Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hypericum”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2005

An anti-staphylococcal acylphloroglucinol from Hypericum foliosum.

An investigation into the antibacterial properties of Hypericum foliosum Aiton. (Guttiferae) has led to the isolation of a new bioactive acylphloroglucinol natural product which by NMR spectroscopy and mass spectrometry was characterised as 1,3,5-trihydroxy-6-[2''',3'''-epoxy-3'''-methyl-butyl]-2-[2''-methyl-butanoyl]-4-[3'-methyl-2''-butenyl]-benzene and is described here for the first time. This metabolite was evaluated against a panel of multidrug-resistant strains of Staphylococcus aureus and minimum inhibitory values ranged from 16 to 32 microg/ml.

Anti-Bacterial Agents↗
PubMed2005

Induction of phenolic compounds in Hypericum perforatum L. cells by Colletotrichum gloeosporioides elicitation.

Changes in phenolic metabolism after elicitation with Colletotrichum gloeosporioides (CG) has been studied in Hypericum perforatum L. (HP) cell suspension cultures. Soluble phenolics were analysed by HPLC-DAD and HPLC-DAD-MS/MS. HP cultures elicited with the CG elicitor showed a significant increase in xanthone accumulation. Xanthone accumulation increased twelve fold when the cells were primed with methyl-jasmonate (MeJ) or salicylic acid (SA), before elicitation. HP cultures exposed only to MeJ produced a set of flavonoids, the flavones which represent a substantial part (approx. 40%) of the total flavonoids accumulated in these cells. The possible importance of xanthones as a component of defence mechanism of HP against biotic stress is discussed.

Acetates↗
PubMed2006

Xanthones from Hypericum chinense.

Six xanthones, 1,3,7-trihydroxy-2-(2-hydroxy-3-methyl-3-butenyl)-xanthone (1), 1,7-dihydroxy-2,3-[2''-(1-hydroxy-1-methylethyl)-dihydrofurano]-xanthone (2), 1,3,7-trihydroxy-5-methoxyxanthone (3), 1,7-dihydroxy-5,6-dimethoxyxanthone (4), 4,5-dihydroxy-2,3-dimethoxyxanthone (5), 1,3-dihydroxy-2,4-dimethoxyxanthone (6) and 21 known xanthones were isolated from the leaves and stems of Hypericum chinense. Their structures were established based on spectroscopic studies.

Hypericum↗
PubMed2006

Anti-staphylococcal acylphloroglucinols from Hypericum beanii.

As part of an ongoing project to investigate the anti-staphylococcal properties of the Hypericum genus, an acylphloroglucinol, 1,5-dihydroxy-2-(2'-methylpropionyl)-3-methoxy-6-methylbenzene (1), was isolated from the dichloromethane extract of the aerial parts of H. beanii (Guttiferae), together with a minor related acylphloroglucinol 1,5-dihydroxy-2-(2'-methylbutanoyl)-3-methoxy-6-methylbenzene (2) as a mixture in a 5:2 ratio. The known compounds 1,7-dihydroxyxanthone (3), stigmasterol, catechin and shikimic acid were also isolated from this plant. The structures of the compounds were characterized by extensive 1- and 2D NMR spectroscopy and mass spectrometry. The minimum inhibitory concentration (MIC) values the acylphloroglucinol mixture and (3) against a panel of multidrug-resistant strains of Staphylococcus aureus ranged from 16-32 microg/ml to 128-256 microg/ml, respectively.

Anti-Bacterial Agents↗
PubMed2006

Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS.

The newly established hyphenated instrumentation of LC/DAD/SPE/NMR and LC/UV/(ESI)MS techniques have been applied for separation and structure verification of the major known constituents present in Greek Hypericum perforatum extracts. The chromatographic separation was performed on a C18 column. Acetonitrile-water was used as a mobile phase. For the on-line NMR detection, the analytes eluted from column were trapped one by one onto separate SPE cartridges, and hereafter transported into the NMR flow-cell. LC/DAD/SPE/NMR and LC/UV/MS allowed the characterization of constituents of Greek H. perforatum, mainly naphtodianthrones (hypericin, pseudohypericin, protohypericin, protopseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, quercitrin, isoquercitrin, hyperoside, astilbin, miquelianin, I3,II8-biapigenin) and phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid). Two phloroglucinols (hyperfirin and adhyperfirin) were detected for the first time, which have been previously reported to be precursors in the biosynthesis of hyperforin and adhyperforin.

