Pterodon emarginatus Seed Preparations: Antiradical Activity, Chemical Characterization, and In Silico ADMET Parameters of ß-caryophyllene and Farnesol.

The study of medicinal plants and their active compounds is relevant to maintaining knowledge of traditional medicine and to the development of new drugs of natural origin with lower environmental impact. From the seeds of the Brazilian plant Pterodon emarginatus, six different preparations were obtained: essential oil (EO), ethanol extract (EthE) prepared using the traditional method, and four extracts using solvents at different polarities, such as n-hexane, chloroform, ethyl acetate, and methanol (HexE, ChlE, EtAE, and MetE). Chemical characterization was carried out with gas chromatography, allowing the identification of several terpenoids as characteristic components. The two sesquiterpenes ß-caryophyllene and farnesol were identified in all preparations of Pterodon emarginatus, and their amounts were also evaluated. Furthermore, the total flavonoid and phenolic contents of the extracts were assessed. Successively, the antiradical activity with DPPH and ORAC assays and the influence on cell proliferation by the MTT test on the human colorectal adenocarcinoma (HT-29) cell line of the preparations and the two compounds were evaluated. Lastly, an in silico study of adsorption, distribution, metabolism, excretion, and toxicity (ADMET) showed that ß-caryophyllene and farnesol could be suitable candidates for development as drugs. The set of data obtained highlights the potential medicinal use of Pterodon emarginatus seeds and supports further studies of both plant preparations and isolated compounds, ß-caryophyllene and farnesol, for their potential use in disease with free radical involvement as age-related chronic disorders.

Effect of multiple error sources on the calibration uncertainty.

The calibration uncertainty associated with the determination of metals at trace levels in a drinking water sample by ICP-MS was estimated when signals were affected by two error contributions, namely instrumental errors and operational condition errors. The calibration uncertainty was studied by using J concentration levels measured I times, as usual in experimental calibration procedures. The instrumental error was random in character whilst the operational error was assumed systematic at each concentration level but random among the J levels. The presence or the absence of the two error contributions was determined with an F-test between the ordinary least squares residual variance of the mean responses at each concentration and a pooled variance of the replicates. The theory was applied to the calibration of 30 elements present in a multi-standard solution and then to the analysis of boron, calcium, lithium, barium and manganese in a real drinking water sample. The need of using the proposed approach as calibration for almost all the analyzed elements resulted evident. The presence or the absence of the two error contributions was determined with an F-test between the ordinary least squares residual variance of the mean responses at each concentration and a pooled variance of the replicates. It was found that in the former instance the uncertainty determined using a two-components variance regression was greater than that obtainable from the one-variance regression.

Radical scavenging and antimicrobial activities of Croton zehntneri, Pterodon emarginatus and Schinopsis brasiliensis essential oils and their major constituents: estragole, trans-anethole, ß-caryophyllene and myrcene.

The essential oils (EOs) from the Brazilian species Croton zehntneri, Pterodon emarginatus and Schinopsis brasiliensis were examined for their chemical constituents, and antioxidant and antimicrobial activities. The composition of EOs was determined by using gas chromatography coupled with mass spectrometry analysis, while the antioxidant activity was evaluated through the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. Furthermore, the antimicrobial activity was investigated against Escherichia coli and Pseudomonas aeruginosa (both Gram-negative), Staphylococcus aureus (Gram-positive) and Candida parapsilosis (fungus). The main components of C. zehntneri, P. emarginatus and S. brasiliensis were identified as estragole, trans-anethole, ß-caryophyllene and myrcene. Among the EOs, P. emarginatus showed the highest antioxidant activity, with an IC50 of 7.36 mg/mL and a Trolox equivalent antioxidant capacity of 3748 µmol/g determined by DPPH and ORAC assays, respectively. All EOs showed low activities against the bacterial strains tested, whereas the C. zehntneri oil and its main constituent estragole exhibited an appreciable antifungal activity against C. parapsilosis.

Characterization and quantification of N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine biocide by NMR, HPLC/MS and titration techniques.

The present paper reports the determination of the tri-amine N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) present in a raw material called LONZABAC used to formulate various, widely used commercial biocides. The active principle, TA, is present in LONZABAC together with other molecules at lower concentration levels. Three independent analytical approaches, namely solution NMR spectroscopy, liquid chromatography coupled to high resolution mass spectrometry (LC/HRMS) and acid-base titration in mixed solvent, were used to overcome the problem of the non-availability of the active principle as high purity standard. NMR analysis of raw material, using a suitable internal standard, evidenced in all analyzed lots the presence of the active principle, the N-dodecyl-1,3-propanediamine (DA) and the n-dodecylamine (MA) and the absence of non-organic, NMR-inactive species. NMR peak integration led to a rough composition of the MA:DA:TA as 1:9:90. The LC/HRMS analysis allowed the accurate determination of DA and MA and confirmed in all samples the presence of the TA, which was estimated by difference: MA=1.4±0.3%, DA=11.1±0.7%, TA=87.5±1.3%. The obtained results were used to setup an easy, rapid and cheap acid-base titration method able to furnish a sufficiently accurate evaluation of the active principle both in the raw material and in diluted commercial products. For the raw material the results were: TA+MA=91.1±0.8% and DA-MA=8.9±0.8%, statistically coherent with LC/MS ones. The LC/MS approach demonstrated also its great potentialities to recognize trace of the biocide components both in environmental samples and in the formulated commercial products.

Use of electrochemical transient techniques to obtain thermodynamic and kinetic data on aqueous Fe(III)-1,6-dimethyl-4-hydroxy-3-pyridinecarboxylate and Fe(III)-4-hydroxy-2-methyl-3-pyridinecarboxylate complexes.

Voltammetric experiments were used to demonstrate the possibility to rapidly obtain stability constants, E degrees values and kinetic parameters of Fe(III) complexes with 1,6-dimethyl-4-hydroxy-3-pyridinecarboxylic acid (DQ716) at pH 2.3 and 4-hydroxy-2-methyl-3-pyridinecarboxylic acid (DQ2) at pH 3. Fe(III) diffusion coefficient (D(Fe)= 5.5.10(-6) cm(2)/s), heterogeneous electron transfer kinetic constant (k degrees = 2.7.10(-4)cm/s), symmetry coefficient (alpha= 0.57) and Fe(III)/Fe(II) standard reduction potential (E degrees = 0.53 V vs. SCE) were determined beforehand and used to obtain all the other results. Digital simulation together with potentiometric data were used to define the whole reaction system in terms of thermodynamic and kinetic parameters. In particular, E degrees and the dissociation kinetic constant, k(b), of the 1:1 (E degrees = 0.22 V vs. SCE, k(b)= 0.032 s(-1)), 1:2 (E degrees = 0.098 V vs. SCE; k(b)= 0.22 s(-1)) and 1:3 (E degrees < or =-0.29 V vs. SCE, k(b)= 157.9 s(-1)) Fe(III)/DQ716 complexes, were estimated. Stability constants of the Fe(II) complexes were computed from these values. The voltammetric data were also interpreted with two independent formalisms: (1) solution of an equation system and (2) a curve fitting method based on the Koutecky-Levich equation. Both approaches allowed us to obtain the speciation of a Fe(III)/DQ716 solution at pH 2.3. Moreover, the second approach allowed the evaluation of the kinetic contributions, the stepwise stability constant of Fe(III)L(2) (7.65 +/- 0.07), and to define the mathematical formalization of the experimental result which link some key-points of the voltammetric curve (inflection points and plateaux) to D(Fe), k degrees , alpha(j) and E degrees . This approach was also successfully applied to obtain the speciation of a Fe(III)/DQ2 solution at pH 3.

Dependence of calibration sensitivity of a polysulfone/Ru(II)-tris(4,7-diphenyl-1,10-phenanthroline)-based oxygen optical sensor on its structural parameters.

The optimum performance of an optical oxygen sensor based on polysulfone (PSF)/[Ru(II)-Tris(4,7-diphenyl-1,10-phenanthroline)] octylsulfonate (Ru(dpp)OS) was checked by carefully tuning the parameters affecting the membrane preparation. In particular, membranes having thickness ranging between 0.2 and 8.0 microm with various luminophore concentrations were prepared by dip-coating and tested. The membrane thickness was controlled by tuning the solution viscosity, and was measured both by secondary ion mass spectrometry (SIMS) and by visible spectroscopy (Vis). Luminescence-quenching-based calibration was a single value of the Stern-Volmer constant (K'SV) for membranes containing up to 20 mmol Ru(dpp) g-1 PSF (1.35 microm average thickness). The K'SV value decreased for larger concentration. The highest sensitivity was obtained with membrane thickness around 1.6 microm, having a response time close to 1 s. Thicker membranes exhibited an emission saturation effect and were characterized by longer response time. The K'SV behavior was interpreted on the basis of a mathematical approach accounting for the contribution of luminescence lifetime (tau0), oxygen diffusion coefficient (DO2) and oxygen solubility inside the membrane (sO2) establishing the role of all of them and allowing their experimental determination. Moreover, a simple experimental way to estimate K'SV without needing calibration was proposed. It was based either on the light emission asymmetry or on the percent variation of light emission on passing from pure nitrogen to pure oxygen.