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At least 829 records · Page 46Linked to original sources
PubMed1999

Inhibition of human sperm motility by specific herbs used in alternative medicine.

PURPOSE: Our purpose was to analyze sperm motility parameters in the presence of herbs. METHODS: Washed sperm were incubated in either saw-palmetto (Serenoa repens, Permixon Sabal serrulatum), echinacea purpura, ginkgo biloba, St. John's wort (Hypericum perforatum), or control medium. Parameters were measured on a Hamilton-Thorn analyzer after 1, 4, 24, and 48 hr at 37 degrees C. RESULTS: Sperm motility was inhibited at the high concentration (0.6 mg/mL) of St. John's wort. Curvilinear velocities and beat cross frequencies also decreased, but not hyperactivation. High-concentration saw-palmetto, echinacea, or gikgo inhibited motility at 24 and 48 hr. CONCLUSIONS: A potent inhibition of sperm motility was seen in St. John's wort unrelated to changes in pH. Furthermore, sperm viability was compromised in St. John's wort, suggesting a spermicidal effect. Metabolic changes were observed in saw-palmetto-treated sperm. High-concentration echinacea purpura interfered with sperm enzymes. Ginkgo did not have an antioxidant effect on sperm motility.

Cell Survival↗
PubMed2006

Pro-apoptotic properties of hyperforin in leukemic cells from patients with B-cell chronic lymphocytic leukemia.

The effects of the hyperforin (HF), a natural phloroglucinol purified from Hypericum perforatum, were investigated ex vivo on leukemic cells from patients with B-cell chronic lymphocytic leukemia (B-CLL). HF was found to promote apoptosis of B-CLL cells, as shown by time- and dose-dependent stimulation of phosphatidylserine externalization and DNA fragmentation, by disruption of the mitochondrial transmembrane potential, caspase-3 activation and cleavage of the caspase substrate PARP-1. Moreover, HF-induced downregulation of Bcl-2 and Mcl-1, two antiapoptotic proteins that control mitochondrial permeability. HF also downregulated two proteins which are overexpressed by B-CLL patients' cells, the cell cycle inhibitor p27kip1 through caspase-dependent cleavage into a p23 form, and the nitric oxid (NO) synthase of type 2 (inducible NO synthase). This latter was accompanied by reduction in the production of NO known to be antiapoptotic in B-CLL cells. Preventing effects of the general caspase inhibitor z-VAD-fmk indicated that HF-promoted apoptosis of B-CLL cells was mostly caspase dependent. Furthermore, normal B lymphocytes purified from healthy donors appeared less sensitive to HF-induced apoptosis than B-CLL cells. These results indicate that HF may be of interest in the development of new therapies for B-CLL based on the induction of apoptosis and combination with cell cycle-dependent antitumor drugs.

Apoptosis↗
PubMed2004

Hypericin as a potential phototherapeutic agent in superficial transitional cell carcinoma of the bladder.

Photodynamic therapy (PDT) involves the local or systemic administration of a photosensitizing drug that, upon light irradiation and presence of oxygen, results in tissue damage such as tumor destruction. Hypericin, a hydroxylated phenanthroperylenequinone, is obtained from Hypericum perforatum plants. Hypericin exhibits a high fluorescence quantum yield, and its presence in the tissue can easily be visualized. Interestingly, when instilled into the human bladders, hypericin selectively accumulates in the bladder carcinoma lesions, with the specificity and sensitivity of detecting CIS reaching up to 98.5 and 93%, respectively. Due to this selective accumulation of hypericin in bladder carcinoma lesions, the compound is now used as a fluorescent diagnostic tool for superficial bladder cancer. However, hypericin is also a photosensitizer with a potent photocytotoxic activity. Taken together, these data indicate that hypericin could be used for whole bladder wall PDT of superficial bladder tumors. This review focuses on the more recent in vitro and in vivo evaluation of hypericin as a photodynamic agent in the treatment of superficial transitional cell carcinoma (TCC) bladder tumors.

Animals↗
PubMed2000

An efficient screen for reproductive pathways using mature seeds of monocots and dicots.

