Lipophilicity Profiles Research Articles

Two-year study of lipophilic marine toxin profile in mussels of the North-central Adriatic Sea: First report of azaspiracids in Mediterranean seafood

Since the late 1980s, the North-central Adriatic Sea has frequently experienced blooms of harmful algal species, producing marine lipophilic toxins (MLTs) which accumulate in mussels and pose a serious threat to consumer health. Here, we present a 2-year LC-MS/MS study (2012–2014) of the MLT profile in mussels from the North-central Adriatic Sea in the context of the presence of toxic phytoplankton concentrations in seawater. Okadaic acid increased in mussels from all areas during the summer and autumn-winter periods with a rising trend between 2012 and 2014. In the same periods, Dinophysis sp. increased in abundance in seawater, but the highest densities of algae did not always coincide with the highest levels of toxins in mussels. Yessotoxins (YTXs) content in mussel increased sharply in the autumn-winter periods even exceeding the legal limit; although this accumulation did not always correlated with the YTX-producers in water (such as Lingulodinium polyedrum and Protoceratium reticulatum) a massive bloom of Gonyaulax spinifera was reported in November 2013, suggesting the role of this species in YTXs shellfish contamination. Traces of Azaspiracid 2 (AZA-2) were observed often in mussels during the study period, confirming for the first time the presence of this biotoxin in Mediterranean seafood.

Advanced PAH pollution monitoring by bivalves

Polycyclic aromatic hydrocarbons (PAH) are broad environmental contaminants, which, due to their lipophilic profile, tend to be absorbed on particles and finally accumulate in marine environments. Due to their cumulative power of adsorption, bivalves are major bioindicators of PAH pollution. Substantial research has been performed on the effects of PAH pollution on marine bivalves. Here we review PAH analysis using bivalves and effects of PAH on bivalves. Specific focus is given on: (1) PAH analytical methodologies and their performance, (2) levels of marine PAH as measured through bivalves within the last decade; current pollution status and (3) health effects of PAH on bivalves.

Design of gem-difluoro-bis-tetrahydrofuran as P2 ligand for HIV-1 protease inhibitors to improve brain penetration: synthesis, X-ray studies, and biological evaluation.

The structure-based design, synthesis, biological evaluation, and X-ray structural studies of fluorine-containing HIV-1 protease inhibitors are described. The synthesis of both enantiomers of the gem-difluoro-bis-THF ligands was carried out in a stereoselective manner using a Reformatskii-Claisen reaction as the key step. Optically active ligands were converted into protease inhibitors. Two of these inhibitors, (3R,3aS,6aS)-4,4-difluorohexahydrofuro[2,3-b]furan-3-yl(2S,3R)-3-hydroxy-4-((N-isobutyl-4-methoxyphenyl)sulfonamido)-1-phenylbutan-2-yl) carbamate (3) and (3R,3aS,6aS)-4,4-difluorohexahydrofuro[2,3-b]furan-3-yl(2S,3R)-3-hydroxy-4-((N-isobutyl-4-aminophenyl)sulfonamido)phenylbutan-2-yl) carbamate (4), exhibited HIV-1 protease inhibitory Ki values in the picomolar range. Both 3 and 4 showed very potent antiviral activity, with respective EC50 values of 0.8 and 3.1 nM against the laboratory strain HIV-1LAI . The two inhibitors exhibited better lipophilicity profiles than darunavir, and also showed much improved blood-brain barrier permeability in an in vitro model. A high-resolution X-ray structure of inhibitor 4 in complex with HIV-1 protease was determined, revealing that the fluorinated ligand makes extensive interactions with the S2 subsite of HIV-1 protease, including hydrogen bonding interactions with the protease backbone atoms. Moreover, both fluorine atoms on the bis-THF ligand formed strong interactions with the flap Gly 48 carbonyl oxygen atom.

