Protective effect of rosemary (Rosmarinus officinalis) against diethylnitrosamine-induced renal injury in rats

Abstract

Context: The kidney plays a central role in detoxification and excretion of toxic metabolites, and therefore, is susceptible to toxicity by xenobiotics.

Objective: To investigate the protective effect of Rosmarinus officinalis (rosemary) powder and its essential (volatile) oil against diethylnitrosamine (DEN)-induced renal injury in rats.

Materials and methods: Phenolic and flavonoid components were characterised in rosemary powder using HPLC-UV instrument while rosemary essential oil (E.O) was investigated via GC-MS technique. In rat model, rosemary was administrated orally (in diet) for two months. Lipid profile, antioxidant biomarkers, kidney functions and histopathological examinations were assessed.

Results: Hesperidin (4878.88?ppm) and ellagic acid (403.57?ppm) are among the major phenolic and flavonoid constituents in rosemary powder. Camphor (18.36%) and α-pinene (12.74%) represent the main E.O active ingredients. Rats treated with rosemary E.O showed a significant elevation in serum HDL (28.28%) accompanied by a decrease in LDL (115.47%). A significant decrease in serum creatinine and urea was also reported (69.72 and 109.89%, respectively). Moreover, serum glutathione peroxidise (GSH-Px) activity has been significantly increased. Kidney histopathological examinations confirmed the protective effect against DEN-induced abnormalities.

Conclusion: Rosemary (powder/E.O) was able to reduce or even prevent the severity of diethylnitrosamine-induced renal dysfunction.     

Mn3O4 nanoparticles: Synthesis,characterization and their antimicrobial and anticancer activity against A549 and MCF-7 cell lines

Due to their inexpensive and eco-friendly nature, and existence of manganese in various oxidation states and their natural abundance have attained significant attention for the formation of Mn₃O₄ nanoparticles (Mn₃O₄ NPs). Herein, we report the preparation of Mn₃O₄ nanoparticles using manganese nitrate as a precursor material by utilization of a precipitation technique. The as-prepared Mn₃O₄ nanoparticles (Mn₃O₄ NPs) were characterized by using X-ray powder diffraction (XRD), UV–Visible spectroscopy (UV–Vis), High-Resolution Transmission electron microscopy (HRTEM), Field emission scanning electron microscopy (FESEM), Thermal gravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FT-IR). The antimicrobial properties of the as-synthesized Mn₃O₄ nanoparticles were investigated against numerous bacterial and fungal strains including S. aureus, E. coli, B. subtilis, P. aeruginosa, A. flavus and C. albicans. The Mn₃O₄ NPs inhibited the growth of S. aureus with a minimum inhibitory concentration (MIC) of 40 μg/ml and C. albicans with a MIC of 15 μg/ml. Furthermore, the Mn₃O₄ NPs anti-cancer activity was examined using MTT essay against A549 lung and MCF-7 breast cancer cell lines. The Mn₃O₄ NPs revealed significant activity against the examined cancer cell lines A549 and MCF-7. The IC₅₀ values of Mn₃O₄ NPs with A549 cell line was found at concentration of 98 µg/mL and MCF-7 cell line was found at concentration of 25 µg/mL.     

Configuration and Conformation Studies of Nucleoside Analogues Based on the Benzo[c]furan Core

Abstract

The glycone 1,3-dihydro-1-hydroxy-3-hydroxymethylbenzo[c]furan (1, R =H, B =OH) has been coupled to the regular nucleoside bases to a series of novel nucleoside analogues (1, B = thymine, adenine). Both cis and trans forms of these compounds have been obtained and the configuration is unequivocally established by NMR. The assignment of stereochemistry for each isomer of the compounds was initially based on the magnitude of the coupling between the dihydrohran ring protons. The NMR spectra of the 1,3-dihydrobenzo[c]fran system have been investigated for several compounds with one or no substituent in the dihydrohran ring. The observed coupling between H-1 and H-3 in a cis arrangement is in the range 0–2 Hz and the corresponding trans coupling is in the range 2.0–3.4 Hz. The data in Table 1 indicate that there are several spectral features which taken together strongly support the assignment of a common configuration to the compounds with a measurable cross-ring coupling. Further support is found in the NOESY spectrum of the mixed isomers of 1 (R = Bn, B = T). This spectrum showed a strong contact between the thymine proton, H-6, and H-3′ in the trans isomer (protons on the same side of the fixan ring) but no analogous contact in the cis isomer (protons on the opposite side of the furan ring).     

p42/p44-MAPK and PI3K are sufficient for IL-6 family cytokines/gp130 to signal to hypertrophy and survival in cardiomyocytes in the absence of JAK/STAT activation

