Design,synthesis, biological evaluation,and molecular modeling studies of chalcone-rivastigmine hybrids as cholinesterase inhibitors

A series of novel chalcone-rivastigmine hybrids were designed, synthesized, and tested in vitro for their ability to inhibit human acetylcholinesterase and butyrylcholinesterase. Most of the target compounds showed hBChE selective activity in the micro- and submicromolar ranges. The most potent compound 3 exhibited comparable IC₅₀ to the commercially available drug (rivastigmine). To better understand their structure activity relationships (SAR) and mechanisms of enzyme-inhibitor interactions, kinetic and molecular modeling studies including molecular docking and molecular dynamics (MD) simulations were carried out. Furthermore, compound 3 blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells and shows the required druggability and low cytotoxicity, suggesting this hybrid is a promising multifunctional drug candidate for Alzheimer’s disease (AD) treatment.     

Analysis of potassium iodate reduction in tissue homogenates using high performance liquid chromatography–inductively coupled plasma-mass spectrometry

Potassium iodate (KIO₃) and potassium iodide (KI) are the major salt iodization agents used worldwide. Unlike iodide (I⁻), iodate (IO₃⁻) should be reduced to I⁻ before it can be effectively used by the thyroid. In this study, we developed a new method for analyzing IO₃⁻ and I⁻ in tissue homogenates using high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP-MS). We further applied the method to demonstrate the KIO₃ reduction process by tissues in vitro. The effects of KIO₃ on the total antioxidative activity (TAA) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) were also investigated here. Finally, we found that IO₃⁻ can be reduced to I⁻ by tissue homogenates and IO₃⁻ irreversibly decreases the antioxidant capability of tissues. Our studies suggest that KIO₃ might have a big effect on the redox balance of tissue and would further result in oxidative stress of organisms.     

Structural analysis and antioxidative properties of mutan (water-insoluble glucan) and carboxymethyl mutan from Streptococcus mutans

Streptococcus mutans (MTCC 497) was grown anaerobically in acidic Brain heart infusion (BHI) medium with 15 % sucrose to produce cell-bound and extracellular water-insoluble polysaccharide mutan. Fourier transformed infrared (FTIR) and ¹³C NMR studies revealed a mixed linkage of α-1−3 and α-1–6 mutan with a production yield of 1.8 g/L. Mutan has a branched structure with a molecular weight (M_w) of 5654 Da. Water-insoluble mutan was carboxymethylated at 0.93 degrees of substitution. FTIR spectra with characteristic peaks at 1603 cm⁻¹ and 1418 cm⁻¹ due to symmetric and asymmetric vibrations of the COO- group confirmed carboxymethylation. Thermal gravimetric analysis showed that native mutan and carboxymethyl mutan exhibited higher thermal stability. Carboxymethylation enhanced solubility and antioxidative radical-scavenging activity. The in-vitro antioxidative radical scavenging analysis revealed 52 % and 47 % inhibition of DPPH and ABTS radicals.     

Using some growth stimuli,a comparative study of salt tolerance in two tomatoes cultivars and a related wild line with special reference to superoxide dismutases and related micronutrients

Salinity is a major global problem that threatens the agricultural sector, especially in areas that suffer from a shortage of water. It motivates ionic toxicity, osmotic and oxidative stresses, which greatly inhibits plant performances and crop productivites. However, micronutrients (MNs) or plant extracts, like germinated maize grain extract (gMGE), have been reported to minimize the effects of salt stress on plant growth and returns. Therefore, this study aimed at evaluating the influences of MNs or gMGE applied as foliar sprays on growth, physio-biochemical indices, and antioxidative system components in three genotypes of tomato plants stressed by 9 dS m⁻¹ NaCl. This salinity level markedly increased Na⁺ content, lipid peroxidation, ion leakage, and markers related to oxidative stress (superoxide; O₂⁻ and hydrogen peroxide; H₂O₂). Besides, marked increases in activities of enzymatic (especially different forms of superoxide dismutase; SODs) and non-enzymatic antioxidants and osmoprotectant compounds were also observed. In contrast, growth, photosynthetic capacity including hill reaction activity (HRA), K⁺/Na⁺ ratio, tissue cell integrity (e.g., cell water content and membrane stability), and K⁺ and MNs contents decreased significantly under stress. However, compared to MNs, gMGE significantly improved the activities of the antioxidative system components (particularly SODs) and osmoprotectants, which were reflected in reduced Na⁺ accumulation, lipid peroxidation, ion leakage, and oxidative stress. These results were coupled with remarkable elevations in photosynthetic capacity including HRA, K⁺/Na⁺ ratio, tissue cell integrity, K⁺ content, and MNs contents, all of which were reflected in the enhancement of plant growth. Compared to local tomato cultivars (e.g., Castle Rock and C10), the wild line “0043-1” had better results. The interaction of three factors; salt stress, promoters, and tomato genotypes was significant. The wild tomato line “0043-1” as the best salt-tolerant is a good candidate for implication in breeding programs for tolerance to salinity to produce salt-tolerant cultivars for use to maximize tomato growth and productivity in saline environments.     

