Structure, Antimicrobial Activity, Hirshfeld Analysis, and Docking Studies of Three Silver(I) Complexes-Based Pyridine Ligands

Three broad spectrum Ag(I) complexes against MDR (multi drug resistance) and ATCC standard bacteria as well as the fungus C. albicans were presented. The three well-known structurally-related Ag(I) complexes, [Ag(pyridine-3-carboxaldhyde)2NO3], 1, [Ag3(2-pyridone)3(NO3)3]n, 2, and [Ag(3-hydroxypyridine)2]NO3, 3, were prepared by the direct combination of AgNO3 with the corresponding pyridine ligands in a water-ethanol mixture. 1 and 3 are molecular compounds while, 2 is a 2D coordination polymer with sheets bridged by strong homoleptic R2,2(8) hydrogen bonds between ligands giving the ins topology. Different contacts affecting the molecular packing in their crystal structures were computed by employing Hirshfeld analysis. Charge transferences from the ligand groups to Ag(I) were analyzed using natural population analysis. The effect of protonation and metal coordination on the tautomerism of 2-pyridone was analyzed using data from the Cambridge Structure Database (CSD). It was found that Lewis acid attachment to both N and O sites favor a state in between the two formal tautomers. All compounds were significantly more active than 17 tested commercial antibiotics against three clinically isolated strains of Ps. Aeruginosa, with 2 and 3 performing best on average against all ten tested bacterial strains but with 3 containing less Ag per weight. Finally, docking studies were carried out to unravel the inhibition mechanism of the synthesized silver(I) complexes

Dosimetric, radiobiological and secondary cancer risk evaluation in head-and-neck three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, and volumetric modulated arc therapy: A phantom study

This analysis estimated secondary cancer risks after volumetric modulated arc therapy (VMAT) and compared those risks to the risks associated with other modalities of head-and-neck (H&N) radiotherapy. Images of H&N anthropomorphic phantom were acquired with a computed tomography scanner and exported via digital imaging and communications in medicine (DICOM) standards to a treatment planning system. Treatment plans were performed using a VMAT dual-arc technique, a nine-field intensity-modulated radiation therapy (IMRT) technique, and a four-field three-dimensional conformal therapy (3DCRT) technique. The prescription dose was 66.0 Gy for all three techniques, but to accommodate the range of dosimeter responses, we delivered a single dose of 6.60 Gy to the isocenter. The lifetime risk for secondary cancers was estimated according to National Council on Radiation Protection and Measurements (NCRP) Report 116. VMAT delivered the lowest maximum doses to esophagus (23 Gy), and normal brain (40 Gy). In comparison, maximum doses for 3DCRT were 74% and 40%, higher than those for VMAT for the esophagus, and normal brain, respectively. The normal tissue complication probability and equivalent uniform dose for the brain (2.1%, 0.9%, 0.8% and 3.8 Gy, 2.6 Gy, 2.3 Gy) and esophagus (4.2%, 0.7%, 0.4% and 3.7 Gy, 2.2 Gy, 1.8 Gy) were calculated for the 3DCRT, IMRT and VMAT respectively. Fractional esophagus OAR volumes receiving more than 20 Gy were 3.6% for VMAT, 23.6% for IMRT, and 100% for 3DCRT. The calculations for mean doses, NTCP, EUD and OAR volumes suggest that the risk of secondary cancer induction after VMAT is lower than after IMRT and 3DCRT

Exogenous Application of Zinc Sulphate at Heading Stage of Wheat Improves the Yield and Grain Zinc Biofortification

Wheat is the leading staple food in the world, particularly in developing countries, which lacks a mechanism of zinc absorption; when compared to pulses, more attention is consequently important to be given to the wheat crop. Micronutrient deficiencies and especially zinc deficiency influences one-third of the world population. In addition to this, it is also essential for the growth and development of plants and animals. A pot and field experiment was conducted to check the effect of foliar application of zinc sulphate on three different wheat varieties at the same time. Treatment consisted of three zinc levels (control, 4%, 6%) in the form of zinc sulphate (21% Zn) applications were applied on various wheat varieties (Zincol, Fakher-e-Bhakkar, Faisalabad-2008) at different growth stages (tillering, booting and heading). Different zinc levels showed different results on wheat varieties in both experiments. Results revealed that var. Fakher-e-Bhakkar was best at 6% zinc application for more plant height, the number of spikelets, spike length, 100-grain weight, biological and grain yield per plant as compared to other varieties and treatments. Antioxidants and nutritional quality (protein, gluten, starch and zinc contents) showed variable behavior both on wheat varieties and zinc application. It is concluded that Fakher-e-Bhakkar was found to be the most responsive cultivar at 6% zinc application for improvement in growth, yield-related traits and nutritional quality. So it is recommended for achieving maximum yield and yield components and grain zinc contents of wheat under agro-climatic conditions of Layyah, Punjab-Pakistan

Synthesis and characterisation of thiobarbituric acid enamine derivatives, and evaluation of their α-glucosidase inhibitory and anti-glycation activity

A new series of thiobarbituric (thiopyrimidine trione) enamine derivatives and its analogues barbituric acid derivatives was synthesised, characterised, and screen for in vitro evaluation of α-glucosidase enzyme inhibition and anti-glycation activity. This series of compounds were found to inhibit α-glucosidase activity in a reversible mixed-type manner with IC50 between 264.07 ± 1.87 and 448.63 ± 2.46 µM. Molecular docking studies indicated that compounds of 3g, 3i, 3j, and 5 are located close to the active site of α-glucosidase, which may cover the active pocket, thereby inhibiting the binding of the substrate to the enzyme. Thiopyrimidine trione derivatives also inhibited the generation of advanced glycation end-products (AGEs), which cause long-term complications in diabetes. While, compounds 3a–k, 5, and 6 showed significant to moderate anti-glycation activity (IC50 = 31.5 ± 0.81 to 554.76 ± 9.1 µM)

Microbial transformation of the steroidal alkaloid dictyophlebine by Rhizopus stolonifer

Devkota KP, Choudhary MI, Nawaz SA, et al. Microbial transformation of the steroidal alkaloid dictyophlebine by Rhizopus stolonifer. Chemical & Pharmaceutical Bulletin. 2007;55(4):682-684.The microbial transformation of a steroidal alkaloid, dictyophlebine (1) with Rhizopus stolonifer (ATCC 10404) afforded three oxidized metabolites 2-4. Compound 2 was found to be a new product. These metabolites were structurally characterized on the basis of modern spectroscopic techniques. Their inhibitory activity towards acetyl- and butyrylcholinesterase has been evaluated and the new product 2 has been found to be more potent than the parent compound and other metabolites