Comparison of methods for the extraction of flavonoids from birch leaves (Betula pendula Roth.) carried out using high-performance liquid chromatography

Keinänen, Markku

doi:10.1021/jf00035a032

Cited by 24 publications

(12 citation statements)

References 20 publications

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“…We also found a marked difference between extractions with anhydrous organic solvents and solvents containing water. The solvents most commonly used to extract phlorotannins from F. vesiculosus have been aqueous mixtures of ethanol and acetone (e.g., Ragan and Glombitza, 1986), and in several studies the efficiencies of different solvents in extracting tannins have been similar to ours (Hagerman, 1988;Keinänen, 1993;Salminen, 2003). The solubility of most phenolic compounds in polar extractant enables for instance the use of LC-ESI-MS, which requires at least semipolar conditions, to analyze polyphenols (Wang and Cole, 1997).…”

Section: Discussionmentioning

confidence: 98%

CONTENTS OF SOLUBLE, CELL-WALL-BOUND AND EXUDED PHLOROTANNINS IN THE BROWN ALGA Fucus vesiculosus, WITH IMPLICATIONS ON THEIR ECOLOGICAL FUNCTIONS

et al. 2005

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Abstract-Phlorotannins are ubiquitous secondary metabolites in brown algae that are phenotypically plastic and suggested to have multiple ecological roles. Traditionally, phlorotannins have been quantified as total soluble phlorotannins. Here, we modify a quantification procedure to measure, for the first time, the amount of cell-wall-bound phlorotannins. We also optimize the quantification of soluble phlorotannins. We use these methods to study the responses of soluble and cell-wall-bound phlorotannin to nutrient enrichment in growing and nongrowing parts of the brown alga Fucus vesiculosus. We also examine the effects of nutrient shortage and herbivory on the rate of phlorotannin exudation. Concentrations of cell-wall-bound phlorotannins were much lower than concentrations of soluble phlorotannins; we also found that nutrient treatment over a period of 41 days affected only soluble phlorotannins. Concentrations of each phlorotannin type correlated positively between growing and nongrowing parts of individual seaweeds. However, within nongrowing thalli, soluble and cell-wall-bound phlorotannins were negatively correlated, whereas within growing thalli there was no correlation. Phlorotannins were exuded from the thallus in all treatments. Herbivory increased exudation, while a lack of nutrients had no effect on exudation. Because the amount of cell-wall-bound phlorotannins is much smaller than the amount of soluble phlorotannins, the major function of phlorotannins appears to be a secondary one.

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Section: Discussionmentioning

confidence: 98%

CONTENTS OF SOLUBLE, CELL-WALL-BOUND AND EXUDED PHLOROTANNINS IN THE BROWN ALGA Fucus vesiculosus, WITH IMPLICATIONS ON THEIR ECOLOGICAL FUNCTIONS

et al. 2005

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“…Temperature, solvent concentration, and extraction time are the most important factors that influence the extraction efficacy in terms of quality and yield. Mixtures of ethanol and water were chosen as nontoxic and environmentally friendly solvents, which have been shown to be effective in the extraction of quercetin glycosides (10). The determined response variables are representatives of the phytochemical characteristics of the prepared extracts.…”

Section: Introductionmentioning

confidence: 99%

Influence of Extraction Parameters on the Phytochemical Characteristics of Extracts from Buckwheat (Fagopyrum esculentum) Herb

Hinneburg

Neubert

2004

J. Agric. Food Chem.

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In recent years, the interest in herbal medicinal products, especially in the field of dermatology and cosmetics, has risen enormously. Many plant-derived substances show photoprotective properties in terms of absorption of UV radiation and preventing photodamage to molecular structures of human skin. Modern phytopharmaceutics as well as phytocosmetics require standardized, defined extracts from the herbal matrix. Buckwheat herb is rich in flavonoids, which have been identified as potent antioxidants. Up to now, there have been no systematic investigations available concerning the extraction conditions for phenolic substances from buckwheat herb. In this paper, we report the influence of three extraction parameters, ethanol concentration, temperature, and extraction time, on the response variables extractable matter, antioxidant activity, and content of fagopyrin, rutin, and chlorogenic acid. Our results suggest that an extract with good antioxidant activity, a high content of phenolics, and a low content of the phototoxic fagopyrin can be yielded by agitated maceration with 30% ethanol at 60 degrees C for 2 h. Furthermore, there is good correlation between the antioxidant activity and the rutin content, whereas the extractable matter is not an appropriate parameter for extract quality. Huge differences in the content of rutin and chlorogenic acid when using herbal drugs from different suppliers confirm the demand of standardized procedures for the production of herbal drugs.