Lipophilic shellfish toxins in Dinophysis caudata picked cells and in shellfish from the East China Sea

We reported previously that okadaic acid (OA) and dinophysistoxin-1 (DTX1) were responsible for diarrhetic shellfish poisoning (DSP) incidents due to consuming cultivated mussels (Mytilus galloprovincialis) in coastal cities near the East China Sea in May 2011. Pectenotoxin-2 (PTX2) and its seco acids were also present in these mussels. Causative species of microalgae were not identified because detailed information on the location of the contaminated shellfish was not recorded. In order to explore potential causes for these poisoning events, the lipophilic toxin profiles in picked cells of Dinophysis and in shellfish samples collected from two mariculture zones in the East China Sea were analyzed in the present study. Single-cell isolates (100 cells total for each location) of Dinophysis were collected from the aquaculture zones of Gouqi Island (Ningbo City, Zhejiang Province) and Qingchuan Bay (Ningde City, Fujian Province) in July and September 2013, respectively, for lipophilic toxin profiling. Shellfish samples collected over the course of a year from the Gouqi Island aquaculture zone and mussels (M. galloprovincialis) collected four times from the Qingchuan Bay aquaculture zone were tested for lipophilic toxins by LC-MS/MS. The Dinophysis cells isolated from both sampling sites were identified under the light microscope as Dinophysis caudata. Average quota of PTX2, the predominant toxin in D. caudata isolated from the coastal waters of Gouqi Island and Qingchuan Bay, was 0.58 and 2.8 pg/cell, respectively. Only trace amounts of OA and DTX1 were detected in D. caudata. PTX2, PTX2sa, 7-epi-PTX2sa, OA, and/or DTX1 were found in samples of mussels (M. galloprovincialis and Mytilus coruscus) collected in the Gouqi Island aquaculture zone from the end of May to the beginning of July 2013. PTX2, PTX2sa, and 7-epi-PTX2sa were also detected in oyster (Crassostrea gigas) during that period, but almost no OA and DTX1 were present. Gymnodimine (GYM) was detected in almost all mussel (M. coruscus) samples, with the highest levels occurring in winter. Trace amounts of pectenotoxins (PTXs) and OAs were also found in mussels (M. galloprovincialis) collected from Qingchuan Bay. D. caudata is suggested as an important source of PTXs in shellfish cultivated in the East China Sea. This is the first report of toxin profiles for single-cell isolates of Dinophysis in the East China Sea.

Discovery of pyridyl sulfonamide 11-beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors for the treatment of metabolic disorders

A previous disclosure from this lab highlighted the discovery of pyridyl amides as potent 11β-HSD1 inhibitors. In order to build additional novelty and polarity into this chemotype, replacement of the hydrogen-bonding carbonyl (CO) pharmacophore with the bioisosteric sulfonyl (SO2) group was examined. Despite initial comparisons suggesting the corresponding sulfonamides exhibited weaker activity versus their carbonyl counterparts, further optimization was performed in an effort to identify various potent and unique leads for the program. Judicious incorporation of polar moieties resulted in the identification of compounds with enhanced potency and lipophilicity profiles, resulting in leads with superior aqueous solubility and liver microsomal stability.

High throughput determination log Po/w/pKa/log Do/w of drugs by combination of UHPLC and CE methods

In 1997 Valkó et al. developed a generic fast gradient HPLC method, based on the calculation of the chromatographic hydrophobicity index (CHI) from the gradient retention times, in order to measure lipophilicity. We have enhanced the correlations between CHI and log Po/w and adapted the rapid gradient HPLC method to UHPLC obtaining excellent resolution and repeatability in a short analysis time (<4min). log Po/w values can be easily obtained from these CHI measurements but, unfortunately, these correlations are only valid for non-ionized compounds. Consequently, in order to determine the effective log Po/w value at a particular pH, a fast high-throughput method for pKa determination was required. The IS-CE method is a fast and attractive alternative to other methods for pKa determination, since it offers multiple advantages compared to them: low amounts of test compounds and reagents are needed, high purity is not required, specific interactions between test compounds and buffers are corrected, etc. In addition, it allows the determination of a pKa value in less than 5 minutes. Both CHI and IS-CE have been combined in order to describe a high throughput alternative in order to determine the lipophilicity profiles of bioactive compounds.

