Ultrasound-Assisted Extraction: Effect of Extraction Time and Solvent Power on the Levels of Polyphenols and Antioxidant Activity of Mesembryanthemum edule L. Aizoaceae Shoots

Purpose: To investigate the influence of extraction conditions assisted by ultrasound on the quality of extracts obtained from Mesembryanthemum edule shoots.Methods: The extraction procedure was carried out in an ultrasonic bath. The effect of two solvents (methanol and ethanol) and two extraction times (5 and 10 min) were evaluated on the basis of the phenolic content and antioxidant activity of the plant extract.Results: Significant variability in phenolic content and antioxidant activity, depending on the solvent (S), and to a lesser degree, extraction duration (D) and their interaction (S/D) were found. Methanol extract was significantly richer in total polyphenols than ethanol extract, their levels being 104.7 and 74.2 mg GAE.g-1DW, respectively. For the two solvents used, longer extraction duration yielded higher polyphenol content. The ethanol extract exhibited higher antioxidant activity than the methanol extract. Moreover, Also, the longer sonication duration (10 min) yielded extracts with higher antioxidant activities.Conclusion: The antioxidant capacity of M. edule is strongly influenced by the nature of the extracting solvent and the duration of sonication extraction.Keywords: Antioxidant activity, Extraction duration, Mesembryanthemum edule, Polyphenols, Sonicatio

Phenolic nature, occurrence and polymerization degree as marker of environmental adaptation in the edible halophyte Mesembryanthemum edule

AbstractMesembryanthemum edule is an edible medicinal halophyte traditionally used to treat several human diseases. In this study, particular importance was attached to the influence of environmental conditions on phenolic composition and antioxidant activities of two M. edule provenances from contrasting climatic regions (Djerba and Monastir sampled from arid and superior semi-arid bioclimatic stages, respectively). Shoot phenolic content was evaluated using colorimetric method and its composition was identified by HPLC analysis with or without thiolysis. Antioxidant activities were assessed by five in vitro antioxidant systems. Results showed that the two M. edule provenances were significantly different according to their antioxidant activity as well as their polyphenol profiles. Indeed, plants from Djerba (lack of rainfall and long light hour periods) exhibited stronger antioxidant activity together with higher phenolic content. For instance, Djerba provenance shoots showed much lower IC50 (4.8μgml−1) and EC50 (80μgml−1) values for DPPH and Fe-reducing tests, respectively. In addition, the superiority of this provenance (Djerba) was more marked as compared to positive controls (BHT, BHA, and VitC). HPLC identification revealed also an important difference between the two provenances on major flavonoid components. This difference was confirmed by the mean degrees of tannin polymerization (DPn) which was higher in Djerba plants. These data suggest that M. edule adaptation to environmental stresses proceeds through induced particular phenol quality and DPn for the improvement of their antioxidant capacities to protect plant tissues against oxidative stress

Anti-aging activities of extracts from Tunisian medicinal halophytes and their aromatic constituents

Six medicinal halophytes widely represented in North Africa and commonly used in traditional medicine were screened for pharmacological properties to set out new promising sources of natural ingredients for cosmetic or nutraceutical applications. Thus, Citrullus colocynthis, Cleome arabica, Daemia cordata, Haloxylon articulatum, Pituranthos scoparius and Scorzonera undulata were examined for their in vitro antioxidant (DPPH scavenging and superoxide anion-scavenging, β-carotene bleaching inhibition and iron-reducing tests), antibacterial (microdi- lution method, against four human pathogenic bacteria) and anti-tyrosinase activities. Besides, their aromatic com- position was determined by RP-HPLC. H. articulatum shoot extracts exhibited the strongest antioxidant activity and inhibited efficiently the growth of Salmonella enterica and Escherichia coli. P. scoparius and C. arabica inhibited slightly monophenolase, whereas H. articulatum was the most efficient inhibitor of diphenolase activity. Furthermore, H. articulatum exhibited the highest aromatic content (3.4 % DW), with dopamine as the major com- pound. These observations suggest that shoot extract of H. articulatum, and to a lesser extent of C. arabica, could otic as well as new natural skin lightening agents. Also, possible implication of aromatic compounds in anti-tyrosinase activity is discussed

Multisensory Integration and Attention in Autism Spectrum Disorder: Evidence from Event-Related Potentials

Abstract Successful integration of various simultaneously perceived perceptual signals is crucial for social behavior. Recent findings indicate that this multisensory integration (MSI) can be modulated by attention. Theories of Autism Spectrum Disorders (ASDs) suggest that MSI is affected in this population while it remains unclear to what extent this is related to impairments in attentional capacity. In the present study Event-related potentials (ERPs) following emotionally congruent and incongruent face-voice pairs were measured in 23 high-functioning, adult ASD individuals and 24 age-and IQ-matched controls. MSI was studied while the attention of the participants was manipulated. ERPs were measured at typical auditory and visual processing peaks, namely, P2 and N170. While controls showed MSI during divided attention and easy selective attention tasks, individuals with ASD showed MSI during easy selective attention tasks only. It was concluded that individuals with ASD are able to process multisensory emotional stimuli, but this is differently modulated by attention mechanisms in these participants, especially those associated with divided attention. This atypical interaction between attention and MSI is also relevant to treatment strategies, with training of multisensory attentional control possibly being more beneficial than conventional sensory integration therapy

