Plant phenolic compounds and the isolation of plant enzymes

Loomis, W.David; Battaile, J.

doi:10.1016/s0031-9422(00)82157-3

Cited by 806 publications

(323 citation statements)

References 56 publications

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“…An aliquot of crude extract (20 mg extracted DM) dissolved in 2 ml 50% [v/v] aqueous methanol, was diluted 1:25 with water and passed over a preconditioned SPE-C18 cartridge (Varian Bond Elute, 3cc, 2 g sorbens) and the eluate was collected. Then the cartridge was stepwise eluted with each two reservoir volumes (10 ml) of 40, 60, 70, 80, 90 and 100% [v/v] Loomis & Battaile (1966). A suspension of PVPP in water (2 g PVPP/20 ml water) was added to an aliquot of the crude extract (v/v 1:1) and stored overnight at 4°C.…”

Section: Fractionation Of Crude Extractsmentioning

confidence: 99%

Allelopathic activity of Stratiotes aloides on phytoplankton—towards identification of allelopathic substances

Mulderij¹,

Mau²,

Donk³

et al. 2007

Shallow Lakes in a Changing World

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The allelopathic activity of the aquatic macrophyte, Stratiotes aloides, was determined with laboratory experiments. Active compounds exuded in the medium or present in plant tissue were extracted using standard procedures and solid phase extraction (SPE). The activity towards various cyanobacteria and chlorophytes was tested in two different bioassay systems using agar plates and liquid cultures of phytoplankton. Extracts and exudates of S. aloides affected phytoplankton growth. SPE-enriched exudates and enriched water from a natural Stratiotes stand caused inhibition of target species, however, also some controls were active. Phytoplankton species exhibited differential sensitivity to extracts of S. aloides. We observed inhibitory and stimulatory effects on phytoplankton. In general, more cyanobacteria than other phytoplankton species were inhibited, and the inhibition of cyanobacteria was stronger. In most cases, nutrient (P or K) limitation of Synechococcus elongatus and Scenedesmus obliquus decreased the sensitivity of these species towards allelochemicals from Stratiotes aloides, except for P-limited cultures of Scenedesmus. The allelopathically active compound(s) from Stratiotes are moderately lipophilic and most likely no phenolic compounds. Our results indicate that allelopathy (besides nutrient interference and shading) might also account for the low phytoplankton and filamentous algae densities in the vicinity of Stratiotes plants, at least during certain phases of the life-cycle of Stratiotes.

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Section: Fractionation Of Crude Extractsmentioning

confidence: 99%

Allelopathic activity of Stratiotes aloides on phytoplankton—towards identification of allelopathic substances

Mulderij¹,

Mau²,

Donk³

et al. 2007

Shallow Lakes in a Changing World

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“…Este polímero tem uma habilidade marcante para remover compostos fenólicos de soluções, devido à sua baixa solubilidade. Esse polímero tem sido usado por diversos pesquisadores [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][56][57][58] para separar compostos fenólicos naturais de diversos extratos enzimáticos. Este seu bom desempenho é atribuído à formação de pontes de hidrogênio 56 entre os substratos naturais e o polímero PVP como mostrado na Figura 1.…”

Section: Determinação Da Atividade E Proteína Total Da Enzimaunclassified

“…Este seu bom desempenho é atribuído à formação de pontes de hidrogênio 56 entre os substratos naturais e o polímero PVP como mostrado na Figura 1. Outras substâncias e polímeros também têm sido usados para remoção dos compostos fenólicos durante a obtenção dos extratos brutos como resinas de troca iônica, L-cisteína, policaprolactam e polietileno glicol [56][57][58][59][60][61] . Entretanto, estudos desenvolvidos em nosso laboratório [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] , mostraram que os PVPs são os melhores agentes protetores.…”

Section: Determinação Da Atividade E Proteína Total Da Enzimaunclassified

Uso analítico de tecidos e de extratos brutos vegetais como fonte enzimática

Fatibello‐Filho¹,

Vieira²

2002

Quím. Nova

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“…To the suspension is added 0.6 g insoluble polyvinylpyrrolidone (Polyclar AT, G. A. F. (Great Britain) Ltd., ManChester, purified by acid washing [13]) and the cells are disrupted ultrasonically as previously described [3]. The fraction designated "homogenate" is the supernatant obtained after sedimenting unbroken cells, debris and polyvinylpyrrolidone a t 1,500 x g for 10 min.…”

Section: Preparation Of Chlorella Subcellular Enzymementioning

confidence: 99%

The Mechanism of Formation of Polyunsaturated Fatty Acids by Photosynthetic Tissue

Gurr

Robinson

James

1969

European Journal of Biochemistry

142

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Labelled oleic acid, which is used as a substrate in studying the conversion of oleate into linoleate by Chlorella chloroplasts, is rapidly incorporated into the phospholipids. The phosphatidyl choline fraction accounts for almost all of the phospholipid label. Desaturation to linoleate lags behind the incorporation into lipids, but the newly synthesized linoleate remains esterified to phosphatidyl choline.[1-14C]Oleoy1-phosphatidyl choline, incubated with chloroplasts, is converted into [1-14C]-linoleoyl-phosphatidyl choline, but considerable difficulties arise in presenting the lipid to the enzyme in an acceptable form. Oleoyl-phosphatidyl choline formed in situ, however, does not present these difficulties and is desaturated a t a faster rate than the CoA derivative under conditions in which unesterified fatty acid cannot be LLactivated", and hence cannot be desatmated. We conclude that the precursor fatty acid can be transferred directly from the lipid to the desaturase enzyme and the product immediately accepted by a lipid to form a "desaturationacylation" cycle. Our data neither prove, nor exclude the possibility that the fatty acid is transformed while still attached to the lipid in ester linkage. esters are not the true substrates for the "desaturase". The work of Nagai and Bloch [6] with the stearoylacyl carrier protein desaturase of Euglena gracilis might suggest that the acyl carrier protein ester is the true substrate. However, the experiments of Nichols and James [7,8] have pointed to the possibility that phospholipids and glycolipids may have an important role to play in fatty acid transformations, while, more specifically, Harris et al. 141 have speculated about the possibility that phosphatidyl choline, which has a striklingly high specific activity with respect to newly biosynthesized linoleate in Chlorelh, may have special importance for the desaturation reaction.I n this paper, we shall report further studies which confirm that phosphatidyl choline is an important intermediate in the conversion of oleate into linoleate. MATERIALS AND METHODSMost of the procedures have been documented in an earlier paper [3]. However, some additional techniques have been used. Thin Layer ChromatographyTotal lipids were separated on thin layers (0.25 mm) of Silica Gel G with the solvent system:

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Plant phenolic compounds and the isolation of plant enzymes

Cited by 806 publications

References 56 publications

Allelopathic activity of Stratiotes aloides on phytoplankton—towards identification of allelopathic substances

Allelopathic activity of Stratiotes aloides on phytoplankton—towards identification of allelopathic substances

Uso analítico de tecidos e de extratos brutos vegetais como fonte enzimática

The Mechanism of Formation of Polyunsaturated Fatty Acids by Photosynthetic Tissue

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