Note Variations in Hypericin Concentrations in Hypericum perforatum L. and Commercial Products

Constantine, G.H.; Karchesy, Joseph J.

doi:10.1076/phbi.36.5.365.4651

Cited by 33 publications

(22 citation statements)

References 6 publications

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“…Por outro lado, na análise de flores e frutos de H. perforatum coletados em diferentes regiões da Itália, a rutina foi encontrada em maior quantidade do que a quercetina e seus derivados (Pietta et al 2001). As variações observadas no perfil dos flavonóides analisados podem ser conseqüência das diferenças nas condições ambientais, da variabilidade genética ou das partes da planta utilizadas para a análise, fatores que comprovadamente alteram a produção dos metabólitos secundários (Büter et al 1998;Constantine & Karchesy 1998).…”

Section: Discussionunclassified

“…Embora vários estudos tenham determinado a presença deste composto em plantas de hipérico, as concentrações variam amplamente de acordo com a origem do material. Por exemplo, plantas coletadas no Canadá apresentaram 0,01 a 0,06% de hipericina, enquanto nos Estados Unidos a variação foi de 0,11 a 0,38% (Jensen et al 1995;Constantine & Karchesy 1998). Além de tal variação, foi relatado que as partes aéreas vegetativas de hipérico apresentam teores de hipericina menores do que o das flores (Kazlauskas & Bagdonaitë 2004).…”

Section: Discussionunclassified

“…Como a eficácia dos extratos de hipérico não está diretamente relacionada a apenas um constituinte, a qualidade fitoquímica do material bruto deve ser avaliada quanto à presença e à concentração de compostos previamente determinados como benéficos (Gray et al 2003). Além disso, a quantidade de moléculas bioativas nas plantas de hipérico pode ser alterada por vários fatores, como época do ano (Southwell & Bourke 2001), partes da planta (Constantine & Karchesy 1998), variações genotípicas e ambientais (Büter et al 1998) e níveis de ploidia (Kosuth et al 2003). As técnicas utilizadas para coleta, secagem e armazenamento do material vegetal também podem alterar os teores dos compostos bioativos (Martins et al 1998;Böttcher et al 2003).…”

Section: Introductionunclassified

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Alteração dos metabólitos secundários em plantas de Hypericum perforatum L. (Hypericaceae) submetidas à secagem e ao congelamento

2007

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RESUMO -(Alteração dos metabólitos secundários em plantas de Hypericum perforatum L. (Hypericaceae) submetidas à secagem e ao congelamento). Nos últimos anos, o interesse por Hypericum perforatum tem aumentado devido à sua ação antiviral, antidepressiva e moduladora de apoptose em células neoplásicas. O preparo do material vegetal, após ser colhido, envolve freqüentemente a dessecação ou o congelamento e posterior armazenamento, processos que podem alterar o perfil dos metabólitos secundários. Neste sentido, este trabalho avaliou o efeito da secagem, do congelamento e da estocagem sob baixas temperaturas na quantidade de flavonóides e de hipericina nas partes vegetativas de plantas de hipérico. Ramos de hipérico foram submetidos à secagem a 25, 30, 50 e 70 °C, congelados em nitrogênio líquido ou congelados e armazenados a -20 °C por 10, 20 e 30 dias. A quantificação dos flavonóides e de hipericina foi realizada por cromatografia líquida de alta eficiência (CLAE). Os teores de flavonóides e de hipericina foram afetados pela temperatura de secagem. Secagem a 25 °C causou redução nos teores de grande parte dos metabólitos analisados, enquanto a 50 °C, os teores de rutina livre e glicosilada, de quercetina e quercitrina glicosiladas e de hipericina foram preservados. Apigenina livre e canferol não sofreram reduções significativas nas suas concentrações, independente das temperaturas de secagem. O tratamento de congelamento e imediata análise das amostras não alterou o perfil dos flavonóides, mas causou redução do nível de hipericina nas plantas de hipérico. Palavras-chave: flavonóides, hipericina, metabolismo secundário, plantas medicinais, produtos naturais ABSTRACT -(Secondary metabolite content in Hypericum perforatum L. (Hypericaceae) plants submitted to drying and freezing). In recent years, interest inHypericum perforatum has increased due to its antiviral, antidepressive and apoptosis-inducing properties. Plant material preparation after harvesting often includes dehydration or freezing and further storage, and these procedures can lead to variations in the secondary metabolite profile. In this study the effects of drying, freezing and storage at -20 ºC on flavonoid and hypericin content in H. perforatum were evaluated. Leaves and stems of H. perforatum were dried at 25, 30, 50 and 70 ºC, frozen in liquid nitrogen or frozen and then stored at -20 ºC for 10, 20 and 30 days. Flavonoid and hypericin quantification was performed by High Performance Liquid Chromatography (HPLC). Levels of both flavonoids and hypericin were affected by drying temperature. Drying at 25 ºC resulted in lower levels of most of the metabolites analyzed while at 50 ºC, levels of free and conjugated rutin, conjugated quercetin and quercitrin as well as hypericin content were maintained when compared to fresh samples. Free apigenin and kaempferol did not show any significant variation, regardless of drying temperature. Freezing did not affect the profile of flavonoids, but it led to significant reduction in hypericin content.