Wax ester and lipophilic compound profiling of Euglena gracilis by gas chromatography-mass spectrometry: toward understanding of wax ester fermentation under hypoxia

Lipids are being increasingly used as biodiesel feedstock, and several saturated wax esters from Euglena gracilis are candidates for outdoor bulk production. Wax ester fermentation in Euglena is strongly increased by hypoxia, but key events underlying the metabolic shift toward wax ester biosynthesis are poorly understood. Profiling of wax esters and other lipophilic compounds is the first step for research toward the clarification of wax ester fermentation molecular mechanisms, and thus, a simple and comprehensive platform for their profiling is required. In this study, we established a profiling method for wax esters and lipophilic compounds in Euglena using gas chromatography-mass spectrometry (GC–MS). Using this method, we compared accumulation profiles of wax esters and lipophilic compounds between a wild-type Euglena Z strain and a bleached SM-ZK strain. Both the wild-type and the bleached strains contained C14:0 fatty acid-C14:0 fatty alcohol as a dominant wax ester. Wax ester fermentation initiated 4 h after the cessation of oxygen supply by halting the culture agitation resulting in linear increase and proportional changes of wax ester amounts during 24 h. However, complete anoxia by nitrogen gas aeration inhibited wax ester production and the addition of bicarbonates reversed the inhibition, suggesting that there is a need for an additional carbon source for wax ester fermentation under anoxia. Our simple method enables the investigation of metabolic responses leading to wax ester fermentation in Euglena.

Synthesis, antibacterial and antitubercular activities of benzimidazole bearing substituted 2-pyridone motifs

A series of benzimidazole bearing 2-pyridones 5a–r were synthesized and evaluated for their in vitro antibacterial and antitubercular activity. Further, all compounds were examined for their cytotoxic study on VERO cell line and characterized by well-known spectral techniques. It was observed that the compounds 5h, 5i, 5k, 5q and 5r were found to possess significant broad spectrum antibacterial activity (12.5–100 μg/mL of MIC), while compounds 5g-5i, 5k and 5l proved to be the most potent antitubercular activity in range of 2.76–20.4 μM of MIC at low level of cytotoxicity, indicating good selectivity. From SAR studies, lipophilic profile of compounds was remarkably vital for antibacterial activity, while MIC values of antitubercular activity could not be directly correlated with lipophilicity.

Lipophilic profile of the edible halophyte Salicornia ramosissima

Salicornia ramosissima J. Woods is considered, in the Iberian Peninsula and France, a gourmet product. Nevertheless, is one of the less studied Salicornia species. In this work, GC-MS was employed to, for the first time; fully characterise the lipophilic profile of S. ramosissima and to assess the effect of natural and extra irrigation in that profile. The obtained data showed esterified and free fatty acids, fatty alcohol, sterols, alkanes and aromatic acid derivatives, being palmitic acid, tetracosanol and octacosanol the most abundant compounds. The extra irrigation increases significantly (P<0.001) the content of esterified lipophilic compounds. Stigmastanol, 24-ethyl-δ(22)-coprostenol, several secondary fatty alcohols and dicarboxylic acids were identified for the first time in Salicornia genus. Several of the detected compounds are known to have health benefits and our results suggest that S. ramosissima should be considered as an important dietary source of lipophilic phytochemicals.

Synthesis and antibacterial and cytotoxic activities of new N-3 substituted thiazolidine-2,4-dione derivatives bearing the pyrazole moiety.

Two new series of N-3 substituted thiazolidine-2,4-dione derivatives bearing the pyrazole moiety (5a-j and 7a-j) were synthesized and assessed in vitro for their efficacy as antibacterial agents against gram-positive and gram-negative bacterial strains. Among the tested compounds, 7b, 7c, 7i, and 7j were found to be active against gram-positive bacteria (Staphylococcus aureus and Streptococcus pyogenes) with minimum inhibitory concentration (MIC) values in the range of 6.25-25 µg/mL, and some compounds were also tested against methicillin-resistant S. aureus (MRSA). Compounds 7c and 7j inhibited the growth of MRSA at MIC values of 6.25 and 12.5 µg/mL, respectively. The influence of the lipophilicity (C log P) on the biological profile (MIC) of the prepared products was also discussed. From the standpoint of structure-activity relationship studies, it was observed that the lipophilic profiles of the compounds were crucial for their antibacterial activities. Further, the results of the MTT cytotoxicity studies on a human cervical cancer cell line (HeLa) and a mouse embryonic fibroblast cell line (NIH 3T3) suggested that compounds 7b, 7c, 7i, and 7j were endowed with low levels of cytotoxicity.