Seed samples of 32 species (obligate and facultative sexuals and apomicts of monocots and dicots) were investigated by flow cytometry to reveal the pathway of reproduction. Ten different pathways of seed formation could be reconstructed considering whether the female and/or male gametes were reduced or unreduced, the embryos arose via the zygotic or parthenogenetic route and the endosperm via the pseudogamous or autonomous route. The screen is suited to select sporophytic or gametophytic mutants in sexual species, to identify pure sexual or obligate apomictic genotypes from facultative apomictic species, and to analyze the inheritance of the individual reproductive processes. Corresponding unique results are presented for Arabidopsis, Arabis, Hypericum and Poa. The screen of mature seeds by flow cytometry yielded more information about the reproductive behavior of individual plants than any other available test, and is very useful both in basic research and plant breeding.

Plant Physiological Phenomena↗
PubMed1999

Hypericin as a non-antioxidant inhibitor of NF-kappa B.

NF-kappa B is a transcription factor involved in immune and inflammatory responses. Here we show that micromolar concentrations of hypericin inhibited the PMA- and TNF-alpha-induced activation of NF-kappa B in HeLa and TC10 cells, respectively. In contrast, NF-kappa B activated by H2O2 was not influenced by hypericin, indicating a pathway-specificity of hypericin. Hyperforin and a Hypericum perforatum extract standardised on 0.15% hypericin and 5% hyperforin were not active at pharmacologically relevant concentrations. The PMA/TNF-alpha-induced transcription of a reporter gene, which is under the control of the NF-kappa B-dependent IL-6 promoter, was strongly reduced by preincubation with hypericin.

Animals↗
PubMed2001

The utilization of antidepressants in community-dwelling and institutionalized elderly--results form a representative survey in Germany.

Given its widespread occurrence and consequences, old-age depression has to be regarded as a major public health problem. Drug treatment has been proven effective in the majority of elderly individuals suffering from depression. This study presents pharmacoepidemiological data regarding the use of prescribed antidepressants and those purchased over the counter in the elderly. Furthermore, it links the data to simultaneously assessed depressive symptomatology. A representative survey on the utilization of prescription and over-the-counter antidepressant drugs and depressive symptomatology in community-dwelling (n = 1193) and institutionalized elderly individuals (n = 470) aged 75 and over was conducted in an urban region of Germany. Antidepressant use was found to be remarkably low (synthetic antidepressants: 2.2% of community dwelling individuals, 3.6% of institutionalized individuals; phytopharmaca containing hypericum perforatum: 4.2% of community dwelling individuals, 2.8% of institutionalized individuals). Two-thirds of the individuals treated with synthetic antidepressants received tri- and tetracyclic drugs, which were given at lower dosages than recommended for depression treatment. Selective serotonin reuptake inhibitors (SSRIs) were introduced in community-dwelling individuals only; none of the individuals cared for in residential and nursing homes received SSRIs. Only a minority of individuals with depressive symptoms were treated with antidepressants. The data suggests underutilization of antidepressants in the elderly, in which institutionalized elderly seem especially disadvantaged. The results call for increased efforts to discuss mental health issues in the public and to share scientific knowledge about symptoms, course and treatment options for depression. Furthermore, geronto-psychiatric competence of medical professionals, especially GPs, has to be systematically developed.

Aged↗
PubMed2001

Stimulation of glutamate, aspartate and gamma-aminobutyric acid release from synaptosomes by hyperforin.

Hyperforin is one pharmacologically active constituent of the medicinal herb Hypericum perforatum. The mechanism of its antidepressant-like activity is currently considered to be the inhibition of synaptic reuptake of neurotransmitters. Here, we will demonstrate that it also stimulates the release of glutamate from rat cortical synaptosomes, and that this effect is preceded by an increase in their free calcium [Ca2+]i levels. These hyperforin-related effects were also observed in the absence of Ca2+ in the medium. Although we noted enhanced glutamate, aspartate and GABA release under the influence of hyperforin, the release of various other amino acids was not enhanced. In contrast, reserpine did not influence the release of any of the amino acids studied. Adding hyperforin to synaptosomal suspension decreased their pHi, which returned to basal levels under certain incubation conditions. It also prevented the generation of ATP-induced pH gradients of isolated synaptic vesicles, and preformed pH-gradients were reversed by it. We will discuss the implications of our studies in understanding the mechanisms of hyperforin activity in relation to current findings on its pharmacological activity profile. Our observations suggest that neurotransmitter release stimulation from synaptosomes and the previously reported reuptake inhibitory properties of hyperforin are consequences of its effects on synaptosomal ionic homeostasis, and that it is not a reserpine-like agent.

