Analysis of the Electron Density of a Water Molecule Encapsulated by Two Cholic Acid Residues.

Cholic acid is a trihydroxy bile acid with a nice peculiarity: the average distance between the oxygen atoms (O7 and O12) of the hydroxy groups located at C7 and C12 carbon atoms is 4.5 Å, a value which perfectly matches with the O/O tetrahedral edge distance in Ih ice. In the solid phase, they are involved in the formation of hydrogen bonds with other cholic acid units and solvents. This fact was satisfactorily used for designing a cholic dimer which encapsulates one single water molecule between two cholic residues, its oxygen atom (Ow) being exactly located at the centroid of a distorted tetrahedron formed by the four steroid hydroxy groups. The water molecule participates in four hydrogen bonds, with the water simultaneously being an acceptor from the 2 O12 (hydrogen lengths are 2.177 Å and 2.114 Å) and a donor towards the 2 O7 (hydrogen bond lengths are 1.866 Å and 1.920 Å). These facts suggest that this system can be a nice model for the theoretical study of the formation of ice-like structures. These are frequently proposed to describe the water structure found in a plethora of systems (water interfaces, metal complexes, solubilized hydrophobic species, proteins, and confined carbon nanotubes). The above tetrahedral structure is proposed as a reference model for those systems, and the results obtained from the application of the atoms in molecules theory are presented here. Furthermore, the structure of the whole system allows a division into two interesting subsystems in which water is the acceptor of one hydrogen bond and the donor of another. The analysis of the calculated electron density is performed through its gradient vector and the Laplacian. The calculation of the complexation energy used correction of the basis set superposition error (BSSE) with the counterpoise method. As expected, four critical points located in the H…O bond paths were identified. All calculated parameters obey the proposed criteria for hydrogen bonds. The total energy for the interaction in the tetrahedral structure is 54.29 kJ/mol, while the summation obtained of the two independent subsystems and the one between the alkyl rings without water is only 2.5 kJ/mol higher. This concordance, together with the calculated values for the electron density, the Laplacian of the electron density, and the lengths of the oxygen atom and the hydrogen atom (involved in the formation of each hydrogen bond) to the hydrogen bond critical point, suggests that each pair of hydrogen bonds can be considered independent of each other.

Effect of Gold Nanoparticles on the Physical Properties of an Epoxy Resin.

The effect of doping the bisphenol A diglycidyl ether (DGEBA)/m-xylylenediamine (mXDA) system with gold nanoparticles (AuNP) has been studied with differential scanning calorimetry (DSC), thermogravimetric analysis, dynamic mechanical analysis (DMA), and dielectric analysis (DEA). The evolved heat (ΔHt), the glass transition temperature (Tg), and the associated activation energies of this relaxation process have been determined. Below a certain concentration of AuNPs (=8.5%, in mg AuNP/g epoxy matrix), Tg decreases linearly with the concentration of AuNPs, but above it, Tg is not affected. The degree of conversion α of this epoxy system was analyzed by the semiempirical Kamal's model, evidencing that diffusion correction is required at high values of α. Activation energy values suggest that AuNPs can cause some impediments at the beginning of the crosslinking process (n-order mechanism). The slight difference between the initial decomposition temperature, as well as the temperature for which the degradation rate is at a maximum, for both systems can be accepted to be within experimental error. Mechanical properties (tension, compression, and bending tests) are not affected by the presence of AuNPs. Dielectric measurements show the existence of a second Tg at high temperatures, which was analyzed using the Tsagarapoulos and Eisenberg model of the mobility restrictions of network chains bound to the filler.

Efficient Synthesis of 2-Aminopyridine Derivatives: Antibacterial Activity Assessment and Molecular Docking Studies.