Blackberry (Rubus sp. var. Loch Ness) Extract Reduces Obesity Induced by a Cafeteria Diet and Affects the Lipophilic Metabolomic Profile in Rats

Blackberry (Rubus sp. var. Loch Ness) Extract Reduces Obesity Induced by a Cafeteria Diet and Affects the Lipophilic Metabolomic Profile in Rats Blackberries (Rubus sp. var. Loch Ness) contain large amounts of anthocyanins and flavonols, which have several health benefits. The present study was designed to determine the effects of a methanolic blackberry extract in rats fed a cafeteria diet. Weaned female rats were assigned to one of three dietary groups: standard pellet diet (SD), cafeteria diet (CD) and cafeteria diet supplemented with Rubus extract (CRD) for 90 days. Plasma metabolites and insulin were analyzed with commercial kits and fatty acid profile was measured by gas chromatography whereas other aliquots were subjected to metabolomics fingerprinting analysis using ultra high efficiency liquid chromatography. Lipoprotein lipase (LPL) activity was determined in fat depots by a radiochemical method. In comparison to the SD group, rats of the CD and CRD groups had increased plasma myristic, palmitic and oleic acids and those of the CD group had increased liver and different adipose tissue weights; t .

GRL-04810 and GRL-05010, Difluoride-Containing Nonpeptidic HIV-1 Protease Inhibitors (PIs) That Inhibit the Replication of Multi-PI-Resistant HIV-1 In Vitro and Possess Favorable Lipophilicity That May Allow Blood-Brain Barrier Penetration

We designed, synthesized, and identified two novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs), GRL-04810 and GRL-05010, containing the structure-based designed privileged cyclic ether-derived nonpeptide P2 ligand, bis-tetrahydrofuranylurethane (bis-THF), and a difluoride moiety, both of which are active against the laboratory strain HIV-1LAI (50% effective concentrations [EC50s], 0.0008 and 0.003 μM, respectively) with minimal cytotoxicity (50% cytotoxic concentrations [CC50s], 17.5 and 37.0 μM, respectively, in CD4(+) MT-2 cells). The two compounds were active against multi-PI-resistant clinical HIV-1 variants isolated from patients who had no response to various antiviral regimens. GRL-04810 and GRL-05010 also blocked the infectivity and replication of each of the HIV-1NL4-3 variants selected by up to 5 μM lopinavir (EC50s, 0.03 and 0.03 μM, respectively) and atazanavir (EC50s, 0.02 and 0.04 μM, respectively). Moreover, they were active against darunavir (DRV)-resistant variants (EC50 in 0.03 to 0.034 μM range for GRL-04810 and 0.026 to 0.043 μM for GRL-05010), while DRV had EC50s between 0.02 and 0.174 μM. GRL-04810 had a favorable lipophilicity profile as determined with the partition (log P) and distribution (log D) coefficients of -0.14 and -0.29, respectively. The in vitro blood-brain barrier (BBB) permeability assay revealed that GRL-04810 and GRL-05010 may have a greater advantage in terms of crossing the BBB than the currently available PIs, with apparent penetration indexes of 47.8 × 10(-6) and 61.8 × 10(-6) cm/s, respectively. The present data demonstrate that GRL-04810 and GRL-05010 exert efficient activity against a wide spectrum of HIV-1 variants in vitro and suggest that two fluorine atoms added to their bis-THF moieties may well enhance their penetration across the BBB.

