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At least 793 records · Page 44Linked to original sources
PubMed2003

Enhancement of proteolytic processing of the beta-amyloid precursor protein by hyperforin.

We studied the effect of hyperforin, a component of St. John's wort (Hypericum perforatum) extracts, on the processing of the amyloid precursor protein (APP) in rat pheochromocytoma PC12 cells, stably transfected with human wildtype APP. We observed transiently increased release of secretory APP fragments upon hyperforin treatment. Unique features, like a strong reduction of intracellular APP and the time course of soluble APP release, distinguished the effects of hyperforin from those of alkalizing agents and phorbol esters, well known activators of secretory processing of APP. Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), a protonophore, induced an almost identical decrease in intracellular pH in PC12 cells as does hyperforin. Despite this, FCCP induced a less pronounced release of soluble APP fragments and only slightly reduced intracellular APP levels. These results suggest that hyperforin is an activator of secretory processing of APP with a novel mechanism of action not solely dependent on its effects on intracellular pH.

Amyloid beta-Protein Precursor↗
PubMed2004

Suppression of receptor-mediated Ca2+ mobilization and functional leukocyte responses by hyperforin.

We have recently identified hyperforin, a lipophilic constituent of the herb Hypericum perforatum (St. John's wort), as a dual inhibitor of the proinflammatory enzymes cyclooxygenase-1 and 5-lipoxygenase. The aim of the present study was to further elucidate antiinflammatory properties and respective targets of hyperforin. We found that hyperforin inhibited the generation of reactive oxygen species (ROS) as well as the release of leukocyte elastase (degranulation) in human isolated polymorphonuclear leukocytes (PMNL), challenged by the G protein-coupled receptor (GPCR) ligand N-formyl-methionyl-leucyl-phenylalanine (fMLP) with an IC 50 approximately equal 0.3 microM. When PMNL were stimulated with phorbol-12-myristate-13-acetate (PMA) or ionomycin, hyperforin (up to 10 microM) failed to inhibit ROS production and elastase release, respectively. Moreover, hyperforin blocked receptor-mediated Ca(2+) mobilization ( IC 50 approximately equal 0.4 and 4 microM, respectively) in PMNL and monocytic cells, and caused a rapid decline of the intracellular Ca(2+) concentration in resting cells. In contrast, the Ca(2+) influx induced by ionomycin or thapsigargin was not suppressed. Comparative studies with the specific phospholipase C inhibitor U-73122 and hyperforin revealed similarities between both compounds. Thus, U-73122 and hyperforin blocked fMLP- and PAF-induced Ca(2+) mobilization, ROS formation, and elastase release, but failed to suppress these responses when cells were stimulated by PMA or ionomycin. Also, both compounds rapidly decreased basal Ca(2+) levels in resting cells and led to a rapid decline of the Ca(2+) elevations evoked by fMLP or PAF. Our data suggest that hyperforin targets component(s) within G protein signaling cascades that regulate Ca(2+) homeostasis, coupled to proinflammatory leukocyte functions.

Anti-Bacterial Agents↗
PubMed2006

Mitochondria are a primary target of hypericin phototoxicity: synergy of intracellular calcium mobilisation in cell killing.

Hypericin, a naturally occurring anthraquinone synthesised by hypericum, upon light activation exhibits photodynamic cytotoxicity attributed mainly to the production of reactive oxygen species. This study aimed to elucidate the primary subcellular targets and mechanistic aspects of hypericin photosensitization in human prostate carcinoma cells. Depletion of intracellular glutathione (>85%) via inhibition of gamma-glutamyl-cysteine synthase had no effect on hypericin (5 microM) phototoxicity, thus precluding any direct oxidative involvement of H2O2. There was no change in intracellular SOD activity immediately after hypericin irradiation (1.5-5 J cm(-2)). Evaluation of the lysosomal enzyme hexosaminidase activity showed: (a) 60% cell loss 22 h following irradiation (1.5 J cm(-2)) and (b) a steady rate of lysosomal leakage to the cytosol (25%), at the same time and irradiation. However, lysosomal damage appears to be a slower process compared to the rapid loss of mitochondrial function, as reflected from parallel tetrazolium to formazan assays. The activity of cytosolic and mitochondrial aconitase, an enzyme exquisitely sensitive to oxidation, revealed a dose correlated loss of activity in the mitochondria immediately following hypericin photoactivation. The use of ionomycin, which modulates both internal Ca2+ stores and external Ca2+ transport during hypericin photosensitization, profoundly enhanced photocytotoxicity. Our data supports a direct mitochondrial hypericin phototoxicity that does not involve glutathione/H2O2 homeostasis. Further a potential synergistic treatment combining mitochondrial targeting of photosensitisers and Ca2+ mobilisation was identified.