A new and suitable multicomponent one-pot reaction was developed for the synthesis of 2-amino-3-cyanopyridine derivatives. BACKGROUND: This synthesis was demonstrated by the efficient and easy access to a variety of substituted 2-aminopyridines using enaminones as key precursors under solvent-free conditions. METHODS: A range of spectroscopic techniques was used to determine and confirm the chemical structures (FTIR, 1H NMR, 13C NMR). The antimicrobial potency of synthesized compounds (2a-d) was tested using disk diffusion assays, and the Minimum Inhibitory Concentration (MIC) for the active compounds was determined against a panel of microorganisms, including Gram-positive and Gram-negative bacteria and yeasts. Moreover, a docking analysis was conducted by Molecular Operating Environment (MOE) software to provide supplementary information about the potential, as well as an ADME-T prediction to describe the pharmacokinetic properties of the best compound and its toxicity. RESULTS: The results of the antimicrobial activity indicated that compound 2c showed the highest activity against Gram-positive bacteria, particularly S. aureus and B. subtilis whose MIC values were 0.039 ± 0.000 µg·mL-1. The results of the theoretical study of compound 2c were in line with the experimental data and exhibited excellent antibacterial potential. CONCLUSIONS: On the basis of the obtained results, compound 2c can be used as an antibacterial agent model with high antibacterial potency.

Highly Hydrophilic and Lipophilic Derivatives of Bile Salts.

Lipophilicity of 15 derivatives of sodium cholate, defined by the octan-1-ol/water partition coefficient (log P), has been theoretically determined by the Virtual log P method. These derivatives bear highly hydrophobic or highly hydrophilic substituents at the C3 position of the steroid nucleus, being linked to it through an amide bond. The difference between the maximum value of log P and the minimum one is enlarged to 3.5. The partition coefficient and the critical micelle concentration (cmc) are tightly related by a double-logarithm relationship (VirtuallogP=-(1.00±0.09)log(cmcmM)+(2.79±0.09)), meaning that the Gibbs free energies for the transfer of a bile anion from water to either a micelle or to octan-1-ol differ by a constant. The equation also means that cmc can be used as a measurement of lipophilicity. The demicellization of the aggregates formed by three derivatives of sodium cholate bearing bulky hydrophobic substituents has been studied by surface tension and isothermal titration calorimetry. Aggregation numbers, enthalpies, free energies, entropies, and heat capacities, ΔCP,demic, were obtained. ΔCP,demic, being positive, means that the interior of the aggregates is hydrophobic.

Asian Hornet, Vespa velutina Lepeletier 1836 (Hym.: Vespidae), Venom Obtention Based on an Electric Stimulation Protocol.

The yellow-legged Asian hornet (Vespa velutina Lepeletier 1836 (Hymenoptera: Vespidae)) is naturally distributed in China, Southeast Asia, and India; however, recently it has been detected outside of its native area, confirmed as being established in South Korea, Europe, and Japan. Health risks and deaths caused by the invasive Vespa velutina stings have become a public health concern, being the most common cause of anaphylaxis due to hymenopterans in some European regions. This in turn has led to increased demand from medical practitioners and researchers for Vespa velutina venom for diagnostic and therapeutic purposes. In this study, a straightforward, quick, and inexpensive method for obtaining Vespa velutina venom by electric stimulation is described. The venom extracts were analyzed by nuclear magnetic resonance spectroscopy (1H-NMR). The availability of Vespa velutina venom will lead to improved diagnostic and therapeutic methods, mainly by venom immunotherapy (VIT), in patients allergic to this invasive species.

Structure-Based Site of Metabolism (SOM) Prediction of Ligand for CYP3A4 Enzyme: Comparison of Glide XP and Induced Fit Docking (IFD).

Metabolism is one of the prime reasons where most of drugs fail to accomplish their clinical trials. The enzyme CYP3A4, which belongs to the superfamily of cytochrome P450 enzymes (CYP), helps in the metabolism of a large number of drugs in the body. The enzyme CYP3A4 catalyzes oxidative chemical processes and shows a very broad range of ligand specificity. The understanding of the compound's structure where oxidation would take place is crucial for the successful modification of molecules to avoid unwanted metabolism and to increase its bioavailability. For this reason, it is required to know the site of metabolism (SOM) of the compounds, where compounds undergo enzymatic oxidation. It can be identified by predicting the accessibility of the substrate's atom toward oxygenated Fe atom of heme in a CYP protein. The CYP3A4 enzyme is highly flexible and can take significantly different conformations depending on the ligand with which it is being bound. To predict the accessibility of substrate atoms to the heme iron, conventional protein-rigid docking methods failed due to the high flexibility of the CYP3A4 protein. Herein, we demonstrated and compared the ability of the Glide extra precision (XP) and Induced Fit docking (IFD) tool of Schrodinger software suite to reproduce the binding mode of co-crystallized ligands into six X-ray crystallographic structures. We extend our studies toward the prediction of SOM for compounds whose experimental SOM is reported but the ligand-enzyme complex crystal structure is not available in the Protein Data Bank (PDB). The quality and accuracy of Glide XP and IFD was determined by calculating RMSD of docked ligands over the corresponding co-crystallized bound ligand and by measuring the distance between the SOM of the ligand and Fe atom of heme. It was observed that IFD reproduces the exact binding mode of available co-crystallized structures and correctly predicted the SOM of experimentally reported compounds. Our approach using IFD with multiple conformer structures of CYP3A4 will be one of the effective methods for SOM prediction.

Extraction and Physicochemical Characterization of Chitin Derived from the Asian Hornet, Vespa velutina Lepeletier 1836 (Hym.: Vespidae).

Fifteen years ago, at least one multimated female yellow-legged Asian hornet (Vespa velutina Lepeletier 1836) arrived in France, which gave rise to a pan-European invasion. In this study, the isolation and characterization of chitin (CHI) that was obtained from Vespa velutina (CHIVV) is described. In addition, an easy procedure is carried out to capture the raw insect, selectively and with high rates of success. The chitin contents of dry VV was observed to be 11.7%. Fourier transform infrared spectroscopy (FTIR), solid-state NMR (ssNMR), elemental analysis (EA), scanning electron microscopy (SEM), and thermogravimetric analysis (TG) characterized the physicochemical properties of CHIVV. The obtained CHIVV is close to pure (43.47% C, 6.94% H, and 6.85% N), and full acetylated with a value of 95.44%. Additionally, lifetime and kinetic parameters such as activation E and the frequency factor A using model-free and model-fitting methods, were determined. For CHIVV the solid state mechanism that follows the thermodegradation is of type F2 (random nucleation around two nuclei). The invasive Asian hornet is a promising alternative source of CHI, based on certain factors, such as the current and probable continued abundance of the quantity and quality of the product obtained.

Ultrasound Assisted Synthesis of 4-(Benzyloxy)-N-(3-chloro-2-(substitutedphenyl)-4-oxoazetidin-1-yl) Benzamide as Challenging Anti-Tubercular Scaffold.

A series of ten novel derivatives of 4-(benzyloxy)-N-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1-yl) benzamide 6a⁻j were synthesized in good yield from the key compound 4-(benzyloxy)-N'-(substituted benzylidene) benzo hydrazide, called Schiff 's bases 5a⁻j, by Staudinger reaction ([2 + 2] ketene-imine cycloaddition reaction) with chloro acetyl chloride in the presence of catalyst tri ethylamine and solvent dimethyl formamide (DMF), by using ultra-sonication as one of the green chemistry tools. All the synthesised compounds were evaluated for in vitro anti-tubercular activity against Mycobacterium tuberculosis (MTB) and most of them showed promising activity with an IC50 value of less than 1 µg/mL. To establish the safety, all the synthesized compounds were further tested for cytotoxicity against the human cancer cell line HeLa and all 6a⁻j compounds were found to be non-cytotoxic in nature. The molecular docking study was carried out with essential enzyme InhA (FabI/ENR) of Mycobacterium responsible for cell wall synthesis which suggests that 6a and 6e are the most active derivatives of the series. The theoretical evaluation of cell permeability based on Lipinski's rule of five has helped to rationalize the biological results and hence the synthesized azetidinone derivatives 6a⁻j were also analyzed for physicochemical evaluation that is, absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties and the results showed that all the derivatives could comply with essential features required for a potential lead in the anti-tubercular drug discovery process.

Analysis of an old controversy: The compensation temperature for micellization of surfactants.

The actual significance of the so-called compensation temperature Tc for micellization of surfactants is reviewed. It is demonstrated that it is possible to obtain as many Tc values as the number of temperature intervals in which the dependencies of enthalpy and entropy changes with temperature are analyzed. The value of each Tc will be the central value To of each temperature interval. These two facts suggest that Tc is simply such experimental To. Thus any physical interpretation derived from Tc is unfounded.

Ionic Liquid-Promoted Synthesis of Novel Chromone-Pyrimidine Coupled Derivatives, Antimicrobial Analysis, Enzyme Assay, Docking Study and Toxicity Study.

Herein, we report an environmentally friendly, rapid, and convenient ionic liquid ([Et3NH][HSO4])-promoted facile synthesis of ethyl 4-(6-substituted-4-oxo-4H-chromen-3-yl)-6-methyl-2-thioxo/oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives 4(a-f) and 4-(6-substituted-4-oxo-4H-chromen-3-yl)-6-methyl-2-thioxo/oxo-1,2,3,4-tetrahydropyrimidine-5- carbohydrazide derivatives 6(a-f). All the synthesized derivatives 4(a-f) and 6(a-f) were evaluated for their in vitro antifungal and antibacterial activity, by method recommended by National Committee for Clinical Laboratory Standards (NCCLS). The compound 6c bearing a fluoro group on the chromone ring and oxygen and a hydrazino group (-NHNH2) on the pyrimidine ring, was found to be the most potent antibacterial compound amongst the synthesized derivatives. The compound 6f bearing a methoxy group (-OCH3) on the chromone ring and sulphur group on the pyrimidine ring, was found to exhibit equipotent antifungal activity when compared with the standard drug miconazole. A D-alanine-D-alanine ligase (DdlB) enzyme assay study and an ergosterol extraction and quantitation assay study were performed to predict the mode of action of the synthesized compounds. A molecular docking study was performed to predict the binding interactions with receptors and mode of action of the synthesized derivatives. Further, analysis of the ADMET parameters for the synthesized compounds has shown that these compounds have good oral drug-like properties and can be developed as oral drug candidates. To establish the antimicrobial selectivity and safety, the most active compounds 6c and 6f were further tested for cytotoxicity against the human cancer cell line HeLa and were found to be non-cytotoxic in nature. An in vivo acute oral toxicity study was also performed for the most active compounds 6c and 6f and the results indicated that the compounds are non-toxic in nature.

Ionic Liquid-Catalyzed Green Protocol for Multi-Component Synthesis of Dihydropyrano[2,3-c]pyrazoles as Potential Anticancer Scaffolds.

A series of 6-amino-4-substituted-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles 5a-j were synthesized via one-pot, four-component condensation reactions of aryl aldehydes 1a-j, propanedinitrile (2), hydrazine hydrate (3) and ethyl acetoacetate (4) under solvent-free conditions. We report herein the use of the Brønsted acid ionic liquid (BAIL) triethylammonium hydrogen sulphate [Et3NH][HSO4] as catalyst for this multi-component synthesis. Compared with the available reaction methodology, this new method has consistent advantages, including excellent yields, a short reaction time, mild reaction conditions and catalyst reusability. Selected synthesized derivatives were evaluated for in vitro anticancer activity against four human cancer cell lines viz. melanoma cancer cell line (SK-MEL-2), breast cancer cell line(MDA-MB-231), leukemia cancer cell line (K-562) and cervical cancer cell line (HeLa). Compounds 5b, 5d, 5g, 5h and 5j exhibited promising anticancer activity against all selected human cancer cell lines, except HeLa. Molecular docking studies also confirmed 5b and 5d as good lead molecules. An in silico ADMET study of the synthesized anticancer agents indicated good oral drug-like behavior and non-toxic nature.

Facile Synthesis of Novel Coumarin Derivatives, Antimicrobial Analysis, Enzyme Assay, Docking Study, ADMET Prediction and Toxicity Study.

The work reports the synthesis under solvent-free condition using the ionic liquid [Et3NH][HSO4] as a catalyst of fifteen novel 3-((dicyclohexylamino)(substituted phenyl/heteryl)-methyl)-4-hydroxy-2H-chromen-2-onederivatives 4a-o as potential antimicrobial agents. The structures of the synthesized compounds were confirmed by IR, ¹H-NMR, 13C-NMR, mass spectral studies and elemental analyses. All the synthesized compounds were evaluated for their in vitro antifungal and antibacterial activity. The compound 4k bearing 4-hydroxy-3-ethoxy group on the phenyl ring was found to be the most active antifungal agent. The compound 4e bearing a 2,4-difluoro group on the phenyl ring was found to be the most active antibacterial agent. The mode of action of the most promising antifungal compound 4k was established by an ergosterol extraction and quantitation assay. From the assay it was found that 4k acts by inhibition of ergosterol biosynthesis in C. albicans. Molecular docking studies revealed a highly spontaneous binding ability of the tested compounds to the active site of lanosterol 14α-demethylase, which suggests that the tested compounds inhibit the synthesis of this enzyme. The synthesized compounds were analyzed for in silico ADMET properties to establish oral drug like behavior and showed satisfactory results. To establish the antimicrobial selectivity and safety, the most active compounds 4e and 4k were further tested for cytotoxicity against human cancer cell line HeLa and were found to be non-cytotoxic in nature. An in vivo acute oral toxicity study was also performed for the most active compounds 4e and 4k and results indicated that the compounds are non-toxic.

Microwave-Assisted Facile Synthesis, Anticancer Evaluation and Docking Study of N-((5-(Substituted methylene amino)-1,3,4-thiadiazol-2-yl)methyl) Benzamide Derivatives.

In the present work, 12 novel Schiff's bases containing a thiadiazole scaffold and benzamide groups coupled through appropriate pharmacophore were synthesized. These moieties are associated with important biological properties. A facile, solvent-free synthesis of a series of novel 7(a-l) N-((5-(substituted methylene amino)-1,3,4-thiadiazol-2-yl)methyl) benzamide was carried out under microwave irradiation. Structures of the synthesized compounds were confirmed by IR, NMR, mass spectral study and elemental analysis. All the synthesized hybrids were evaluated for their in vitro anticancer activity against a panel of four human cancer cell lines, viz. SK-MEL-2 (melanoma), HL-60 (leukemia), HeLa (cervical cancer), MCF-7 (breast cancer) and normal breast epithelial cell (MCF-10A) using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay method. Most of the synthesized compounds exhibited promising anticancer activity, showed comparable GI50 values comparable to that of the standard drug Adriamycin. The compounds 7k, 7l, 7b, and 7a were found to be the most promising anticancer agents in this study. A molecular docking study was performed to predict the probable mechanism of action and computational study of the synthesized compounds 7(a-l) was performed to predict absorption, distribution, metabolism, excretion and toxicity (ADMET) properties, by using QikProp v3.5 (Schrödinger LLC). The results showed the good oral drug-like behavior of the synthesized compounds 7(a-l).

Ultrasound Mediated One-Pot, Three Component Synthesis, Docking and ADME Prediction of Novel 5-Amino-2-(4-chlorophenyl)-7-Substituted Phenyl-8,8a-dihydro-7H-(1,3,4)thiadiazolo(3,2-α)pyrimidine-6-carbonitrile Derivatives as Anticancer Agents.

