Potential anthelmintics: polyphenols from the tea plant <Emphasis Type="Italic">Camellia sinensis</Emphasis> L. are lethally toxic to <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis>

A novel gallate of tannin, (−)-epigallocatechin-(2β→O→7′,4β→8′)-epicatechin-3′-O-gallate (8), together with (−)-epicatechin-3-O-gallate (4), (−)-epigallocatechin (5), (−)-epigallocatechin-3-O-gallate (6), and (+)-gallocatechin-(4α→8′)-epigallocatechin (7), were isolated from the tea plant Camellia sinensis (L.) O. Kuntze var. sinensis (cv., Yabukita). The structure of 8, including stereochemistry, was elucidated by spectroscopic methods and hydrolysis. The compounds, along with commercially available pyrogallol (1), (+)-catechin (2), and (−)-epicatechin (3), were examined for toxicity towards egg-bearing adults of Caenorhabditis elegans. The anthelmintic mebendazole (9) was used as a positive control. Neither 2 nor 3 were toxic but the other compounds were toxic in the descending order 8, 7 ≈ 6, 9, 4, 5, 1. The LC₅₀ (96 h) values of 8 and 9 were evaluated as 49 and 334 μmol L⁻¹, respectively. These data show that many green tea polyphenols may be potential anthelmintics.     

Acute toxicity of nonylphenols and bisphenol A to the embryonic development of the abalone <Emphasis Type="Italic">Haliotis diversicolor supertexta</Emphasis>

Acute toxic effects and mechanisms of two typical endocrine disrupting chemicals, nonylphenols (NPs) and bisphenol A (BPA), to the embryonic development of the abalone Haliotis diversicolor supertexta, were investigated by the two-stage embryo toxicity test. The 12-h median effective concentrations (EC₅₀) of NPs and BPA to the trochophore development were 1016.22 and 30.72 μg L⁻¹, respectively, and the respective 96-h EC₅₀ values based on the completion of metamorphosis (another experimental endpoint) were reduced to 11.65 and 1.02 μg L⁻¹. Longer exposure time and magnified exposure concentrations in the benthic diatom, that serves as both food source and settlement substrate during the metamorphosis, via bioaccumulation, led to the higher sensitivity of metamorphosis to target EDCs compared with the trochophore development. The hazard concentrations for 5% of the species (HC₅) could be employed as the safety thresholds for the embryonic development of the abalone. The 12-h HC₅ values of NPs and BPA were 318.68 and 13.93 μg L⁻¹, respectively, and the respective 96-h HC₅ values were 0.99 and 0.18 μg L⁻¹, which were at environmentally relevant levels. Results of proteomic responses revealed that NPs and BPA altered various functional proteins in the abalone larvae with slight differences between each chemical and affected various physiological functions, such as energy and substance metabolism, cell signalling, formation of cytoskeleton and cilium, immune and stress responses at the same time, leading to the failure of metamorphosis.     

Lignans from the flowers of <Emphasis Type="Italic">Osmanthus fragrans</Emphasis> var. <Emphasis Type="Italic">aurantiacus</Emphasis> and their inhibition effect on NO production

A new lignan, (7R,7′R,8R,8′R)-8-hydroxypinoresinol 8-O-β-D-glucopyranoside 4′-methyl ether (7), was isolated from the flowers of Osmanthus fragrans var. aurantiacus along with six known lignans: (+)-phillygenin (1), phillyrin (2), (−)-phillygenin (3), (−)-epipinoresinol-β-D-glucoside (4), taxiresinol (5), and (−)-olivil (6). The structure of the new compound was elucidated on the basis of 1D- and 2D-NMR spectroscopic analysis and specific rotation data. The compounds isolated from the flowers of O. fragrans var. aurantiacus were evaluated for inhibitory activities on nitric oxide production in lipopolysaccharide-stimulated macrophage RAW 264.7 cells. (+)-Phillygenin (1), phillyrin (2), and (−)-phillygenin (3) exerted the strongest inhibitory activities on NO production with IC₅₀ values of 25.5, 18.9, and 25.5 μM, respectively. These compounds may prove beneficial in the development of natural agents for prevention and treatment of inflammatory diseases.     