Lipophilicity, biomimetic retention profile and antioxidant activity of selenium species

The lipophilicity and biomimetic retention profile of three selenium species, methyl-seleninic acid (MSA), Se-Methyl-selenocysteine (MeSeC) and dimethyl-selenourea (DMeSeU), were established. Lipophilicity was measured by the shaking flask method, while for chromatography one reversed-phase (Discovery C-18) column and three biomimetic stationary phases, namely immobilized artificial membrane (IAM), human serum albumin (HSA) and α1-acid glycoprotein (AGP) were employed, under different mobile phase conditions. These results were combined with previous data obtained under analogous conditions on eight selenium species including selenites (Se(IV)), selenates (Se(VI)), selenomethionine (SeMet), selenocystine (SeCyst), selenocystamine (SeCM), selenourea (SeU), dimethylselenide ((CH3)2Se) and dimethyldiselenide ((CH3)2Se2). The combined data were further used to establish relations between biomimetic retention factors and lipophilicity, the effect of the presence of reduced glutathione (GSH) to retention, as well as to determine the oxidation potential by means of cyclic voltammetry. According to their anode potentials in cyclic voltammetry, only the urea analogues, SeU and, especially, DMeSeU, exhibited considerable antioxidant properties. Moreover IAM retention of Se(IV), Se(VI), SeMet and MeSeC was correlated with Caco-2 apparent permeability coefficient (Papp) available in literature. IAM retention data were further converted to percentage of human oral absorption according to a relevant equation reported in the literature, while from HSA retention results the plasma protein binding was estimated. According to these values, low biopersistence in the human body may be anticipated.

Species-specific lipophilicity of thyroid hormones and their precursors in view of their membrane transport properties

A total of 30 species-specific partition coefficients of three thyroid hormones (thyroxine, liothyronine, reverse liothyronine) and their two biological precursors (monoiodotyrosine, diiodotyrosine) are presented. The molecules were studied using combined methods of microspeciation and lipophilicity. Microspeciation was carried out by 1H NMR-pH and UV-pH titration techniques on the title compounds and their auxiliary derivatives of reduced complexity. Partition of some of the individual microspecies was mimicked by model compounds of the closest possible similarity, then correction factors were determined and introduced. Our data show that the iodinated aromatic ring system is the definitive structural element that fundamentally determines the lipophilicity of thyroid hormones, whereas the protonation state of the aliphatic part plays a role of secondary importance. On the other hand, the lipophilicity of the precursors is highly influenced by the protonation state due to the relative lack of overwhelmingly lipophilic moieties. The different logp values of the positional isomers liothyronine and reverse liothyronine represent the importance of steric and electronic factors in lipophilicity. Our investigations provided clear indication that overall partition, the best membrane transport – predicting physico-chemical parameter depends collectively on the site-specific basicity and species-specific partition coefficient. At physiological pH these biomolecules are strongly amphipathic due to the lipophilic aromatic rings and hydrophilic amino acid side chains which can well be the reason why thyroid hormones cannot cross membranes by passive diffusion and they are constituents of biological membranes.The lipophilicity profile of thyroid hormones and their precursors are calculated and depicted in terms of species-specific lipophilicities over the entire pH range.

Partition coefficients of ionizable solutes in aqueous micellar two-phase systems

The potential of micellar cloud point systems for extraction processes has been demonstrated for a broad range of different applications. The extraction is based on the phenomenon that aqueous non-ionic surfactant solutions split into two phases if the temperature is increased beyond a certain temperature, the so called cloud point temperature (CPT). Recently, aqueous micellar two-phase systems have been implemented in a counter current extraction. However, almost equally important for large scale applications is the recovery of the solute from micellar solutions, which remains a serious concern considering micellar cloud point systems as alternative to conventional solvents. In conventional solvent extraction processes the influence of the pH on the partitioning of ionizable solutes is an important parameter to control the extraction and back extraction efficiency. However, the partitioning of ionizable solutes such as organic acids and bases in micellar two-phase systems has not been studied so far. In this work the partitioning of various ionizable solutes including phenolic as well as pharmaceutical active compounds has been investigated. Lipophilicity profiles of all solutes were analyzed for the system TritonX-114/water in a pH range between 2 and 12. Further, the influence of temperature, solute concentration, as well as different salt concentrations on the partitioning of charged solutes was investigated. Experimental results are verified by means of predicted values using the thermodynamic model COSMO-RS. The results reveal that COSMO-RS can be applied to predict the partitioning of ionizable solutes in micellar biphasic systems, when the phase behavior of the pure surfactant is known.Based on these data optimal strategies for large scale micellar extraction processes are proposed and validated by means of a continuous pilot plant micellar extraction column.

