Catalytic performance of PVP-coated CuO nanosheets under environmentally friendly conditions.

Aromatic nitro compounds are an increasing concern worldwide due to their potential toxicity, prompting a quest for efficient removal approaches. This study established a simple and environmentally friendly method to synthesize a highly efficient, recoverable and stable CuO nanosheets catalyst to overcome public health and environmental problems caused by nitro aromatic compounds. In the current research, the effect of different concentrations of copper nitrate on the size and shape of CuO nanostructures in the chemical synthesis was studied. The CuO nanosheets were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectrophotometry. It was found that at concentrations of 0.07 M and 0.1 M of copper nitrate, pure CuO was formed. The FTIR results showed that carbonyl group in PVP coordinated with CuO and formed a protective layer. The as-synthesized CuO nanosheets with an average width of 60 ± 23 nm and length of 579 ± 154 were used as a catalyst for highly selective and efficient reduction of aromatic nitro and aromatic carboxylic acid to the corresponding amine and alcohol compounds. The reduction reaction was monitored by either UV-Vis absorption spectroscopy or high performance liquid chromatography (HPLC). 4-Nitrophenol and 4-nitroaniline were reduced to corresponding amine compounds within 12 min and 6 min, respectively in the presence of a reasonable amount of catalyst and reducing agent. The CuO nanosheets also exhibited excellent stability. The catalyst can be reused without loss of its activity after ten runs.

Synthesis and structure-activity relationship studies of 2,4-thiazolidinediones and analogous heterocycles as inhibitors of dihydrodipicolinate synthase.

Dihydrodipicolinate synthase (DHDPS), responsible for the first committed step of the diaminopimelate pathway for lysine biosynthesis, has become an attractive target for the development of new antibacterial and herbicidal agents. Herein, we report the discovery and exploration of the first inhibitors of E. coli DHDPS which have been identified from screening lead and are not based on substrates from the lysine biosynthesis pathway. Over 50 thiazolidinediones and related analogues have been prepared in order to thoroughly evaluate the structure-activity relationships against this enzyme of significant interest.

Towards novel herbicide modes of action by inhibiting lysine biosynthesis in plants.

Weeds are becoming increasingly resistant to our current herbicides, posing a significant threat to agricultural production. Therefore, new herbicides with novel modes of action are urgently needed. In this study, we exploited a novel herbicide target, dihydrodipicolinate synthase (DHDPS), which catalyses the first and rate-limiting step in lysine biosynthesis. The first class of plant DHDPS inhibitors with micromolar potency against Arabidopsis thaliana DHDPS was identified using a high-throughput chemical screen. We determined that this class of inhibitors binds to a novel and unexplored pocket within DHDPS, which is highly conserved across plant species. The inhibitors also attenuated the germination and growth of A. thaliana seedlings and confirmed their pre-emergence herbicidal activity in soil-grown plants. These results provide proof-of-concept that lysine biosynthesis represents a promising target for the development of herbicides with a novel mode of action to tackle the global rise of herbicide-resistant weeds.

A Simple Add-and-Display Method for Immobilisation of Cancer Drug on His-tagged Virus-like Nanoparticles for Controlled Drug Delivery.

pH-responsive virus-like nanoparticles (VLNPs) hold promising potential as drug delivery systems for cancer therapy. In the present study, hepatitis B virus (HBV) VLNPs harbouring His-tags were used to display doxorubicin (DOX) via nitrilotriacetic acid (NTA) conjugation. The His-tags served as pH-responsive nanojoints which released DOX from VLNPs in a controlled manner. The His-tagged VLNPs conjugated non-covalently with NTA-DOX, and cross-linked with folic acid (FA) were able to specifically target and deliver the DOX into ovarian cancer cells via folate receptor (FR)-mediated endocytosis. The cytotoxicity and cellular uptake results revealed that the His-tagged VLNPs significantly increased the accumulation of DOX in the ovarian cancer cells and enhanced the uptake of DOX, which improved anti-tumour effects. This study demonstrated that NTA-DOX can be easily displayed on His-tagged VLNPs by a simple Add-and-Display step with high coupling efficiency and the drug was only released at low pH in a controlled manner. This approach facilitates specific attachment of any drug molecule on His-tagged VLNPs at the very mild conditions without changing the biological structure and native conformation of the VLNPs.

