESULTS: The contents of all non-volatile components, i.e. synephrine, limonin, phenolic acids and flavonoids, decreased with delayed harvest time. The volatiles thujene, α-pinene, ß-pinene, d-citronellol, d-citronellal, decanal, linalool, geraniol, l-cis-carveol, terpinen-4-ol, α-terpineol, carvacrol, perillaldehyde, methyl 2-(methylamino)benzoate and d-limonene were considered the characteristic components for distinguishing CRCP harvested at different stages. Phenolic acids, synephrine and limonin were stable at different drying temperatures; however, high-temperature drying at 60 °C induced a significant transformation in the flavonoids (especially polymethoxyflavones) and volatile substances in CRCP. CONCLUSIONS: The results suggested that most of the bioactive components declined with the growth of Citrus reticulata 'Chachi'. And it is believed that the fresh peel should be naturally sun-dried or dried at low temperature (30 or 45 °C) rather than at high temperature (60 °C) to prevent excessive loss of nutrients. © 2020 Society of Chemical Industry.


Assuntos
Citrus/química , Manipulação de Alimentos/métodos , Frutas/crescimento & desenvolvimento , Extratos Vegetais/química , Monoterpenos Acíclicos/análise , Monoterpenos Bicíclicos/análise , Citrus/crescimento & desenvolvimento , Monoterpenos Cicloexânicos/análise , Flavonoides/análise , Frutas/química , Temperatura
19.
J Sci Food Agric ; 101(6): 2247-2255, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33009828

RESUMO

BACKGROUND: It is well known that duration of pre-drying storage impacts on hop quality. However, little knowledge exists regarding its actual effects on valuable hop components. To investigate these effects, fresh hop cones were stored for 5 or 24 h and dried for 210 min at 65 °C thereafter. Furthermore, to understand the effect of freezing hop cones on the essential oil content, both fresh and stored samples were frozen before and after drying. RESULTS: The results from gas chromatography analysis show an increase in linalool, ß-caryophyllene, humulene, geraniol content and decrease in myrcene content dependent on the period of storage. Total colour difference ΔE values of 4.61 and 5.27 were obtained for fresh and stored hops respectively, indicating discoloration of hops during storage. Modelling of moisture curves revealed the Wang and Singh model to be suitable, with R adj 2 values of 0.978 and 0.989 and root-mean-square error values of 0.037 and 0.019 for fresh and stored hops respectively. CONCLUSION: The results from this study provide an in-depth understanding on the changes occurring within the hop cones both during storage and drying and will further help hop processors optimize their storage times.


Assuntos
Dessecação/métodos , Manipulação de Alimentos/métodos , Humulus/química , Óleos Voláteis/química , Monoterpenos Acíclicos/análise , Alcenos/análise , Cromatografia Gasosa , Temperatura Alta , Sesquiterpenos Monocíclicos/análise , Sesquiterpenos Policíclicos/análise , Fatores de Tempo
20.
Chem Biodivers ; 17(11): e2000542, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33231346

RESUMO

Warburgia salutaris, known as 'Pepper bark', is an ethnomedicinally important tree found in the southern regions of Africa. A total of 75 fresh leaf specimens of W. salutaris (n=40 wild and 35 cultivated) were collected from the Limpopo (wild) and KwaZulu-Natal provinces (cultivated), two distinct locations in South Africa. In this study, the leaf essential oils obtained by hydrodistillation were characterized using gas chromatography coupled to mass spectrometry/flame ionization detection (GC/MS/FID). More than 15 compounds, accounting for 90-99 % of the total oil composition were identified. The analysis revealed that myrcene (0.6-65.3 %), (E)-ß-ocimene (nd-56.9 %), (Z)-ß-ocimene (nd-19.1 %), α-pinene (nd-19.1 %) and limonene (nd-11.7 %) are major constituents of W. salutaris essential oils. Chemometric analysis revealed two major chemotypes within the essential oils with a modeled variation of approximately 60 %. Linalool and germacrene D were revealed as markers associated with the wild-harvested oils, while cultivated oils were distinguished by higher levels of limonene and α-humulene. The intra-population variation indicated two chemically distinct chemotypes from three different populations, however, the season of harvest did not have a direct influence on the chemical profiles of the essential oils.


Assuntos
Magnoliopsida/química , Óleos Voláteis/química , Monoterpenos Acíclicos/análise , Análise Discriminante , Cromatografia Gasosa-Espectrometria de Massas , Análise dos Mínimos Quadrados , Magnoliopsida/metabolismo , Óleos Voláteis/análise , Folhas de Planta/química , Folhas de Planta/metabolismo , Análise de Componente Principal , Estações do Ano , Sesquiterpenos de Germacrano/análise , África do Sul
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA