Development of a HS-SPME-GC/MS protocol assisted by chemometric tools to study herbivore-induced volatiles in Myrcia splendens

Publication date: 1 December 2017
Source:Talanta, Volume 175
Author(s): Érica A. Souza Silva, Giovanni Saboia, Nina C. Jorge, Camila Hoffmann, Rosy Mary dos Santos Isaias, Geraldo L.G. Soares, Claudia A. Zini
A headspace solid phase microextraction (HS-SPME) method combined with gas chromatography-mass spectrometry (GC/MS) was developed and optimized for extraction and analysis of volatile organic compounds (VOC) of leaves and galls of Myrcia splendens. Through a process of optimization of main factors affecting HS-SPME efficiency, the coating divivnilbenzene-carboxen-polydimethylsiloxane (DVB/Car/PDMS) was chosen as the optimum extraction phase, not only in terms of extraction efficiency, but also for its broader analyte coverage. Optimum extraction temperature was 30°C, while an extraction time of 15min provided the best compromise between extraction efficiencies of lower and higher molecular weight compounds. The optimized protocol was demonstrated to be capable of sampling plant material with high reproducibility, considering that most classes of analytes met the 20% RSD FDA criterion. The optimized method was employed for the analysis of three classes of M. splendens samples, generating a final list of 65 tentatively identified VOC, including alcohols, aldehydes, esters, ketones, phenol derivatives, as well as mono and sesquiterpenes. Significant differences were evident amongst the volatile profiles obtained from non-galled leaves (NGL) and leaf-folding galls (LFG) of M. splendens. Several differences pertaining to amounts of alcohols and aldehydes were detected between samples, particularly regarding quantities of green leaf volatiles (GLV). Alcohols represented about 14% of compounds detected in gall samples, whereas in non-galled samples, alcohol content was below 5%. Phenolic derived compounds were virtually absent in reference samples, while in non-galled leaves and galls their content ranged around 0.2% and 0.4%, respectively. Likewise, methyl salicylate, a well-known signal of plant distress, amounted for 1.2% of the sample content of galls, whereas it was only present in trace levels in reference samples. Chemometric analysis based on Heatmap associated with Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) provided a suitable tool to differentiate VOC profiles in vegetal material, and could open new perspectives and opportunities in agricultural and ecological studies for the detection and identification of herbivore-induced plant VOC emissions.

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Hydrogen bubble dynamic template fabrication of nanoporous Cu film supported by graphene nanaosheets: A highly sensitive sensor for detection of nitrite

Publication date: 1 December 2017
Source:Talanta, Volume 175
Author(s): Mir Reza Majidi, Seyran Ghaderi
High surface area nanoporous Cu film (NPCF) has been successfully synthesized using a hydrogen bubble dynamic template on the graphene nanosheets (GNs) modified glassy carbon electrode (GCE). The effect of different synthesis conditions such as applied potential and deposition time on the NPCF morphology was investigated. The structure and constituent of the NPCF-GNs/GCE were characterized by scanning electron microscopy (SEM), energy-dispersive x-ray (EDX), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and electrochemical methods. The study on electrocatalytic performance of the NPCF-GNs/GCE demonstrated that this electrode has excellent catalytic activity toward nitrite oxidation. The quantitative measurement of nitrite by amperometric method showed a wide concentration range (0.1–100µmolL⁻¹) with a detection limit and a sensitivity of 8.87 × 10⁻⁸molL⁻¹ and 3.1 AL/molcm², respectively. The excellent electrochemical response and high sensitivity of the proposed electrode were attributed to the 3D structure of NPCF and the synergic effect of NPCF and GNs. Furthermore, this electrode showed some other advantages including good repeatability, high reproducibility, long-term stability and anti-interference performance toward nitrite sensing. The applicability of the proposed electrode was proved by successful determination of nitrite in real samples (tap water, river water and sausage samples).

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Improved voltammetric method for simultaneous determination of Pt and Rh using second derivative signal transformation – application to environmental samples