Adenosine Triphosphate↗
PubMed2001

Effects of hyperforin on the fluidity of brain membranes.

Hyperforin, an acylphloroglucinol derivative isolated from Hypericum perforatum (St. John's wort, SJW), affects several ionic conductance mechanisms in brain cells by an as yet unknown mechanism. We tested the effects of hyperforin on the fluidity of crude brain membranes from young guinea pigs. We performed fluidity measurements with three different fluorescent probes. Diphenylhexatriene (DPH) and trimethylammonium-diphenylhexatriene (TMA-DPH) anisotropy measurements were inversely correlated with the flexibility of fatty acids in the membrane hydrocarbon core and in the hydrophilic area of membrane phospholipids, respectively. The ratio of pyrene excimer to monomer fluorescence intensities was used as an indicator of membrane annular and bulk fluidity. Incubation of brain membranes with relatively high concentrations of hyperforin sodium salt (10 micromol/l) resulted in increased DPH and decreased TMA-DPH anisotropy, respectively, indicating that hyperforin modifies specific membrane structures in different ways. It decreases the flexibility of fatty acids in the membrane hydrocarbon core, but fluidizes the hydrophilic region of membrane phospholipids. Interestingly, relatively low concentrations of hyperforin (0.3 micromol/l) significantly decreased the annular fluidity of lipids close to membrane proteins. These findings are remarkable, as inhibition of several neurotransmitter-uptake systems and modulation of several ionic conductance mechanisms by hyperforin occur in the same concentration range. However, bulk fluidity was unchanged by this low hyperforin concentration. The results emphasise a physicochemical interaction of hyperforin with specific membrane structures that probably contribute to its novel pharmacological properties.

Animals↗
PubMed2001

Hyperforin stimulates intracellular calcium mobilisation and enhances extracellular acidification in DDT1-MF2 smooth muscle cells.

Hyperforin, an acylphloroglucinol derivative, is a major constituent of St. John's wort extract (Hypericum perforatum L.), which is used in treating depressive disorders. Hyperforin has been demonstrated as a modulator of several neuronal ion channels, and inhibits smooth-muscle contraction induced by various neurotransmitters. To evaluate the spasmolytic properties of hyperforin in more detail, we performed studies on the hamster vas deferens smooth muscle cell line DDT1-MF2. In a first series of experiments, we determined the effect of hyperforin on intracellular Ca2+ concentration ([Ca2+]i) using the fluorochrome fura-2. These investigations were supplemented in a second series of assays, where the effects on cellular metabolism were analysed by measuring the rate of extracellular release of acidic metabolites with the help of a microphysiometer. Hyperforin (0.3-10 microg/ml) caused a concentration-dependent elevation of [Ca2+]i and extracellular acidification rate (ECAR). Both of these effects were independent of extracellular Ca2+. To elucidate whether the increase of [Ca2+]i by hyperforin causes or results from its ECAR-stimulating properties, we used various pharmacological tools to reveal the sequence of events and the molecular mechanisms involved. Our results suggest that hyperforin induces release of Ca2+ from as yet unidentified sources. Since the ECAR stimulation was inhibited to a different extent by the intracellular Ca2+ chelator BAPTA as well as by inhibitors of plasmalemmal and mitochondrial Na+/Ca2+ exchange, but not by inhibitors of Na+/H+ antiport, the intracellular Ca2+ increase seems to be essential for this hyperforin effect. However, further studies are needed to establish the exact mode of action, and to deduce whether this aspect of hyperforin activity contributes to its antidepressant and neuroprotective effects.

Acids↗
PubMed2002

Interference of plant extracts, phytoestrogens and antioxidants with the MTT tetrazolium assay.