Aconitate Hydratase↗
PubMed2005

Amentoflavone and its derivatives as novel natural inhibitors of human Cathepsin B.

Cathepsin B (CatB) is a member of the papain superfamily of cysteine proteases and has been implicated in the pathology of numerous diseases, including arthritis and cancer. Amentoflavone is found in a number of plants with medicinal properties, including Ginkgo biloba and Hypericum perforatum (St. John's Wort). Herein, we report the structure-activity relationship (SAR) and binding mechanism of three biflavones, amentoflavone (AMF1), 4'''-methylamentoflavone (AMF2) and 7'',4'''-dimethylamentoflavone (AMF3), isolated from Taxodium mucronatum by us as novel natural inhibitors of human CatB with strong inhibitory activities at IC50 values of 1.75, 1.68 and 0.55muM, respectively. Density functional theory (DFT) method was applied to optimize the geometry structures of AMF1, AMF2 and AMF3 at the B3LYP/6-31G* level. FlexX was explored to dock the three biflavones to the binding sites of CatB, and to get a better understanding of vital interactions between these biflavones and CatB. A good correlation between the calculated quantum descriptors and the experimental inhibitory activities suggested that quantum model of these potential inhibitors is reliable. Through geometry and electron structure analysis of AMFs, it was observed that the CH3 substitute at 7'' and 4''' positions could not vary the difference in geometry structure significantly, but increase the electron density of A-ring, HOMO energy, hydrophobic property, and improve inhibitory activity. Structural and energetic analysis of AMFs and AMFs-CatB complexes showed that the electron-donor site is the A-ring, which shows the highest HOMO energy distribution, and the electron-acceptor site is the F-ring, which shows the highest LUMO energy distribution in AMFs, and the pi-pi interaction between A-ring and residue Trp221, two hydrogen bonds (O5 and Trp221; O4 and Gln23 ), hydrophobic interaction between the C-ring and residue Cys29 and CH3 substitutes at 7'' and 4''' might play a crucial role in the inhibition of AMFs on CatB. Results indicated that AMFs are new natural reversible inhibitors that would be useful in developing potent inhibitors of CatB.

Biflavonoids↗
PubMed2004

Analytical procedure for the in-vial derivatization--extraction of phenolic acids and flavonoids in methanolic and aqueous plant extracts followed by gas chromatography with mass-selective detection.

An in-vial simple method for the combined derivatization and extraction of phenolic acids and flavonoids from plant extracts and their direct determination with GC-MS, is described. The method is taking advantage of the beneficial potentials of phase transfer catalysis (PTC). Catalysts in soluble and polymer-bound form were tested with the latter being the format of choice due to its high reaction yield and facile separation from the rest of the reaction system. Optimization of experimental conditions was established. Chromatographic separation of eight phenolic acids and four flavonoids methylated via the PTC derivatization step was achieved in 45 min. The detection limits for the described GC-MS(SIM) method of analysis ranged between 2 and 40 ng/ml whereas limits of quantitation fall in the range 5-118 ng/ml, with flavonoids accounting for the lowest sensitivity due to their multiple reaction behavior. Four methanolic extracts from Tilia europea, Urtica dioica, Mentha spicata and Hypericum perforatum grown wild in north-western Greece and four aquatic infusions from commercially available Mentha spicata, Origanum dictamnus, Rosemarinus officinalis and Sideritis cretica were analyzed. Good trueness of the method was demonstrated as no matrix effects were found for the analytes concerned.

Flavonoids↗
PubMed2004

Coronary artery disease and depression.