Chromatography, Liquid↗
PubMed2005

Effect of water and temperature stress on the content of active constituents of Hypericum brasiliense Choisy.

Hypericum brasiliense is a medicinal herb containing several compounds with important pharmacological activity. In this study, we investigated the effects of water stress (waterlogging and drought) and temperature (low and high, constant and alternate) on the content of betulinic acid and phenolic compounds (quercetin, rutin, 1,5-dihydroxyxanthone, isouliginosin B) in this species. In general, the water stress increased the levels of all of the compounds analyzed, particularly some of the phenolic compounds. On the other hand, the responses to alternating temperatures varied according to the compound. The results for plants kept in growth chambers indicated that low light intensity might have influenced the levels of the compounds. There was also a reallocation of carbon, with water-stressed plants showing a reduction in growth while the levels of the compounds increased. In the temperature treatments, such an increase was evident only for the phenolic compounds.

Cold Temperature↗
PubMed2001

Catalytic inhibition of human DNA topoisomerase IIalpha by hypericin, a naphthodianthrone from St. John's wort (Hypericum perforatum).

St. John's wort (Hypericum perforatum) is the most widely used herbal medicine for the treatment of depression. However, concerns have arisen about the potential of its interaction with other drugs due to the induction of cytochrome P450 isozymes 1A2 and 3A4 by the components hypericin and hyperforin, respectively. Structurally similar natural products are often employed as antitumor agents due to their action as inhibitors of DNA topoisomerases, nuclear enzymes that modify DNA during cellular proliferation. Preliminary findings that hypericin inhibited the DNA relaxation activity of topoisomerase IIalpha (topo II; EC 5.99.1.3) led us to investigate the mechanism of enzyme inhibition. Rather than stabilizing the enzyme in covalent complexes with DNA (cleavage complexes), hypericin inhibited the enzyme prior to DNA cleavage. In vitro assays indicate that hypericin is a potent antagonist of cleavage complex stabilization by the chemotherapeutics etoposide and amsacrine. This antagonism appears to be due to the ability of hypericin to intercalate or distort DNA structure, thereby precluding topo II binding and/or DNA cleavage. Supporting its non-DNA damaging, catalytic inhibition of topo II, hypericin was shown to be equitoxic to both wild-type and amsacrine-resistant HL-60 leukemia cell lines. Moreover, hypericin was incapable of stimulating DNA damage-responsive gene promoters that are activated by etoposide. As with the in vitro topo II assay, antagonism of DNA damage stimulated by 30 microM etoposide was evident in leukemia cells pretreated with 5 microM hypericin. Since many cancer patients experience clinical depression and concomitantly self-medicate with herbal remedies, extracts of St. John's wort should be investigated further for their potential to antagonize topo II-directed chemotherapy regimens.

Anthracenes↗
PubMedDate not supplied

Anti-inflammatory and analgesic activity of Hypericum empetrifolium Willd. (Guttiferae).

A methanolic extract of Hypericum empetrifolium Willd. was evaluated for anti-inflammatory properties in rats (subplantar edema induced by carrageenan) and analgesic effects in mice (hot plate and writhing tests). Our results showed that the methanolic extract exhibits a significant anti-inflammatory activity and analgesic effects only in one of the experimental models (writhing test). Therefore, we may suppose that the methanolic extract of H. empetrifolium is active against inflammatory pain.

Analgesics, Non-Narcotic↗
PubMed2002

On-line coupling of capillary isotachophoresis and capillary zone electrophoresis for the determination of flavonoids in methanolic extracts of Hypericum perforatum leaves or flowers.

Five flavonoids (hyperoside, isoquercitrin, quercitrin, quercetin and rutin) were separated and determined in extracts of Hypericum perforatum leaves or flowers by capillary zone electrophoresis (CZE) with isotachophoretic (ITP) sample pre-treatment using on-line column coupling configuration. The background electrolyte (BGE) used in the CZE step was different from the leading and terminating ITP electrolytes but all the electrolytes contained 20% (v/v) of methanol. The optimal leading electrolyte was 10 mM HCl of pH* approximately 7.2 (adjusted with Tris) and the terminating electrolyte was 50 mM H3BO3 of pH* approximately 8.2 (adjusted with barium hydroxide). This operational system allowed to concentrate and pre-separate selectively the flavonoid fraction from other plant constituents before the introduction of the flavonoids into the CZE capillary. The BGE for the CZE step was 50 mM Tris buffer of pH* approximately 8.75 containing 25 mM N-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid as co-ion and 55 mM H3BO3 as complex-forming agent. The ITP-CZE method with spectrophotometric detection at 254 nm was suitable for the quantitation of the flavonoids in real natural samples; kaempferol was used as internal standard. The limit of detection for quercetin-3-O-glycosides was 100 ng ml(-1) and calibration curves were rectilinear in the range 1-10 microg ml (-1) for most of the analytes. The RSD values ranged between 0.9 and 2.7% (n=3) when determining approximately 0.07-1.2% of the individual flavonoids in dried medicinal plants.