The effect of differential signalling by IL-6 and leukaemia inhibitory factor (LIF) which signal by gp130 homodimerisation or LIFRβ/gp130 heterodimerisation on survival and hypertrophy was studied in neonatal rat cardiomyocytes. Both LIF and IL-6 [in the absence of soluble IL-6 receptor (sIL-6Rα)] activated Erk1/2, JNK1/2, p38-MAPK and PI3K signalling peaking at 20 min and induced cytoprotection against simulated ischemia-reperfusion injury which was blocked by the MEK1/2 inhibitor PD98059 but not the p38-MAPK inhibitor SB203580. In the absence of sIL-6R, IL-6 did not induce STAT1/3 phosphorylation, whereas IL-6/sIL-6R and LIF induced STAT1 and STAT3 phosphorylation. Furthermore, IL-6/sIL-6R induced phosphorylation of STAT1 Tyr⁷⁰¹ and STAT3 Tyr⁷⁰⁵ were enhanced by SB203580. IL-6 and pheneylephrine (PE), but not LIF, induced cardiomyocyte iNOS expression and nitric oxide (NO) production. IL-6, LIF and PE induced cardiomyocyte hypertrophy, but with phenotypic differences in ANF and SERCA2 expression and myofilament organisation with IL-6 more resembling PE than LIF. Transfection of cardiomyocytes with full length or truncated chimaeric gp130 cytoplasmic domain/Erythropoietin receptor (EpoR) extracellular domain fusion constructs showed that the membrane proximal Box 1 and Box 2 containing region of gp130 was necessary and sufficient for MAPK and PI3K activation; hypertrophy; SERCA2 expression and iNOS/NO induction in the absence of JAK/STAT activation. In conclusion, IL-6 can signal in cardiomyocytes independent of sIL-6R and STAT1/3 and furthermore, that Erk1/2 and PI3K activation by IL-6 are both necessary and sufficient for induced cardioprotection. In addition, p38-MAPK may act as a negative feedback regulator of JAK/STAT activation in cardiomyocytes.     

Dipeptide hydrolysis by the dinuclear zinc enzyme human renal dipeptidase: Mechanistic insights from DFT calculations

The reaction mechanism of the dinuclear zinc enzyme human renal dipeptidase is investigated using hybrid density functional theory. This enzyme catalyzes the hydrolysis of dipeptides and β-lactam antibiotics. Two different protonation states in which the important active site residue Asp288 is either neutral or ionized were considered. In both cases, the bridging hydroxide is shown to be capable of performing the nucleophilic attack on the substrate carbonyl carbon from its bridging position, resulting in the formation of a tetrahedral intermediate. This step is followed by protonation of the dipeptide nitrogen, coupled with C-N bond cleavage. The calculations establish that both cases have quite feasible energy barriers. When the Asp288 is neutral, the hydrolytic reaction occurs with a large exothermicity. However, the reaction becomes very close to thermoneutral with an ionized Asp288. The two zinc ions are shown to play different roles in the reaction. Zn1 binds the amino group of the substrate, and Zn2 interacts with the carboxylate group of the substrate, helping in orienting it for the nucleophilic attack. In addition, Zn2 stabilizes the oxyanion of the tetrahedral intermediate, thereby facilitating the nucleophilic attack.     

Quantum chemical modeling of enzymatic reactions: the case of 4-oxalocrotonate tautomerase

The reaction mechanism of 4-oxalocrotonate tautomerase (4-OT) is studied using the density functional theory method B3LYP. This enzyme catalyzes the isomerisation of unconjugated alpha-keto acids to their conjugated isomers. Two different quantum chemical models of the active site are devised and the potential energy curves for the reaction are computed. The calculations support the proposed reaction mechanism in which Pro-1 acts as a base to shuttle a proton from the C3 to the C5 position of the substrate. The first step (proton transfer from C3 to proline) is shown to be the rate-limiting step. The energy of the charge-separated intermediate (protonated proline-deprotonated substrate) is calculated to be quite low, in accordance with measured pKa values. The results of the two models are used to evaluate the methodology employed in modeling enzyme active sites using quantum chemical cluster models.     

Inhibition of S. aureus alpha-hemolysin and B. anthracis lethal toxin by beta-cyclodextrin derivatives

Many pathogens utilize the formation of transmembrane pores in target cells in the process of infection. A great number of pore-forming proteins, both bacterial and viral, are considered to be important virulence factors, which makes them attractive targets for the discovery of new therapeutic agents. Our research is based on the idea that compounds designed to block the pores can inhibit the action of virulence factors, and that the chances to find high affinity blocking agents increase if they have the same symmetry as the target pore. Recently, we demonstrated that derivatives of beta-cyclodextrin inhibited anthrax lethal toxin (LeTx) action by blocking the transmembrane pore formed by the protective antigen (PA) subunit of the toxin. To test the broader applicability of this approach, we sought beta-cyclodextrin derivatives capable of inhibiting the activity of Staphylococcus aureus alpha-hemolysin (alpha-HL), which is regarded as a major virulence factor playing an important role in staphylococcal infection. We identified several amino acid derivatives of beta-cyclodextrin that inhibited the activity of alpha-HL and LeTx in cell-based assays at low micromolar concentrations. One of the compounds was tested for the ability to block ion conductance through the pores formed by alpha-HL and PA in artificial lipid membranes. We anticipate that this approach can serve as the basis for a structure-directed drug discovery program to find new and effective therapeutics against various pathogens that utilize pore-forming proteins as virulence factors.