Oregano essential oil: influence of the chemical composition on the inhibitory activity against Salmonella Enteritidis

Este trabalho avaliou a interferência da origem e do teor de compostos fenólicos de óleo essencial de orégano (OEO) de cinco marcas comerciais provenientes de diferentes regiões do mundo, na atividade inibitória frente à Salmonella Enteritidis (SE). A composição de cada OEO foi determinada por cromatografia gasosa acoplada ao espectrômetro de massas (CG-IE-MS). A atividade inibitória frente SE in vitro foi avaliada pela técnica de difusão em poços, empregando-se soluções alcoólicas a 0,1; 0,2; 0,5; 1,0; ou 2,0%, observando-se a formação de halo de inibição após incubação a 30 °C por 24 horas. Como resultado da análise por CG-IE-MS, foram identificados dezessete componentes voláteis. Todos OEO analisados neste trabalho possuíam carvacrol como componente principal e apresentaram atividade antimicrobiana frente a SE nas cinco concentrações testadas. A ação inibitória das cinco marcas comerciais avaliadas não apresentou diferença estatística significativa (p > 0,05), porém o OEO proveniente da região do Mediterrâneo com p-cimeno e γ-terpineno, além de carvacrol, apresentou maiores halos de inibição de SE que os demais OEO. Concluiu-se que a multiplicação de Salmonella Enteritidis in vitro pode ser inibida por OEO cuja ação antimicrobiana independe da região produtora de orégano. No entanto, óleos essenciais que possuem p-cimeno e γ-terpineno, além de carvacrol, podem ter o seu efeito antimicrobiano potencializado.This study evaluated the influence of the origin and content of phenolic compounds in five Oregano Essential Oil (OEO) brands, from different part of the world, on the inhibitory activity against Salmonella Enteritidis (SE). The composition of each OEO was determined by gas chromatography coupled to mass spectrometry (GC-MS-IE). The inhibitory activity on SE was evaluated by the agar well diffusion test using alcoholic solutions at 0.1, 0.2, 0.5, 1.0, or 2.0%, observing the formation of inhibition halos after 24 hours of incubation at 30 °C. Using a GC-MS-IE seventeen volatile components were identified. Carvacrol was the major component of all OEO samples. They were active against SE in all tested concentrations. The differences in the inhibitory activity presented by the five brands were not significant (p > 0.05), but the OEO from the Mediterranean, which contained p-cymene and γ-terpinene besides carvacrol, resulted in larger inhibition halos than the other OEO. It was concluded that the in vitro growth of Salmonella Enteritidis can be inhibited by OEO, regardless the region in which oregano is produced. However, the essential oils that contain carvacrol, p- cymene, and γ-terpinene may present a more effective antimicrobial effect.CNPq - MES

Avaliação da atividade antioxidante utilizando sistema beta-caroteno/ácido linoléico e método de seqüestro de radicais DPPH• Evaluation of the antioxidant activity using the <FONT FACE=Symbol>b</font>-carotene/linoleic acid system and the DPPH scavenging method

A atividade antioxidante de extratos de frutas (acerola, amora, açaí e morango) e compostos puros foi avaliada por meio de dois métodos: sistema beta-caroteno/ácido linoléico e método de seqüestro de radicais livres (DPPH• - 2,2-difenil-1-picrilhidrazila). As metodologias foram previamente adaptadas para a realização em microplacas, de forma a reduzir a quantidade de reagentes e amostras necessárias, aumentar o número de análises simultâneas e permitir a automatização das leituras de absorbância. Os resultados mostraram que a atividade antioxidante dos extratos metanólicos dos frutos estava de acordo com a apresentada pelos compostos puros, isto é ácido ascórbico e compostos fenólicos, nos dois sistemas. O extrato de acerola, devido ao seu alto conteúdo de vitamina C, comportou-se como pró-oxidante e os de açaí, amora e morango como antioxidantes no sistema beta-caroteno/ácido linoléico. Entretanto, quando avaliado pelo método de seqüestro de radicais livres, o extrato de acerola apresentou a maior atividade antioxidante, seguido pelos extratos de amora, açaí e morango. As adaptações realizadas nos métodos de avaliação de atividade antioxidante utilizando microplaca permitiram a realização de múltiplas análises simultâneas, além de minimizar significativamente o uso de reagentes e amostras.<br>The antioxidant activity of fruit extracts (acerola, açaí, black-berry and strawberry) and pure compounds has been analysed by two methods: beta-carotene/linoleic acid and DPPH•(2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. First, those methodologies were adapted to be performed in microplates, in order to reduce the sample and reagent amounts, to increase the number of simultaneous analyses and to automate absorbance lectures. The results showed that the antioxidant activity of the fruit extracts was in accordance with those of pure ascorbic acid and phenolic compounds, in the two systems. The acerola extract, due to its high vitamin C content, acted as pro-oxidant, but açaí, black-berry and strawberry extracts acted as antioxidants in -carotene/linoleic acid system. However, by the DPPH• radical scavenging assay the acerola extract presented the highest antioxidant activity, followed by açaí, black-berrry and strawberrry. The adaptation of methods to evaluate the antioxidant activity using microplate allowed the realization of multiple analyses simultaneously and minimized significantly the use of reagents and samples