Publication date: 1 December 2017
Source:Talanta, Volume 175
Author(s): Carlos E. Monteiro, Antonio Cobelo-Garcia, Miguel Caetano, Margarida M. Correia dos Santos
The determination of Platinum-group elements (PGE) in relevant environmental matrices is a challenging task. Sensitive and accurate analytical procedures for simultaneous determination of Pt and Rh are still needed. In this study, we report for the first time on the use of second derivative signal transformation to the ultra-trace simultaneous determination of Pt and Rh by Adsorptive Cathodic Stripping Voltammetry (AdCSV). With that step, the ill-defined peaks typically observed in the original voltammograms are transformed into well-shaped peaks, resulting in accurate detection. The experimental conditions were investigated and optimised: a suitable electrolyte for both elements, with less reagents consumption, (0.25M H2SO4, 0.05M HCl, 0.01M FA and 0.5mM HZ), deposition time (td) and deposition potential (Ed). For td = 120s and Ed = −0.75V, linear relationships r > 0.999 were obtained in the concentration range up to 5.8ngL⁻¹ (27 pM) for Pt and up to 3.4ngL⁻¹ (34 pM) for Rh. Limits of detection were 0.2ngL⁻¹ for Pt and 0.08ngL⁻¹ for Rh. Lower values can be achieved by increasing the deposition time. Limits of quantification, LOQ, calculated as 3 times LOD, were 0.5ngL⁻¹ for Pt and 0.2ngL⁻¹ for Rh. The sensitivity of Pt was affected by elevated Zn concentrations, whereas a minor effect was observed for Rh. However, Pt and Rh determinations were not influenced using the standard addition method. Precision as intermediate precision and expressed as relative standard deviation, based on Pt and Rh spiked solutions and digested road dust CRM BCR-723 was 17% and 20% for Pt and Rh, respectively. Recoveries of CRM were around 90% for both elements. The method was successfully applied in the simultaneous determination of Pt and Rh in sediments from Tagus estuary and, for the first time, dissolved Rh was determined in water samples of a waste water treatment plant. Application of this technique in a multidisciplinary approach will be a relevant contribution to the current understanding of PGE cycle and fate in the environment.

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Oral reproductive and developmental toxicity of Lignosus rhinocerotis mycelium in rat

Publication date: 17 August 2017
Source:Journal of Ethnopharmacology, Volume 208
Author(s): Bo-Yi Jhou, Hsiao-Hui Liu, Shu-Hsing Yeh, Chin-Chu Chen
Ethnopharmacological relevanceLignosus rhinocerotis (L. rhinocerotis), also known as the tiger milk mushroom, is widely used as traditional medicine and as soup ingredient in Malaysia and Hong Kong. It is edible and is used traditionally for the treatment of fever, cough, asthma, wounds, chronic hepatitis, gastric ulcers and cancers. In view of its safety profile, little information is found in scientific literature. The objective of this study is to investigate developmental toxicity of L. rhinocerotis in pregnant Sprague-Dawley (SD) rats.Materials and methodsEighty pregnant SD female rats were used in this study for three treatment groups and a control group, each consisting of 20 pregnant female rats. Three doses of 850mg/kg/day (Low-dose), 1700mg/kg/day (Mid-dose) and 3400mg/kg/day (High-dose) were selected for the study, whereas 10mL/kg distilled water was served as the control. Examinations were conducted on pregnant rats and fetuses respects to mortality, body weight, body weights gains, food consumption and clinical observations. The pregnant females were gross necropsied on G20, followed by maternal and fetus examination, to evaluate the teratogenicity, reproductive and developmental performance of L. rhinocerotis mycelium.ResultsResults showed that no L. rhinocerotis mycelium-related animal death and abnormal clinical sign were noted. No statistical differences were noted in maternal mean body weight and maternal mean body weight gains. Some animals in the high-dose group appeared audible respiration due to dosing accident, it resulted in lower food consumption but not relevant to L. rhinocerotis mycelium treatment. In maternal gross necropsy, no L. rhinocerotis mycelium-related gross lesion was noted. In maternal examination, parameters of gravid uterus weight, implantation number, corpora lutea number, litter size, live or dead fetal number, male or female fetus number, resorption number, fetal sex ratio (M/F), pre-implantation loss and post-implantation loss were all within the normal reference ranges and showed no significant difference when compared to the control group. In fetus examination, including external, visceral and skeletal evaluations, there were no significant changes between any of the L. rhinocerotis mycelium treated groups and the control group.ConclusionsBased on the study results, the no-observable-adverse-effect level (NOAEL) for pregnant female rats under the conditions of this study was 3400mg/kg/day.