Boric Acids↗
PubMed2001

Adhyperforin as a contributor to the effect of Hypericum perforatum L. in biochemical models of antidepressant activity.

The present paper describe investigations which demonstrate that hyperforin is not the only phloroglucinol derivative in extracts of the medicinal plant Hypericum perforatum L., which possess a biological activity. Hyperforin was the major lipophilic constituent in two different extracts, whereas the amount of adhyperforin was approximately 10 times lower. Adhyperforin, like hyperforin, is a potent inhibitor of the uptake of dopamine, serotonin and noradrenaline. Neither hyperforin nor adhyperforin inhibited binding of the cocaine analogue, [3H]WIN 35,428 to the dopamine transporter. However, the known antidepressives imipramine, nomifensine and fluoxetine all inhibited binding of [3H]WIN 35,428, indicating that hyperforin and adhyperforin do not bind to the same site on the dopamine transporter as these compounds. Furthermore, hyperforin and adhyperforin did not prevent dopamine binding, but inhibited dopamine translocation. Our studies further support recent reports suggesting that the effect of hyperforin on uptake of monoamines is probably not caused by a direct effect of hyperforin on known sites on the transporters.

Animals↗
PubMed2003

Step by step removal of hyperforin and hypericin: activity profile of different Hypericum preparations in behavioral models.

Herbal extracts of Hypericum perforatum L. (St. John's wort, SJW) are now successfully competing for status as a standard antidepressant therapy. Because of this, great effort has been devoted to identifying the antidepressive active compounds. In the present study we used the following strategy to evaluate the relative pharmacological importance of various extract components: 1. preparation of an hydroalcoholic SJW extract containing both hyperforin (3.2%) and hypericin (0.15%) (extract A); 2. step by step removal of hyperforin and hypericin led to the following extracts: Extract B, devoid of hyperforin but still containing hypericin (0.14%) and Extract C, free of hypericin and hyperforin but enriched in flavonoids ( approximately 12%). We characterized the in vivo activity profile of all three preparations using the tail suspension test (TST) in mice and the forced swimming test (FST) in rats as screening models. We further investigated the activity of pure hyperforin. Extract B and C (500 mg/kg each) as well as pure hyperforin (8 mg/kg) significantly shortened immobility time in the TST after acute pre-treatment whereas extract A was inactive. In the FST all three extracts decreased immobility time in a dosage of 500 mg/kg after acute as well as after repeated treatment. The present results clearly show that an SJW extract free of hyperforin and hypericin exerts antidepressant activity in behavioral models, supporting our working hypothesis that flavonoids are part of the constituents responsible for the therapeutic efficacy of SJW extracts. We also could show that hyperforin contributes to the beneficial properties of SJW extract, confirming the hypothesis that the crude SJW extract contains several constituents with antidepressant activity.

Administration, Oral↗
PubMed2000

Effect of St. John's wort (Hypericum perforatum) on cytochrome P-450 2D6 and 3A4 activity in healthy volunteers.

The effects of the herb St. John's wort (Hypericum perforatum), a purported antidepressant, on the activity of cytochrome P-450 (CYP) 2D6 and 3A4 was assessed in seven normal volunteers. Probe substrates dextromethorphan (2D6 activity) and alprazolam (3A4 activity) were administered orally with and without the co-administration of St. John's wort. Urinary concentrations of dextromethorphan and dextrorphan were quantified and dextromethorphan metabolic ratios (DMRs) determined. Plasma samples were collected (0-60 hrs) for alprazolam pharmacokinetic analysis sufficient to estimate tmax, Cmax, t 1/2, and AUC. Validated HPLC methods were used to quantify all compounds of interest. No statistically significant differences were found in any estimated pharmacokinetic parameter for alprazolam or DMRs. These results suggest that St. John's wort, when taken at recommended doses for depression, is unlikely to inhibit CYP 2D6 or CYP 3A4 activity.