Effects of propofol on the leukocyte nitric oxide pathway: in vitro and ex vivo studies in surgical patients

This study was designed to evaluate the mechanism by which propofol modifies leukocyte production of nitric oxide (NO) in humans. In vitro experiments used whole blood from healthy volunteers (n = 10 samples/experiment). Ex vivo experiments studied the effects of an intravenous dose of 2.5 mg propofol per kilogram body weight followed by intravenous infusion of 4 mg kg⁻¹ h⁻¹ in surgical patients in ASA class I or II (n = 20). In whole blood, neutrophils and plasma, we measured NO production and the activities of the enzymes nitric oxide synthase [inducible (iNOS) and constitutive (cNOS)] and cyclooxygenase [constitutive (COX-1) and inducible (COX-2)]. Concentrations of interleukins (IL-1β, IL−6, and IL−10) and tumor necrosis factor-alpha (TNFα) were measured in plasma. In blood from healthy donors, propofol increased NO production and cNOS activity. The concentration of propofol that increased NO production by 50% (EC₅₀) was 23.5 μM, and the EC₅₀ of propofol for cNOS was 18.6 μM. In blood from surgical patients, propofol increased NO production by 52% and cNOS activity by 57%. Propofol inhibited iNOS activity in vitro; the concentration that reduced activity by 50% (IC₅₀) was 19.9 μM. In surgical patients propofol inhibited iNOS activity by 53%. COX-1 and COX-2 activities were inhibited in vitro (IC₅₀ 32.6 and 187 μM, respectively) and in surgical patients (53 and 81% inhibition, respectively). Plasma concentrations of IL-1β, IL-6, and TNFα were significantly reduced in surgical patients (32, 23, and 21% inhibition, respectively). None of these parameters were modified in a group of patients (n = 10) anesthetized with sevoflurane. We conclude that propofol stimulated constitutive NO production and inhibited inducible NO production, possibly by curtailing the stimulation of iNOS by inflammatory mediators in surgical patients.     

Antiviral triterpenes fromPrunella vulgaris

Two triterpenes 1 and 2 with antiviral activity againstHerpes simplex virus type 1in vitro were isolated fromPrunella vulgaris. Each compound caused a significant reduction in viral cytopathic effect whenvero cells were exposed to them for 72 hours after viral challenge. They were identified asbetulinic acid(1) and 2α, 3α-dihydroxyurs-12-en-28-oic acid(2) on the basis of their spectroscopic properties. The antiviral activity of them was estimated as EC₅₀=30 μg/ml(1) and 8 μg/ml(2), respectively by plaque reduction assay.     

CYP3A4 inhibitors isolated from a marine derived fungus <Emphasis Type="Italic">Penicillium</Emphasis> species

More than 50% of clinically used drugs are thought to be metabolized by cytochrome P450 (CYP) 3A4. Discovery of new, inexpensive, CYP3A4 inhibitors will reduce drug dosages needed to cure patients. In our search for new inhibitors of the enzyme CYP3A4, extracts from 102 marine fungi were screened. Seven of the extracts had potent CYP3A4 inhibitory activity. Four aromatic compounds were isolated from an extract of a culture of one of these, a Penicillium sp., and were identified as 3-methoxyphenol (1), 4-methoxyphenylacetic acid (2), 4-(2-hydroxyethyl)phenol (3), and 4-hydroxy-2-methoxyacetanilide (4) by use of spectroscopic data. Interestingly, compound 3 at 250 μg mL⁻¹did not inhibit CYP3A4 whereas compounds 1, 2 and 4 had CYP inhibitory activity with IC₅₀ values of 2.0, 1.6 and 0.41 μg mL⁻¹, respectively.     

Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (<Emphasis Type="Italic">Scenedesmus obliquus</Emphasis>) and a consumer (<Emphasis Type="Italic">Daphnia magna</Emphasis>)

The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10–100 μl l⁻¹ that were far below the No Observed Effect Concentration (NOEC) value of 1,000 μl l⁻¹ for growth inhibition. The NOEC-value of FFD-6 for colony-induction was 3 μl l⁻¹. Daphnia survival was strongly affected by FFD-6, yielding LC_50–24h and LC_50–48h of 148 and 26 μl l⁻¹, respectively. In addition, clearance rates of Daphnia feeding on unicellular Scenedesmus were inhibited by FFD-6, yielding a 50% inhibition (EC_50–1.5h) at 5.2 μl l⁻¹ with a NOEC of 0.5 μl l⁻¹. When Daphnia were offered FFD-6-induced food in which eight-celled colonies (43 × 29 μm) were most abundant, clearance rates (~0.14 ml ind.⁻¹ h⁻¹) were only 25% the rates of animals that were offered non-induced unicellular (15 × 5 μm) Scenedesmus (~0.56 ml ind.⁻¹ h⁻¹). As FFD-6 concentrations in the treated food used in the experiments were far below the NOEC for clearance rate inhibition, it is concluded that the feeding rate depression was caused by the altered morphology of the Scenedesmus moving them out of the feeding window of the daphnids. The surfactant evoked a response in Scenedesmus that is similar to the natural chemically induced defensive reaction against grazers and could disrupt the natural information conveyance between these plankton organisms.     

Dexmedetomidine inhibits muscarinic type 3 receptors expressed in <Emphasis Type="Italic">Xenopus</Emphasis> oocytes and muscarine-induced intracellular Ca<Superscript>2+</Superscript> elevation in cultured rat dorsal root ganglia cells

Dexmedetomidine, an α₂-adrenoceptor agonist, has been approved for clinical use, although the mechanism of dexmedetomidine action has not been fully elucidated. Several studies have shown that G protein-coupled receptors (GPCRs) are recognized as targets for anesthetics and analgesics. Therefore, it is of interest to determine whether dexmedetomidine affects the function of GPCRs other than the α₂-adrenoceptor. We examined the effects of dexmedetomidine on M₁, M₃, 5-HT_2C, substance P, and orexin 1 receptors in Xenopus oocytes expressing individual receptors. In addition, we investigated the effects of dexmedetomidine on muscarinic receptor-mediated changes in [Ca²⁺]_i in the dorsal root ganglia (DRG) of 3-week-old Wister rats. Dexmedetomidine did not affect the 5-HT_2C-, or substance P-induced Cl⁻ currents and had little inhibition on the orexin A-induced current in oocytes expressing the respective receptors. The compound also had little effect on the acetylcholine (ACh, 1 μM)-induced Ca²⁺-activated Cl⁻ currents in Xenopus oocytes expressing M₁ receptors. In contrast, dexmedetomidine inhibited the ACh-induced currents in Xenopus oocytes expressing M₃ receptors; 1 nM, 10 nM, 100 nM, and 1 μM dexmedetomidine reduced the current to 66.5 ± 4.8, 51.3 ± 12, 34.6 ± 11, and 26.8 ± 6.4% of the control value, respectively (EC₅₀ = 3.5 ± 0.7 nM). Dexmedetomidine reduced the ACh-induced Cl⁻ currents after treatment with the selective protein kinase C inhibitor GF109203X. Moreover, the compound inhibited the muscarinic receptor-mediated increases in [Ca²⁺]_i in cultured DRG cells in a concentration-dependent manner. Dexmedetomidine inhibits the function of M₃ receptors, in addition to its agonistic effects on α₂-adrenoceptors, which provides further insight into the pharmacological properties of dexmedetomidine.     