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Acute, sub-acute toxicity and antioxidant activities (in vitro and in vivo) of Reichardia picroide crude extract

Publication date: 17 August 2017
Source:Journal of Ethnopharmacology, Volume 208
Author(s): Sana Aouachria, Sabah Boumerfeg, Abderrahim Benslama, Faycel Benbacha, Thoraya Guemmez, Seddik Khennouf, Lekhmici Arrar, Abderrahmane Baghiani
Ethnopharmacological relevanceReichardia picroide is a species mainly used for alimentary purposes, but it is traditionally known to be used as hypoglycemiant, diuretic, depurative, galactagogue and tonic.Aim of the studyTo date, there are no studies corroborating both its safety and antioxidant activities. The objective of the present study, thus, was to assess the safety profile of Reichardia picroide methanolic extract (RPE) and as well as on its antioxidant and antihemolytic activities.Materials and methodsThe acute toxicity of RPE was carried out based on OECD guidelines 425. Signs accompanying toxicity and possible death of animals were monitored for two weeks to ascertain the median lethal dose (LD50) of the RPE. In sub-acute toxicity study, the extract was administered by gavage at the doses of 250, 500 and 1000mg/kg/day for 21 consecutive days. The antioxidant activity of RPE was investigated through various methods both in vitro and in vivo.ResultsThe admistrated doses did not produce mortality or changes in general behaviors of the tested males and females mice. The LD50 was found to be superior to 5000mg/kg DW. Moreover, daily administration of RPE at doses ranged from 500 to 1000mg/kg could result in alteration of liver and kidney histology. Significant decrease in liver enzymes (ALT and AST), urea and creatinine levels in female plasma was recorded. The RPE was, in vitro, strong in DPPH scavenging and hemolytic inhibition, benificial in lipid peroxidation inhibition and reducing power. In addition, it exhibited, in vivo, a strong effect on GSH level increasing and lipid peroxidation inhibition in liver and kidney.ConclusionsIt can be suggested, based on the results of this study, that the crude extract of Reichardia picroide was non-toxic in acute administration and the use of this extract is safe at doses ≤ 250mg/kg. This study supports the application of Reichardia picroides in alimentary and traditional medicine purposes. Moreover, antioxidant activity results suggested that Reichardia picroide had potent antioxidant activities and could be utilized as new natural antioxidant in food and therapeutics.

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A framework for the targeted selection of herbs with similar efficacy by exploiting drug repositioning technique and curated biomedical knowledge

Publication date: 17 August 2017
Source:Journal of Ethnopharmacology, Volume 208
Author(s): Sang-Jun Yea, Bu-Yeo Kim, Chul Kim, Mun Yong Yi
Ethno pharmacological relevancePlants have been the most important natural resources for traditional medicine and for the modern pharmaceutical industry. They have been in demand in regards to finding alternative medicinal herbs with similar efficacy. Due to the very low probability of discovering useful compounds by random screening, researchers have advocated for using targeted selection approaches. Furthermore, because drug repositioning can speed up the process of drug development, an integrated technique that exploits chemical, genetic, and disease information has been recently developed. Building upon these findings, in this paper, we propose a novel framework for the targeted selection of herbs with similar efficacy by exploiting drug repositioning technique and curated modern scientific biomedical knowledge, with the goal of improving the possibility of inferring the traditional empirical ethno-pharmacological knowledge.Materials and methodsTo rank candidate herbs on the basis of similarities against target herb, we proposed and evaluated a framework that is comprised of the following four layers: links, extract, similarity, and model. In the framework, multiple databases are linked to build an herb-compound-protein-disease network which was composed of one tripartite network and two bipartite networks allowing comprehensive and detailed information to be extracted. Further, various similarity scores between herbs are calculated, and then prediction models are trained and tested on the basis of theses similarity features.ResultsThe proposed framework has been found to be feasible in terms of link loss. Out of the 50 similarities, the best one enhanced the performance of ranking herbs with similar efficacy by about 120–320% compared with our previous study. Also, the prediction model showed improved performance by about 180–480%. While building the prediction model, we identified the compound information as being the most important knowledge source and structural similarity as the most useful measure.ConclusionsIn the proposed framework, we took the knowledge of herbal medicine, chemistry, biology, and medicine into consideration to rank herbs with similar efficacy in candidates. The experimental results demonstrated that the performances of framework outperformed the baselines and identified the important knowledge source and useful similarity measure.

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Noninvasive assessment of cutaneous alterations in mice exposed to whole body gamma irradiation using optical imaging techniques

Abstract

We report the results of a study carried out to investigate the potential of optical techniques such as optical coherence tomography, Mueller matrix spectroscopy, and cross-polarization imaging for noninvasive monitoring of the ionizing radiation exposure-induced alterations in cutaneous tissue of mice. Radiation dose-dependent changes were observed in tissue microvasculature and tissue optical parameters like retardance and depolarization as early as 1 h post radiation exposure. Results suggest that these optical techniques may allow early detection of radiation dose-dependent alterations which could help in screening of population exposed to radiation.

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