The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay is a widely used screening method to measure cell viability and proliferation. When testing the effects of kaempferol on breast cancer cell number (crystal violet staining) and viability (MTT tetrazolium assay) conflicting results were obtained. Cell number decreased but MTT formazan formation increased, suggesting a direct interaction of kaempferol with the MTT tetrazolium reduction. Direct reductive potential was observed in a cell-free system for the presumptive phytoestrogens kaempferol and resveratrol, and extracts of Hypericum perforatum L. and Cimicifuga racemosa L. All agents led to instantaneous dark blue formazan formation in the absence of cells. Additionally, antioxidants such as ascorbic acid, vitamin E and N-acetylcysteine interfered with the MTT tetrazolium assay. When MCF7 and HS578 cells treated with kaempferol were washed before addition of MTT tetrazolium, the direct reduction of dye was reduced significantly. These results indicate that the MTT tetrazolium assay may lead to false positive results when testing natural compounds with intrinsic reductive potential.

Acetylcysteine↗
PubMed2003

Plasma levels of hypericin in presence of procyanidin B2 and hyperoside: a pharmacokinetic study in rats.

The biological evaluation of hypericin in various test models is hampered by its poor water solubility. In former studies we have shown that the water solubility of hypericin was remarkably enhanced in the presence of the procyanidins or flavonol glycosides of Hypericum extract. The present pharmacokinetic study was designed to find out whether the improved water solubility in the presence of procyanidin B2 or hyperoside is correlated to increased plasma levels of hypericin. Plasma levels of hypericin in rats in the presence and absence of procyanidin B2 or hyperoside were determined by reversed phase HPLC using fluorimetric detection. Both compounds increased the oral bioavailability of hypericin by ca. 58 % (B2) and 34 % (hyperoside). Procyanidin B2 and hyperoside had a different influence on the plasma kinetics of hypericin; median maximal plasma levels of hypericin were detected after 360 min (C max : 8.6 ng/mL) for B2, and after 150 min (C max : 8.8 ng/mL) for hyperoside. It can be speculated that, when administered together with these compounds, a significant accumulation of hypericin in rat plasma in the presence of both polyphenols might be responsible for the observed increased in vivo activity.

Administration, Oral↗
PubMed2005

Hyperforin acts as an angiogenesis inhibitor.

Hyperforin is a plant compound from Hypericum perforatum that inhibits tumor cell proliferation in vitro by induction of apoptosis. Here, we report that hyperforin also acts as an angiogenesis inhibitor in vitro and in vivo. In vitro, hyperforin blocked microvessel formation of human dermal microvascular endothelial cells (HDMEC) on a complex extracellular matrix. Furthermore, hyperforin reduced proliferation of HDMEC in a dose-dependent manner, without displaying toxic effects or inducing apoptosis of the cells. To evaluate the antiangiogenic activity of hyperforin in vivo, Wistar rats were subcutaneously injected with MT-450 mammary carcinoma cells and were treated with peritumoral injections of hyperforin or solvent. Hyperforin significantly inhibited tumor growth, induced apoptosis of tumor cells and reduced tumor vascularization, as shown by in situ staining of CD31-positive microvessels in the tumor stroma. These data suggest that, in addition to the induction of tumor cell apoptosis, hyperforin can also suppress angiogenesis by a direct, non-toxic effect on endothelial cells.

Angiogenesis Inhibitors↗
PubMed2001

Red wine decreases cyclosporine bioavailability.