Herein, we report an environmentally friendly, rapid, and convenient one-pot ultrasound-promoted synthesis of 5-amino-2-(4-chlorophenyl)-7-substituted phenyl-8,8a-dihydro-7H-(1,3,4)thiadiazolo(3,2-α)pyrimidine-6-carbonitrile derivatives. The in-vitro anticancer activities of these compounds were evaluated against four human tumor cell lines. Among all the synthesized derivatives, compound 4i, which has substituent 3-hydroxy-4-methoxyphenyl is found to have the highest GI50 value of 32.7 µM, 55.3 µM, 34.3 µM, 28.9 µM for MCF-7, K562, HeLa and PC-3 cancer cell lines respectively. A docking study of the newly synthesized compounds were performed, and the results showed good binding mode in the active site of thymidylate synthase enzyme. ADME properties of synthesized compounds were also studied and showed good drug like properties.

A rapid and sensitive determination of hypoxic radiosensitizer agent nimorazole in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

A highly sensitive, accurate and robust LC-MS/MS method was developed and validated for determination of nimorazole (NMZ) in rat plasma using metronidazole (MNZ) as internal standard (IS). The analyte and IS were extracted from plasma by precipitating protein with acetonitrile and were chromatographed using an Agilent Poroshell 120, EC-C18 column. The mobile phase was composed of a mixture of acetonitrile and 0.1 % formic acid (85:15 v/v). The total run time was 1.5 min and injection volume was 5 µL. Multiple reaction monitoring mode using the transitions of m/z 227.1 → m/z 114.0 for MNZ and m/z 172.10 → m/z 128.1 for IS were monitored on a triple quadrupole mass spectrometer, operating in positive ion mode. The calibration curve was linear in the range of 0.25-200 ng/mL (r(2) > 0.9996) and the lower limit of quantification was 0.25 ng/mL in the rat plasma samples. Recoveries of NMZ ranged between 88.05 and 95.25%. The precision (intra-day and inter-day) and accuracy of the quality control samples were 1.25-8.20% and -2.50-3.10, respectively. The analyte and IS were found to be stable during all sample storage and analysis procedures. The LC-MS/MS method described here was validated and successfully applied to pharmacokinetic study in rats.

Novel microwave-assisted synthesis of the immunomodulator organotellurium compound ammonium trichloro(dioxoethylene-O,O')tellurate (AS101).

Ammonium trichloro[1,2-ethanediolato-O,O']-tellurate (AS101) is the most important synthetic Te compound from the standpoint of its biological activity. It is a potent immunomodulator with a variety of potential therapeutic applications and antitumoral action in several preclinical and clinical studies. An experimental design has been used to develop and optimize a novel microwave-assisted synthesis (MAOS) of the AS101. In comparison to the results observed in the literature, refluxing Te(IV) chloride and ethylene glycol in acetonitrile (Method A), or by refluxing Te(IV) chloride and ammonium chloride in ethylene glycol (Method B), it was found that the developed methods in the present work are an effective alternative, because although performance slightly decreases compared to conventional procedures (75% vs. 79% by Method A, and 45% vs. 51% by Method B), reaction times decreased from 4 h to 30 min and from 4 h to 10 min, by Methods A and B respectively. MAOS is proving to be of value in the rapid synthesis of compounds with new and improved biological activities, specially based on the benefit of its shorter reaction times.

Structure elucidation and HPLC-MS/MS determination of a potential biomarker for estradiol administration in cattle.

Administration of hormonal compounds as growth promoters in livestock farming was banned by Council Directive 96/22/EC. However, this kind of substances is sometimes reported within the framework of European monitoring residue plans. Various analytical methods have been previously developed to screen for their misuse, and they are now especially efficient for monitoring the illegal administration of synthetic and semisynthetic hormones. Nevertheless, proving an exogenous administration of hormones from natural origin (i.e., estradiol-17ß or progesterone) still remains a challenge for European authorities. These target compounds are indeed always present in the animal matrix, and the establishment of reference thresholds appears very difficult because of the extreme variability existing among animals. In 2011, a metabolomics study was performed on serum samples obtained from cows treated with estradiol-17ß (or its ester estradiol benzoate) and from control animals using a high-performance liquid chromatography (HPLC)-LTQ-Orbitrap system. After appropriate data processing and multivariate statistical analysis (orthogonal partial least squares discriminant analysis), it was possible to highlight one potential biomarker candidate of estradiol treatments in bovine animals. Now, this biomarker has been structurally elucidated as a dipeptide, and its usefulness has been tested through a targeted HPLC-MS/MS method. Its presence in the previous samples has been confirmed and also in additional samples from estradiol-treated animals.

