Determination of Element Concentration of Brewed Tea Consumed in Iran Using ICP-OES: A Risk Assessment Study.

Tea is a popular drink enjoyed by many people around the world. However, it is important to note that impurities and contaminants in tea can potentially threaten human health when consumed. The main objective of this research is to assess the concentration of 16 trace elements (As, Fe, Al, Co, B, Li, Cd, Ba, Pb, Cr, Zn, Hg, Ni, Mn, Sb, and Sn) present in different types brewed of tea by using the ICP-OES (the inductively coupled plasma optical emission spectrometer) device, and the human health risks related to its use were evaluated. In this study, manganese (Mn) indicated the highest mean concentration in black (917.64 µg/kg) and green tea (912.89 µg/kg), respectively. Our study showed that the highest mean concentration of element boron (B) was (44.36 µg/kg) in Stachys lavandulifolia brewed tea. Among different packaging, tea bag samples had the highest concentration of Mn (1025.65 µg/kg) and aluminum (Al) (396.63 µg/kg). However, those unpacked posed the lowest content of Mn (188.13 µg/kg) and Al (100.47 µg/kg). The lead (Pb), mercury (Hg), and cadmium (Cd) concentrations in all samples were lower than the maximum limit of the Iranian standard and the WHO. In general, the amount of tea metal in Iranian samples was higher than in imported samples. Also, increasing the brewing time (10 min) can be effective in the solubility and extraction of metals such as B, Hg, cobalt (Co), iron (Fe), and lithium (Li). Further, the correlation between the amount of metals and type in tea samples was evaluated with principal component analysis. Based on the conducted non-carcinogenic risk assessment by the Monte Carlo simulation, the hazard index (HI), due to ingestion of heavy metals via tea in the 5-min brewing of tea, was 7.39E - 03 and 2.09E - 03, and in the 10-min brewing of tea, it was 3.20E - 02 and 9.07E - 03 for children and adults, respectively. Therefore, there was no significant non-carcinogenic risk from tea consumption.

Interaction of neutral and protonated Tamoxifen with the DPPC lipid bilayer using molecular dynamics simulation.

Tamoxifen as an antiestrogen is successfully applied for the clinical treatment of breast cancer in pre- and post-menopausal women. Due to the side effects related to the oral administration of Tamoxifen (such as deep vein thrombosis, pulmonary embolism, hot flushes, ocular disturbances and some types of cancer), liposomal drug delivery is recommended for taking this drug. Drug encapsulation in a liposomal or lipid drug delivery system improves the pharmacokinetic and pharmacodynamic properties. In this regard, we carried out 200-ns molecular dynamics (MD) simulations for three systems (pure DPPC and neutral and protonated Tamoxifen-loaded DPPC). Here, DPPC is a model lipid bilayer to provide us with conditions like liposomal drug delivery systems to investigate the interactions between Tamoxifen and DPPC lipid bilayers and to estimate the preferred location and orientation of the drug molecule inside the bilayer membrane. Properties such as area per lipid, membrane thickness, lateral diffusion coefficient, order parameters and mass density, were surveyed. With insertion of neutral and protonated Tamoxifen inside the DPPC lipid bilayers, area per lipid and membrane thickness increased slightly. Also, Tamoxifen induce ordering of the hydrocarbon chains in DPPC bilayer. Analysis of MD trajectories shows that neutral Tamoxifen is predominantly found in the hydrophobic tail region, whereas protonated Tamoxifen is located at the lipid-water interface (polar region of DPPC lipid bilayers).

A fatal SARS-coronavirus-2 induced bone marrow aplasia complicated with invasive fungal infection and severe neutropenic enterocolitis.

BACKGROUND: Immunization against the coronavirus disease 2019 (COVID-19) began in January 2021 in Iran; nonetheless, due to a lack of vaccination among children under 12, this age group is still at risk of SARS-CoV-2 infection and its complications. CASE PRESENTATION: SARS-CoV-2 infection was diagnosed in a 6-year-old girl who had previously been healthy but had developed a fever and pancytopenia. The bone marrow aspiration/biopsy demonstrated just hypocellular marrow without signs of leukemia. She was worked up for primary and secondary causes of pancytopenia. Except for a repeated reactive HIV antibody/Ag P24 assay, all test results were inconclusive. After a thorough diagnostic investigation, the cross-reactivity of the HIV antibody/Ag P24 test with SARS-CoV-2 antibodies was confirmed. The patient did not develop any COVID-19-related signs and symptoms, but she did get a severe invasive fungal infection and neutropenic enterocolitis. She died as a result of disseminated intravascular coagulopathy. CONCLUSION: It is critical to recognize children infected with SARS-CoV-2 who exhibit atypical clinical manifestations of COVID-19, such as persistent pancytopenia. SARS-CoV-2 infection can cause severe and deadly consequences in children; thus, pediatricians should be aware of COVID-19's unusual signs and symptoms mimicking other conditions such as aplastic anemia.