BACKGROUND: Many commonly ingested substances such as grapefruit juice and Hypericum perforatum (St John's wort) have been found to interact with important therapeutic agents such as cyclosporine (INN, ciclosporin). The mechanism for these interactions is thought to involve modulation of the activity of the drug-metabolizing enzyme cytochrome P4503A4 (CYP3A4) and/or the drug transport protein Pglycoprotein. In vitro data suggest that red wine may interact with CYP3A4 substrates such as cyclosporine. METHODS: We conducted a randomized, 2-way crossover study of 12 healthy individuals. Subjects received a single 8-mg/kg dose of oral cyclosporine with water (control) and with 12 oz of red wine (Blackstone Merlot, 1996; Blackstone Winery, Graton, Calif). Whole blood was analyzed for cyclosporine and 6 metabolites by specific fluorescence polarization immunoassay and tandem liquid chromatography-mass spectrometry. Blood levels of cyclosporine were compared between the 2 arms. RESULTS: Red wine caused a 50% increase in the oral clearance of cyclosporine. Systemic exposure as measured by the area under the concentration-versus-time curve (AUC) and peak concentration (C(max)) were significantly decreased by red wine. However, half-life was not affected, suggesting that red wine decreased cyclosporine absorption. In vitro, the solubility of cyclosporine in red wine appeared to be lower than in water. CONCLUSIONS: Administration of cyclosporine with red wine causes a significant decrease in cyclosporine exposure. Because cyclosporine is a narrow therapeutic range compound, caution may be warranted with concomitant intake of red wine and cyclosporine.

Adult↗
PubMed1973

Ultraviolet patterns on rear of flowers: basis of disparity of buds and blossoms.

Flowers of Jasminium primulinum and Hypericum spp. have ultraviolet patterns on the reverse surface of the corolla. Those areas of the surface that are exposed to the outside in the bud are ultraviolet absorbent, whereas the portions that come into view at maturity in the open blossom are ultraviolet reflectant. Buds and blossoms, as a result, appear different in color to insects sensitive to ultraviolet light. Experimental evidence indicates that the ultraviolet-absorbent quality of the outer surface of the bud is a consequence of exposure itself, attributable possibly to a "sun tanning" effect.

Journal Article↗
PubMed1988

Therapeutic agents with dramatic antiretroviral activity and little toxicity at effective doses: aromatic polycyclic diones hypericin and pseudohypericin.

Two aromatic polycyclic diones hypericin and pseudohypericin have potent antiretroviral activity; these substances occur in plants of the Hypericum family. Both compounds are highly effective in preventing viral-induced manifestations that follow infections with a variety of retroviruses in vivo and in vitro. Pseudohypericin and hypericin probably interfere with viral infection and/or spread by direct inactivation of the virus or by preventing virus shedding, budding, or assembly at the cell membrane. These compounds have no apparent activity against the transcription, translation, or transport of viral proteins to the cell membrane and also no direct effect on the polymerase. This property distinguishes their mode of action from that of the major antiretro-virus group of nucleoside analogues. Hypericin and pseudohypericin have low in vitro cytotoxic activity at concentrations sufficient to produce dramatic antiviral effects in murine tissue culture model systems that use radiation leukemia and Friend viruses. Administration of these compounds to mice at the low doses sufficient to prevent retroviral-induced disease appears devoid of undesirable side effects. This lack of toxicity at therapeutic doses extends to humans, as these compounds have been tested in patients as antidepressants with apparent salutary effects. Our observations to date suggest that pseudohypericin and hypericin could become therapeutic tools against retroviral-induced diseases such as acquired immunodeficiency syndrome (AIDS).

Animals↗
PubMed2002

Pharmacokinetic interactions between herbal remedies and medicinal drugs.

1. The use of herbal products to treat a wide range of conditions is rising rapidly, leading to increased intake of phytochemicals. Recent studies revealed potentially fatal interactions between herbal remedies and traditional drugs. 2. In transplant patients, self-medication with St John's wort (Hypericum perforatum) has led to a drop in plasma levels of the immunosuppressant drug cyclosporine, causing tissue rejection. 3. Intake of St John's wort increases the expression of intestinal P-glycoprotein and the expression of CYP3A4 in the liver and intestine. The combined up-regulation in intestinal P-glycoprotein and hepatic and intestinal CYP3A4 impairs the absorption and stimulates the metabolism of cyclosporine, leading to subtherapeutic plasma levels. The St John's wort component, hyperforin, contributes to the induction of CYP3A4. 4. St John's wort also enhances the metabolism of other CYP3A4 substrates including the protease inhibitors indinavir and nevirapine, oral contraceptives, and tricyclic antidepressants such as amitriptyline. 5. Other herbal remedies with the potential to modulate cytochrome P450 activity and thus participate in interactions with conventional drugs include Milk thistle, Angelica dahurica, ginseng, garlic preparations, Danshen and liquorice. 6. Herbal products are currently not subject to the rigorous testing indispensable for conventional drugs. However, if potential drug interactions are to be predicted, it is essential that the ability of herbal products to interfere with drug-metabolizing enzyme systems is fully established.