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Section: Discussionunclassified

Section: Introductionunclassified

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Alteração dos metabólitos secundários em plantas de Hypericum perforatum L. (Hypericaceae) submetidas à secagem e ao congelamento

2007

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“…However, it is also possible that St. John's wort may enhance serotonin neurotransmission through a novel mechanism, for example, by increasing the firing rate of brain serotonergic neurons. The present study sought to determine which, if any, of these possible actions can be attributed to St. John's wort.Because the chemical composition, quality, and purity of St. John's wort has been shown to vary considerably across different preparations (Constantine and Karchesy 1998;Kurth and Spreemann 1998;Liu et al 2000), results obtained with one may not generalize to others. Since most of the clinical and experimental stud- 25 , NO .…”

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“…Because the chemical composition, quality, and purity of St. John's wort has been shown to vary considerably across different preparations (Constantine and Karchesy 1998;Kurth and Spreemann 1998;Liu et al 2000), results obtained with one may not generalize to others. Since most of the clinical and experimental stud-ies on St. John's wort have been conducted with a particular hydromethanolic extract called LI 160, which is contained in Jarsin® 300, we selected this preparation for our studies.…”

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Effects of Standardized Extracts of St. John's Wort on the Single-Unit Activity of Serotonergic Dorsal Raphe Neurons in Awake Cats Comparisons with Fluoxetine and Sertraline

Fornal

Metzler

Mirescu

et al. 2001

Neuropsychopharmacology

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St. John's wort, p.o.) and i.v.). Both preparations were found to have no effect on neuronal activity. This contrasts sharply with the action of fluoxetine and sertraline (2 mg/kg, p.o.) 8-hydroxy-2-(di-n-propylamino)tetralin (10 g/kg, i.v.). Overall, these -hydroxytryptamine (serotonin); ElectrophysiologyThe medicinal plant Hypericum perforatum L., commonly known as St. John's wort, appears to be an effective antidepressant with few side effects (Hippius 1998;Wheatley 1998;Vitiello 1999). In Germany, where extracts of the plant are licensed as a medication, St. John's wort or hypericum is used more extensively than et al. 1996). Since the publication of that influential report, several other systematic reviews (and one metaanalysis) have appeared which further support the antidepressant efficacy of hypericum (Josey and Tackett 1999;Kim et al. 1999;Stevinson and Ernst 1999;Gaster and Holroyd 2000). Furthermore, in comparison with other antidepressants, St. John's wort is well tolerated and has a low side effect profile (Linde et al. 1996;Ernst et al. 1998 Despite its widespread use, the active constituents and mechanism of antidepressant action of St. John's wort remain largely unknown (Bennett et al. 1998;Nathan 1999). A number of studies have shown that crude hypericum preparations and some of the constituents can inhibit monoamine oxidase (MAO) activity in vitro (Demisch et al. 1989;Thiede and Walper 1994;Cott 1997;. However, the clinical relevance of this pharmacological effect is questionable, since it occurs only at high concentrations and has not been observed in vivo (Bladt and Wagner 1994;Yu 2000). More recent studies have focused on the capacity of St. John's wort to inhibit the uptake of brain monoamines, particularly serotonin Neary and Bu 1999). Perovic and Müller (1995) were the first to report that a crude hypericum extract inhibited the uptake of serotonin in rat cortical synaptosomes at relatively low concentrations and conclude that the antidepressant activity of St. John's wort is due to this action. Hypericum has also been shown to inhibit the synaptosomal uptake of dopamine and norepinephrine, at concentrations similar to those found to inhibit the uptake of serotonin . In subsequent studies, the chemical substance hyperforin was identified as one of the major uptake-inhibiting components of St. John's wort Chatterjee et al. 1998;Singer et al. 1999). The content of this substance has recently been associated with the clinical antidepressant action of St. John's wort (Laakmann et al. 1998), suggesting that hyperforin is at least partially responsible for the antidepressant properties of the herb. Other evidence suggest that hypericum extracts may enhance the release of serotonin from presynaptic stores (Gobbi et al. 1999). Neurochemical studies have shown that St. John's wort increases serotonin metabolism and/or turnover in various brain regions (Calapai et al. 1999;Yu 2000). Finally, it has been hypothesized that the clinical efficacy of St. John's wort may result from a combinati...