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“…O extrato aquoso apresentou um rendimento significativamente superior aos demais, comprovando, portanto, a eficácia deste solvente, que certamente foi maximizada pela utilização de material previamente desidratado [12]. Este resultado, segundo JULKUNEN-TIITTO [11], é devido à predominância de compostos fenólicos em vegetais, os quais, em sua maioria, são solúveis em solventes polares.…”

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Atividade antioxidante de extratos de coentro (Coriandrum sativum L. )

Mélo¹,

Filho²,

Guerra³

et al. 2003

Ciênc. Tecnol. Aliment.

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A oxidação lipídica, uma das principais causas de deterioração de alimentos, pode ser prevenida pela adição de antioxidantes, dos quais os sintéticos, BHA (butil hidroxianisol), BHT (butil hidroxitolueno), PG (propil galato) e TBHQ (terc-butil hidroquinona) são os mais utilizados. O emprego destes compostos, entretanto, tem sido alvo de questionamentos quanto a sua inocuidade, motivando a busca de antioxidantes naturais que possam atuar, isolados ou sinergicamente com outros aditivos, em substituição aos sintéticos [9,13,23,24].Pesquisas realizadas nos últimos anos relatam que muitos vegetais apresentam, em sua constituição, compostos com ação antioxidante, dentre os quais destacam-se as especiarias, ingredientes utilizados no preparo de alimentos, desde os primórdios da História, para melhorar ou ressaltar suas características organolépti-cas, bem como preservá-las. O efeito antioxidante de especiarias e ervas foi inicialmente evidenciado por CHIPAULT et al. [4], em 32 especiarias, das quais o alecrim e a sálvia foram consideradas as mais eficazes. Posteriormente, esta ação foi comprovada no orégano e no tomilho [14,18,25] RESUMOA atividade antioxidante de diferentes extratos de coentro (Coriandrum sativum L.), isolados, associados entre si e com o BHT foi investigada. A ação antioxidante, exercida pelos extratos etéreo, etanólico e aquoso, obtidos por processo de extração seqüencial, foi avaliada através de sistema modelo β-caroteno/ácido linoléico e os compostos responsáveis por esta ação identificados. O efeito sinergista entre os extratos aquoso e etéreo foi avaliado utilizado o planejamento fatorial 2 2 . Os extratos aquoso, etéreo e etanólico exibiram 69,83%, 61,89% e 40,50%, respectivamente, de proteção contra a oxidação. Compostos fenólicos foram detectados nos dois primeiros extratos e constatada a presença de carotenóides no etéreo. Ao combinar os dois extratos, em diferentes concentrações, o percentual de inibição da oxidação foi inferior ao dos extratos isolados, demonstrando não haver sinergismo entre eles. Associações de diferentes concentrações de BHT com o extrato aquoso exibiram elevada ação antioxidante, enquanto com o extrato etéreo esta ação foi levemente superior a do extrato isolado. A habilidade dos extratos aquoso e etéreo em retardar a oxidação pode ser atribuída, respectivamente, aos seus constituintes fenólicos e carotenóides. O extrato aquoso pode ser considerado como um potencial antioxidante, cuja ação pode ser intensificada ao ser empregado juntamente com BHT. Palavras-chave: coentro; antioxidante; sinergismo. SUMMARYANTIOXIDANT ACTIVITY OF CORIANDER EXTRACTS (Coriandrum sativum L.). The antioxidant activity of different extracts of coriander (Coriandrum sativum), isolated and/or combined with itself and BHT, was investigated. The etheric, ethanolic and aqueous extracts obtained by sequential extraction were evaluated for antioxidant action in a β-carotene/acid linoléico model system and the active compounds identified. The antioxidant synergistic effect between aqueous and ether...

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Comparison of methods for the extraction of flavonoids from birch leaves (Betula pendula Roth.) carried out using high-performance liquid chromatography

Cited by 24 publications

References 20 publications

CONTENTS OF SOLUBLE, CELL-WALL-BOUND AND EXUDED PHLOROTANNINS IN THE BROWN ALGA Fucus vesiculosus, WITH IMPLICATIONS ON THEIR ECOLOGICAL FUNCTIONS

CONTENTS OF SOLUBLE, CELL-WALL-BOUND AND EXUDED PHLOROTANNINS IN THE BROWN ALGA Fucus vesiculosus, WITH IMPLICATIONS ON THEIR ECOLOGICAL FUNCTIONS

Influence of Extraction Parameters on the Phytochemical Characteristics of Extracts from Buckwheat (Fagopyrum esculentum) Herb

Atividade antioxidante de extratos de coentro (Coriandrum sativum L. )

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