Synthesis, Molecular Dynamics Simulation, and In-vitro Antitumor Activity of Quinazoline-2,4,6-triamine Derivatives as Novel EGFR Tyrosine Kinase Inhibitors.

Background: Developing a potent and safe scaffold is challenging in anti-cancer drug discovery. Objectives: The study focused on developing novel series of compounds based on the inhibition of epidermal growth factor receptor tyrosine kinase (EGFR-TK) as one of the most promising compounds in cancer therapy. Methods: In this study, a novel series of quinazoline-2,4,6-triamine derivatives were designed and synthesized through intramolecular C-H activation reaction of para-nitro aniline, trichloroacetonitrile, and isocyanides employing a one-pot reaction. Results: The in-vitro antitumor activities of the compounds which showed acceptable inhibitory effects were investigated against breast (MCF-7), lung (A-549), and colon (HT-29) cancer cell lines by employing MTT assay. All compounds had the most negligible cytotoxicity toward normal fibroblast human cell lines. Based on structural and thermodynamics analysis results, it was found that Met 769 is a key residue in interaction with all inhibitors through the formation of hydrogen bonds with high occupancies with the amine group on the quinazoline ring of inhibitors. Also, there was a good consistency between calculated ΔG binding and experimental IC50 values of compounds 10d, 10e, and erlotinib. Conclusions: Compound 10e had an extensive range of antitumor activity on three diverse cell lines comparable with erlotinib and doxorubicin reference drugs. Also, compound 10d showed selective cytotoxicity against cancerous lung cells (A-549). On the other side, computational studies confirmed that Met 769 is a crucial residue in interaction with all inhibitors.

BRAF Mutation Analysis in Primary Acral Melanoma of 41 Cases from South of Iran.

BACKGROUND & OBJECTIVE: Acral melanoma (AM) is a common type of cutaneous melanoma that occurs in the skin of the palms, soles, and nail beds. This malignancy, like other types of cancer, has different genetic alterations. To date, despite decades of research the roles of oncogenic BRAF mutations in the pathogenesis of AM has not been fully clarified. The present study was designed to identify V600E mutation in patients with AM from the south of Iran. METHODS: The samples were collected from the pathology lab archive of Shiraz University of Medical Sciences (2015-2020). A total of 41 patients with primary invasive AM underwent excisional biopsy or amputation were collected to evaluate BRAF V600E mutation using Polymerase Chain Reaction (PCR) and Sanger sequencing. RESULTS: Total number of 41cases (21 male and 20 female) and age range of 34-87 years were enrolled. The histological subtypes were 24 acral lentiginous melanomas (ALM), 10 cases of nodular melanoma (NM), and 7 cases of superficial spreading melanoma (SSM). In our study, only one case (a 44-year-old male with nail bed AM and the histological subtype of acral lentigenous melanoma) showed BRAF-V600E mutation. CONCLUSION: These findings suggest that the population of our interest showed a very low prevalence of this mutation providing novel insights into the pathobiology of AM and its related treatment.

Docking Screens of Noncovalent Interaction Motifs of the Human Subtype-D2 Receptor-75 Schizophrenia Antipsychotic Complexes with Physicochemical Appraisal of Antipsychotics.

Chemoinformatics appraisal and molecular docking were employed to investigate 225 complexes of 75 schizophrenia antipsychotics with the dopamine receptor subtypes D2R, D3R, and D4R. Considering the effective noncovalent interactions in the subtype-D2 receptor selectivity of antipsychotics, this study evaluated the possible physicochemical properties of ligands underlying the design of safer and more effective antipsychotics. The pan-assay interference compounds (PAINs) include about 25% of typical antipsychotics and 5% of atypicals. Popular antipsychotics like haloperidol, clozapine, risperidone, and aripiprazole are not PAINs. They have stronger interactions with D2R and D4R, but their interactions with D3R are slightly weaker, which is similar to the behavior of dopamine. In contrast to typical antipsychotics, atypical antipsychotics exhibit more noncovalent interactions with D4R than with D2R. These results suggest that selectivity to D2R and D4R comes from the synergy between hydrophobic and hydrogen-bonding interactions through their concomitant occurrence in the form of a hydrogen-bonding site adorned with hydrophobic contacts in antipsychotic-receptor complexes. All the antipsychotics had more synergic interactions with D2R and D4R in comparison with D3R. The atypical antipsychotics made a good distinction between the subtype D2 receptors with high selectivity to D4R. Among the popular antipsychotics, haloperidol, clozapine, and risperidone have hydrophobic-hydrogen-bonding synergy with D4R, while aripiprazole profits with D2R. The most important residue participating in the synergic interactions was threonine for D2R and cysteine for D4R. This work could be useful in informing and guiding future drug discovery and development studies aimed at receptor-specific antipsychotics.