Synthesis and in vitro Bioactivity Evaluation of New Galactose and Fructose Ester Derivatives of 5-Aminosalicylic Acid.

Inflammatory bowel disease (IBD) is the main risk factor for developing colorectal cancer which is common in patients of all ages. 5-Aminosalicylic acid (5-ASA), structurally related to the salicylates, is highly active in the treatment of IBD with minor side effects. In this study, the synthesis of galactose and fructose esters of 5-ASA was planned to evaluate the role of glycoconjugation on the bioactivity of the parent drug. The antibacterial activity of the new compounds were evaluated against two Gram-negative and two Gram-positive species of bacteria, with a notable effect observed against Staphylococcus aureus and Escherichia coli in comparisons with the 5-ASA. Cytotoxicity testing over HT-29 and 3T3 cell lines indicated that the toxicity of the new products against normal cells was significantly reduced compared with the original drug, whereas their activity against cancerous cells was slightly decreased. The anti-inflammatory activity test in RAW264.7 macrophage cells indicated that the inhibition of nitric oxide by both of the monosaccharide conjugated derivatives was slightly improved in comparison with the non-conjugated drug.

Effect of annealing temperature on antimicrobial and structural properties of bio-synthesized zinc oxide nanoparticles using flower extract of Anchusa italica.

The use of nontoxic biological compounds in the synthesis of nanomaterials is an economic and eco-friendly approach. The present work was undertaken to develop zinc oxide nanoparticles (ZnO-NPs) by a green method using simple precursor from the solution consisting of zinc acetate and the flower extract of Anchusa italica (A. italica). Effect of annealing temperature on structural and antimicrobial properties was investigated. The crystalline structure of ZnO-NPs was shown using X-ray diffraction (XRD) analysis. Transmission electron microscopy (TEM) results showed that ZnO-NPs are hexagonal in shapes with mean particle size of ~8 and ~14nm at 100°C and 200°C annealing temperatures respectively. The optical band gap was increased from 3.27eV to 3.30eV with the decreasing of the particle size. The antimicrobial activity of ZnO-NPs towards Gram positive (Bacillus megaterium and Stapphylococcus aureus) and Gram negative (Escherichia coli and Salmonella typhimurium) pathogens decreased with the increasing of the heat treating temperature. In vitro cytotoxicity studies on Vero cells, a dose dependent toxicity with non-toxic effect of concentration below 142µg/mL was shown. The results indicated that A. italica is an appropriate reaction media to prepare ZnO-NPs for cosmetic and bio-medical productions.

Hypocholesterolemic activity of monascus fermented product in the absence of monacolins with partial purification for functional food applications.

Hypercholesterolemia is one of the most common chronic diseases in human. Along with chemical therapy traditional medication is used as hypocholesterolemic remedy, however, with unfavorable side effects. Recently, Monascus fermented product (MFP) has become a popular hypocholesterolemic natural supplement. In the present study, the hypocholesterolemic activity of Monascus purpureus FTC5391 fermented product ethanolic extract (MFPe) was investigated in hypercholesterolemic rats. Results showed that MFPe not only reduced the serum total cholesterol (TC), LDL-C, TG concentration, and TC/HDL-C ratio but also increased the HDL-C. Further, solid phase extraction (SPE) was carried out to obtain the hypocholesterolemic bioactive fraction. The high polar fraction of SPE increased the HDL-C (42%) and decreased the TC (53.3%), LDL-C (47%), and TG (50.7%) levels as well as TC/HDL-C ratio (69.1%) in serum. The GC-MS results of the active fraction revealed two main compounds, isosorbide and erythritol, which act as coronary vasodilator compounds.

Various polar tripeptides as asymmetric organocatalyst in direct aldol reactions in aqueous media.

A series of tripeptide organocatalysts containing a secondary amine group and two amino acids with polar side chain units were developed and evaluated in the direct asymmetric intermolecular aldol reaction of 4-nitrobenzaldehyde and cyclohexanone. The effectiveness of short polar peptides as asymmetric catalysts in aldol reactions to attain high yields of enantio- and diastereoselective isomers were investigated. In a comparison, glutamic acid and histidine produced higher % ee and yields when they were applied as the second amino acid in short trimeric peptides. These short polar peptides were found to be efficient organocatalysts for the asymmetric aldol addition reaction in aqueous media.