PHYTOCHEMICAL ANALYSIS OF HYDROETHANOLIC EXTRACTS FROM POWDERED ROOTS OF Panax ginseng C. A. Meyer AND Heteropterys tomentosa A. Juss AND EVALUATION OF THEIR EFFECTS ON ASTROCYTE CELL DEATH

The medicinal plants Panax ginseng C. A. Meyer (Araliaceae) and Heteropterys tomentosa A. Juss (Malpighiaceae) are widely and separately used by the Brazilian population as phytotherapeutics for the same medicinal purposes as tonics and to improve cognition. A chemical analysis was carried out on hydroethanolic extracts of powdered roots from P. ginseng and H. tomentosa using HPLC-DAD-ESI-MS/MS (High Performance Liquid Chromatography coupled to Diode-Array Detector and Electrospray Ionization - Mass Spectrum/Mass Spectrum). The ginsenosides Rg1, Rf, mRg and mRf were the main constituents in a hydroethanolic extract from P. ginseng, while in the hydroethanolic extract from H. tomentosa, caffeoylquinic acid derivatives and astilbin isomers were the main constituents. Concentration-time-effect curves were generated in cultures of astrocytes that were incubated with hydroethanolic extracts of these species to elucidate their toxicities. The P. ginseng extract was nontoxic at all of the tested times and concentrations. The hydroethanolic extract from H. tomentosa demonstrated toxicity at a concentration of 1000 µg/mL. P. ginseng extract had no protective effect against staurosporine. Many studies have demonstrated the neuroprotective effect of ginsenosides, caffeoylquinic derivatives and flavonoids

Influence of plant growth regulators and light on callus induction and bioactive phenolic compounds production in <i>Pyrostegia venusta</i> (Bignoniaceae)

584-590Callus culture allows production of bioactive compounds in a short time when there is limited availability of natural sources. In this work, we analyzed the influence of plant growth regulators and light on callus induction and the phenolic compounds contents in the calli of Pyrostegia venusta. Leaf explants were placed on MS medium containing 2,4-dichlorophenoxiacetic acid and 6-benzylaminopurine in the presence and absence of light. Callus induction was observed in media with plant growth regulators. The calli’s colour and consistency ranged from green and compact to yellow and friable, respectively in the presence and absence of light. The interaction between 4.52 µM 2,4-D and 8.88 µM BAP in the absence of light provided the best friable calli, with total phenol and flavonoid contents at 0.25 ± 0.01 µg ATE mg-1 DW and 0.15 ± 0.02 µg RE mg-1 DW, respectively. Calli presented higher flavonoid contents than those in the initial explants. HPLC-DAD analyses showed bioactive phenolic compounds as gallic, caffeic and benzoic acid derivatives in hydromethanolic extracts of calli

Phytochemical characterisation and bioprospection for antibacterial and antioxidant activities of <i>Lippia alba</i> Brown ex Britton & Wilson (Verbenaceae)

<p>Ethanol extract and fractions obtained from fresh and dry aerial parts of <i>Lippia alba</i> were examined in order to determine their phytochemical composition, antioxidant capacity and antibacterial activities. The ethanol extracts and fractions exhibited an antioxidant effect by the DPPH assay, especially samples of fresh plant. HPLC analysis of the ethyl acetate fractions identified the presence of phenolic acids and flavonoids. The ethanol extract and fractions showed activity against reference and multidrug-resistant strains of <i>Staphylococcus aureus</i> and <i>Enterococcus faecalis</i> (MIC range 2000–250 μg/mL). The hexane and dichloromethane fractions of fresh plant showed better activity against reference strains of <i>Escherichia coli</i> (MIC of 250 and 125 μg/mL, respectively), but all extracts and fractions were less active against multidrug-resistant strains of all the Gram-negative species evaluated. The results showed that the extract and fractions of <i>L alba</i> aerial parts showed antibacterial activity, even against multidrug-resistant Gram-positive bacteria, and antioxidant effect (DPPH assay).</p