COSMO-RS for the prediction of the retention behavior in micellar liquid chromatography based on partition coefficients of non-dissociated and dissociated solutes

Several methods for the description of the retention behavior in micellar liquid chromatography (MLC) were described previously. Thereby, the most common are the linear solvation energy relationships (LSER). However, for the evaluation of the LSER, a number of experimental data are necessary. In this work, the retention data are predicted based on a single data point for a given solute/surfactant combination. The prediction of micelle/water partition coefficients with the COSMO-RS model was evaluated for the nonionic surfactant Brij 35 and the cationic CTAB for 21 solutes. The predicted partition coefficients along with the retention data of a single measurement were combined with a common retention model for the evaluation of partition coefficients. Thus, the description of the retention data based on a minimum of experimental data was realized in this work. The COSMO-RS model appears to be suitable for the flexible and qualitative prediction of the retention data, which is of special benefit, when a large number of solutes are studied. Furthermore, the introduced method is a promising alternative to describe the retention behavior of ionizable solutes, which is of great interest for e.g. pharmaceutical processes and analyses. To evaluate the method, lipophilicity profiles of several solutes were determined with MLC. While for the nonionic surfactant the lipophilicity is similar to the octanol/water system, a contrary phenomenon, namely a significant increase of the partition coefficient with progressive dissociation can be observed with the ionic surfactant. The MLC method proved to be an efficient method for the determination of micelle/water partition coefficients, excluding non-binding and “overbinding” solutes. The introduced COSMO-RS based approach for the estimation of the retention in MLC is especially promising for highly retarding solutes, since it is time and cost saving compared to the experimental determination.

Chemoinformatic analysis of GRAS (Generally Recognized as Safe) flavor chemicals and natural products.

Food materials designated as “Generally Recognized as Safe” (GRAS) are attracting the attention of researchers in their attempts to systematically identify compounds with putative health-related benefits. In particular, there is currently a great deal of interest in exploring possible secondary benefits of flavor ingredients, such as those relating to health and wellness. One step in this direction is the comprehensive characterization of the chemical structures contained in databases of flavoring substances. Herein, we report a comprehensive analysis of the recently updated FEMA GRAS list of flavoring substances (discrete chemical entities only). Databases of natural products, approved drugs and a large set of commercial molecules were used as references. Remarkably, natural products continue to be an important source of bioactive compounds for drug discovery and nutraceutical purposes. The comparison of five collections of compounds of interest was performed using molecular properties, rings, atom counts and structural fingerprints. It was found that the molecular size of the GRAS flavoring substances is, in general, smaller cf. members of the other databases analyzed. The lipophilicity profile of the GRAS database, a key property to predict human bioavailability, is similar to approved drugs. Several GRAS chemicals overlap to a broad region of the property space occupied by drugs. The GRAS list analyzed in this work has high structural diversity, comparable to approved drugs, natural products and libraries of screening compounds. This study represents one step towards the use of the distinctive features of the flavoring chemicals contained in the GRAS list and natural products to systematically search for compounds with potential health-related benefits.

Thyroxine lipophilicity is dominated by its zwitterionic microspecies

Species-specific partition coefficients were determined for a triprotic molecule for the first time. Thyroxine, the vitally important thyroid hormone which exists in solution in the forms of eight microspecies due to its phenolate, amino and carboxylate basic sites, was studied by combined methods of microspeciation and lipophilicity. Partition of the individual microspecies was mimicked by model compounds of the closest possible similarity, then correction factors were determined and introduced. The non-charged microspecies is only 2.40 times as lipophilic as its zwitterionic protonation isomer, showing that for thyroxine the iodinated aromatic rings are the structural elements that determine the lipophilicity of this molecule, and the protonation state of the other substituents plays only a minor role. The overwhelming dominance of the zwitterionic form, however, ensures that its contribution to the overall lipophilicity exceeds 14,500 times that of the non-charged one. This fact is so far the sharpest counter-example of the widespread belief that passive diffusion into lipophilic media is predominated by the non-charged species. The lipophilicity profile of thyroxine is expressed, calculated and depicted in terms of species-specific lipophilicities over the entire pH range.