Dissolved organic carbon reduces uranium toxicity to the unicellular eukaryote <Emphasis Type="Italic">Euglena gracilis</Emphasis>

The influence of dissolved organic carbon (DOC), in the form of Suwannee River fulvic acid (SRFA), on uranium (U) toxicity to the unicellular eukaryote, Euglena gracilis (Z strain), was investigated at pH 6. In a background medium without SRFA, exposure of E. gracilis to 57 μg L⁻¹ U resulted in a 50% reduction in growth (IC₅₀). The addition of 20 mg L⁻¹ DOC (as SRFA), reduced U toxicity 4 to 5-fold (IC₅₀ increased to 254 μg L⁻¹ U). This reduction in toxicity was also evident at more sensitive effect levels with a 10% reduction in growth (IC₁₀) occurring at 5 μg L⁻¹ U in the background medium and at 17 μg L⁻¹ U in the SRFA medium, respectively. This amelioration of toxicity with the addition of SRFA was linked to a decrease in the bioavailability of U, with geochemical speciation modelling predicting 84% of U would be complexed by SRFA. The decrease in bioavailability of U in the presence of SRFA was also evident from the 11–14 fold reduction in the cellular concentration of U compared to that of E. gracilis in the background medium. Stepwise multiple linear regression analyses indicated that UO₂ ²⁺ alone explained 51% of the variation in measured U toxicity to E. gracilis. Preliminary U exposures to E. gracilis in the presence of a reactive oxygen species probe, suggest exposure to ≥60 μg L⁻¹ U may induce oxidative stress, but this endpoint was not considered to be a sensitive biological indicator.     

<Emphasis Type="Italic">In vitro</Emphasis> Na<Superscript>+</Superscript>/K<Superscript>+</Superscript>-ATPase inhibitory activity and antimicrobial activity of sesquiterpenes isolated from <Emphasis Type="Italic">Thujopsis dolabrata</Emphasis>

A series of sesquiterpenes and hinokitiol-related compounds (1–15) was isolated from the essential oil of Thujopsis dolabrata Sieb. et Zucc. var. hondai Makino, and their structures were determined by combined spectroscopic analyses. The inhibitory effects of these compounds on microbial cell growth and Na⁺/K⁺-ATPase were evaluated in vitro. It was found that (−)-elema-1,3,11(13)-trien-12-ol (5), α,β,γ-costol (8), and chamigrenol (11) inhibit the activities of Na⁺/K⁺-ATPase, with IC₅₀ values of 11.2 ± 0.11, 12.2 ± 0.09, and 15.9 ± 0.54 μg/mL, respectively. Thujopsene (1), cedrol (9), γ-cuparenol (10), and chamigrenol (11) showed potent antibacterial activity, with MIC values in the range of 25–50 μg/mL, and β-thujaplicin (12) exhibited a broad spectrum of antibacterial and antifungal activity. These results indicate that these isolated compounds are promising candidates for the development of potent Na⁺/K⁺ ATPase inhibitors and antimicrobial agents.     

Perylene Toxicity in the Estuarine Environment of Ria de Aveiro (Portugal)

Perylene, a 5-ring polycyclic aromatic hydrocarbon is common in estuarine sediments and its toxicity in the benthic and planktonic compartments is not yet clarified. The objectives of this work were: (1) to follow the toxicity of high concentrations of perylene (110 mg l⁻¹) on benthic bacteria and macrofauna (amphipod Corophium multisetosum); (2) to determine the effects of a low load of perylene (2 μg l⁻¹) on the metabolism of suspended bacteriobenthos after 9-day exposure, mimicking the effects of tidal erosion; (3) to contrast the effects of this low perylene load on the particle-free bacterioplankton and on the suspended and particle-adhered bacteriobenthos. No impact was detected in bacterial abundance exposed to 110 mg perylene l⁻¹ for 9 days. This concentration of perylene evoked no acute effects in C. multisetosum but, chronic toxicity assays revealed statistically significant negative effects on survival, growth and number of pregnant females. The bacterioplankton and the suspended bacteriobenthos, exposed to 2 μg perylene l⁻¹ during 2 weeks, responded with altered profiles of activity when compared to the control suspension. These values ranged, respectively, for bacterial biomass production from 134 to 210 and from 24 to 184 μg C l⁻¹ h⁻¹, for aminopeptidase from 1824 to 11,127 and from 1464 to 15,488 nmol l⁻¹ h⁻¹, and for β-glucosidase from 87 to 400 and from 57 to 1278 nmol l⁻¹ h⁻¹. The rate of oxygen consumption in the perylene-exposed suspension (0.04–2.85 mmol O₂ kg⁻¹ dw sed h⁻¹) exhibited a clearly distinct profile in relation to the control (0.57–1.60 mmol O₂ kg⁻¹ dw sed h⁻¹). The overall reactivity of the bacteriobenthos to perylene was interpreted as the result of toxic pressure followed by evolution of a diverse bacterial community.     