Coronary artery disease (CAD) as well as depression are both highly prevalent diseases. Both cause a significant decrease in quality of life for the patient and impose a significant economic burden on society. There are several factors that seem to link depression with the development of CAD and with a worse outcome in patients with established CAD: worse adherence to prescribed medication and life style modifications in depressive patients, as well as higher rates in abnormal platelet function, endothelial dysfunction and lowered heart rate variability. The evidence is growing that depression per se is an independent risk factor for cardiac events in a patient population without known CAD and also in patients with established diagnosis of CAD, particularly after myocardial infarction. Treatment of depression has been shown to improve patients' quality of life. However, it did not improve cardiovascular prognosis in depressed patients even though there is open discussion about the trend to better outcome in treated patients. Large scale clinical trials are needed to answer this question. Selective serotonin reuptake inhibitors seem to be preferable to tricyclic antidepressants for treatment of depressive patients with comorbid CAD because of their good tolerability and absence of significant cardiovascular side effects. Hypericum perforatum (St. John's wort), an increasingly used herbal antidepressant drug should be used with caution due to severe and possibly dangerous interaction with cardioactive drugs.

Antidepressive Agents↗
PubMed2006

Hypericin-loaded nanoparticles for the photodynamic treatment of ovarian cancer.

A photodynamic approach has been suggested to improve diagnosis and therapy of ovarian cancer. As Hypericin (Hy), a natural photosensitizer (PS) extracted from Hypericum perforatum, has been shown to be efficient in vitro and in vivo for the detection or treatment of other cancers, Hy could also be a potent tool for the treatment and detection of ovarian cancer. Due to its hydrophobicity, systemic administration of Hy is problematic. Thus, polymeric nanoparticles (NPs) of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA) were used as a drug delivery system. Hy-loaded NPs were produced with the following characteristics: (i) size in the 200-300 nm range, (ii) negative zeta potential, (iii) low residual PVAL and (iv) drug loading from 0.03 to 0.15% (w/w). Their in vitro photoactivity was investigated on the NuTu-19 ovarian cancer cell model derived from Fischer 344 rats and compared to free drug. Hy-loaded PLA NPs exhibited a higher photoactivity than free drug. Increasing light dose or incubation time with cells induced an enhanced activity of Hy-loaded PLA NPs. Increased NP drug loading had a negative effect on their photoactivity on NuTu-19 cells: at the same Hy concentration, the higher was the drug loading, the lower was the phototoxic effect. The influence of NP drug loading on the Hy release from NPs was also investigated.

Animals↗
PubMed2004

Folk pharmaceutical knowledge in the territory of the Dolomiti Lucane, inland southern Italy.

An ethnopharmacognostic survey on the traditional pharmaceutical knowledge (TPhK) of old and newly introduced natural remedies used for healing humans in a small mountainous area in Central Lucania, inland southern Italy, was carried out using classical ethnographical and ethnobiological methods. Approximately 110 remedies of plant origin (belonging to 103 botanical taxa), 30 of animal origin and 20 mineral or industrial (non-pharmaceutical) products were recorded. Among these remedies, the common use of the aerial parts of Hypericum hircinum and the leaves of Morus alba against cough, and the uncommon uses of Salvia argentea leaves as a haemostatic, of Erigeron acer roots to relieve tooth-aches and arthritic pains, and Elaphe quatuorlineata snake fat for rheumatism are reported for first time in Italy. Moreover, diverse medicinal plants used for uncommon medical purposes and a few biological ingredients used in food preparations with the aim to improve human health were identified. Pharmacological and toxicological considerations relating to possible applications of the recorded traditional knowledge in modern evidence-based medicine are discussed as well. The data that we present here could suggest new inputs for further phytochemical and pharmacological studies among Mediterranean folk pharmacopoeias, and also for sustaining environmentally integrated projects focused on of the maintenance of TPhK via breeding or controlled gathering activities of local medicinal species.

Animals↗
PubMed2005

Polyphenols and antioxidant capacity of Bulgarian medicinal plants.