Animals↗
PubMed2004

Hypericin and photodynamic treatment do not interfere with transport of vitamin C during respiratory burst.

Hypericin is a photosensitizing pigment found in St. John's wort (Hypericum perforatum) displaying a high toxicity towards certain tumors. The fact that some non-tumor cells, especially monocytes and granulocytes, are resistant to its photocytotoxic effects, posed the question whether this insensitivity is due to their ability to accumulate vitamin C, an antioxidant which alleviates the deleterious work of free radicals. HL-60 promyelocytic tumor cells can be differentiated to neutrophilic granulocytes by treatment with dimethylsulfoxide and were used as cell model. In the differentiated cells, treatment with phorbol esters (PMA) stimulates vitamin C (ascorbate) transport. The uptake rates were unaltered by hypericin at concentrations below 1 microM and irradiation with visible light at a light dose of 6 J/cm2. Inhibition by higher concentrations of hypericin was most probably due to a combination of photocytotoxic properties of the dye and oxygen radicals generated during respiratory burst. Superoxide production by NADPH oxidase followed by reduction of ferricytochrome c was inhibited by hypericin. The degree of inhibition was dependent on the concentration of hypericin and light intensity: IC50-values were 1.7 and 0.7 microM under light doses of 3.6 and 10.8 J/cm2, respectively. Oxidative stress, monitored with 2',7'-dichlorofluorescein (DCF) was only slightly decreased by ascorbate even at higher concentrations of hypericin. In contrast to its effect on the ferricytochrome c-reduction, irradiation had no significant influence on DCF-fluorescence. However, the viability of the cells was strongly decreased after photosensitization and no significant improvement was obtained by ascorbate. Results from this work indicate that ascorbate transport per se is not altered during photodynamic therapy and vitamin C does not interfere with hypericin-induced photodamage of cellular targets.

Anthracenes↗
PubMed2005

Dietary supplements and weight control in a middle-age population.

OBJECTIVES: Obesity is rapidly becoming a health problem of epidemic proportions, bringing with it a host of health concerns. This study investigates the association of long-term (10-year) use of 14 nutritional supplements, marketed as weight-control aids, with weight change over the past 10 years among individuals age 53 to 57 years. METHODS: Data are from the VITamins And Lifestyle (VITAL) cohort study of western Washington. Participants (n = 15,655) completed questionnaires about 10-year supplement use, diet, health habits, height, and present and former weights. The following supplements that are sometimes marketed for weight control or loss were examined: multivitamins; vitamins B6 and B12; chromium; coenzyme Q10, dehydroepiandrosterone, essential fatty acids (EFAs), fiber, garlic (Allium sativum), ginkgo (Ginkgo biloba), ginseng (Panax spp.), melatonin, soy, and St. John's wort (Hypericum perforatum). Linear regression was used to model 10-year change in weight from age 45 to ages 53-57, stratified by sex and body mass index (BMI, kg/m2) (normal, overweight, or obese) at age 45 years. Models were controlled for race/ethnicity, education, energy intake, physical activity, weight at age 45 years, and smoking. RESULTS: Among overweight or obese men and women, long-term use of multivitamins, vitamins B6 and B12, and chromium were significantly associated with lower levels of weight gain. For example, with chromium, weight gain in the past 10 years for obese men was 11.7 lb for no use, 6.1 lb for <150 microg/day (10-year average), and a weight loss of 3.1 lb for > or = 150 microg/day (p for trend, <0.05). Among obese women, weight gain was 14.1 lb, 7.9 lb, and 3.2 lb for the three groups respectively (p for trend, <0.01). CONCLUSIONS: These data suggest that long-term users of certain supplements experienced less weight gain than individuals who did not use the supplements. Further study is necessary before recommendations regarding these supplements can be made.

Anti-Obesity Agents↗