Effects of 8-OH-DPAT and WAY-100635 on performance on a time-constrained progressive-ratio schedule

Rationale. Performance on progressive-ratio schedules has been proposed as a means of assessing the effects of drugs on motivation. We have adopted a mathematical model proposed by Killeen to analyse the effects of drugs acting at 5-HT_1A receptors on progressive-ratio performance. According to this model, the relationship between response rate and ratio size is described by a bitonic (inverted-U) function. One parameter of the function, a, expresses the motivational or "activating" effect of the reinforcer (duration of activation of responding produced by the reinforcer), whereas another parameter, δ, expresses the minimum time needed to execute a response and is regarded as an index of "motor capacity". Objective. To examine the effect of the selective 5-HT_1A receptor agonist 8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] and the antagonist WAY-100635 [N-[2-(4-[2-methoxyphenyl]-1-piperazinyl)ethyl]-N-2-pyridinylcyclo-hexanecarboxamide] on progressive-ratio schedule performance. Methods. Sixteen rats responded for a food-pellet reinforcer on a time-constrained progressive-ratio schedule (55-min sessions). In phase 1, they received single doses (s.c.) of 8-OH-DPAT (25, 50, 100, 200 μg kg⁻¹, four treatments at each dose) or the vehicle (0.9% saline solution). In phase 2, they received WAY-100635 (30, 100, 300 μg kg⁻¹) according to the same regimen. In phase 3, they received 8-OH-DPAT (100 μg kg⁻¹) alone or in combination with WAY-100635 (30 μg kg⁻¹). 8-OH-DPAT dose dependently increased the value of a, significant increases being seen with the 50, 100 and 200 μg kg⁻¹ doses. The highest dose also increased δ. WAY-100635 did not significantly alter either a or δ. WAY-100635 significantly attenuated the effect of 8-OH-DPAT on both a and δ. Conclusions. The results suggest that 8-OH-DPAT enhanced the activating effect of the reinforcer (the highest dose may also have induced motor debilitation). The finding that the effect of 8-OH-DPAT on a was attenuated by WAY-100635 implicates 5-HT_1A receptors in this effect. The results are consistent with previous reports that 8-OH-DPAT facilitates feeding and food-reinforced operant responding in rats and suggest that these effects may be brought about by an increase in food motivation. Electronic Publication     

Sensitivity of spore germination and germ tube elongation of Saccharina japonica to metal exposure

The sensitivity of early life stages of the brown seaweed Saccharina japonica to six metals (Cd, Cu, Hg, Ni, Pb, Zn) and two waste-water samples were investigated and a new toxicity bioassay developed. The two endpoints used were spore germination and germ tube elongation with an exposure time of 24 h. Optimal test conditions determined for photon irradiance, pH, salinity and temperature were darkness, pH 8, 35‰ and 15°C, respectively. The toxicity ranking of five metals was: Hg (EC₅₀ of 41 and 42 μg l⁻¹) > Cu (120 and 81 μg l⁻¹) > Ni (2,009 and 1,360 μg l⁻¹) > Zn (3,024 and 3,897 μg l⁻¹) > Pb (4,760 and 4,429 μg l⁻¹) > Cd (15,052 and 7,541 μg l⁻¹) for germination and germ tube elongation, respectively. The sensitivities to Cd, Cu and Ni were greater in germ tube elongation than in germination process. When tested against two different waste-water samples (processed animal and printed circuit board waste-water) values of EC₅₀ were between 21.29 and 32.02% for germination and between 5.33 and 8.98% for germ tube elongation. Despite differences in their chemical composition, the toxic effects of waste-water samples, as indicated by EC₅₀ values, did not differ significantly for the same endpoints. The CV range for both germination and germ tube elongation was between 4.61 and 37.69%, indicating high levels of precision of the tests. The results compare favourably with those from more established test procedures employing micro- and macroalgae. The advantages and potential limitations of the bioassay for the assessment of anthropogenic impacts on coastal ecosystems and commercial cultivation areas in near-shore environments are discussed.     