Extracts of 21 plants used in Bulgarian phytotherapy for the treatment of respiratory, gastrointestinal and other inflammatory disorders were screened in vitro for antioxidant activity and phenolic compounds content. Plant extracts were prepared as herbal teas following the ethnic use. The water-phase TEAC (Trolox equivalent antioxidant capacity) of the teas were compared to that of the famous tea-like beverages mate, rooibos and honeybush, and to that of green and black tea, well known for their high antioxidant potential. The content of total phenolics in the teas was determined spectrometrically according to the Folin-Ciocalteu procedure and calculated as quercetin equivalents (QE). Seven Bulgarian medicinal plants were with high phenolics content and antioxidant properties: Pulmonaria officinalis L. (Boraginaceae) (TEAC 2.02+/-0.14 mM/QE 673.39+/-9.92 microM), Hypericum perforatum L. (Hypericaceae) (TEAC 3.75+/-0.14 mM/QE 881.93+/-6.68 microM), Agrimonia eupatoria L. (Rosaceae) (TEAC 3.76+/-0.5mM/QE 702.29+/-6.82 microM), Origanum vulgare L. (Lamiaceae) (TEAC 5.87+/-0.2mM/QE 1653.61+/-11.52 microM), Melissa officinalis L. (Lamiaceae) (TEAC 4.06+/-0.31 mM/QE 1370.09+/-41.38 microM), Rubus sp. diversa (Rosaceae) (TEAC 4.23+/-0,12 mM/QE 608.95+/-5.95 microM), Cotinus coggygria Scop. (Anacardiaceae) (TEAC 7.05+/-0.19 mM/QE 923.33+/-14.19 microM). Therefore, Bulgarian herbs can be considered to be a rich source of water-soluble antioxidants and/or phenolic compounds as compared to studied foreign plants.

Antioxidants↗
PubMed2006

An ethnobotanical study on the usage of wild medicinal herbs from Kopaonik Mountain (Central Serbia).

An ethnobotanical survey was carried out on the territory of the highest mountain in Central Serbia, Kopaonik, which is characterized by great plant diversity. In total, 83 wild species from 41 families and 96 preparations for use in human therapy were recorded. Among those wild plants which are most commonly used for medicinal purposes, Hypericum perforatum L., Urtica dioica L., Achillea millefolium L., Matricaria chamomilla L., Sambucus nigra L., and Thymus serpyllum L. were particularly highly recommended by the majority of informants as being 'beneficial for all ailments'. The most frequently reported medicinal uses were for treating gastrointestinal ailments (50%), skin injuries and problems (25.6%), followed by respiratory, urinary-genital and cardiovascular problems (20.5%, 20.5%, 19.2%, respectively). Plants with unusual phytotherapeutic uses are Galium verum L. (sedative properties) and Eupatorium cannabinum L. (influenza-like illnesses), while plants with interesting but lesser-known properties include Daphne laureola L. (rheumatism and skin ailments) and Ficaria verna Huds. (tubers for treating haemorrhoids). In addition, 10 wild species used in veterinary medicine, as well as 25 herbs used for human nourishment were noted.

Animals↗
PubMed2004

Hyperforin depletes synaptic vesicles content and induces compartmental redistribution of nerve ending monoamines.

Hyperforin, a phloroglucinol derivative found in Hypericum perforatum (St. John's wort) extracts has antidepressant properties in depressed patients. Hyperforin has a unique pharmacological profile and it inhibits uptake of biogenic monoamines as well as amino acid transmitters. We have recently showed that the monoamines uptake inhibition exerted by hyperforin is related to its ability to dissipate the pH gradient across the synaptic vesicle membrane thereby interfering with vesicular monoamines storage. In the present study we demonstrate that hyperforin induces dose-dependent efflux of preloaded [3H]5HT and [3H]DA from rat brain slices. Moreover, we show that hyperforin attenuates depolarization- dependent release of monoamines, while increasing monoamine release by amphetamine or fenfluramine. It is also demonstrated that preincubation of brain slices with reserpine is associated with dose- dependent blunting of efflux due to hyperforin. Our data indicate that hyperforin-induced efflux of [3H]5HT and [3H]DA reflect elevated cytoplasmic concentrations of the two monoamines secondary to the depletion of the synaptic vesicle content and the compartmental redistribution of nerve ending monoamines.

Analysis of Variance↗
PubMed2005

Comparative screening of plant essential oils: phenylpropanoid moiety as basic core for antiplatelet activity.