Adult↗
PubMed2000

Bisanthraquinone glycosides of Hypericum perforatum with binding inhibition to CRH-1 receptors.

Four new bisanthraquinone glycosides, S-(+)-skyrin-6-O-beta-glucopyranoside (1), R-(-)-skyrin-6-O-beta-glucopyranoside (2), S-(+)-skyrin-6-O-beta-xylopyranoside (3) and S-(+)-skyrin-6-O-beta-alpha-arabinofuranoside (4), have been isolated from an ethanol-water (1:1, v/v) dry extract of the aerial parts of Hypericum perforatum L. The structures were elucidated by spectroscopic methods, mainly NMR and mass spectrometry. Circular dichroism was used to determine their axial stereochemistry revealing 1 and 2 to be atropisomers. 1 and 2 inhibited [125I]sauvagine binding to corticotropin releasing hormone (CRH-1) receptors.

Acetylation↗
PubMed2001

Seasonal variation in hypericin content of Hypericum perforatum L. (St. John's Wort).

Hypericin and pseudohypericin, bioactive constituents in St. John's Wort (Hypericum perforatum), have been determined in the soft tops of the plant that are most likely to be browsed by foraging livestock. In two consecutive seasons, the hypericin/pseudohypericin concentration in a broad leaf biotype varied from a winter minimum of less than 100 ppm to a summer maximum approaching 3000 ppm. In contrast the narrow leaf biotype increased from similar winter values to summer maxima approaching 5000 ppm. The latter biotype was slower in returning to low levels of hypericin/pseudohypericin.

Anthracenes↗
PubMed2002

Jasmonic acid-induced hypericin production in cell suspension cultures of Hypericum perforatum L. (St. John's wort).

Hypericum perforatum L. (St. John's wort) is an herbal remedy widely used in the treatment of mild to moderate depression. Hypericin, a photosensitive napthodianthrone, is believed to be the compound responsible for reversing the depression symptoms. In this study, novel in vitro cell culture systems of H. perforatum were used to monitor the effect of elicitation on cell growth and production of hypericin. A dramatic increase in cell growth and hypericin production was observed after exposure to jasmonic acid (JA). However, other elicitors such as salicylic acid (SA) and fungal cell wall elicitors failed to show any stimulatory effect on either cell growth or hypericin production. Cell cultures treated with JA and incubated in the dark showed increased growth and hypericin production as compared to the cultures grown under light conditions. Jasmonate induction in dark conditions played an important role in growth and hypericin production in cell suspension cultures, to our knowledge an undocumented observation.

Anthracenes↗
PubMed2000

Stimulation of the production of hypericins by mannan in Hypericum perforatum shoot cultures.

Shoot organ cultures were established from callus derived from anthers of Hypericum perforatum flowers and the effect of elicitors on hypericin and pseudohypericin production in shoot organ cultures was investigated. Mannan stimulated pseudohypericin production up to four fold (0.82 mg/g dry wt) and hypericin production up to two fold (0.04 mg/g dry wt.) beta-1,3-glucan and pectin slightly stimulated pseudohypericin production (ca. two fold), but had no effect on hypericin production. On the other hand, yeast extract showed no stimulatory effect, on either hypericin or pseudohypericin production.

Anthracenes↗
PubMed2000

Xanthone 6-hydroxylase from cell cultures of Centaurium erythraea RAFN and Hypericum androsaemium L.

Xanthone 6-hydroxylase activity was detected in the microsomal fractions from two plant cell cultures. The enzyme from cultured cells of Centaurium erythraea (Gentianaceae) exhibited absolute specificity for 1,3,5-trihydroxyxanthone as substrate, whereas xanthone 6-hydroxylase from cell cultures of Hypericum androsaemum (Hypericacaea) preferred the isomeric 1,3,7-trihydroxyxanthone but used 1,3,5-trihydroxyxanthone also to a small extent. Both xanthones were regioselectively hydroxylated in position 6. The xanthone 6-hydoxylases are cytochrome P450 monooxygenases, as shown by their dependence on NADPH and molecular oxygen and their inhibition by carbon monoxide and typical P450 inhibitors. In both cell cultures, xanthone accumulation was preceded by an increase in xanthone 6-hydroxylase activity.

Cells, Cultured↗