Toxicity of lead, cadmium and mercury on embryogenesis, survival, growth and metamorphosis of Meretrix meretrix larvae

In order to assess the toxicity of heavy metals on the early development of Meretrix meretrix, the effects of mercury (Hg), cadmium (Cd) and lead (Pb) on embryogenesis, survival, growth and metamorphosis of larvae were investigated. The EC₅₀ for embryogenesis was 5.4 μg l⁻¹ for Hg, 1014 μg l⁻¹ for Cd and 297 μg l⁻¹ for Pb, respectively. The 96 h LC₅₀ for D-shaped larvae was 14.0 μg l⁻¹ for Hg, 68 μg l⁻¹ for Cd and 353 μg l⁻¹ for Pb, respectively. Growth was significantly retarded at 18.5 μg l⁻¹ (0.1 μM) for Hg, 104 μg l⁻¹ (1 μM) for Cd and 197 μg l⁻¹ (1 μM) for Pb, respectively. The EC₅₀ for metamorphosis, similar to 48 h LC₅₀, was higher than 96 h LC₅₀. Our results indicate that the early development of M. meretrix is highly sensitive to heavy metals and can be used as a test organism for ecotoxicology bioassays in temperate and subtropical regions.     

Comparison of the effects of clozapine and 8-hydroxy-2-(di-<Emphasis Type="Italic">n</Emphasis>-propylamino)tetralin (8-OH-DPAT) on progressive ratio schedule performance: evidence against the involvement of 5-HT<Subscript>1A</Subscript> receptors in the behavioural effects of clozapine

Rationale Performance on progressive ratio schedules has been proposed as a means of assessing the effects of drugs on the efficacy of reinforcers. A mathematical model (Killeen PR (1994) Mathematical principles of reinforcement. Behav Brain Sci 17:105–172) affords a basis for quantifying the effects of drugs on progressive ratio schedule performance. The model postulates a bitonic function relating response rate and ratio size. One parameter of the function, a, expresses the motivational effect of the reinforcer, whereas another parameter, δ, expresses the minimum time needed to execute a response, and is regarded as an index of ‘motor capacity’. Previously we found that the atypical antipsychotic clozapine increased a, indicating an increase in reinforcer efficacy; a similar effect was observed with the 5-hydroxytryptamine (5-HT)_1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). It has been suggested that some of clozapine’s behavioural effects are mediated by agonistic action at 5-HT_1A receptors. Objective This study was conducted to compare the effects of clozapine and 8-OH-DPAT on progressive ratio schedule performance. Methods Rats were trained under a time-constrained progressive ratio schedule (50-min sessions). In experiment 1, they received acute doses of clozapine (4 mg kg⁻¹) and 8-OH-DPAT (100 μg kg⁻¹), alone and in combination with the 5-HT_1A receptor antagonist N-[2-(4-[2-methoxyphenyl]-1-piperazinyl)ethyl]-N-2-yridinylcyclohexanecarboxamide (WAY-100635; 30 μg kg⁻¹). In experiment 2, the effects of clozapine (2, 4 and 8 mg kg⁻¹) and 8-OH-DPAT (25, 50 and 100 μg kg⁻¹) were compared between intact rats and rats whose 5-HTergic pathways had been ablated by 5,7-dihydroxytryptamine (5,7-DHT). Results In both experiments, clozapine and 8-OH-DPAT increased a and δ. In experiment 1, WAY-100635 abolished the effect of 8-OH-DPAT on a and δ, but did not alter clozapine’s effects on these parameters. In experiment 2, the effects of clozapine and 8-OH-DPAT did not differ between sham-lesioned and 5,7-DHT-lesioned rats. Conclusions The results confirm previous findings on the effects of clozapine and 8-OH-DPAT on progressive ratio schedule performance. 8-OH-DPAT’s effects are probably mediated by post-synaptic 5-HT_1A receptors; clozapine’s effects are mediated by a different mechanism, which does not appear to involve 5-HT_1A receptors and which does not depend upon an intact 5-HTergic pathway. Jonathan Francis Rickard (1977–2003), a gifted and dedicated Ph.D. student, made a major contribution to this work     