Triacylglyceride, antioxidant and antimicrobial features of virgin Camellia oleifera, C. reticulata and C. sasanqua Oils.

Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined by ¹H-nuclear magnetic resonance analysis were similar to those reported for olive oils (82.30%-84.47%; 5.69%-7.78%; 0.26%-0.41% and 8.04%-11.2%, for oleic, linoleic, linolenic and saturated acids, respectively). The CR oil showed the best antioxidant potential in the three in vitro models tested. With regard to EC50 values (µg/mL), the order in DPPH radical-scavenging was CR (33.48) < CO (35.20) < CS (54.87). Effectiveness in reducing power was CR (2.81) < CO (3.09) < CS (5.32). IC50 for LPO inhibition were 0.37, 0.52 and 0.75 µg/mL for CR, CO and CS, respectively. All the oils showed antimicrobial activity, and exhibited different selectivity and MICs for each microorganism tested (E. coli, B. cereus and C. albicans). B. cereus was the less sensitive species (MIC: 52.083 ± 18.042 for CO; 41.667 ± 18.042 for CR; 104.167 ± 36.084 for CS mg/mL) and the E. coli was the most sensitive to camellia oil's effect. The standard gentamicin presented higher MIC for E. coli (4.2) than the CR (MIC= 2.6) and CO (MIC = 3.9) oils.

Comprehensive study of honey with protected denomination of origin and contribution to the enhancement of legal specifications.

In this study the characterization of a total of 60 honey samples with Protected Denomination of Origin (PDO) collected over three harvests (2009-2011, inclusive), from the Northeast of Portugal was carried out based on the presence of pollen, physicochemical and microbiological characteristics. All samples were found to meet the European Legislation, but some didn't meet the requirements of the PDO specifications. Concerning the floral origin of honey, our results showed the prevalence of rosemary (Lavandula pedunculata) pollen. The microbiological quality of all the analyzed samples was satisfactory, since fecal coliforms, sulfite-reducing clostridia and Salmonella were absent, and molds and yeasts were detected in low counts. Significant differences between the results were studied using one-way analysis of variance (ANOVA), followed by Tukey's HSD test. The samples were submitted to discriminant function analysis, in order to determine which variables differentiate between two or more naturally occurring groups (Forward Stepwise Analysis). The variables selected were in this order: diastase activity, pH, reducing sugars, free acidity and HMF. The pollen spectrum has perfect discriminatory power. This is the first study in which a honey with PDO was tested, in order to assess its compliance with the PDO book of specifications.

Organic bee pollen: botanical origin, nutritional value, bioactive compounds, antioxidant activity and microbiological quality.

Organic bee pollen (BP, n = 22) harvested from the Douro International Natural Park (DINP, Portugal) was studied. Nine botanical families were found in the mixture of the samples. The water activity and pH ranged 0.21-0.37 and 4.3-5.2, respectively. The BP analyses averaged 67.7% carbohydrates, 21.8% crude protein, 5.2% crude fat and 2.9% ash. The energy ranged from 396.4 to 411.1 kcal/100 g. The principal fatty acid found was linolenic, followed by linoleic acid, palmitic acid and oleic acid. The phenolic and flavonoid contents varied from 12.9 to 19.8 mg of gallic acid equivalents/g of extract and from 4.5 to 7.1 mg of catechin equivalents/g of extract, respectively. The scavenger activity and ß-carotene bleaching assays values (EC50) were 3.0 ± 0.7 mg/mL and 4.6 mg/mL ± 0.9 mg/mL, respectively. E. coli, sulphite-reducing Clostridia, Salmonella and S. aureus were not found. Since there are studies indicating appreciable differences among BPs from different regions, the full characterization of BP from diverse origins still appears to be a sound research priority in order to obtain reliable data about this beehive product.