Bioassay guided isolation and identification of anti-inflammatory and anti-microbial compounds from Urtica dioica L. (Urticaceae) leaves

The present study describes the anti-inflammatory, anti-microbial activity and lipophilic profile with acute toxicological studies of Urtica dioica. Successive extraction of the leaves with organic solvents of increasing polarity and their screening for anti-inflammatory and anti-microbial activity was assessed. Hexane extract showed good anti-inflammatory and anti-microbial activity; hence it was further fractionated using open silica gel column chromatography into 19 sub fractions which were pooled together according to their thin layer chromatography (TLC) profile to give an overall 5 fractions. Among the 5 fractions, fraction-II (FII) at a dose of 200 mg/kg body-weight (bw) exhibits equipotent anti-inflammatory activity (48.83% after 3 h) as that of the standard drug indomethacin (53.48%) in Wistar rats. FII also showed a potent anti-microbial activity against all the tested bacterial strains and its minimum inhibitory concentration (MIC) value was 125, 15.62, 31.25, 250, 31.25, 125 and 7.81 µg/ml against Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae,Pseudomonas aeruginosa, Staphylococcus aureus, Shigella flexneri and Salmonella typhi, respectively which was determined by serial tube dilution method. FII was subjected to gas chromatography-mass spectrometry (GC-MS) analysis in search of potent anti-inflammatory and anti-microbial compound(s). 2,4-Di-t-butylphenol (4.56%), neophytadiene (26.97%), butyl tetradecyl ester (9.53%), dibutyl phthalate (7.45%), bis(2-ethyl hexyl) maleate (8.80%), 1,2-benzenedicarboxylic acid (9.89%) and 2-tert-butyl-4,6-bis(3,5-di-tert-butyl-4-hydroxybenzyl)phenol (3.19%) were the major constituents responsible for both anti-inflammatory and anti-microbial activity of hexane extract of U. dioica. Sub-acute oral toxicity of crude n-hexane extract of U. dioica was carried out in Wistar rats at doses of 250, 500, 1000 and 2000 mg/kg bw to assess the safety index. Hematological parameters from blood and other biochemical parameters from serum confirmed its safety at tested concentrations. Our results corroborate the anti-inflammatory and anti-microbial activity of U. dioica, and could justify its use in folk medicine for the treatment of rheumatic arthritis and other infectious diseases. Key words: Urtica dioica, anti-inflammatory, anti-microbial, minimum inhibitory concentration (MIC), gas chromatography-mass spectrometry (GC-MS), toxicity.

2‐Amino‐3‐(1‐(4‐(4‐(2‐methoxyphenyl) piperazine‐1‐yl)butyl)‐1H‐1,2,3‐triazol‐4‐yl) propanoic acid: synthesized, 99mTc‐tricarbonyl labeled, and bioevaluated as a potential 5HT1A receptor ligand

To develop a novel 5HT1A receptor imaging agent, a new methoxyphenyl piperazine derivative was synthesized and radiolabeled with 99mTc‐tricarbonyl precursor. We used the Cu (I)‐catalyzed cycloaddition of azide and terminal alkynes to synthesize 1, 2, 3 triazole as the metal chelating system. This synthesis provided reliable and reproducible method to attach technetium to the methoxyphenyl piperazine moiety. 99mTc‐tricabonyl labeling of ligand was performed at high radiochemical purity (greater than 95%). The radiolabeled compound was stable at least 24 h in room temperature. In vitro stability study in human serum albumin showed more than 90% stability in 37 °C incubation for 6 h. Biodistribution studies in rat have shown brain hippocampus uptake of 0.31 ± 0.02 %ID/g at 5‐min post‐injection. The favorable in vitro/in vivo stability, lipophilicity, and biodistribution profiles suggest that this radioconjugate is a good candidate for further exploration of its potential clinical application. Copyright © 2012 John Wiley &amp; Sons, Ltd.