Proteomic analysis of kidneys from selenoprotein M transgenic rats in response to increased bioability of selenium

Background

To characterize changes in global protein expression in kidneys of transgenic rats overexpressing human selenoprotein M (SelM) in response to increased bioabivility of selenium (Sel), total proteins extracted from kidneys of 10-week-old CMV/hSelM Tg and wild-type rats were separated by 2-dimensional gel electrophoresis and measured for changes in expression.

Results

Ten and three proteins showing high antioxidant enzymatic activity were up- and down-regulated, respectively, in SelM-overexpressing CMV/hSelM Tg rats compared to controls based on an arbitrary 2-fold difference. Up-regulated proteins included LAP3, BAIAP2L1, CRP2, CD73 antigen, PDGF D, KIAA143 homolog, PRPPS-AP2, ZFP313, HSP-60, and N-WASP, whereas down-regulated proteins included ALKDH3, rMCP-3, and STC-1. After Sel treatment, five of the up-regulated proteins were significantly increased in expression in wild-type rats, whereas there were no changes in CMV/hSelM Tg rats. Only two of the down-regulated proteins showed reduced expression in wild-type and Tg rats after Sel treatment.

Conclusions

These results show the primary novel biological evidences that new functional protein groups and individual proteins in kidneys of Tg rats relate to Sel biology including the response to Sel treatment and SelM expression.     

Distinct composition of human fetal HDL attenuates its anti-oxidative capacity

In human high-density lipoprotein (HDL) represents the major cholesterol carrying lipoprotein class in cord blood, while cholesterol is mainly carried by low-density lipoprotein in maternal serum. Additionally, to carrying cholesterol, HDL also associates with a range of proteins as cargo. We tested the hypothesis that fetal HDL carries proteins qualitatively and quantitatively different from maternal HDL. These differences then contribute to distinct HDL functionality in both circulations. Shotgun proteomics and biochemical analyses were used to assess composition/function of fetal and maternal HDL isolated from uncomplicated human pregnancies at term of gestation. The pattern of analyzed proteins that were statistically elevated in fetal HDL (apoE, proteins involved in coagulation, transport processes) suggests a particle characteristic for the light HDL₂ sub-fraction. In contrast, proteins that were enriched in maternal HDL (apoL, apoF, PON1, apoD, apoCs) have been described almost exclusively in the dense HDL₃ fraction and relevant to its anti-oxidative function and role in innate immunity. Strikingly, PON1 mass and activity were 5-fold lower (p < 0.01) in the fetus, which was accompanied by attenuation of anti-oxidant capacity of fetal HDL. Despite almost equal quantity of CETP in maternal and fetal HDL, its enzymatic activity was 55% lower (p < 0.001) in the fetal circulation, whereas LCAT activity was not altered. These findings indicate that maternally derived HDL differs from fetal HDL with respect to its proteome, size and function. Absence of apoA-1, apoL and PON1 on fetal HDL is associated with decreased anti-oxidative properties together with deficiency in innate immunity collectively indicating distinct HDLs in fetuses.     

Nickel-induced Inhibition of Wheat Root Growth is Related to H2O2 Production, but not to Lipid Peroxidation

Effects of exogenous nickel (Ni: 10 and 200 μM) on growth, mitotic activity, Ni accumulation, H₂O₂ content and lipid peroxidation as well as the activities of various antioxidative enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GSH-Px) were investigated in wheat roots. A considerable Ni accumulation in the roots occurred at both the concentrations. Although Ni at 10 μM did not have any significant effect on root growth, it strongly inhibited the root growth at 200 μM. Mitotic activity in the root tips was not significantly affected by exposure of the seedlings to 10 μM Ni; however, it was almost completely inhibited at 200 μM treatment. Ni stress did not result in any significant changes in CAT and APX activities as well as lipid peroxidation. However, H₂O₂ concentration increased up to 82% over the control in the roots of seedlings exposed to 200 μM Ni. There was a significant decline in both SOD (50%) and GSH-Px (20–30%) activities in the roots when the seedlings were treated with 200 μM Ni. The results indicated that a strong inhibition of wheat root growth caused by Ni stress was not due to enhanced lipid peroxidation, but might be related to the accumulation of H₂O₂ in root tissue.     