An atomistic investigation on the interaction of distamycin A and its derivative with the telomeric G-Quadruplex as anticancer agents by molecular dynamics simulation.

Human telomerase that activates within cancer cells has a telomeric sequence at the 3' end. Each factor that stabilizes the G-quadruplex in guanine-rich telomeric sequences can inhibit the regular telomerase activity. Therefore, the telomeric G-quadruplex is known as a promising target in cancer treatment. In this work, we studied the binding of positively charged distamycin A and its uncharged derivative to the G-quadruplex in a solution environment by Molecular Dynamics (MD) simulation. The binding mechanism and subtle conformational changes were investigated as a result of the ligand attachment. Moreover, binding free energy and clustering analysis describe the stability and flexibility of G-quadruplexes upon ligand binding. Structural analyses displayed that the favorable binding of both ligands imposes significant stability and rigidity in G-quadruplex conformation compared to free G-quadruplex, especially charged distamycin. Hydration pattern and ion distribution were different for free G-quadruplex and both of the ligand complexes. Energy decomposition reveals the electrostatic effect on the stability of G-quadruplex. The radial distribution function displayed the solvent shell and ion moving away from the groove. The hydrogen bond played an essential role in the binding of both ligands, especially for the charged derivative. van der Waals interaction is the only factor that is more important in binding uncharged distamycin into G-quadruplex than the charged one. The calculated ΔGbind showed the stability of both ligands within grooves and good agreement with the experimental binding free energy data. Finally, the results suggest that ligand modification improves the binding mode toward stabilizing G-quadruplexes.

Stabilizing osmolytes' effects on the structure, stability and function of tc-tenecteplase: A one peptide bond digested form of tenecteplase.

Organic osmolytes, as major cellular compounds, cause protein stabilization in the native form. In the present study, the possible chaperone effects of the three naturally occurring osmolytes on the two-chain form of tenecteplase (tc-TNK), a recombinant, genetically engineered mutant tissue plasminogen activator, have been explored by using circular dichroism, steady-state fluorescence, UV-Visible spectroscopy, and in silico experiments. The tc-TNK is derived from the one-chain protein upon disruption of one peptide bond. Thermal denaturation experiments showed a slightly more stabilizing effect of the three co-solvents on the single-chain TNK (sc-TNK) in comparison to that on tc-TNK. Unlike single-chain tenecteplase, the two-chain form undergoes reversible denaturation which is somehow perturbed in some cases as the result of the presence of osmolytes. Very minor changes in the secondary structure and the tertiary structure were observed. The molecular dynamics simulations and comparative structural analysis of catalytic domain of the protein in the single-chain and two-chain forms in pure water, mannitol/water, trehalose/water, and sucrose/water showed that while the stabilizing effect of the three osmolytes on tc-TNK might be induced by preferential accumulation of these molecules around the nonpolar and aromatic residues, that is to say, fewer water-hydrophobic residues' interactions in tc-TNK, sc-TNK is stabilized by preferential exclusion effect.

Protective role of metformin against methamphetamine induced anxiety, depression, cognition impairment and neurodegeneration in rat: The role of CREB/BDNF and Akt/GSK3 signaling pathways.