Antioxidant, Antibacterial, Cytotoxic, and Anti-Inflammatory Potential of the Leaves of Solanum lycocarpum A. St. Hil. (Solanaceae)

Ethanol extract and fractions obtained from leaves of Solanum lycocarpum were examined in order to determine their phenolic composition, antioxidant, antibacterial, anti-inflammatory, and cytotoxic potential. High performance liquid chromatography coupled with DAD analysis indicated that the flavonoids apigenin and kaempferol were the main phenolic compounds present in dichloromethane and ethyl acetate fractions, respectively. The antioxidant activity was significantly more pronounced for dichloromethane, ethyl acetate, and hydroethanol fractions than that of the commercial antioxidant 2,6-di-tert-butyl-4-methylphenol. The hexane and dichloromethane fractions were more active against the tested bacteria. The hydroethanol fraction exhibited significant anti-inflammatory activity at the dose of 75 and 150 mg/kg in the later phase of inflammation. However, the antiedematogenic effect of the higher dose of the ethyl acetate fraction (150 mg/kg) was more pronounced. The ethyl acetate fraction also presented a less cytotoxic effect than the ethanol extract and other fractions. These activities found in S. lycocarpum leaves can be attributed, at least in part, to the presence of phenolic constituents such as flavonoids. This work provided the knowledge of phenolic composition in the extract and fractions and the antioxidant, antibacterial, anti-inflammatory, and cytotoxic activities of leaves of S. lycocarpum

Antioxidant, Antibacterial, Cytotoxic, and Anti-Inflammatory Potential of the Leaves of Solanum lycocarpum A. St. Hil. (Solanaceae)

Ethanol extract and fractions obtained from leaves of Solanum lycocarpum were examined in order to determine their phenolic composition, antioxidant, antibacterial, anti-inflammatory, and cytotoxic potential. High performance liquid chromatography coupled with DAD analysis indicated that the flavonoids apigenin and kaempferol were the main phenolic compounds present in dichloromethane and ethyl acetate fractions, respectively. The antioxidant activity was significantly more pronounced for dichloromethane, ethyl acetate, and hydroethanol fractions than that of the commercial antioxidant 2,6-di-tert-butyl-4-methylphenol. The hexane and dichloromethane fractions were more active against the tested bacteria. The hydroethanol fraction exhibited significant anti-inflammatory activity at the dose of 75 and 150 mg/kg in the later phase of inflammation. However, the antiedematogenic effect of the higher dose of the ethyl acetate fraction (150 mg/kg) was more pronounced. The ethyl acetate fraction also presented a less cytotoxic effect than the ethanol extract and other fractions. These activities found in S. lycocarpum leaves can be attributed, at least in part, to the presence of phenolic constituents such as flavonoids. This work provided the knowledge of phenolic composition in the extract and fractions and the antioxidant, antibacterial, anti-inflammatory, and cytotoxic activities of leaves of S. lycocarpum

Antioxidant, antibacterial and cytotoxic potential of the ripe fruits of <i>Solanum lycocarpum</i> A. St. Hil. (Solanaceae)

<div><p>Ethanol extract (EE) and fractions obtained from the ripe fruits of <i>Solanum lycocarpum</i> were examined in order to determine their phenolic composition, antioxidant capacity, antibacterial activities and cytotoxic potential. High-performance liquid chromatography coupled with DAD analysis indicated that caffeic and chlorogenic acids were the main phenolic compounds present in the EE, dichloromethane (DCM) and ethyl acetate (Ac) fractions. The antioxidant activity assessed by the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radical was significantly more pronounced for DCM and Ac fractions than that of the commercial antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). EE and fractions exhibited selective antibacterial activity against Gram-positive bacteria, especially the hexane (Hex) and DCM fractions. EE and fractions exhibited low toxicity towards the LLC-MK2 cell line, especially the Hex, DCM and Ac fractions. This work provides the knowledge of phenolic composition in the extract and fractions from the ripe fruits of <i>S. lycocarpum</i> and their antioxidant, antibacterial and cytotoxic activities.</p></div