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1.
Molecules ; 26(14)2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34299656

RESUMO

Chemical composition, antioxidant capacity, and antimicrobial activity of lavender essential oils (LEOs) extracted from three different varieties of Lavandula angustifolia Mill. (1-Moldoveanca 4, 2-Vis magic 10, and 3-Alba 7) have been determined. These plants previously patented in the Republic of Moldova were cultivated in an organic agriculture system in the northeastern part of Romania and then harvested in 3 consecutive years (2017-2019) to obtain the essential oils. From the inflorescences in the complete flowering stage, the LEOs were extracted by hydrodistillation. Then, their composition was analyzed by gas chromatography coupled with mass spectrometry (GC-MS) and by Fourier Transformed Infrared spectroscopy (FT-IR). The major identified constituents are as follows: linalool (1: 32.19-46.83%; 2: 29.93-30.97%; 3: 31.97-33.77%), linalyl acetate (1: 17.70-35.18%; 2: 27.55-37.13%; 3: 28.03-35.32%), and terpinen-4-ol (1: 3.63-7.70%; 2: 3.06-7.16%; 3: 3.10-6.53%). The antioxidant capacity as determined by ABTS and DPPH assays indicates inhibition, with the highest activity obtained for LEO var. Alba 7 from 2019. The in vitro antimicrobial activities of the LEOs and combinations were investigated as well, by using the disk diffusion method and minimum inhibitory concentration (MIC) against the Gram-positive bacterial strain Staphylococcus aureus (ATCC 6538), Gram-negative Pseudomonas aeruginosa (ATCC 27858), Escherichia coli (ATCC 25922), the yeast Candida albicans (ATCC 10231), and clinical isolates. Our results have shown that LEOs obtained from the three studied varieties of L. angustifolia manifest significant bactericidal effects against tested microorganisms (Staphylococcus aureus and Escherichia coli), and antifungal effects against Candida albicans. The mixture of LEOs (Var. Alba 7) and geranium, respectively, in tea tree EOs, in different ratios, showed a significant enhancement of the antibacterial effect against all the studied strains, except Pseudomonas aeruginosa.


Assuntos
Anti-Infecciosos , Antioxidantes , Bactérias/crescimento & desenvolvimento , Candida albicans/crescimento & desenvolvimento , Lavandula/química , Óleos Voláteis , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/farmacologia
2.
Molecules ; 26(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34279380

RESUMO

Cannabis sativa L. (hemp) is a plant used in the textile industry and green building material industry, as well as for the phytoremediation of soil, medical treatments, and supplementary food products. The synergistic effect of terpenes, flavonoids, and cannabinoids in hemp extracts may mediate the biogenic synthesis of metal nanoparticles. In this study, the chemical composition of aqueous leaf extracts of three varieties of Romanian hemp (two monoecious, and one dioecious) have been determined by Fourier-Transformed Infrared spectroscopy (FT-IR), high-performance liquid chromatography, and mass spectrometry (UHPLC-DAD-MS). Then, their capability to mediate the green synthesis of silver nanoparticles (AgNPs) and their pottential antibacterial applications were evaluated. The average antioxidant capacity of the extracts had 18.4 ± 3.9% inhibition determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 78.2 ± 4.1% determined by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS™) assays. The total polyphenolic content of the extracts was 1642 ± 32 mg gallic acid equivalent (GAE) L-1. After this, these extracts were reacted with an aqueous solution of AgNO3 resulting in AgNPs, which were characterized by UV-VIS spectroscopy, FT-IR, scanning electron microscopy (SEM-EDX), and dynamic light scattering (DLS). The results demonstrated obtaining spherical, stable AgNPs with a diameter of less than 69 nm and an absorbance peak at 435 nm. The mixture of extracts and AgNPs showed a superior antioxidant capacity of 2.3 ± 0.4% inhibition determined by the DPPH• assay, 88.5 ± 0.9% inhibition as determined by the ABTS•+ assay, and a good antibacterial activity against several human pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens, and Staphylococcus aureus.