BACKGROUND: Methamphetamine is a neuro-stimulant with neurodegenerative effects, and ambiguous mechanism of action. Metformin is an antidiabetic agent with neuroprotective properties but not fully understood mechanisms. The present study investigated the molecular basis of metformin neuroprotection against methamphetamine-induced neurodegeneration. BRIEF METHOD: Sixty adult male rats were randomly divided into six groups: group 1 (received normal saline), group 2 (received 10 mg/kg of methamphetamine) and groups 3, 4, 5 and 6 [received methamphetamine (10 mg/kg) plus metformin (50, 75, 100 and 150 mg/kg) respectively]. Elevated Plus Maze (EPM), Open Field Test (OFT), Forced Swim Test (FST), Tail Suspension Test (TST) and Morris Water Maze (MWM) were used to assess the level of anxiety, depression and cognition in experimental animals. Also animals' hippocampus were isolated and oxidative stress and inflammatory parameters and expression of total and phosphorylated forms of cAMP response element binding (CREB), brain-derived neurotrophic factor (BDNF), protein kinase B (Akt) and glycogen synthase kinase 3 (GSK3) proteins were evaluated by ELISA method. RESULTS: According to the data obtained, methamphetamine caused significant depression, anxiety, motor activity disturbances and cognition impairment in experimental animals. Metformin, in all used doses, decreased methamphetamine induced behavioral disturbances. Also chronic administration of methamphetamine could increase malondialdehyde (MDA), tumor necrosis factor-Alpha (TNF-α) and interleukine-1 beta (IL-1ß) in rats, while caused reduction of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) activities. Metformin, especially in high doses, could prevent these malicious effects of methamphetamine. Also Metformin could activate CREB (both forms), BDNF and Akt (both forms) proteins' expression and inhibited GSK3 (both forms) protein expression in methamphetamine treated rats. SIGNIFICANCE: According to obtained data, metformin could protect the brain against methamphetamine-induced neurodegeneration probably by mediation of CREB/BDNF or Akt/GSK3 signaling pathways. These data suggested that CREB/BDNF or Akt/GSK3 signaling pathways may have a critical role in methamphetamine induced neurotoxicity and/or neuroprotective effects of metformin.

A biophysical study on the mechanism of interactions of DOX or PTX with α-lactalbumin as a delivery carrier.

Doxorubicin and paclitaxel, two hydrophobic chemotherapeutic agents, are used in cancer therapies. Presence of hydrophobic patches and a flexible fold could probably make α-Lactalbumin a suitable carrier for hydrophobic drugs. In the present study, a variety of thermodynamic, spectroscopic, computational, and cellular techniques were applied to assess α-lactalbumin potential as a carrier for doxorubicin and paclitaxel. According to isothermal titration calorimetry data, the interaction between α-lactalbumin and doxorubicin or paclitaxel is spontaneous and the K (M-1) value for the interaction of α-lactalbumin and paclitaxel is higher than that for doxorubicin. Differential scanning calorimetry and anisotropy results indicated formation of α-lactalbumin complexes with doxorubicin or paclitaxel. Furthermore, molecular docking and dynamic studies revealed that TRPs are not involved in α-Lac's interaction with Doxorubicin while TRP 60 interacts with paclitaxel. Based on Pace analysis to determine protein thermal stability, doxorubicin and paclitaxel induced higher and lower thermal stability in α-lactalbumin, respectively. Besides, fluorescence lifetime measurements reflected that the interaction between α-lactalbumin with doxorubicin or paclitaxel was of static nature. Therefore, the authors hypothesized that α-lactalbumin could serve as a carrier for doxorubicin and paclitaxel by reducing cytotoxicity and apoptosis which was demonstrated during our in vitro cell studies.

Paclitaxel inhibited lysozyme fibrillation by increasing colloidal stability through formation of "off-pathway" oligomers.

Protein fibrillation is a challenging issue in medicine, causing many diseases, and an impediment to pharmaceutics and protein industry. Many chemicals, especially polyphenol compounds and aromatic small molecules, have been widely used as an effective strategy to combat protein fibril formation. Hence, understanding mechanisms of fibrillation inhibition and contributing forces in this process are significant. In this study, the inhibitory effect of paclitaxel on lysozyme fibrillation was investigated with respect to thermal and colloidal stability. Fibrillation was monitored with ThT fluorescence, circular dichroism, and AFM; paclitaxel-lysozyme interaction with isothermal titration calorimetry and docking; thermal and colloidal stability with differential scanning calorimetry and zeta-pulse, respectively. Paclitaxel inhibited lysozyme fibrillation, and interacted with lysozyme through hydrogen bonds and van der Waals' interactions. The viability of PC12 cells retrieved as a result of fibrillation inhibition by paclitaxel. Hydrophobic forces dominantly shielded the aggregation-prone region of lysozyme and suppressed the effective interactions between lysozyme monomers. Although paclitaxel did not affect lysozyme's thermal stability, it increased lysozyme's colloidal stability by either increasing the surface charge density or charge distribution on lysozyme. In conclusion, our results suggest a model for paclitaxel's inhibitory role through two complementary steps driving to "off-pathway" oligomer formation and attenuation of fibril formation.