Essential oils extracted from different plants (Anthemis nobilis L., Artemisia dracunculus L., Cannabis sativa L., Cupressus sempervirens L., Cymbopogon citratus (DC.) Stapf., Curcuma longa L., Foeniculum vulgare L., Hypericum perforatum L., Hyssopus officinalis L., Mentha spicata L., Monarda didyma L., Ocimum basilicum L., Ocotea quixos Kosterm., Origanum vulgare L., Pinus nigra J.F. Arnold, Pinus silvestris L., Piper crassinervium Kunth., Rosmarinus officinalis L., Salvia officinalis L., Salvia sclarea L., Santolina chamaecyparissus L., Thymus vulgaris L., Zingiber officinaie L.) were screened in guinea pig and rat plasma in order to assess antiplatelet activity and inhibition of clot retraction. The oils were chemically analysed and a relationship between components and ability to affect hemostasis was evidenced. O. quixos, F. vulgaris, and A. dracunculus showed the highest antiplatelet activity against ADP, Arachidonic Acid and the Thromboxane A2 agonist U46619 (IC50, 4-132 microg ml(-1)), and a good ability to destabilize clot retraction (IC50, 19-180 microg ml(-1)). For these oils a significant correlation between antiplatelet potency and phenylpropanoids content (54-86%) was evidenced thus suggesting a key role for this moiety in the prevention of clot formation. These findings provide the rationale to take in account the antiplatelet activity in the pharmacological screening of natural products containing phenylpropanoids.

Animals↗
PubMed2005

Self-management of psychiatric symptoms using over-the-counter (OTC) psychopharmacology: the S-DTM therapeutic model--Self-diagnosis, self-treatment, self-monitoring.

Pharmacological self-management is becoming more widespread in modernizing societies, as part of a general expansion of health care. This may exert a vital corrective balance to the professionalization of health by ensuring that the individual perspective of patients is not neglected. There are many 'good ideas' for new treatments being published which have a plausible scientific rationale for effectiveness and a low likelihood of harm, yet are essentially ignored by mainstream medical research. The most likely avenue for progress is probably the spread of self-management, together with increased sharing of experience via the internet. There is considerable scope for self-management of psychiatric symptoms with psychoactive medication purchased 'over-the-counter' (OTC) and without prescription. A surprisingly wide range of effective psychoactive agents are available with the potential to self-treat many of the common psychiatric problems. These include 'medical' psychopharmacological agents such as analgesics and antihistamines, a plant extract called St. John's Wort (Hypericum), and physical treatments such as early morning bright light therapy. But self-management currently lacks an explicit therapeutic model. A three stage process of S-DTM - self-diagnosis, self-treatment and self-monitoring is proposed and described in relation to psychiatric symptoms. Self-diagnosis describes the skill of introspection to develop awareness of inner bodily states and emotions. A specific sensation is identified and isolated as the 'focal symptom' for subsequent treatment and monitoring. Self-treatment involves choosing a drug (or other therapy) which is intended to alleviate the focal symptom. Self-monitoring entails a continued awareness of the focal system and of general well-being in order to evaluate effect of therapy. Self-monitoring could involve repeated cycles of dose-adjustment, and on-off ('challenge-dechallenge-rechallenge') therapeutic trials. An example of S-DTM applied to psychiatry might include the attempt to alleviate the fatigue and malaise symptoms underlying a 'depressed' mood by using OTC analgesics such as aspirin, paracetamol/acetaminophen, ibuprofen or codeine. Anxiety symptoms might be self-managed either using an 'unofficial SSRI' (selective serotonin-reuptake inhibitor) such as the antihistamines diphenhydramine or chlorpheniramine; or with St John's Wort/hypericum.

Humans↗
PubMed2006

Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.

The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods.

Anti-Infective Agents↗
PubMed2004

Screening the receptorome to discover the molecular targets for plant-derived psychoactive compounds: a novel approach for CNS drug discovery.

Because psychoactive plants exert profound effects on human perception, emotion, and cognition, discovering the molecular mechanisms responsible for psychoactive plant actions will likely yield insights into the molecular underpinnings of human consciousness. Additionally, it is likely that elucidation of the molecular targets responsible for psychoactive drug actions will yield validated targets for CNS drug discovery. This review article focuses on an unbiased, discovery-based approach aimed at uncovering the molecular targets responsible for psychoactive drug actions wherein the main active ingredients of psychoactive plants are screened at the "receptorome" (that portion of the proteome encoding receptors). An overview of the receptorome is given and various in silico, public-domain resources are described. Newly developed tools for the in silico mining of data derived from the National Institute of Mental Health Psychoactive Drug Screening Program's (NIMH-PDSP) K(i) Database (K(i) DB) are described in detail. Additionally, three case studies aimed at discovering the molecular targets responsible for Hypericum perforatum, Salvia divinorum, and Ephedra sinica actions are presented. Finally, recommendations are made for future studies.