Screening and evaluation of thiourea derivatives for their HIV capsid and human cyclophilin A inhibitory activity

New anti-HIV-1 drugs that target different viral proteins or genes at various steps in the viral life cycle are highly expected. HIV-1 assembly and disassembly (uncoating) processes are critical for the HIV-1 replication. HIV-1 capsid (CA) and human cyclophilin A (CypA) play essential roles in these processes. Using an in vitro screening system, we evaluated 52 thiourea derivatives for their potential CA and CypA-inhibiting activities. The antiviral activity of these compounds is correlated with their CA assembly inhibitory ability and with their anti-PPIase activity, suggesting that these compounds could block HIV-1 replication by disrupting CA assembly and inhibiting the PPIase activity of CypA to interfere with capsid disassembly. Among them, three compounds D4, D5, and D6 displayed the most promising potency with CA-assembly rate 15.78, 18.42, and 7.97(×10⁻⁵) OD/s, and their IC₅₀ for inhibition of PPIase activity 0.45, 0.65, and 0.33 μM, respectively. The potent protein inhibitory activity resulted in their very low EC₅₀ values (≤1.00 μM). They can be used for rational design of novel anti-HIV-1 drugs.     

Anti-oxidative and inhibitory activities on nitric oxide (NO) and prostaglandin E<Subscript>2</Subscript> (COX-2) production of flavonoids from seeds of <Emphasis Type="Italic">Prunus tomentosa</Emphasis> Thunberg

Chemical investigation of the 80% Me₂CO extract from the seeds of Prunus tomentosa led to the isolation and identification of six flavonoids: kaempferol (1), kaempferol 3-O-α-L-rhamnopyranoside (2; afzelin), kaempferol 3-O-β-D-(6-acetyl)-glucopyranosyl(1→4)-α-L-rhamnopyranoside (3; multiflorin A), kaempferol 3-O-β-D-glucopyranosyl(1→4)-α-L-rhamnopyranoside (4; multiflorin B), quercetin 3-O-α-L-rhamnopyranoside (5; quercitrin), and quercetin 3-O-β-D-glucopyranosyl (1→4)-α-L-rhamnopyranoside (6; multinoside A). Anti-oxidative and inhibitory activities on nitric oxide (NO) and prostaglandin E₂ production in interferon-γ (INF-γ) and lipopolysaccharide (LPS)-activated RAW 264.7 cells in vitro (COX-2) of the isolated compounds were evaluated. Compounds 1, 5, and 6 exhibited potent anti-oxidative activity in the DPPH radical scavenging assay with IC₅₀ values of 57.2, 59.4, and 54.3 μg/mL respectively. The positive control, ascorbic acid, had an IC₅₀ of 55.5 μg/mL. Compounds 1, 5, and 6 also reduced COX-2 levels in a dose dependent manner with IC₅₀ values of 10.2, 8.7, and 9.6 μg/mL respectively, with the positive control, indomethacin, having an IC₅₀ of 5.1 μg/mL. All six compounds inhibited NO production in a dose dependent manner with IC₅₀ values of 35.1, 42.8, 40.0, 44.8, 43.7, and 43.9 μg/mL respectively, while the positive control, L-NMMA, had an IC₅₀ of 42.1 μg/mL.     

Cytotoxic 10-(indol-3-yl)-[13]cytochalasans from the fungus <Emphasis Type="Italic">Chaetomium elatum</Emphasis> ChE01

Nine 10-(indol-3-yl)-[13]cytochalasans such as a new chaetoglobosin V (1); two new natural products, prochaetoglobosin III (2) and prochaetoglobosin III_ed (3); six known chaetoglobosins B-D (4–6), F (7), and G (8) and isochaetoglobosin D (9) in addition to two known sterols, 24(R)-5α,8α-epidioxyergosta-6–22-diene-3β-ol (10) and ergosterol (11), were isolated from the fungus Chaetomium elatum ChE01. The structures of these compounds were elucidated by spectroscopic methods. Compounds 1–9 showed cytotoxicity against the human breast cancer (IC₅₀ 2.54–21.29 μM) and cholangiocarcinoma cell lines (IC₅₀ 3.41–86.95 μM).     