Identification of Phytochemicals Targeting c-Met Kinase Domain using Consensus Docking and Molecular Dynamics Simulation Studies.

c-Met receptor tyrosine kinase is a proto-oncogene whose aberrant activation is attributed to a lower rate of survival in most cancers. Natural product-derived inhibitors known as "fourth generation inhibitors" constitute more than 60% of anticancer drugs. Furthermore, consensus docking approach has recently been introduced to augment docking accuracy and reduce false positives during a virtual screening. In order to obtain novel small-molecule Met inhibitors, consensus docking approach was performed using Autodock Vina and Autodock 4.2 to virtual screen Naturally Occurring Plant-based Anti-cancer Compound-Activity-Target database against active and inactive conformation of c-Met kinase domain structure. Two hit molecules that were in line with drug-likeness criteria, desired docking score, and binding pose were subjected to molecular dynamics simulations to elucidate intermolecular contacts in protein-ligand complexes. Analysis of molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area studies showed that ZINC08234189 is a plausible inhibitor for the active state of c-Met, whereas ZINC03871891 may be more effective toward active c-Met kinase domain compared to the inactive form due to higher binding energy. Our analysis showed that both the hit molecules formed hydrogen bonds with key residues of the hinge region (P1158, M1160) in the active form, which is a hallmark of kinase domain inhibitors. Considering the pivotal role of HGF/c-Met signaling in carcinogenesis, our results propose ZINC08234189 and ZINC03871891 as the therapeutic options to surmount Met-dependent cancers.

Polyphenols protect mitochondrial membrane against permeabilization induced by HEWL oligomers: Possible mechanism of action.

Increasing body of evidence suggests that polyphenols frequently interacting with amyloid aggregates and/or interfering with aggregate species to bind biomembranes may serve as a therapeutic approach for the treatment of amyloid-related diseases. Hence, in the present study, the possible effects of three naturally occurring polyphenols including Curcumin, Quercetin, and Resveratrol on mitochondrial membrane permeabilization induced by Hen Egg White Lysozyme (HEWL) oligomers were investigated. Our results indicated that pre-incubation of mitochondrial homogenate with polyphenols considerably inhibit membrane permeabilization in a concentration dependent manner. In parallel, HEWL oligomers, which were co-incubated with the polyphenols, showed less effectiveness on membrane permeabilization, suggesting that toxicity of oligomers was hindered. Using a range of techniques including fluorescence quenching, Nile red binding assay, zeta potential and size measurements, CD (far- and near-UV) spectroscopy, and molecular docking, we found that the polyphenols, structure-dependently, interact with and induce conformational changes in HEWL oligomers, thereby inhibit their toxicity. We proposed a mechanism by which selected polyphenols induce their protective effects through binding to mitochondria and interfering with HEWL oligomer-membrane interactions and/or by direct interaction with HEWL oligomers, induction of conformational changes, and generating far less toxic species. However, additional studies are needed to elucidate the detailed mechanisms involved.

Effects of cholesterol concentration on the interaction of cytarabine with lipid membranes: a molecular dynamics simulation study.

Liposomal cytarabine, DepoCyt, is a chemotherapy agent which is used in cancer treatment. This form of cytarabine has more efficacy and fewer side effects relative to the other forms. Since DepoCyt contains the cytarabine encapsulated within phosphatidylcholine and the sterol molecules, we modeled dioleoylphosphatidylcholine (DOPC)/cholesterol bilayer membrane as a carrier for cytarabine to study drug-bilayer interactions. For this purpose, we performed a series of united-atom molecular dynamics (MD) simulations for 25 ns to investigate the interactions between cytarabine and cholesterol-containing DOPC lipid bilayers. Only the uncharged form of cytarabine molecule was investigated. In this study, different levels of the cholesterol content (0, 20, and 40%) were used. MD simulations allowed us to determine dynamical and structural properties of the bilayer membrane and to estimate the preferred location and orientation of the cytarabine molecule inside the bilayer membrane. Properties such as membrane thickness, area per lipid, diffusion coefficient, mass density, bilayer packing, order parameters, and intermolecular interactions were examined. The results show that by increasing the cholesterol concentration in the lipid bilayers, the bilayer thickness increases and area per lipid decreases. Moreover, in accordance with the experiments, our calculations show that cholesterol molecules have ordering effect on the hydrocarbon acyl chains. Furthermore, the cytarabine molecule preferentially occupies the polar region of the lipid head groups to form specific interactions (hydrogen bonds). Our results fully support the experimental data. Our finding about drug-bilayer interaction is crucial for the liposomal drug design.