Animals↗
PubMed2003

Antagonist effect of pseudohypericin at CRF1 receptors.

St. John's wort (Hypericum perforatum L.) is widely used for the treatment of mild to moderately severe depression. However, the nature of its active principles and the exact mode of antidepressant action are still unknown. It has been suggested repeatedly in preclinical and clinical studies that the content of the acylphloroglucinol hyperforin decisively contributes to the antidepressant efficacy of St. John's wort extracts. Experimental studies in vivo also indicate that the naphthodianthrone hypericin may reduce the activity of the hypothalamic-pituitary-adrenal axis. Exacerbated hypothalamic-pituitary-adrenal activity has often been associated with depressive states in patients. Corticotropin-releasing factor (CRF) seems to be a major determinant in the regulation of the hypothalamic-pituitary-adrenal activity via activation of CRF(1) receptors. In the present study, we investigated the CRF(1) receptor antagonist activity of three main constituents of St. John's wort (hypericin, pseudohypericin and hyperforin) by measuring their effect on CRF-stimulated cAMP formation in recombinant Chinese hamster ovary (CHO) cells. As a selectivity test, the compounds were also tested against calcitonin in the same cells. Of the three compounds tested, only pseudohypericin selectively antagonised CRF (K(B) 0.76 microM). Hypericin and hyperforin affected both CRF and calcitonin with similar potencies and the same type of behaviour (competitive antagonism for hypericin, noncompetitive for hyperforin). It is concluded that pseudohypericin is the only real CRF(1) receptor antagonist of the three constituents tested. In addition, evidence is provided that beside hyperforin, both pseudohypericin and hypericin are implicated in the antidepressant efficacy of St. John's wort.

Animals↗
PubMed2001

Hypericin photo-induced apoptosis involves the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and activation of caspase-8.

Hypericin (HYP) is a photosensitizing pigment from Hypericum perforatum that displays cytotoxic effects in neoplastic cell lines. Therefore, HYP is presently under consideration as a new anticancer drug in photodynamic therapy. Here, we investigated the mechanism of action of HYP photo-induced apoptosis of Jurkat cells compared to the cytostatic drug paclitaxel (PXL). Both photoactivated HYP and PXL similarly increased the activity of caspase-8 and caspase-3, and drug-induced apoptosis of Jurkat cells was completely blocked by inhibitors of caspase-8 (Z-IETD-FMK) and caspase-3 (Z-DEVD-FMK). The involvement of death receptors was analyzed using neutralizing monoclonal antibodies against Fas (SM1/23), FasL (NOK-2) and TNF-R1 (MAB225), and a polyclonal rabbit anti-human TNF-related apoptosis-inducing ligand (TRAIL) antiserum. TRAIL antibody blocked TRAIL-induced and HYP photo-induced, but not PXL-induced apoptosis of Jurkat cells. In contrast, PXL-induced, but not HYP-induced apoptosis was blocked by the SM1/23 and NOK-2 antibodies. Anti-TNF-R1 antibody had no effect. These findings suggest that HYP photo-induced apoptosis of Jurkat cells is mediated in part by the TRAIL/TRAIL-receptor system and subsequent activation of upstream caspases.

Anthracenes↗
PubMedDate not supplied

A1 adenosine receptors and their ligands: overview and recent developments.

Potent adenosine receptor (AR) agonists and antagonists with high selectivity for the A1AR subtype have been developed during the past decades. However, some of the compounds considered to be selective may not be as selective in humans as in rats, and may not be very selective versus the new AR subtypes A3 or A2B. Partial agonists have been developed that may exhibit fewer side effects than full agonists. Low water solubility of many A1 antagonists remains a problem. A1 AR antagonists can be classified as neutral antagonists or inverse agonists; the pharmacological consequences of inverse agonism versus neutral antagonism will have to be the subject of future investigations. Some medicinal plants (e.g. Hypericum perforatum and Valeriana officinalis) contain compounds that are antagonists or partial agonists at A1 ARs; effects on ARs may contribute to their pharmacological activity. 18F- and 11C-labeled A1 AR antagonists have been developed for positron emission tomography studies.

Animals↗