Desiccation induced oxidative stress and its biochemical responses in intertidal red alga Gracilaria corticata (Gracilariales, Rhodophyta)

Intertidal alga Gracilaria corticata growing in natural environment experiences various abiotic stresses during the low tides. The aim of this study was to determine whether desiccation exposure would lead to oxidative stress and its effect varies with exposure periods. This study gives an account of various biochemical changes in G. corticata following the exposure to desiccation for a period of 0 (control), 1, 2, 3 and 4 h under controlled conditions. During desiccation, G. corticata thalli showed dramatic loss of water by almost 47% when desiccated for 4 h. The enhanced production of reactive oxygen species (ROS) and increased lipid peroxidation observed during the exposure of 3-4 h were chiefly contributed by higher lipoxygenase (LOX) activity with the induction of two new LOX isoforms (LOX-2, ∼85 kDa; LOX-3, ∼65 kDa). The chlorophyll, carotenoids and phycobiliproteins (phycoerythrin and phycocyanin) were increased during initial 2 h exposure compared to control and thereafter declined in the succeeding exposure. The antioxidative enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione peroxidase (GPX) and the regeneration rate of reduced ascorbate (AsA) and glutathione (GSH) increased during desiccation up to 2-3 h. Further, the isoforms of antioxidant enzymes Mn-SOD (∼150 kDa), APX-4 (∼110 kDa), APX-5 (∼45 kDa), GPX-1 (∼80 kDa) and GPX-2 (∼65 kDa) responded specifically to the desiccation exposure. Compared to control, a relative higher content of both free and bound insoluble putrescine and spermine together with enhanced n-6 PUFAs namely C20:4(n-6) and C20:3(n-6) fatty acids found during 2 h exposure reveals their involvement in defence reactions against the desiccation induced oxidative stress.     

Treatment of carrots with spent green tea extract reduces the soft rot of Pectobacterium spp.

In the present study the antibacterial activity of spent green tea (SGT) was evaluated against Pectobacterium spp. causing soft rot incidence. Gas chromatography and mass spectroscopy (GC-MS) analysis reveal the presence of caffeine in the SGT extracts. Time kill assay revealed that SGT was able to kill Pectobacterium spp. at 18 h at 10 × MIC and at 24 h at 1 × MIC concentration. SGT led to the significant decrease in pectin lyase (PL), polygalcturonase (PG) and pectin methyl esterase activity in carrots challenge inoculated with Pectobacterium spp. SGT treated carrots recorded low degree of maceration, and relative electrolyte leakage (REL) values and also maintained high β carotene content, phenolic content and total antioxidant percentage. Based on the results of this study it could be concluded that SGT was able to offer protection to carrot against soft rot causing Pectobacterium spp. under post-harvest storage conditions.     

In-vitro antioxidative,antiinflammatory properties of Aurea helianthus leaf extract a Korean traditional medicinal plant

The leaf of Aurea helianthus (A. helianthus Jinhuakui) is popularly used in China traditional medicine, however, scientific evidence on its antioxidant properties rarely studied. In this study, biological activities of A. helianthus leave’s 80% ethanol extract (AHL) were investigated. The measured total polyphenol and flavonoid content of AHL was 184.24 ± 5.01 mg GAE/g and 102.53 ± 0.98 mg NAR/g. AHL showed the highest α, α-diphenyl-β-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activities of 98.30 ± 0.18% at 1000 µg/mL. DPPH and ABTS radical scavenging activities significantly increased in a AHL concentration-dependent manner. AHL treatment significantly suppressed the generation of pro-inflammatory mediators, including nitric oxide (NO), in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. AHL demonstrated strong anti-inflammatory activity that reduced NO production in LPS-stimulated RAW 264.7 cells. To test the potential protective effect of AHL, the antioxidant capacity, on the cell growth, viability of a human hepatoma cell (HepG2) and Raw 264.7 cell were investigated. AHL also enhanced cytotoxicity on the proliferation of HepG2 cells and was capable of inhibiting 56% against LPS at 400 µg/mL. The results of this study the potential of AHL as an excellent antioxidant substance for inhibiting inflammatory mediators. Therefore, AHL may be used as a therapeutic approach to various inflammatory diseases.