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Effect of St John's Wort on Drug Metabolism by Induction of Cytochrome P450 3A4 Enzyme

Markowitz¹

2003

JAMA

332

154

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Context St John's wort is a popular herbal product used to treat depression but it has been implicated in drug interactions. Objective To assess the potential of St John's wort administration to alter the activity of the cytochrome P450 (CYP) enzymes extensively involved in drug metabolism. Design, Setting, and Participants Open-label crossover study with fixed treatment order conducted March 2002 to February 2003 in a US general clinical research center involving 12 healthy volunteers (6 men and 6 women) aged 22 to 38 years before and after 14 days of administration of St John's wort. Intervention Participants were given probe drugs (30 mg of dextromethorphan and 2 mg of alprazolam) to establish baseline CYP 3A4 and CYP 2D6 activity. After a minimum 7-day washout period, participants began taking one 300-mg tablet 3 times per day. After 14 days of St John's wort administration, participants were given the probe drugs along with 1 St John's wort tablet to establish postadministration CYP activity; the St John's wort dosing regimen was continued for 48 hours. Main Outcome Measures Changes in plasma pharmacokinetics of alprazolam as a probe for CYP 3A4 activity and the ratio of dextromethorphan to its metabolite, dextrorphan, in urine as a probe for CYP 2D6 activity. Results A 2-fold decrease in the area under the curve for alprazolam plasma concentration vs time (PϽ.001) and a 2-fold increase in alprazolam clearance (PϽ.001) were observed following St John's wort administration. Alprazolam elimination halflife was shortened from a mean (SD) of 12.4 (3.9) hours to 6.0 (2.4) hours (PϽ.001). The mean (SD) urinary ratio of dextromethorphan to its metabolite was 0.006 (0.010) at baseline and 0.014 (0.025) after St John's wort administration (P=.26). Conclusions A 14-day course of St John's wort administration significantly induced the activity of CYP 3A4 as measured by changes in alprazolam pharmacokinetics. This suggests that long-term administration of St John's wort may result in diminished clinical effectiveness or increased dosage requirements for all CYP 3A4 substrates, which represent at least 50% of all marketed medications.

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Note Variations in Hypericin Concentrations in Hypericum perforatum L. and Commercial Products

Cited by 33 publications

References 6 publications

Alteração dos metabólitos secundários em plantas de Hypericum perforatum L. (Hypericaceae) submetidas à secagem e ao congelamento

Alteração dos metabólitos secundários em plantas de Hypericum perforatum L. (Hypericaceae) submetidas à secagem e ao congelamento

Effects of Standardized Extracts of St. John's Wort on the Single-Unit Activity of Serotonergic Dorsal Raphe Neurons in Awake Cats Comparisons with Fluoxetine and Sertraline

Effect of St John's Wort on Drug Metabolism by Induction of Cytochrome P450 3A4 Enzyme

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