Assuntos
Antibacterianos/química , Cannabis/química , Química Verde/métodos , Nanopartículas Metálicas/química , Extratos Vegetais/química , Antioxidantes/química , Folhas de Planta/química , Polifenóis/análise , Prata/química
3.
Sci Rep ; 10(1): 21322, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33288856

RESUMO

Satureja hortensis is one of the representative plants from the Lamiaceae family, and its essential oil has been used in various applicative fields, from the food industry to aromatherapy. The changes that occur in heated samples at different temperatures (160, 175, 190 ºC) over different periods (0.5 and 2.5 h) in Satureja hortensis essential oil composition and chemical properties were evaluated. The results showed that the major chemical composition constituents of the investigated essential oil are γ-terpinene + α-terpinolene and carvacrol + p-cymene and the thermal behavior is dependent on the content. This composition drastically changes through the heating of the samples and causes significant changes in thermal behavior. The present study demonstrated that the concentration of carvacrol in S. hortensis essential oil is increasing after heating treatment, and the sample heated at 190 ºC for 2.5 h contained more than 91% carvacrol. This simple treatment is a rapid way to obtain carvacrol from the essential oil that has high potential as a natural preservative suitable for the food industry and alternative and complementary medicine.

4.
J Sci Food Agric ; 99(14): 6324-6332, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31260108

RESUMO

BACKGROUND: The oils obtained from grape seeds are becoming a valuable way of exploiting winery waste and their properties are scrutinized for evaluating the potential usages. We examined the oils extracted with petroleum ether from grape seeds of four varieties of grapes (Cabernet Sauvignon, Feteasca Neagra, Merlot and Pinot Noir) from Romania looking at the influence of the fatty acid profile and of the antioxidants on their thermal behavior. RESULTS: The fatty acid profiles of the oils were evaluated by 1 H-NMR spectroscopy, and the oil antioxidant capacity was determined by cupric ion reducing antioxidant capacity (CUPRAC) method. The main fatty acid component in all the oils is linoleic acid (over 70%), which, due to its known health benefits, make the oils of commercial interest. The thermal stability of grape seed oils appears to be mainly influenced by the percentage of polyunsaturated fatty acids in their composition, less polyunsaturated fatty acids making the oils more stable. The antioxidant compounds affect only the initial stage of the decomposition by limiting the formation of hydroperoxides in the allylic positions of the fatty acid chain. CONCLUSION: Compared to pure samples of glyceryl-unsaturated fatty acids (glyceryl-trioleate, glyceryl-trilinoleate), the grape seed oils exhibit higher thermal stability, due to the presence of antioxidant compounds and to a synergistic action of unsaturated and saturated fatty acids, smaller percentage of the polyunsaturated and higher percentage of the saturated fatty acids enhancing the stability. © 2019 Society of Chemical Industry.


Assuntos
Óleos Vegetais/química , Vitis/química , Antioxidantes/química , Antioxidantes/isolamento & purificação , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Temperatura Alta , Óleos Vegetais/isolamento & purificação , Romênia , Sementes/química
5.
PLoS One ; 13(7): e0200314, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29995918

RESUMO

The aim of the present study was to establish the influence of high-temperature heating on the composition and thermal behavior of coffee oils obtained from Arabica green and roasted coffee beans, respectively. Morphological studies performed using scanning electron microscopy revealed the oil bodies uniformly distributed within the cells in both types of coffee beans analyzed. The obtained oils have a fatty acid composition rich in linoleic acid, palmitic acid, oleic acid, stearic acid, arachidic acid and linolenic acid. The total content of saturated fatty acids of investigated oils was 49.38 and 46.55%, the others being unsaturated fatty acids. The thermal behavior and thermo-oxidative stability of coffee oils extracted from green coffee beans and roasted coffee beans, the coffee oil high-temperature heated up to 200 °C, were investigated using simultaneous thermal analysis TG/DTG/DTA, in an oxidizing atmosphere. The data obtained for the analyzed samples depend mainly on the nature and compositions of fatty acids, and to a lesser extent on the roasting process of the coffee beans and the high-temperature heating process of the extracted oil. The chromatographic and TG/DTG/DTA data suggest that Arabica coffee oil has great potential for use in technological processes which require high-temperature heating (e.g. food industry or pastries).


Assuntos
Café/química , Extratos Vegetais/química , Óleos Vegetais/química , Café/ultraestrutura , Ácidos Graxos/análise , Cromatografia Gasosa-Espectrometria de Massas , Temperatura Alta , Microscopia Eletrônica de Varredura , Oxirredução , Sementes/química , Sementes/ultraestrutura
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