Prosobranch snails as test organisms for the assessment of endocrine active chemicals––an overview and a guideline proposal for a reproduction test with the freshwater mudsnail <Emphasis Type="Italic">Potamopyrgus antipodarum</Emphasis>

Recently, prosobranch snails have been recommended as promising candidates for test organisms for the assessment of endocrine active chemicals. Three prosobranch snail species, the freshwater mudsnail Potamopyrgus antipodarum, the freshwater ramshorn snail Marisa cornuarietis, and the marine netted whelk Nassarius reticulatus are portrayed and their respective biotests are presented together with results of laboratory experiments and biological effect monitoring surveys in the field. All characterized species are highly sensitive toward xeno-androgens [triphenyltin (TPT), tributyltin (TBT), methyltestosterone (MT) and fenarimol (FEN)], and xeno-estrogens [bisphenol A (BPA), octylphenol (OP), ethinylestradiol], and show effects at environmentally relevant, rather low concentrations in laboratory experiments. For exposure to the xeno-androgen TPT, EC₁₀ values range between 15.9 and 29.0 ng as Sn/L (sediment 0.03 μg as Sn/kg), for TBT, EC₁₀ values are found between 3.42 and 37.8 ng as Sn/L (sediment 2.98 μg as Sn/kg) and effect concentrations for FEN are calculated as 18.6 ng/L (EC₁₀) and 0.19 μg/kg (EC₅₀ sediment; EC₁₀ not calculable). Exposure to xeno-estrogens yielded EC₁₀ values of 13.9 ng/L (0.19 μg/kg) for BPA, a NOEC of <1 μg/L (EC₁₀ of 0.004 μg/kg) for OP and a NOEC of 1 ng/l (EC₁₀ sediment of 2.2 μg/kg) for ethinylestradiol. Responses to androgens comprised the development of imposex and the reduction of fertility or embryo production, effects of estrogens included the stimulation of egg production and embryo production, and the increased weight of glands. Also, biological effect monitoring studies with P. antipodarum and N. reticulatus in several rivers or estuarine areas revealed the capacity of the biotests to detect an androgenic or estrogenic potential of sediment samples. A comparison of the three test species with regard to sensitivity and practical aspects in routine application favors the freshwater mudsnail P. antipodarum for a standardized procedure, and this reproduction test will be introduced into the OECD guideline program for standardization in the near future.     

A new acyclic diterpene acid and bioactive compounds from <Emphasis Type="Italic">Knema glauca</Emphasis>

Investigation of the chemical constituents of the fruits of Knema glauca (Myristicaceae) yielded a new acyclic diterpene acid, named glaucaic acid 4, together with four acylphenols, including 1-(2,6-dihydroxyphenyl) tetradecan-1-one 1, malabaricone A 6, dodecanoylphloroglucinol 7 and 1-(2,4,6-trihydroxyphenyl)-9-phenylnonan-1-one 8, two lignans sesamin 2 and asarinin 3, and a flavan, myristinin D 5. In addition, myristinin A 9 and (±)-7,4′-dihydroxy-3′-methoxyflavan 10 were isolated from its leaves and stems, respectively. When tested against small-cell lung cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines, compounds 1, 6–8 and 10 displayed weak to moderate cytotoxicity. The acylphenols 6–8 displayed antituberculosis activity against the microbe Mycobacterium tuberculosis with MIC values of 25, 50 and 100 μg/mL, respectively, and antiviral activity against herpes simplex virus type 1, with 7 as the most active compound (IC₅₀ = 3.05 μg/mL). Malabaricone A 6 was also active against the malarial parasite Plasmodium falciparum with an IC₅₀ value of 2.78 μg/mL.