2012 Activity Report of the Regional Research Programme on Hadrontherapy for the ETOILE Center

2012 is the penultimate year of financial support by the CPER 2007-2013 for ETOILE's research program, sustained by the PRRH at the University Claude Bernard. As with each edition we make the annual review of the research in this group, so active for over 12 years now. Over the difficulties in the decision-making process for the implementation of the ETOILE Center, towards which all our efforts are focussed, some "themes" (work packages) were strengthened, others have progressed, or have been dropped. This is the case of the eighth theme (technological developments), centered around the technology for rotative beam distribution heads (gantries) and, after being synchronized with the developments of ULICE's WP6, remained so by ceasing its activities, coinciding also with the retirement of its historic leader at IPNL, Marcel Bajard. Topic number 5 ("In silico simulations") has suffered the departure of its leader, Benjamin Ribba, although the work has still been provided by Branka Bernard, a former postdoctoral fellow in Lyon Sud, and now back home in Croatia, still in contract with UCBL for the ULICE project. Aside from these two issues (and the fact that the theme "Medico-economical simulations" is now directly linked to the first one ("Medical Project"), the rest of the teams are growing, as evidenced by the publication statistics at the beginning of this report. This is obviously due to the financial support of our always faithful regional institutions, but also to the synergy that the previous years, the European projects, the arrival of the PRIMES LabEx, and the national France Hadron infrastructure have managed to impulse. The Rhone-Alpes hadron team, which naturally includes the researchers of LPC at Clermont, should also see its influence result in a strong presence in France Hadron's regional node, which is being organized. The future of this regional research is not yet fully guaranteed, especially in the still uncertain context of ETOILE, but the tracks are beginning to emerge to allow past and present efforts translate into a long future that we all want to see established. Each of the researchers in PRRH is aware that 2013 will be (and already is) the year of great challenge : for ETOILE, for the PRRH, for hadron therapy in France, for French hadrontherapy in Europe (after the opening and beginning of treatments in the German [HIT Heidelberg, Marburg], Italian [CNAO, Pavia] and Austrian [MedAustron, Wien Neuerstadt]) centers. Let us meet again in early 2014 for a comprehensive review of the past and a perspective for the future ..

Sustained antiproliferative mechanisms by RB24, a targeted precursor of multiple inhibitors of epidermal growth factor receptor and a DNA alkylating agent in the A431 epidermal carcinoma of the vulva cell line

Recently, with the purpose of enhancing the potency of epidermal growth factor receptor (EGFR)-based therapies, we designed a novel strategy termed ‘Cascade-release targeting’ that seeks to develop molecules capable of degrading to multiple tyrosine kinase (TK) inhibitors and highly reactive electrophiles, in a stepwise fashion. Here we report on the first prototype of this model, RB24, a masked methyltriazene, that in addition to being an inhibitor on its own was designed to degrade to RB14, ZR08, RB10+a DNA alkylating methyldiazonium species. The cascade degradation of RB24 requires the generation of two reactive electrophiles: (a) an iminium ion and (b) a methyldiazonium ion. Thus, we surmise that these species could alkylate the active site of EGFR, thereby irreversibly blocking its action and that DNA damage could be induced by the methyldiazonium. Using the EGFR-overexpressing human epidermoid carcinoma of the vulva cell line, A431, we demonstrate herein that (a) RB24 and its derived species (e.g. RB14, ZR08) irreversibly inhibit EGFR autophosphorylation, (b) RB24 induced significant levels of DNA strand breaks, (c) sustained inhibition of EGFR by RB24 was associated with blockade of MAPK activation and c-fos gene expression, (d) RB24 induced irreversible cell growth inhibition with a 100-fold greater potency than Temodal™, a clinical methyltriazene. The pronounced growth inhibitory potency of RB24 was attributed to its ability to simultaneously damage DNA and irreversibly block EGFR TK activity

EGFR-targeting drugs in combination with cytotoxic agents: from bench to bedside, a contrasted reality

The clinical experience recently reported with epidermal growth factor receptor (EGFR)-targeting drugs confirms the synergistic interactions observed between these compounds and conventional cytotoxic agents, which were previously established at the preclinical stage. There are, however, examples of major gaps between the bench and the bedside. Particularly demonstrative is the failure of the tyrosine kinase inhibitors (TKIs) (gefitinib and erlotinib) combined with chemotherapy in pretreated nonsmall cell lung cancer patients. These discrepancies can be due to several factors such as the methodology used to evaluate TKI plus cytotoxic agent combinations in preclinical models and the insufficient consideration given to the importance of the drug sequences for the tested combinations. Recent advances in understanding the biologic basis of acquired resistance to these agents have great potential to improve their clinical effectiveness. The purpose of this review is to critically examine the experimental conditions of the preclinical background for anti-EGFR drug–cytotoxic agent combinations and to attempt to explain the gap between clinical observations and preclinical data