Comparison of phenolic content and antioxidant activity of Actaea racemosa L. and Actaea cordifolia DC

Actaea racemosa L. is used as a component of drugs or dietary supplements to alleviate the menopause symptoms. Its biological activity is associated with the presence of phenolic compounds. In our work, the analysis of isoflavones and phenolic acids – caffeic acid (CA), ferulic acid and isoferulic acid (iFA) – both free and bonded in two species of Actaea, was conducted using HPLC-PAD technique. Moreover, the antioxidant effect of extracts from different parts of the investigated plants was determined on the basis of DPPH assay. Significant variation of CA and iFA content was observed. The highest content of CA was found in A. racemosa, while Actaea cordifolia contained the highest amount of iFA. Isoflavones were not found in the investigated plants. The antioxidant activity assay showed the high free radical-scavenging ability of the extracts obtained from different parts of the plant.     

Charge transport through extended molecular wires with strongly correlated electrons

Electron–electron interactions are at the heart of chemistry and understanding how to control them is crucial for the development of molecular-scale electronic devices. Here, we investigate single-electron tunneling through a redox-active edge-fused porphyrin trimer and demonstrate that its transport behavior is well described by the Hubbard dimer model, providing insights into the role of electron–electron interactions in charge transport. In particular, we empirically determine the molecule''s on-site and inter-site electron–electron repulsion energies, which are in good agreement with density functional calculations, and establish the molecular electronic structure within various oxidation states. The gate-dependent rectification behavior confirms the selection rules and state degeneracies deduced from the Hubbard model. We demonstrate that current flow through the molecule is governed by a non-trivial set of vibrationally coupled electronic transitions between various many-body ground and excited states, and experimentally confirm the importance of electron–electron interactions in single-molecule devices.

Experimental studies of electron transport through an edge-fused porphyrin oligomer in a graphene junction are interpreted within a Hubbard dimer framework.     

Electrochemistry of copper efflux oxidase-like multicopper oxidases involved in copper homeostasis

Multicopper oxidases are widely studied enzymes catalyzing the oxygen reduction reaction. Among this family, one class belongs to the copper efflux oxidases. They are far less studied in bioelectrochemistry mainly because of the low potential at which they reduce O₂. However, the presence of a specific domain rich in methionine residues covering the first copper electron acceptor induces fundamental issues regarding the electron transfer pathway. In addition, as they are involved in copper homeostasis, the understanding of their catalytic mechanism may have important consequences in therapeutic applications. We present here the last findings reported on copper efflux oxidases based on electrochemical tools. We focus on the proposed roles of the methionine-rich domain in the electron transfer process. Especially, copper binding to this domain and consequences on the interfacial electron transfer process appear to be two fundamental aspects to discuss.     

Optimization and Verification of Droplet Digital PCR Even-Specific Methods for the Quantification of GM Maize DAS1507 and NK603

In recent years, digital polymerase chain reaction (dPCR), a new molecular biology technique, has been gaining in popularity. Among many other applications, this technique can also be used for the detection and quantification of genetically modified organisms (GMOs) in food and feed. It might replace the currently widely used real-time PCR method (qPCR), by overcoming problems related to the PCR inhibition and the requirement of certified reference materials to be used as a calibrant. In theory, validated qPCR methods can be easily transferred to the dPCR platform. However, optimization of the PCR conditions might be necessary. In this study, we report the transfer of two validated qPCR methods for quantification of maize DAS1507 and NK603 events to the droplet dPCR (ddPCR) platform. After some optimization, both methods have been verified according to the guidance of the European Network of GMO Laboratories (ENGL) on analytical method verification (ENGL working group on “Method Verification.” (2011) Verification of Analytical Methods for GMO Testing When Implementing Interlaboratory Validated Methods). Digital PCR methods performed equally or better than the qPCR methods. Optimized ddPCR methods confirm their suitability for GMO determination in food and feed.     

Effect of sample pre-treatment on isoflavones quantification in soybean

High performance liquid chromatography is the most common technique for analysing isoflavones in soy; however, the appropriate sample pre-treatment is required, including extraction and, often, hydrolysis. In the present work, the kinetics of extraction was investigated with regard to the number of extraction steps and their duration for the exhaustive extraction of bonded forms of isoflavones and aglycones. In addition, a systematic experimental study of hydrolysis depending on the temperature and acidity of the medium was conducted. The results showed that the assisted methods were more effective for the isolation of isoflavones. Moreover, ^the differences between the results obtained using ultrasound-assisted extraction (UAE), microwave-assisted extraction and pressurised liquid extraction were not statistically significant; however, the appropriate number of extraction steps and their duration for UAE were required. The investigation also revealed that, due to the varying susceptibility of glycosides on conversion to free forms and the stability of the aglycones obtained, two parallel hydrolysis procedures should be conducted to obtain the highest hydrolysis efficiency. The optimised conditions, taking into account the shortest time combined with the highest efficiency, were as follows: 4 M HCl and 60 min for genistein; 8 M HCl and 30 min for glycitein and daidzein.     

Targeting Cancer with PCPA‐Drug Conjugates: LSD1 Inhibition‐Triggered Release of 4‐Hydroxytamoxifen

Targeting cancer with small molecule prodrugs should help overcome problems associated with conventional cancer‐targeting methods. Herein, we focused on lysine‐specific demethylase 1 (LSD1) to trigger the controlled release of anticancer drugs in cancer cells, where LSD1 is highly expressed. Conjugates of the LSD1 inhibitor trans‐2‐phenylcyclopropylamine (PCPA) were used as novel prodrugs to selectively release anticancer drugs by LSD1 inhibition. As PCPA‐drug conjugate (PDC) prototypes, we designed PCPA‐tamoxifen conjugates 1 a and 1 b , which released 4‐hydroxytamoxifen in the presence of LSD1 in vitro. Furthermore, 1 a and 1 b inhibited the growth of breast cancer cells by the simultaneous inhibition of LSD1 and the estrogen receptor without exhibiting cytotoxicity toward normal cells. These results demonstrate that PDCs provide a useful prodrug method that may facilitate the selective release of drugs in cancer cells.